diff --git a/BACKEND_SETUP.md b/BACKEND_SETUP.md
index b8d3de0..82fe63e 100644
--- a/BACKEND_SETUP.md
+++ b/BACKEND_SETUP.md
@@ -78,7 +78,6 @@ erp-backend/
 │   │   │   ├── warehouses/
 │   │   │   ├── payment-terms/
 │   │   │   ├── delivery-terms/
-│   │   │   ├── asset-categories/
 │   │   │   ├── departments/
 │   │   │   ├── designations/
 │   │   │   ├── plants/
@@ -1180,7 +1179,7 @@ module.exports = router;
 
 ### 9.4 Masters module pattern
 
-Every master (UOM, Item Categories, Brands, GST Rates, Warehouses, Payment Terms, Delivery Terms, Asset Categories, Departments, Designations, Plants, etc.) follows the **same four-file pattern as Vendors**, scaled down — simple `name`/`code` fields, no document-number generation, RBAC permission code `MASTERS`. Build one master fully (UOM is simplest) as the template, then replicate for the rest.
+Every master (UOM, Item Categories, Brands, GST Rates, Warehouses, Payment Terms, Delivery Terms, Departments, Designations, Plants, etc.) follows the **same four-file pattern as Vendors**, scaled down — simple `name`/`code` fields, no document-number generation, RBAC permission code `MASTERS`. Build one master fully (UOM is simplest) as the template, then replicate for the rest. Assets use the same item category / subcategory masters (no separate asset category APIs).
 
 `src/modules/masters/index.js` aggregates all sub-routers:
 
@@ -1197,7 +1196,6 @@ router.use('/gst-rates', require('./gst-rates/gst-rates.routes'));
 router.use('/warehouses', require('./warehouses/warehouses.routes'));
 router.use('/payment-terms', require('./payment-terms/payment-terms.routes'));
 router.use('/delivery-terms', require('./delivery-terms/delivery-terms.routes'));
-router.use('/asset-categories', require('./asset-categories/asset-categories.routes'));
 router.use('/departments', require('./departments/departments.routes'));
 router.use('/designations', require('./designations/designations.routes'));
 router.use('/plants', require('./plants/plants.routes'));
@@ -1276,7 +1274,6 @@ BigInt.prototype.toJSON = function () {
 /api/v1/masters/warehouses
 /api/v1/masters/payment-terms
 /api/v1/masters/delivery-terms
-/api/v1/masters/asset-categories
 /api/v1/masters/departments
 /api/v1/masters/designations
 /api/v1/masters/plants
diff --git a/BACKEND_TASKS.md b/BACKEND_TASKS.md
index b7dfedc..cd3082c 100644
--- a/BACKEND_TASKS.md
+++ b/BACKEND_TASKS.md
@@ -162,15 +162,15 @@ Each sub-master supports: `GET /` (list), `GET /:id`, `POST /`, `PUT /:id`, `DEL
 | Status | Sub-master | Base path |
 |--------|------------|-----------|
 | [x] | UOM | `/masters/uom` |
-| [x] | Item Categories | `/masters/item-categories` |
-| [x] | Item Subcategories | `/masters/item-subcategories` |
+| [x] | Item Categories | `/masters/item-categories` | Optional asset defaults: `code_prefix`, `default_useful_life_years`, `default_depreciation_method` |
+| [x] | Item Subcategories | `/masters/item-subcategories` | Filter: `item_category_id` — shared by items + assets |
 | [x] | Items | `/masters/items` |
 | [x] | Brands | `/masters/brands` |
 | [x] | GST Rates | `/masters/gst-rates` |
 | [x] | Payment Terms | `/masters/payment-terms` |
 | [x] | Delivery Terms | `/masters/delivery-terms` |
-| [x] | Asset Categories | `/masters/asset-categories` |
-| [x] | Asset Subcategories | `/masters/asset-subcategories` | Filter: `asset_category_id` |
+| [~] | Asset Categories | removed — use Item Categories |
+| [~] | Asset Subcategories | removed — use Item Subcategories |
 | [x] | Departments | `/masters/departments` |
 | [x] | Designations | `/masters/designations` |
 | [x] | Locations | `/masters/locations` | Unified plants + warehouses (`type`: `plant` \| `warehouse`) |
@@ -178,7 +178,7 @@ Each sub-master supports: `GET /` (list), `GET /:id`, `POST /`, `PUT /:id`, `DEL
 | [x] | Warehouses | `/masters/warehouses` | Alias — warehouse locations only |
 | [x] | Document Series | `/masters/document-series` |
 
-**Masters total:** 14 modules × 5 endpoints = **70 APIs** [x]
+**Masters total:** 12 modules × 5 endpoints (+ plants/warehouses aliases) — asset category masters retired; assets use item categories
 
 ---
 
diff --git a/docs/MODULE_DATA_FLOW.html b/docs/MODULE_DATA_FLOW.html
index 2dbff02..bd10b60 100644
--- a/docs/MODULE_DATA_FLOW.html
+++ b/docs/MODULE_DATA_FLOW.html
@@ -210,27 +210,36 @@
     }
 
     .diagram-viewport {
-      overflow: auto;
-      max-height: 70vh;
-      padding: 1rem;
-      cursor: grab;
+      position: relative;
+      overflow: hidden;
+      height: min(70vh, 560px);
+      min-height: 280px;
       background: #fafbfc;
+      touch-action: none;
+      user-select: none;
     }
 
+    .diagram-viewport.can-pan { cursor: grab; }
     .diagram-viewport.is-panning { cursor: grabbing; }
 
+    .diagram-stage {
+      position: absolute;
+      inset: 0;
+      overflow: hidden;
+    }
+
     .diagram-canvas {
       display: inline-block;
-      min-width: 100%;
       transform-origin: 0 0;
-      transition: transform 0.12s ease-out;
+      will-change: transform;
     }
 
     .diagram-canvas .mermaid,
     .diagram-canvas svg {
       display: block;
-      margin: 0 auto;
+      margin: 0;
       max-width: none !important;
+      pointer-events: none;
     }
 
     .diagram-fullscreen {
@@ -302,25 +311,36 @@
 
     .diagram-fullscreen-viewport {
       flex: 1;
-      overflow: auto;
-      padding: 2rem;
-      cursor: grab;
-      display: flex;
-      align-items: flex-start;
-      justify-content: center;
+      position: relative;
+      overflow: hidden;
+      background: #0f172a;
+      touch-action: none;
+      user-select: none;
     }
 
+    .diagram-fullscreen-viewport.can-pan { cursor: grab; }
     .diagram-fullscreen-viewport.is-panning { cursor: grabbing; }
 
+    .diagram-fullscreen-stage {
+      position: absolute;
+      inset: 0;
+      overflow: hidden;
+    }
+
     .diagram-fullscreen-canvas {
       display: inline-block;
-      transform-origin: center center;
+      transform-origin: 0 0;
+      will-change: transform;
       background: var(--surface);
       border-radius: 8px;
       padding: 1.5rem;
       box-shadow: 0 25px 50px rgba(0, 0, 0, 0.35);
     }
 
+    .diagram-fullscreen-canvas svg {
+      pointer-events: none;
+    }
+
     .diagram-fullscreen-hint {
       position: absolute;
       bottom: 1rem;
@@ -357,7 +377,9 @@
       main { margin-left: 0; max-width: 100%; }
       .diagram { break-inside: avoid; }
       .diagram-toolbar { display: none; }
-      .diagram-viewport { max-height: none; overflow: visible; }
+      .diagram-viewport { height: auto; min-height: 0; overflow: visible; }
+      .diagram-stage { position: static; overflow: visible; }
+      .diagram-canvas { transform: none !important; }
     }
   </style>
 </head>
@@ -462,7 +484,7 @@ flowchart LR
         M2[item-categories / subcategories / items]
         M3[brands / gst-rates]
         M4[payment-terms / delivery-terms]
-        M5[asset-categories / subcategories]
+        M5[item-categories / subcategories]
         M6[departments / designations]
         M7[locations / plants / warehouses]
         M8[document-series]
@@ -565,7 +587,10 @@ flowchart TD
     PT --> PO
     DT[delivery_terms] --> PO
 
-    ACAT[asset_categories] --> ASUB[asset_subcategories]
+    ICAT[item_categories] --> ISUB[item_subcategories]
+    ISUB --> ITEMS[items]
+    ICAT --> ASSETS[assets]
+    ISUB --> ASSETS
     ACAT --> ASSET
     ACAT --> GRN_AUTO[GRN auto-asset creation]
     ASUB --> ASSET
@@ -646,12 +671,12 @@ stateDiagram-v2
         <tbody>
           <tr><td><code>asset_code</code></td><td><code>document_series</code> via <code>ASSET_{category.code}</code></td></tr>
           <tr><td><code>asset_name</code></td><td>Item name (+ <code>#N</code> if qty &gt; 1)</td></tr>
-          <tr><td><code>asset_category_id</code> / <code>asset_subcategory_id</code></td><td>From GRN line payload</td></tr>
+          <tr><td><code>item_category_id</code> / <code>item_subcategory_id</code></td><td>From item master (optional GRN line override)</td></tr>
           <tr><td><code>plant_id</code></td><td>From PO</td></tr>
           <tr><td><code>warehouse_id</code>, <code>vendor_id</code>, <code>po_id</code>, <code>grn_id</code>, <code>grn_item_id</code></td><td>From GRN</td></tr>
           <tr><td><code>purchase_date</code></td><td><code>grn.grn_date</code></td></tr>
           <tr><td><code>purchase_cost</code></td><td><code>grn_items.rate</code></td></tr>
-          <tr><td><code>useful_life_years</code>, <code>depreciation_method</code></td><td>From <code>asset_categories</code> defaults</td></tr>
+          <tr><td><code>useful_life_years</code>, <code>depreciation_method</code></td><td>From <code>item_categories</code> defaults</td></tr>
           <tr><td><code>condition</code></td><td><code>NEW</code></td></tr>
           <tr><td><code>status</code></td><td><code>IN_USE</code></td></tr>
         </tbody>
@@ -667,7 +692,7 @@ flowchart TB
     end
 
     subgraph Validate["normalizeAssetPayload validations"]
-        V1[asset_category + subcategory match]
+        V1[item_category + subcategory match]
         V2[plant / dept / warehouse / user refs]
         V3[vendor / PO / GRN / grn_item refs]
         V4[disposal_date required if DISPOSED/SCRAPPED]
@@ -801,7 +826,7 @@ flowchart TD
         <pre class="mermaid">
 flowchart TD
     subgraph Inputs
-        CAT[asset_categories defaults]
+        CAT[item_categories defaults]
         FORM[User form fields]
     end
 
@@ -951,9 +976,11 @@ erDiagram
     items ||--o{ purchase_order_items : ordered
     items ||--o{ grn_items : received
 
-    asset_categories ||--o{ asset_subcategories : has
-    asset_categories ||--o{ assets : classifies
-    asset_subcategories ||--o{ assets : sub_classifies
+    item_categories ||--o{ item_subcategories : has
+    item_categories ||--o{ items : classifies
+    item_categories ||--o{ assets : classifies
+    item_subcategories ||--o{ items : sub_classifies
+    item_subcategories ||--o{ assets : sub_classifies
 
     assets ||--o{ asset_amc_contracts : has
     assets ||--o{ asset_insurance_policies : insured_by
@@ -1039,15 +1066,17 @@ erDiagram
       <button type="button" class="diagram-fullscreen-close" id="diagram-fullscreen-close" title="Exit fullscreen (Esc)">×</button>
     </div>
     <div class="diagram-fullscreen-viewport" id="diagram-fullscreen-viewport">
-      <div class="diagram-fullscreen-canvas" id="diagram-fullscreen-canvas"></div>
+      <div class="diagram-fullscreen-stage" id="diagram-fullscreen-stage">
+        <div class="diagram-fullscreen-canvas" id="diagram-fullscreen-canvas"></div>
+      </div>
     </div>
-    <div class="diagram-fullscreen-hint">Fullscreen: scroll to zoom · drag to pan · + / − / 0 keys · Esc to exit</div>
+    <div class="diagram-fullscreen-hint">Drag to move · Scroll or Ctrl+scroll to zoom · + / − / 0 keys · Esc to exit</div>
   </div>
 
   <script>
-    const ZOOM_MIN = 0.25;
-    const ZOOM_MAX = 4;
-    const ZOOM_STEP = 0.2;
+    const ZOOM_MIN = 0.2;
+    const ZOOM_MAX = 5;
+    const ZOOM_STEP = 0.15;
     const ZOOM_DEFAULT = 1;
 
     function clampZoom(value) {
@@ -1061,7 +1090,8 @@ erDiagram
         <button type="button" data-action="zoom-out" title="Zoom out (-)">−</button>
         <span class="diagram-zoom-label" data-zoom-label>100%</span>
         <button type="button" data-action="zoom-in" title="Zoom in (+)">+</button>
-        <button type="button" data-action="zoom-reset" title="Reset zoom (0)">Reset</button>
+        <button type="button" data-action="zoom-reset" title="Reset view (0)">Reset</button>
+        <button type="button" data-action="zoom-fit" title="Fit to view">Fit</button>
         <span class="spacer"></span>
         <button type="button" data-action="fullscreen" title="Fullscreen (F)">⛶ Fullscreen</button>
       `;
@@ -1072,100 +1102,204 @@ erDiagram
       return toolbar;
     }
 
-    function applyZoom(state) {
-      state.canvas.style.transform = `scale(${state.zoom})`;
-      state.label.textContent = `${Math.round(state.zoom * 100)}%`;
+    class DiagramViewer {
+      constructor({ viewport, stage, canvas, label, wheelNeedsModifier = true }) {
+        this.viewport = viewport;
+        this.stage = stage;
+        this.canvas = canvas;
+        this.label = label;
+        this.wheelNeedsModifier = wheelNeedsModifier;
+        this.zoom = ZOOM_DEFAULT;
+        this.panX = 0;
+        this.panY = 0;
+        this.isPanning = false;
+        this.pointerId = null;
+        this.lastPointer = { x: 0, y: 0 };
+        this.bindEvents();
+      }
+
+      render() {
+        this.canvas.style.transform = `translate(${this.panX}px, ${this.panY}px) scale(${this.zoom})`;
+        if (this.label) {
+          this.label.textContent = `${Math.round(this.zoom * 100)}%`;
+        }
+      }
+
+      getViewportPoint(clientX, clientY) {
+        const rect = this.stage.getBoundingClientRect();
+        return { x: clientX - rect.left, y: clientY - rect.top };
+      }
+
+      zoomAt(clientX, clientY, delta) {
+        const point = this.getViewportPoint(clientX, clientY);
+        const prevZoom = this.zoom;
+        const nextZoom = clampZoom(prevZoom + delta);
+        if (nextZoom === prevZoom) return;
+
+        this.panX = point.x - ((point.x - this.panX) * nextZoom) / prevZoom;
+        this.panY = point.y - ((point.y - this.panY) * nextZoom) / prevZoom;
+        this.zoom = nextZoom;
+        this.render();
+      }
+
+      zoomBy(delta, centerToStage = true) {
+        const rect = this.stage.getBoundingClientRect();
+        const x = centerToStage ? rect.left + rect.width / 2 : rect.left;
+        const y = centerToStage ? rect.top + rect.height / 2 : rect.top;
+        this.zoomAt(x, y, delta);
+      }
+
+      reset() {
+        this.zoom = ZOOM_DEFAULT;
+        this.panX = 0;
+        this.panY = 0;
+        this.render();
+        this.centerContent();
+      }
+
+      fitToView() {
+        const svg = this.canvas.querySelector('svg');
+        if (!svg) {
+          this.reset();
+          return;
+        }
+
+        const stageRect = this.stage.getBoundingClientRect();
+        const bbox = svg.getBBox();
+        const pad = 24;
+        const scaleX = (stageRect.width - pad * 2) / bbox.width;
+        const scaleY = (stageRect.height - pad * 2) / bbox.height;
+        const fitZoom = clampZoom(Math.min(scaleX, scaleY, 1));
+
+        this.zoom = fitZoom;
+        this.panX = (stageRect.width - bbox.width * fitZoom) / 2 - bbox.x * fitZoom;
+        this.panY = (stageRect.height - bbox.height * fitZoom) / 2 - bbox.y * fitZoom;
+        this.render();
+      }
+
+      centerContent() {
+        const svg = this.canvas.querySelector('svg');
+        if (!svg) return;
+
+        const stageRect = this.stage.getBoundingClientRect();
+        const bbox = svg.getBBox();
+        this.panX = (stageRect.width - bbox.width * this.zoom) / 2 - bbox.x * this.zoom;
+        this.panY = (stageRect.height - bbox.height * this.zoom) / 2 - bbox.y * this.zoom;
+        this.render();
+      }
+
+      handleAction(action) {
+        switch (action) {
+          case 'zoom-in':
+            this.zoomBy(ZOOM_STEP);
+            break;
+          case 'zoom-out':
+            this.zoomBy(-ZOOM_STEP);
+            break;
+          case 'zoom-reset':
+            this.reset();
+            break;
+          case 'zoom-fit':
+            this.fitToView();
+            break;
+          default:
+            break;
+        }
+      }
+
+      bindEvents() {
+        this.viewport.classList.add('can-pan');
+
+        this.viewport.addEventListener('pointerdown', (e) => {
+          if (e.button !== 0) return;
+          if (e.target.closest('button')) return;
+          this.isPanning = true;
+          this.pointerId = e.pointerId;
+          this.lastPointer = { x: e.clientX, y: e.clientY };
+          this.viewport.classList.add('is-panning');
+          this.viewport.setPointerCapture(e.pointerId);
+          e.preventDefault();
+        });
+
+        this.viewport.addEventListener('pointermove', (e) => {
+          if (!this.isPanning || e.pointerId !== this.pointerId) return;
+          this.panX += e.clientX - this.lastPointer.x;
+          this.panY += e.clientY - this.lastPointer.y;
+          this.lastPointer = { x: e.clientX, y: e.clientY };
+          this.render();
+          e.preventDefault();
+        });
+
+        const endPan = (e) => {
+          if (!this.isPanning || (e.pointerId !== undefined && e.pointerId !== this.pointerId)) return;
+          this.isPanning = false;
+          this.pointerId = null;
+          this.viewport.classList.remove('is-panning');
+          if (this.viewport.hasPointerCapture(e.pointerId)) {
+            this.viewport.releasePointerCapture(e.pointerId);
+          }
+        };
+
+        this.viewport.addEventListener('pointerup', endPan);
+        this.viewport.addEventListener('pointercancel', endPan);
+        this.viewport.addEventListener('lostpointercapture', () => {
+          this.isPanning = false;
+          this.pointerId = null;
+          this.viewport.classList.remove('is-panning');
+        });
+
+        this.viewport.addEventListener(
+          'wheel',
+          (e) => {
+            if (this.wheelNeedsModifier && !e.ctrlKey && !e.metaKey) return;
+            e.preventDefault();
+            const delta = e.deltaY > 0 ? -ZOOM_STEP : ZOOM_STEP;
+            this.zoomAt(e.clientX, e.clientY, delta);
+          },
+          { passive: false }
+        );
+      }
     }
 
-    function setupPan(viewport, getZoom) {
-      let panning = false;
-      let startX = 0;
-      let startY = 0;
-      let scrollLeft = 0;
-      let scrollTop = 0;
+    const diagramViewers = [];
+    let fullscreenViewer = null;
+    let fullscreenToolbarReady = false;
 
-      viewport.addEventListener('mousedown', (e) => {
-        if (e.button !== 0 || getZoom() <= 1) return;
-        if (e.target.closest('button')) return;
-        panning = true;
-        viewport.classList.add('is-panning');
-        startX = e.clientX;
-        startY = e.clientY;
-        scrollLeft = viewport.scrollLeft;
-        scrollTop = viewport.scrollTop;
-        e.preventDefault();
-      });
-
-      window.addEventListener('mousemove', (e) => {
-        if (!panning) return;
-        viewport.scrollLeft = scrollLeft - (e.clientX - startX);
-        viewport.scrollTop = scrollTop - (e.clientY - startY);
-      });
-
-      window.addEventListener('mouseup', () => {
-        if (!panning) return;
-        panning = false;
-        viewport.classList.remove('is-panning');
-      });
-    }
-
-    function setupWheelZoom(viewport, state, applyFn, requireModifier) {
-      viewport.addEventListener('wheel', (e) => {
-        if (requireModifier && !e.ctrlKey && !e.metaKey) return;
-        e.preventDefault();
-        const delta = e.deltaY > 0 ? -ZOOM_STEP : ZOOM_STEP;
-        state.zoom = clampZoom(state.zoom + delta);
-        applyFn(state);
-      }, { passive: false });
-    }
-
-    const diagramStates = [];
-    let activeFullscreenState = null;
-
-    function openFullscreen(diagramState) {
+    function openFullscreen(sourceViewer) {
       const overlay = document.getElementById('diagram-fullscreen');
-      const canvas = document.getElementById('diagram-fullscreen-canvas');
       const viewport = document.getElementById('diagram-fullscreen-viewport');
+      const stage = document.getElementById('diagram-fullscreen-stage');
+      const canvas = document.getElementById('diagram-fullscreen-canvas');
       const title = document.getElementById('diagram-fullscreen-title');
       const toolbarHost = document.getElementById('diagram-fullscreen-toolbar');
 
-      title.textContent = diagramState.title;
-      canvas.innerHTML = '';
-      const clone = diagramState.canvas.cloneNode(true);
-      clone.style.transform = '';
-      canvas.appendChild(clone);
+      title.textContent = sourceViewer.title || 'Diagram';
+      canvas.innerHTML = sourceViewer.canvas.innerHTML;
 
-      const fsState = {
-        zoom: diagramState.zoom,
-        canvas: clone,
-        label: toolbarHost.querySelector('[data-zoom-label]'),
-        viewport,
-        source: diagramState,
-      };
-
-      if (!toolbarHost.dataset.ready) {
-        const fsToolbar = createToolbar((action) => handleDiagramAction(fsState, action, true));
-        toolbarHost.innerHTML = '';
-        toolbarHost.appendChild(fsToolbar);
-        toolbarHost.dataset.ready = '1';
-        setupPan(viewport, () => fsState.zoom);
-        setupWheelZoom(viewport, fsState, (s) => {
-          applyZoom(s);
-          if (s.source) {
-            s.source.zoom = s.zoom;
-            applyZoom(s.source);
-          }
-        }, false);
+      if (!fullscreenToolbarReady) {
+        const toolbar = createToolbar((action) => {
+          if (action === 'fullscreen') return;
+          if (fullscreenViewer) fullscreenViewer.handleAction(action);
+        });
+        toolbarHost.appendChild(toolbar);
+        fullscreenToolbarReady = true;
       }
 
-      fsState.label = toolbarHost.querySelector('[data-zoom-label]');
-      applyZoom(fsState);
-      activeFullscreenState = fsState;
+      if (!fullscreenViewer) {
+        fullscreenViewer = new DiagramViewer({
+          viewport,
+          stage,
+          canvas,
+          label: toolbarHost.querySelector('[data-zoom-label]'),
+          wheelNeedsModifier: false,
+        });
+      }
+
+      fullscreenViewer.fitToView();
+
       overlay.classList.add('is-open');
       overlay.setAttribute('aria-hidden', 'false');
       document.body.style.overflow = 'hidden';
-      viewport.scrollTop = 0;
-      viewport.scrollLeft = 0;
     }
 
     function closeFullscreen() {
@@ -1173,60 +1307,21 @@ erDiagram
       overlay.classList.remove('is-open');
       overlay.setAttribute('aria-hidden', 'true');
       document.body.style.overflow = '';
-      activeFullscreenState = null;
-    }
-
-    function handleDiagramAction(state, action, fromFullscreen) {
-      switch (action) {
-        case 'zoom-in':
-          state.zoom = clampZoom(state.zoom + ZOOM_STEP);
-          applyZoom(state);
-          if (fromFullscreen && state.source) {
-            state.source.zoom = state.zoom;
-            applyZoom(state.source);
-          }
-          break;
-        case 'zoom-out':
-          state.zoom = clampZoom(state.zoom - ZOOM_STEP);
-          applyZoom(state);
-          if (fromFullscreen && state.source) {
-            state.source.zoom = state.zoom;
-            applyZoom(state.source);
-          }
-          break;
-        case 'zoom-reset':
-          state.zoom = ZOOM_DEFAULT;
-          applyZoom(state);
-          if (fromFullscreen && state.source) {
-            state.source.zoom = ZOOM_DEFAULT;
-            applyZoom(state.source);
-            state.viewport.scrollTop = 0;
-            state.viewport.scrollLeft = 0;
-          } else if (state.viewport) {
-            state.viewport.scrollTop = 0;
-            state.viewport.scrollLeft = 0;
-          }
-          break;
-        case 'fullscreen':
-          if (!fromFullscreen) openFullscreen(state);
-          break;
-        default:
-          break;
-      }
+      fullscreenViewer = null;
     }
 
     function wrapDiagrams() {
       document.querySelectorAll('.diagram').forEach((diagram, index) => {
-        const section = diagram.closest('main')?.querySelector(`h2, h3`);
         let title = `Diagram ${index + 1}`;
         const prevHeading = diagram.previousElementSibling;
         if (prevHeading && (prevHeading.tagName === 'H2' || prevHeading.tagName === 'H3')) {
           title = prevHeading.textContent.trim();
         }
 
-        const toolbar = createToolbar((action) => handleDiagramAction(state, action, false));
         const viewport = document.createElement('div');
         viewport.className = 'diagram-viewport';
+        const stage = document.createElement('div');
+        stage.className = 'diagram-stage';
         const canvas = document.createElement('div');
         canvas.className = 'diagram-canvas';
 
@@ -1234,22 +1329,32 @@ erDiagram
           canvas.appendChild(diagram.firstChild);
         }
 
-        viewport.appendChild(canvas);
+        stage.appendChild(canvas);
+        viewport.appendChild(stage);
+
+        const viewer = new DiagramViewer({
+          viewport,
+          stage,
+          canvas,
+          label: null,
+          wheelNeedsModifier: true,
+        });
+        viewer.title = title;
+        viewer.element = diagram;
+
+        const toolbar = createToolbar((action) => {
+          if (action === 'fullscreen') {
+            openFullscreen(viewer);
+            return;
+          }
+          viewer.handleAction(action);
+        });
+        viewer.label = toolbar.querySelector('[data-zoom-label]');
+        viewer.render();
+
         diagram.appendChild(toolbar);
         diagram.appendChild(viewport);
-
-        const state = {
-          zoom: ZOOM_DEFAULT,
-          canvas,
-          label: toolbar.querySelector('[data-zoom-label]'),
-          viewport,
-          title,
-          element: diagram,
-        };
-
-        setupPan(viewport, () => state.zoom);
-        setupWheelZoom(viewport, state, applyZoom, true);
-        diagramStates.push(state);
+        diagramViewers.push(viewer);
       });
     }
 
@@ -1257,35 +1362,32 @@ erDiagram
 
     document.addEventListener('keydown', (e) => {
       const fsOpen = document.getElementById('diagram-fullscreen').classList.contains('is-open');
-      const target = fsOpen && activeFullscreenState ? activeFullscreenState : null;
+      const viewer = fsOpen
+        ? fullscreenViewer
+        : diagramViewers.find((v) => {
+            const rect = v.element.getBoundingClientRect();
+            return rect.top < window.innerHeight && rect.bottom > 0;
+          });
+
+      if (!viewer) return;
 
       if (e.key === 'Escape' && fsOpen) {
         closeFullscreen();
         return;
       }
 
-      if (!target && !e.target.closest('.diagram')) return;
-
-      const state = target || diagramStates.find((s) => s.element.contains(document.activeElement))
-        || diagramStates.find((s) => {
-          const rect = s.element.getBoundingClientRect();
-          return rect.top < window.innerHeight && rect.bottom > 0;
-        });
-
-      if (!state) return;
-
       if (e.key === '+' || e.key === '=') {
         e.preventDefault();
-        handleDiagramAction(state, 'zoom-in', !!target);
+        viewer.handleAction('zoom-in');
       } else if (e.key === '-' || e.key === '_') {
         e.preventDefault();
-        handleDiagramAction(state, 'zoom-out', !!target);
+        viewer.handleAction('zoom-out');
       } else if (e.key === '0') {
         e.preventDefault();
-        handleDiagramAction(state, 'zoom-reset', !!target);
-      } else if ((e.key === 'f' || e.key === 'F') && !target) {
+        viewer.handleAction('zoom-reset');
+      } else if ((e.key === 'f' || e.key === 'F') && !fsOpen) {
         e.preventDefault();
-        openFullscreen(state);
+        openFullscreen(viewer);
       }
     });
 
@@ -1300,7 +1402,7 @@ erDiagram
 
     wrapDiagrams();
     mermaid.run({ querySelector: '.mermaid' }).then(() => {
-      diagramStates.forEach(applyZoom);
+      diagramViewers.forEach((viewer) => viewer.fitToView());
     });
   </script>
 </body>
diff --git a/docs/MODULE_DATA_FLOW.md b/docs/MODULE_DATA_FLOW.md
index 67699bc..2a78eb0 100644
--- a/docs/MODULE_DATA_FLOW.md
+++ b/docs/MODULE_DATA_FLOW.md
@@ -69,15 +69,14 @@ flowchart LR
         ROLES["/roles CRUD + permissions matrix"]
     end
 
-    subgraph Masters["/masters/* (14 sub-masters)"]
+    subgraph Masters["/masters/* (item categories shared with assets)"]
         M1[uom]
         M2[item-categories / subcategories / items]
         M3[brands / gst-rates]
         M4[payment-terms / delivery-terms]
-        M5[asset-categories / subcategories]
-        M6[departments / designations]
-        M7[locations / plants / warehouses]
-        M8[document-series]
+        M5[departments / designations]
+        M6[locations / plants / warehouses]
+        M7[document-series]
     end
 
     subgraph Procurement
@@ -180,11 +179,12 @@ flowchart TD
     PT --> PO
     DT[delivery_terms] --> PO
 
-    ACAT[asset_categories] --> ASUB[asset_subcategories]
-    ACAT --> ASSET
-    ACAT --> GRN_AUTO[GRN auto-asset creation]
-    ASUB --> ASSET
-    ASUB --> GRN_AUTO
+    ICAT[item_categories] --> ISUB[item_subcategories]
+    ISUB --> ITEMS[items]
+    ICAT --> ASSET
+    ICAT --> GRN_AUTO[GRN auto-asset creation]
+    ISUB --> ASSET
+    ISUB --> GRN_AUTO
 
     ITEMS --> PO_ITEMS
     ITEMS --> GRN_ITEMS
@@ -260,12 +260,12 @@ stateDiagram-v2
 |---|---|
 | `asset_code` | `document_series` via `ASSET_{category.code}` |
 | `asset_name` | Item name (+ `#N` if qty > 1) |
-| `asset_category_id` / `asset_subcategory_id` | From GRN line payload |
+| `item_category_id` / `item_subcategory_id` | From item master (optional GRN line override) |
 | `plant_id` | From PO |
 | `warehouse_id`, `vendor_id`, `po_id`, `grn_id`, `grn_item_id` | From GRN |
 | `purchase_date` | `grn.grn_date` |
 | `purchase_cost` | `grn_items.rate` |
-| `useful_life_years`, `depreciation_method` | From `asset_categories` defaults |
+| `useful_life_years`, `depreciation_method` | From `item_categories` defaults |
 | `condition` | `NEW` |
 | `status` | `IN_USE` |
 
@@ -281,7 +281,7 @@ flowchart TB
     end
 
     subgraph Validate["normalizeAssetPayload validations"]
-        V1[asset_category + subcategory match]
+        V1[item_category + subcategory match]
         V2[plant / dept / warehouse / user refs]
         V3[vendor / PO / GRN / grn_item refs]
         V4[disposal_date required if DISPOSED/SCRAPPED]
@@ -418,7 +418,7 @@ flowchart TD
 ```mermaid
 flowchart TD
     subgraph Inputs
-        CAT[asset_categories defaults]
+        CAT[item_categories defaults]
         FORM[User form fields]
     end
 
@@ -573,9 +573,11 @@ erDiagram
     items ||--o{ purchase_order_items : ordered
     items ||--o{ grn_items : received
 
-    asset_categories ||--o{ asset_subcategories : has
-    asset_categories ||--o{ assets : classifies
-    asset_subcategories ||--o{ assets : sub_classifies
+    item_categories ||--o{ item_subcategories : has
+    item_categories ||--o{ items : classifies
+    item_categories ||--o{ assets : classifies
+    item_subcategories ||--o{ items : sub_classifies
+    item_subcategories ||--o{ assets : sub_classifies
 
     assets ||--o{ asset_amc_contracts : has
     assets ||--o{ asset_insurance_policies : insured_by
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index ba363ea..1778640 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -136,44 +136,6 @@ model asset_service_visits {
 }
 
 /// This table contains check constraints and requires additional setup for migrations. Visit https://pris.ly/d/check-constraints for more info.
-model asset_categories {
-  id                                       BigInt    @id @default(autoincrement())
-  code                                     String    @unique @db.VarChar(20)
-  name                                     String    @db.VarChar(150)
-  code_prefix                              String    @unique @db.VarChar(10)
-  default_useful_life_years                Int?
-  default_depreciation_method              String?   @db.VarChar(20)
-  is_active                                Boolean   @default(true)
-  created_by                               BigInt?
-  updated_by                               BigInt?
-  created_at                               DateTime  @default(now()) @db.Timestamptz(6)
-  updated_at                               DateTime  @default(now()) @db.Timestamptz(6)
-  deleted_at                               DateTime? @db.Timestamptz(6)
-  users_asset_categories_created_byTousers users?    @relation("asset_categories_created_byTousers", fields: [created_by], references: [id], onUpdate: NoAction)
-  users_asset_categories_updated_byTousers users?    @relation("asset_categories_updated_byTousers", fields: [updated_by], references: [id], onUpdate: NoAction)
-  asset_subcategories                      asset_subcategories[]
-  assets                                   assets[]
-}
-
-model asset_subcategories {
-  id                                          BigInt           @id @default(autoincrement())
-  asset_category_id                           BigInt
-  code                                        String           @unique @db.VarChar(30)
-  name                                        String           @db.VarChar(150)
-  is_active                                   Boolean          @default(true)
-  created_by                                  BigInt?
-  updated_by                                  BigInt?
-  created_at                                  DateTime         @default(now()) @db.Timestamptz(6)
-  updated_at                                  DateTime         @default(now()) @db.Timestamptz(6)
-  deleted_at                                  DateTime?        @db.Timestamptz(6)
-  users_asset_subcategories_created_byTousers users?           @relation("asset_subcategories_created_byTousers", fields: [created_by], references: [id], onUpdate: NoAction)
-  asset_categories                            asset_categories @relation(fields: [asset_category_id], references: [id], onUpdate: NoAction)
-  users_asset_subcategories_updated_byTousers users?           @relation("asset_subcategories_updated_byTousers", fields: [updated_by], references: [id], onUpdate: NoAction)
-  assets                                      assets[]
-
-  @@index([asset_category_id], map: "idx_asset_subcategories_category_id")
-}
-
 model asset_transfers {
   id                                                          BigInt       @id @default(autoincrement())
   asset_id                                                    BigInt
@@ -208,8 +170,8 @@ model assets {
   id                                      BigInt              @id @default(autoincrement())
   asset_code                              String              @unique @db.VarChar(30)
   asset_name                              String              @db.VarChar(200)
-  asset_category_id                       BigInt
-  asset_subcategory_id                    BigInt?
+  item_category_id                        BigInt
+  item_subcategory_id                     BigInt?
   brand_model                             String?             @db.VarChar(200)
   manufacturer                            String?             @db.VarChar(200)
   serial_number                           String?             @db.VarChar(100)
@@ -248,8 +210,8 @@ model assets {
   asset_insurance_policies                asset_insurance_policies[]
   asset_service_visits                    asset_service_visits[]
   asset_transfers                         asset_transfers[]
-  asset_categories                        asset_categories    @relation(fields: [asset_category_id], references: [id], onUpdate: NoAction)
-  asset_subcategories                     asset_subcategories? @relation(fields: [asset_subcategory_id], references: [id], onUpdate: NoAction)
+  item_categories                         item_categories     @relation(fields: [item_category_id], references: [id], onUpdate: NoAction)
+  item_subcategories                      item_subcategories? @relation(fields: [item_subcategory_id], references: [id], onUpdate: NoAction)
   users_assets_assigned_to_user_idTousers users?              @relation("assets_assigned_to_user_idTousers", fields: [assigned_to_user_id], references: [id], onUpdate: NoAction)
   users_assets_created_byTousers          users?              @relation("assets_created_byTousers", fields: [created_by], references: [id], onUpdate: NoAction)
   departments                             departments?        @relation(fields: [department_id], references: [id], onUpdate: NoAction)
@@ -261,8 +223,8 @@ model assets {
   vendors_assets_vendor_idTovendors       vendors?            @relation("assets_vendor_idTovendors", fields: [vendor_id], references: [id], onUpdate: NoAction)
   warehouse     locations?          @relation("AssetWarehouseLocation", fields: [warehouse_id], references: [id], onUpdate: NoAction)
 
-  @@index([asset_category_id], map: "idx_assets_category_id")
-  @@index([asset_subcategory_id], map: "idx_assets_subcategory_id")
+  @@index([item_category_id], map: "idx_assets_item_category_id")
+  @@index([item_subcategory_id], map: "idx_assets_item_subcategory_id")
   @@index([department_id], map: "idx_assets_dept_id")
   @@index([plant_id], map: "idx_assets_plant_id")
 }
@@ -480,6 +442,9 @@ model item_categories {
   id                                      BigInt               @id @default(autoincrement())
   code                                    String               @unique @db.VarChar(30)
   name                                    String               @db.VarChar(100)
+  code_prefix                             String?              @unique @db.VarChar(10)
+  default_useful_life_years               Int?
+  default_depreciation_method             String?              @db.VarChar(20)
   is_active                               Boolean              @default(true)
   created_by                              BigInt?
   updated_by                              BigInt?
@@ -490,6 +455,7 @@ model item_categories {
   users_item_categories_updated_byTousers users?               @relation("item_categories_updated_byTousers", fields: [updated_by], references: [id], onUpdate: NoAction)
   item_subcategories                      item_subcategories[]
   items                                   items[]
+  assets                                  assets[]
 }
 
 model item_subcategories {
@@ -507,6 +473,7 @@ model item_subcategories {
   item_categories                            item_categories @relation(fields: [item_category_id], references: [id], onUpdate: NoAction)
   users_item_subcategories_updated_byTousers users?          @relation("item_subcategories_updated_byTousers", fields: [updated_by], references: [id], onUpdate: NoAction)
   items                                      items[]
+  assets                                     assets[]
 }
 
 model items {
@@ -856,10 +823,6 @@ model users {
   asset_insurance_policies_asset_insurance_policies_updated_byTousers asset_insurance_policies[] @relation("asset_insurance_policies_updated_byTousers")
   asset_service_visits_asset_service_visits_created_byTousers asset_service_visits[] @relation("asset_service_visits_created_byTousers")
   asset_service_visits_asset_service_visits_updated_byTousers asset_service_visits[] @relation("asset_service_visits_updated_byTousers")
-  asset_categories_asset_categories_created_byTousers       asset_categories[]      @relation("asset_categories_created_byTousers")
-  asset_categories_asset_categories_updated_byTousers       asset_categories[]      @relation("asset_categories_updated_byTousers")
-  asset_subcategories_asset_subcategories_created_byTousers asset_subcategories[]   @relation("asset_subcategories_created_byTousers")
-  asset_subcategories_asset_subcategories_updated_byTousers asset_subcategories[]   @relation("asset_subcategories_updated_byTousers")
   asset_transfers_asset_transfers_from_user_idTousers       asset_transfers[]       @relation("asset_transfers_from_user_idTousers")
   asset_transfers_asset_transfers_to_user_idTousers         asset_transfers[]       @relation("asset_transfers_to_user_idTousers")
   asset_transfers_asset_transfers_transferred_byTousers     asset_transfers[]       @relation("asset_transfers_transferred_byTousers")
diff --git a/scripts/patch-assets-views.sql b/scripts/patch-assets-views.sql
index 013bfb2..7699d79 100644
--- a/scripts/patch-assets-views.sql
+++ b/scripts/patch-assets-views.sql
@@ -26,7 +26,7 @@ CREATE VIEW v_asset_expiry_alerts AS
     END AS alert_level
   FROM asset_amc_contracts amc
   JOIN assets a ON a.id = amc.asset_id
-  JOIN asset_categories ac_cat ON ac_cat.id = a.asset_category_id
+  JOIN item_categories ac_cat ON ac_cat.id = a.item_category_id
   JOIN locations p ON p.id = a.plant_id AND p.type = 'plant'
   LEFT JOIN departments d ON d.id = a.department_id
   LEFT JOIN vendors v ON v.id = amc.vendor_id
@@ -47,7 +47,7 @@ UNION ALL
     END
   FROM asset_insurance_policies ins
   JOIN assets a ON a.id = ins.asset_id
-  JOIN asset_categories ac_cat ON ac_cat.id = a.asset_category_id
+  JOIN item_categories ac_cat ON ac_cat.id = a.item_category_id
   JOIN locations p ON p.id = a.plant_id AND p.type = 'plant'
   LEFT JOIN departments d ON d.id = a.department_id
   WHERE ins.is_active = TRUE AND ins.deleted_at IS NULL AND a.deleted_at IS NULL
@@ -66,7 +66,7 @@ UNION ALL
       WHEN (a.warranty_expiry_date - CURRENT_DATE) <= 90 THEN 'INFO'
     END
   FROM assets a
-  JOIN asset_categories ac_cat ON ac_cat.id = a.asset_category_id
+  JOIN item_categories ac_cat ON ac_cat.id = a.item_category_id
   JOIN locations p ON p.id = a.plant_id AND p.type = 'plant'
   LEFT JOIN departments d ON d.id = a.department_id
   WHERE a.warranty_expiry_date IS NOT NULL AND a.deleted_at IS NULL
@@ -95,7 +95,7 @@ SELECT
   amc.contract_no AS amc_contract_no,
   amc.end_date AS amc_end_date
 FROM assets a
-JOIN asset_categories ac_cat ON ac_cat.id = a.asset_category_id
+JOIN item_categories ac_cat ON ac_cat.id = a.item_category_id
 JOIN locations p ON p.id = a.plant_id AND p.type = 'plant'
 LEFT JOIN departments d ON d.id = a.department_id
 JOIN LATERAL (
@@ -144,7 +144,7 @@ SELECT
   (lsv.next_service_date - CURRENT_DATE) AS service_due_in_days,
   a.created_at
 FROM assets a
-JOIN asset_categories ac ON ac.id = a.asset_category_id
+JOIN item_categories ac ON ac.id = a.item_category_id
 JOIN locations p ON p.id = a.plant_id AND p.type = 'plant'
 LEFT JOIN departments d ON d.id = a.department_id
 LEFT JOIN locations w ON w.id = a.warehouse_id AND w.type = 'warehouse'
diff --git a/scripts/patch-unify-item-asset-categories.sql b/scripts/patch-unify-item-asset-categories.sql
new file mode 100644
index 0000000..64aed01
--- /dev/null
+++ b/scripts/patch-unify-item-asset-categories.sql
@@ -0,0 +1,234 @@
+-- Unify asset categories onto item_categories / item_subcategories
+-- Run against PostgreSQL before deploying BE that expects item_* FKs on assets.
+--
+-- Pre-check (optional):
+--   SELECT ac.code, ac.name AS asset_cat, ic.name AS item_cat
+--   FROM asset_categories ac
+--   JOIN item_categories ic ON UPPER(ac.code) = UPPER(ic.code)
+--    AND ac.deleted_at IS NULL AND ic.deleted_at IS NULL;
+
+BEGIN;
+
+-- =========================================================
+-- 1) Extend item_categories with asset defaults
+-- =========================================================
+ALTER TABLE item_categories
+  ADD COLUMN IF NOT EXISTS code_prefix VARCHAR(10),
+  ADD COLUMN IF NOT EXISTS default_useful_life_years INT,
+  ADD COLUMN IF NOT EXISTS default_depreciation_method VARCHAR(20);
+
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM pg_constraint WHERE conname = 'item_categories_code_prefix_key'
+  ) THEN
+    ALTER TABLE item_categories
+      ADD CONSTRAINT item_categories_code_prefix_key UNIQUE (code_prefix);
+  END IF;
+END $$;
+
+-- =========================================================
+-- 2) Mapping tables
+-- =========================================================
+CREATE TEMP TABLE map_asset_category (
+  old_asset_category_id BIGINT PRIMARY KEY,
+  new_item_category_id  BIGINT NOT NULL
+);
+
+CREATE TEMP TABLE map_asset_subcategory (
+  old_asset_subcategory_id BIGINT PRIMARY KEY,
+  new_item_subcategory_id  BIGINT NOT NULL
+);
+
+-- =========================================================
+-- 3) Upsert asset_categories -> item_categories
+-- =========================================================
+WITH src AS (
+  SELECT *
+  FROM asset_categories
+  WHERE deleted_at IS NULL
+),
+matched AS (
+  SELECT s.id AS old_id, ic.id AS new_id
+  FROM src s
+  JOIN item_categories ic
+    ON UPPER(ic.code) = UPPER(s.code)
+   AND ic.deleted_at IS NULL
+),
+inserted AS (
+  INSERT INTO item_categories (
+    code, name, code_prefix,
+    default_useful_life_years, default_depreciation_method,
+    is_active, created_by, updated_by, created_at, updated_at
+  )
+  SELECT
+    s.code,
+    s.name,
+    s.code_prefix,
+    s.default_useful_life_years,
+    s.default_depreciation_method,
+    s.is_active,
+    s.created_by,
+    s.updated_by,
+    s.created_at,
+    s.updated_at
+  FROM src s
+  WHERE NOT EXISTS (
+    SELECT 1 FROM matched m WHERE m.old_id = s.id
+  )
+  RETURNING id, code
+)
+INSERT INTO map_asset_category (old_asset_category_id, new_item_category_id)
+SELECT old_id, new_id FROM matched
+UNION ALL
+SELECT s.id, i.id
+FROM src s
+JOIN inserted i ON UPPER(i.code) = UPPER(s.code);
+
+UPDATE item_categories ic
+SET
+  code_prefix = COALESCE(ic.code_prefix, ac.code_prefix),
+  default_useful_life_years = COALESCE(ic.default_useful_life_years, ac.default_useful_life_years),
+  default_depreciation_method = COALESCE(ic.default_depreciation_method, ac.default_depreciation_method),
+  updated_at = NOW()
+FROM asset_categories ac
+JOIN map_asset_category m ON m.old_asset_category_id = ac.id
+WHERE ic.id = m.new_item_category_id
+  AND ac.deleted_at IS NULL;
+
+-- =========================================================
+-- 4) Upsert asset_subcategories -> item_subcategories
+-- =========================================================
+WITH src AS (
+  SELECT asub.*, m.new_item_category_id
+  FROM asset_subcategories asub
+  JOIN map_asset_category m ON m.old_asset_category_id = asub.asset_category_id
+  WHERE asub.deleted_at IS NULL
+),
+matched AS (
+  SELECT s.id AS old_id, isub.id AS new_id
+  FROM src s
+  JOIN item_subcategories isub
+    ON UPPER(isub.code) = UPPER(s.code)
+   AND isub.deleted_at IS NULL
+),
+inserted AS (
+  INSERT INTO item_subcategories (
+    item_category_id, code, name,
+    is_active, created_by, updated_by, created_at, updated_at
+  )
+  SELECT
+    s.new_item_category_id,
+    s.code,
+    s.name,
+    s.is_active,
+    s.created_by,
+    s.updated_by,
+    s.created_at,
+    s.updated_at
+  FROM src s
+  WHERE NOT EXISTS (
+    SELECT 1 FROM matched m WHERE m.old_id = s.id
+  )
+  RETURNING id, code
+)
+INSERT INTO map_asset_subcategory (old_asset_subcategory_id, new_item_subcategory_id)
+SELECT old_id, new_id FROM matched
+UNION ALL
+SELECT s.id, i.id
+FROM src s
+JOIN inserted i ON UPPER(i.code) = UPPER(s.code);
+
+UPDATE item_subcategories isub
+SET
+  item_category_id = mcat.new_item_category_id,
+  updated_at = NOW()
+FROM map_asset_subcategory msub
+JOIN asset_subcategories asub ON asub.id = msub.old_asset_subcategory_id
+JOIN map_asset_category mcat ON mcat.old_asset_category_id = asub.asset_category_id
+WHERE isub.id = msub.new_item_subcategory_id;
+
+-- =========================================================
+-- 5) Remap assets to item_* columns
+-- =========================================================
+ALTER TABLE assets
+  ADD COLUMN IF NOT EXISTS item_category_id BIGINT,
+  ADD COLUMN IF NOT EXISTS item_subcategory_id BIGINT;
+
+UPDATE assets a
+SET
+  item_category_id = mapped.new_item_category_id,
+  item_subcategory_id = mapped.new_item_subcategory_id,
+  updated_at = NOW()
+FROM (
+  SELECT
+    a2.id AS asset_id,
+    mcat.new_item_category_id,
+    msub.new_item_subcategory_id
+  FROM assets a2
+  JOIN map_asset_category mcat
+    ON mcat.old_asset_category_id = a2.asset_category_id
+  LEFT JOIN map_asset_subcategory msub
+    ON msub.old_asset_subcategory_id = a2.asset_subcategory_id
+) mapped
+WHERE a.id = mapped.asset_id;
+
+DO $$
+DECLARE missing_count BIGINT;
+BEGIN
+  SELECT COUNT(*) INTO missing_count
+  FROM assets
+  WHERE deleted_at IS NULL
+    AND item_category_id IS NULL;
+
+  IF missing_count > 0 THEN
+    RAISE EXCEPTION '% active assets could not be mapped to item_category_id', missing_count;
+  END IF;
+END $$;
+
+ALTER TABLE assets
+  ALTER COLUMN item_category_id SET NOT NULL;
+
+DO $$
+BEGIN
+  IF NOT EXISTS (
+    SELECT 1 FROM pg_constraint WHERE conname = 'assets_item_category_id_fkey'
+  ) THEN
+    ALTER TABLE assets
+      ADD CONSTRAINT assets_item_category_id_fkey
+      FOREIGN KEY (item_category_id) REFERENCES item_categories (id);
+  END IF;
+
+  IF NOT EXISTS (
+    SELECT 1 FROM pg_constraint WHERE conname = 'assets_item_subcategory_id_fkey'
+  ) THEN
+    ALTER TABLE assets
+      ADD CONSTRAINT assets_item_subcategory_id_fkey
+      FOREIGN KEY (item_subcategory_id) REFERENCES item_subcategories (id);
+  END IF;
+END $$;
+
+CREATE INDEX IF NOT EXISTS idx_assets_item_category_id ON assets (item_category_id);
+CREATE INDEX IF NOT EXISTS idx_assets_item_subcategory_id ON assets (item_subcategory_id);
+
+-- =========================================================
+-- 6) Drop dependent views, then old asset category FKs / columns / tables
+-- =========================================================
+DROP VIEW IF EXISTS v_asset_expiry_alerts CASCADE;
+DROP VIEW IF EXISTS v_asset_next_service CASCADE;
+DROP VIEW IF EXISTS v_assets CASCADE;
+
+ALTER TABLE assets DROP CONSTRAINT IF EXISTS assets_asset_category_id_fkey;
+ALTER TABLE assets DROP CONSTRAINT IF EXISTS assets_asset_subcategory_id_fkey;
+DROP INDEX IF EXISTS idx_assets_category_id;
+DROP INDEX IF EXISTS idx_assets_subcategory_id;
+ALTER TABLE assets DROP COLUMN IF EXISTS asset_category_id;
+ALTER TABLE assets DROP COLUMN IF EXISTS asset_subcategory_id;
+
+DROP TABLE IF EXISTS asset_subcategories;
+DROP TABLE IF EXISTS asset_categories;
+
+COMMIT;
+
+-- Recreate reporting views after this script:
+--   psql ... -f scripts/patch-assets-views.sql
diff --git a/src/docs/assets-routes.yaml b/src/docs/assets-routes.yaml
index 56c7abd..97cee28 100644
--- a/src/docs/assets-routes.yaml
+++ b/src/docs/assets-routes.yaml
@@ -5,11 +5,11 @@ components:
   schemas:
     AssetsCreateBody:
       type: object
-      required: [asset_name, asset_category_id, asset_subcategory_id, plant_id]
+      required: [asset_name, item_category_id, item_subcategory_id, plant_id]
       properties:
         asset_name: { type: string, example: 'CNC Lathe Machine' }
-        asset_category_id: { type: integer, example: 1 }
-        asset_subcategory_id: { type: integer, example: 1 }
+        item_category_id: { type: integer, example: 1 }
+        item_subcategory_id: { type: integer, example: 1 }
         plant_id: { type: integer, example: 1 }
         brand_model: { type: string }
         manufacturer: { type: string }
@@ -43,8 +43,8 @@ components:
       minProperties: 1
       properties:
         asset_name: { type: string }
-        asset_category_id: { type: integer }
-        asset_subcategory_id: { type: integer }
+        item_category_id: { type: integer }
+        item_subcategory_id: { type: integer }
         plant_id: { type: integer }
         brand_model: { type: string }
         manufacturer: { type: string }
@@ -410,8 +410,8 @@ paths:
         - { name: search, in: query, schema: { type: string } }
         - { name: status, in: query, schema: { type: string } }
         - { name: condition, in: query, schema: { type: string } }
-        - { name: asset_category_id, in: query, schema: { type: integer } }
-        - { name: asset_subcategory_id, in: query, schema: { type: integer } }
+        - { name: item_category_id, in: query, schema: { type: integer } }
+        - { name: item_subcategory_id, in: query, schema: { type: integer } }
         - { name: plant_id, in: query, schema: { type: integer } }
         - { name: department_id, in: query, schema: { type: integer } }
         - { name: is_active, in: query, schema: { type: boolean } }
diff --git a/src/docs/completed-routes.yaml b/src/docs/completed-routes.yaml
index 75c32ca..692b078 100644
--- a/src/docs/completed-routes.yaml
+++ b/src/docs/completed-routes.yaml
@@ -3,13 +3,11 @@ tags:
   - name: UOM
   - name: Item Categories
   - name: Item Subcategories
-  - name: Asset Subcategories
   - name: Items
   - name: Brands
   - name: GST Rates
   - name: Payment Terms
   - name: Delivery Terms
-  - name: Asset Categories
   - name: Departments
   - name: Designations
   - name: Locations
@@ -85,6 +83,9 @@ components:
       properties:
         code: { type: string, example: 'RAW' }
         name: { type: string, example: 'Raw Material' }
+        code_prefix: { type: string, nullable: true, example: 'MCH', description: Optional; used for asset code series when category is used for assets }
+        default_useful_life_years: { type: integer, nullable: true, example: 15 }
+        default_depreciation_method: { type: string, nullable: true, enum: [SLM, WDV, OTHER], example: SLM }
         is_active: { type: boolean, example: true }
     ItemCategoriesUpdateBody:
       type: object
@@ -92,6 +93,9 @@ components:
       properties:
         code: { type: string, example: 'RAW' }
         name: { type: string, example: 'Raw Material' }
+        code_prefix: { type: string, nullable: true, example: 'MCH' }
+        default_useful_life_years: { type: integer, nullable: true, example: 15 }
+        default_depreciation_method: { type: string, nullable: true, enum: [SLM, WDV, OTHER], example: SLM }
         is_active: { type: boolean, example: true }
     ItemSubcategoriesCreateBody:
       type: object
@@ -215,42 +219,6 @@ components:
         name: { type: string, example: 'Free on Road' }
         description: { type: string, example: 'Delivered to site' }
         is_active: { type: boolean, example: true }
-    AssetCategoriesCreateBody:
-      type: object
-      required: [code, name, code_prefix, default_useful_life_years, default_depreciation_method]
-      properties:
-        code: { type: string, example: 'MCH' }
-        name: { type: string, example: 'Plant & Machinery' }
-        code_prefix: { type: string, example: 'MCH' }
-        default_useful_life_years: { type: integer, example: 15 }
-        default_depreciation_method: { type: string, enum: [SLM, WDV, OTHER], example: WDV }
-        is_active: { type: boolean, example: true }
-    AssetCategoriesUpdateBody:
-      type: object
-      minProperties: 1
-      properties:
-        code: { type: string, example: 'MCH' }
-        name: { type: string, example: 'Plant & Machinery' }
-        code_prefix: { type: string, example: 'MCH' }
-        default_useful_life_years: { type: integer, example: 15 }
-        default_depreciation_method: { type: string, enum: [SLM, WDV, OTHER], example: WDV }
-        is_active: { type: boolean, example: true }
-    AssetSubcategoriesCreateBody:
-      type: object
-      required: [asset_category_id, code, name]
-      properties:
-        asset_category_id: { type: integer, example: 1 }
-        code: { type: string, example: 'CNC' }
-        name: { type: string, example: 'CNC Machines' }
-        is_active: { type: boolean, example: true }
-    AssetSubcategoriesUpdateBody:
-      type: object
-      minProperties: 1
-      properties:
-        asset_category_id: { type: integer, example: 1 }
-        code: { type: string, example: 'CNC' }
-        name: { type: string, example: 'CNC Machines' }
-        is_active: { type: boolean, example: true }
     DepartmentsCreateBody:
       type: object
       required: [name]
@@ -1079,148 +1047,6 @@ paths:
           description: Deleted
           content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
         "404": { description: Not found }
-  /masters/asset-categories:
-    get:
-      tags: [Asset Categories]
-      summary: List Asset Categories
-      parameters:
-        - in: query
-          name: page
-          schema: { type: integer, default: 1 }
-        - in: query
-          name: limit
-          schema: { type: integer, default: 20, maximum: 100 }
-        - in: query
-          name: search
-          schema: { type: string }
-        - in: query
-          name: is_active
-          schema: { type: boolean }
-      responses:
-        "200":
-          description: List fetched
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-    post:
-      tags: [Asset Categories]
-      summary: Create Asset Categorie
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema: { $ref: "#/components/schemas/AssetCategoriesCreateBody" }
-      responses:
-        "201":
-          description: Created
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "409": { description: Duplicate key }
-  /masters/asset-categories/{id}:
-    parameters:
-      - in: path
-        name: id
-        required: true
-        schema: { type: string }
-    get:
-      tags: [Asset Categories]
-      summary: Get Asset Categorie by id
-      responses:
-        "200":
-          description: Fetched
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "404": { description: Not found }
-    put:
-      tags: [Asset Categories]
-      summary: Update Asset Categorie
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema: { $ref: "#/components/schemas/AssetCategoriesUpdateBody" }
-      responses:
-        "200":
-          description: Updated
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "404": { description: Not found }
-    delete:
-      tags: [Asset Categories]
-      summary: Delete Asset Categorie
-      responses:
-        "200":
-          description: Deleted
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "404": { description: Not found }
-  /masters/asset-subcategories:
-    get:
-      tags: [Asset Subcategories]
-      summary: List Asset Subcategories
-      parameters:
-        - in: query
-          name: page
-          schema: { type: integer, default: 1 }
-        - in: query
-          name: limit
-          schema: { type: integer, default: 20, maximum: 100 }
-        - in: query
-          name: search
-          schema: { type: string }
-        - in: query
-          name: is_active
-          schema: { type: boolean }
-        - in: query
-          name: asset_category_id
-          schema: { type: integer }
-          description: Filter by parent asset category
-      responses:
-        "200":
-          description: List fetched
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-    post:
-      tags: [Asset Subcategories]
-      summary: Create Asset Subcategory
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema: { $ref: "#/components/schemas/AssetSubcategoriesCreateBody" }
-      responses:
-        "201":
-          description: Created
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "409": { description: Duplicate key }
-  /masters/asset-subcategories/{id}:
-    parameters:
-      - in: path
-        name: id
-        required: true
-        schema: { type: string }
-    get:
-      tags: [Asset Subcategories]
-      summary: Get Asset Subcategory by id
-      responses:
-        "200":
-          description: Fetched
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "404": { description: Not found }
-    put:
-      tags: [Asset Subcategories]
-      summary: Update Asset Subcategory
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema: { $ref: "#/components/schemas/AssetSubcategoriesUpdateBody" }
-      responses:
-        "200":
-          description: Updated
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "404": { description: Not found }
-    delete:
-      tags: [Asset Subcategories]
-      summary: Delete Asset Subcategory
-      responses:
-        "200":
-          description: Deleted
-          content: { application/json: { schema: { $ref: "#/components/schemas/ApiResponse" } } }
-        "404": { description: Not found }
   /masters/departments:
     get:
       tags: [Departments]
diff --git a/src/docs/grn-routes.yaml b/src/docs/grn-routes.yaml
index 42332df..85e7799 100644
--- a/src/docs/grn-routes.yaml
+++ b/src/docs/grn-routes.yaml
@@ -19,8 +19,8 @@ components:
         expiry_date: { type: string, format: date, nullable: true }
         storage_location: { type: string, example: 'Rack A-12' }
         remarks: { type: string, example: 'Partial receipt' }
-        asset_category_id: { type: integer, nullable: true, example: 1, description: Required when PO item is an asset item }
-        asset_subcategory_id: { type: integer, nullable: true, example: 1, description: Required when PO item is an asset item }
+        item_category_id: { type: integer, nullable: true, example: 1, description: Optional override; defaults from PO item master when omitted }
+        item_subcategory_id: { type: integer, nullable: true, example: 1, description: Optional override; defaults from PO item master when omitted }
     GrnCreateBody:
       type: object
       required: [grn_date, po_id, warehouse_id, items]
diff --git a/src/modules/assets/assets.helpers.js b/src/modules/assets/assets.helpers.js
index 545f539..ec8d611 100644
--- a/src/modules/assets/assets.helpers.js
+++ b/src/modules/assets/assets.helpers.js
@@ -8,8 +8,8 @@ const SOFT_DELETE_TABLES = new Set([
   'users',
   'purchase_orders',
   'grn',
-  'asset_categories',
-  'asset_subcategories',
+  'item_categories',
+  'item_subcategories',
 ]);
 
 const toDateOnly = (value) => {
diff --git a/src/modules/assets/assets.service.js b/src/modules/assets/assets.service.js
index 29edd67..6778b45 100644
--- a/src/modules/assets/assets.service.js
+++ b/src/modules/assets/assets.service.js
@@ -14,8 +14,17 @@ const {
 const { assertReference, toDateOnly } = require('./assets.helpers');
 
 const assetInclude = {
-  asset_categories: { select: { id: true, code: true, name: true, code_prefix: true } },
-  asset_subcategories: { select: { id: true, code: true, name: true, asset_category_id: true } },
+  item_categories: {
+    select: {
+      id: true,
+      code: true,
+      name: true,
+      code_prefix: true,
+      default_useful_life_years: true,
+      default_depreciation_method: true,
+    },
+  },
+  item_subcategories: { select: { id: true, code: true, name: true, item_category_id: true } },
   plant: { select: { id: true, code: true, name: true } },
   departments: { select: { id: true, name: true } },
   warehouse: { select: { id: true, code: true, name: true } },
@@ -50,8 +59,8 @@ const assetSeriesCode = (categoryCode) => `ASSET_${categoryCode}`;
 const sanitizeAsset = (asset) => {
   if (!asset) return null;
   const {
-    asset_categories,
-    asset_subcategories,
+    item_categories,
+    item_subcategories,
     plant,
     departments,
     warehouse,
@@ -82,8 +91,8 @@ const sanitizeAsset = (asset) => {
     purchase_cost: purchaseCost,
     salvage_value: salvageValue,
     depreciation_rate: depreciationRate,
-    asset_category: asset_categories || null,
-    asset_subcategory: asset_subcategories || null,
+    item_category: item_categories || null,
+    item_subcategory: item_subcategories || null,
     plant: plant || null,
     department: departments || null,
     warehouse: warehouse || null,
@@ -101,8 +110,8 @@ const sanitizeAsset = (asset) => {
       useful_life_years: rest.useful_life_years,
       purchase_date: rest.purchase_date,
     }),
-    asset_categories: undefined,
-    asset_subcategories: undefined,
+    item_categories: undefined,
+    item_subcategories: undefined,
     departments: undefined,
     users_assets_assigned_to_user_idTousers: undefined,
     vendors_assets_vendor_idTovendors: undefined,
@@ -147,29 +156,29 @@ const assertDisposalFields = (status, disposalDate) => {
   }
 };
 
-const assertAssetSubcategory = async (subcategoryId, categoryId) => {
+const assertItemSubcategory = async (subcategoryId, categoryId) => {
   const subcategory = await assertReference(
-    'asset_subcategories',
+    'item_subcategories',
     subcategoryId,
-    'asset_subcategory_id'
+    'item_subcategory_id'
   );
-  if (subcategory.asset_category_id.toString() !== BigInt(categoryId).toString()) {
-    throw new ApiError(422, 'asset_subcategory_id does not belong to the selected asset_category_id');
+  if (subcategory.item_category_id.toString() !== BigInt(categoryId).toString()) {
+    throw new ApiError(422, 'item_subcategory_id does not belong to the selected item_category_id');
   }
   return subcategory;
 };
 
 const normalizeAssetPayload = async (payload, { isCreate = false } = {}) => {
   const category = await assertReference(
-    'asset_categories',
-    payload.asset_category_id,
-    'asset_category_id'
+    'item_categories',
+    payload.item_category_id,
+    'item_category_id'
   );
-  if (isCreate && !payload.asset_subcategory_id) {
-    throw new ApiError(422, 'asset_subcategory_id is required');
+  if (isCreate && !payload.item_subcategory_id) {
+    throw new ApiError(422, 'item_subcategory_id is required');
   }
-  if (payload.asset_subcategory_id) {
-    await assertAssetSubcategory(payload.asset_subcategory_id, payload.asset_category_id);
+  if (payload.item_subcategory_id) {
+    await assertItemSubcategory(payload.item_subcategory_id, payload.item_category_id);
   }
   await assertPlant(payload.plant_id, 'plant_id');
   if (payload.department_id)
@@ -212,9 +221,9 @@ const normalizeAssetPayload = async (payload, { isCreate = false } = {}) => {
 
   return {
     asset_name: payload.asset_name,
-    asset_category_id: BigInt(payload.asset_category_id),
-    asset_subcategory_id: payload.asset_subcategory_id
-      ? BigInt(payload.asset_subcategory_id)
+    item_category_id: BigInt(payload.item_category_id),
+    item_subcategory_id: payload.item_subcategory_id
+      ? BigInt(payload.item_subcategory_id)
       : null,
     brand_model: payload.brand_model || null,
     manufacturer: payload.manufacturer || null,
@@ -294,9 +303,9 @@ const listAssets = async (query) => {
     deleted_at: null,
     ...(query.status ? { status: query.status } : {}),
     ...(query.condition ? { condition: query.condition } : {}),
-    ...(query.asset_category_id ? { asset_category_id: BigInt(query.asset_category_id) } : {}),
-    ...(query.asset_subcategory_id
-      ? { asset_subcategory_id: BigInt(query.asset_subcategory_id) }
+    ...(query.item_category_id ? { item_category_id: BigInt(query.item_category_id) } : {}),
+    ...(query.item_subcategory_id
+      ? { item_subcategory_id: BigInt(query.item_subcategory_id) }
       : {}),
     ...(query.plant_id ? { plant_id: BigInt(query.plant_id) } : {}),
     ...(query.department_id ? { department_id: BigInt(query.department_id) } : {}),
@@ -333,11 +342,11 @@ const updateAsset = async (id, payload, userId, requestId) => {
   const existing = await getAssetOrThrow(id);
   const merged = {
     asset_name: payload.asset_name ?? existing.asset_name,
-    asset_category_id: payload.asset_category_id ?? existing.asset_category_id,
-    asset_subcategory_id:
-      payload.asset_subcategory_id !== undefined
-        ? payload.asset_subcategory_id
-        : existing.asset_subcategory_id,
+    item_category_id: payload.item_category_id ?? existing.item_category_id,
+    item_subcategory_id:
+      payload.item_subcategory_id !== undefined
+        ? payload.item_subcategory_id
+        : existing.item_subcategory_id,
     brand_model: payload.brand_model !== undefined ? payload.brand_model : existing.brand_model,
     manufacturer: payload.manufacturer !== undefined ? payload.manufacturer : existing.manufacturer,
     serial_number:
diff --git a/src/modules/assets/assets.validation.js b/src/modules/assets/assets.validation.js
index f3732ad..9574386 100644
--- a/src/modules/assets/assets.validation.js
+++ b/src/modules/assets/assets.validation.js
@@ -16,8 +16,8 @@ const {
 
 const assetFields = {
   asset_name: Joi.string().max(200).required(),
-  asset_category_id: Joi.number().integer().positive().required(),
-  asset_subcategory_id: Joi.number().integer().positive().required(),
+  item_category_id: Joi.number().integer().positive().required(),
+  item_subcategory_id: Joi.number().integer().positive().required(),
   brand_model: Joi.string().max(200).allow(null, '').optional(),
   manufacturer: Joi.string().max(200).allow(null, '').optional(),
   serial_number: Joi.string().max(100).allow(null, '').optional(),
@@ -59,8 +59,8 @@ const createAssetSchema = Joi.object(assetFields);
 
 const updateAssetSchema = Joi.object({
   asset_name: assetFields.asset_name.optional(),
-  asset_category_id: assetFields.asset_category_id.optional(),
-  asset_subcategory_id: assetFields.asset_subcategory_id.optional(),
+  item_category_id: assetFields.item_category_id.optional(),
+  item_subcategory_id: assetFields.item_subcategory_id.optional(),
   brand_model: assetFields.brand_model,
   manufacturer: assetFields.manufacturer,
   serial_number: assetFields.serial_number,
@@ -101,8 +101,8 @@ const listAssetsQuerySchema = Joi.object({
   condition: Joi.string()
     .valid(...ASSET_CONDITIONS)
     .optional(),
-  asset_category_id: Joi.number().integer().positive().optional(),
-  asset_subcategory_id: Joi.number().integer().positive().optional(),
+  item_category_id: Joi.number().integer().positive().optional(),
+  item_subcategory_id: Joi.number().integer().positive().optional(),
   plant_id: Joi.number().integer().positive().optional(),
   department_id: Joi.number().integer().positive().optional(),
   is_active: Joi.boolean().optional(),
diff --git a/src/modules/grn/grn.repository.js b/src/modules/grn/grn.repository.js
index 84758ff..a4df026 100644
--- a/src/modules/grn/grn.repository.js
+++ b/src/modules/grn/grn.repository.js
@@ -4,7 +4,7 @@ const { recalculatePoStatus } = require('./grn.poStatus');
 
 const createAssetsForLine = async (
   tx,
-  { grn, grnItem, item, assetCategory, assetSubcategory, plantId, assetCodes, userId }
+  { grn, grnItem, item, itemCategory, itemSubcategory, plantId, assetCodes, userId }
 ) => {
   const createdAssets = [];
 
@@ -13,8 +13,8 @@ const createAssetsForLine = async (
       data: {
         asset_code: assetCodes[index],
         asset_name: assetCodes.length > 1 ? `${item.item_name} #${index + 1}` : item.item_name,
-        asset_category_id: assetCategory.id,
-        asset_subcategory_id: assetSubcategory.id,
+        item_category_id: itemCategory.id,
+        item_subcategory_id: itemSubcategory.id,
         plant_id: BigInt(plantId),
         warehouse_id: grn.warehouse_id,
         vendor_id: grn.vendor_id,
@@ -23,8 +23,8 @@ const createAssetsForLine = async (
         grn_item_id: grnItem.id,
         purchase_date: grn.grn_date,
         purchase_cost: grnItem.rate,
-        useful_life_years: assetCategory.default_useful_life_years,
-        depreciation_method: assetCategory.default_depreciation_method,
+        useful_life_years: itemCategory.default_useful_life_years,
+        depreciation_method: itemCategory.default_depreciation_method,
         condition: 'NEW',
         status: 'IN_USE',
         created_by: userId ? BigInt(userId) : null,
@@ -67,8 +67,8 @@ const createGrnWithReceipt = async ({ grnNumber, header, items, assetPlans, user
           grn,
           grnItem,
           item: plan.item,
-          assetCategory: plan.assetCategory,
-          assetSubcategory: plan.assetSubcategory,
+          itemCategory: plan.itemCategory,
+          itemSubcategory: plan.itemSubcategory,
           plantId: plan.plantId,
           assetCodes: plan.assetCodes,
           userId,
diff --git a/src/modules/grn/grn.service.js b/src/modules/grn/grn.service.js
index 57cbcea..ea3aac7 100644
--- a/src/modules/grn/grn.service.js
+++ b/src/modules/grn/grn.service.js
@@ -108,6 +108,8 @@ const getReceivablePoOrThrow = async (poId) => {
               item_code: true,
               item_name: true,
               is_asset_item: true,
+              item_category_id: true,
+              item_subcategory_id: true,
             },
           },
         },
@@ -175,48 +177,51 @@ const validateAndBuildItems = async (po, payloadItems) => {
 
     const item = poItem.items;
     if (item.is_asset_item && acceptedQty > 0) {
-      if (!row.asset_category_id) {
+      const categoryId = row.item_category_id ?? item.item_category_id;
+      const subcategoryId = row.item_subcategory_id ?? item.item_subcategory_id;
+
+      if (!categoryId) {
         throw new ApiError(
           422,
-          `Line ${row.line_no}: asset_category_id is required for asset items`
+          `Line ${row.line_no}: item_category_id is required for asset items (set on item master or GRN line)`
         );
       }
-      if (!row.asset_subcategory_id) {
+      if (!subcategoryId) {
         throw new ApiError(
           422,
-          `Line ${row.line_no}: asset_subcategory_id is required for asset items`
+          `Line ${row.line_no}: item_subcategory_id is required for asset items (set on item master or GRN line)`
         );
       }
 
-      const assetCategory = await prisma.asset_categories.findFirst({
-        where: { id: BigInt(row.asset_category_id), deleted_at: null, is_active: true },
+      const itemCategory = await prisma.item_categories.findFirst({
+        where: { id: BigInt(categoryId), deleted_at: null, is_active: true },
       });
-      if (!assetCategory) throw new ApiError(422, `Line ${row.line_no}: invalid asset_category_id`);
+      if (!itemCategory) throw new ApiError(422, `Line ${row.line_no}: invalid item_category_id`);
 
-      const assetSubcategory = await prisma.asset_subcategories.findFirst({
-        where: { id: BigInt(row.asset_subcategory_id), deleted_at: null, is_active: true },
+      const itemSubcategory = await prisma.item_subcategories.findFirst({
+        where: { id: BigInt(subcategoryId), deleted_at: null, is_active: true },
       });
-      if (!assetSubcategory) {
-        throw new ApiError(422, `Line ${row.line_no}: invalid asset_subcategory_id`);
+      if (!itemSubcategory) {
+        throw new ApiError(422, `Line ${row.line_no}: invalid item_subcategory_id`);
       }
-      if (assetSubcategory.asset_category_id.toString() !== assetCategory.id.toString()) {
+      if (itemSubcategory.item_category_id.toString() !== itemCategory.id.toString()) {
         throw new ApiError(
           422,
-          `Line ${row.line_no}: asset_subcategory_id does not belong to asset_category_id`
+          `Line ${row.line_no}: item_subcategory_id does not belong to item_category_id`
         );
       }
 
       const units = Math.floor(acceptedQty);
       const assetCodes = [];
       for (let unit = 0; unit < units; unit += 1) {
-        assetCodes.push(await nextDocumentNumber(assetSeriesCode(assetCategory.code)));
+        assetCodes.push(await nextDocumentNumber(assetSeriesCode(itemCategory.code)));
       }
 
       assetPlans.push({
         po_item_id: poItem.id,
         item,
-        assetCategory,
-        assetSubcategory,
+        itemCategory,
+        itemSubcategory,
         plantId: po.plant_id,
         assetCodes,
       });
diff --git a/src/modules/grn/grn.validation.js b/src/modules/grn/grn.validation.js
index a03474a..3f7db54 100644
--- a/src/modules/grn/grn.validation.js
+++ b/src/modules/grn/grn.validation.js
@@ -14,8 +14,8 @@ const grnItemSchema = Joi.object({
   expiry_date: Joi.date().iso().allow(null).optional(),
   storage_location: Joi.string().max(100).allow(null, '').optional(),
   remarks: Joi.string().allow(null, '').optional(),
-  asset_category_id: Joi.number().integer().positive().allow(null).optional(),
-  asset_subcategory_id: Joi.number().integer().positive().allow(null).optional(),
+  item_category_id: Joi.number().integer().positive().allow(null).optional(),
+  item_subcategory_id: Joi.number().integer().positive().allow(null).optional(),
 });
 
 const createGrnSchema = Joi.object({
diff --git a/src/modules/masters/asset-categories/asset-categories.controller.js b/src/modules/masters/asset-categories/asset-categories.controller.js
deleted file mode 100644
index f307ab4..0000000
--- a/src/modules/masters/asset-categories/asset-categories.controller.js
+++ /dev/null
@@ -1,30 +0,0 @@
-const asyncHandler = require('../../../utils/asyncHandler');
-const ApiResponse = require('../../../utils/ApiResponse');
-const service = require('./asset-categories.service');
-
-const create = asyncHandler(async (req, res) => {
-  const data = await service.createAssetCategories(req.body, req.user?.id, req.id);
-  res.status(201).json(new ApiResponse(201, data, 'asset_categories created successfully'));
-});
-
-const list = asyncHandler(async (req, res) => {
-  const result = await service.listAssetCategories(req.query);
-  res.json(new ApiResponse(200, result.data, 'asset_categories list fetched', result.meta));
-});
-
-const getOne = asyncHandler(async (req, res) => {
-  const data = await service.getAssetCategoriesById(req.params.id);
-  res.json(new ApiResponse(200, data, 'asset_categories fetched'));
-});
-
-const update = asyncHandler(async (req, res) => {
-  const data = await service.updateAssetCategories(req.params.id, req.body, req.user?.id, req.id);
-  res.json(new ApiResponse(200, data, 'asset_categories updated successfully'));
-});
-
-const remove = asyncHandler(async (req, res) => {
-  await service.deleteAssetCategories(req.params.id, req.user?.id, req.id);
-  res.json(new ApiResponse(200, null, 'asset_categories deleted successfully'));
-});
-
-module.exports = { create, list, getOne, update, remove };
diff --git a/src/modules/masters/asset-categories/asset-categories.routes.js b/src/modules/masters/asset-categories/asset-categories.routes.js
deleted file mode 100644
index 38e5684..0000000
--- a/src/modules/masters/asset-categories/asset-categories.routes.js
+++ /dev/null
@@ -1,17 +0,0 @@
-const express = require('express');
-const authenticate = require('../../../middlewares/auth.middleware');
-const authorize = require('../../../middlewares/rbac.middleware');
-const validate = require('../../../middlewares/validate.middleware');
-const controller = require('./asset-categories.controller');
-const { createSchema, updateSchema, listQuerySchema } = require('./asset-categories.validation');
-
-const router = express.Router();
-
-router.use(authenticate);
-router.get('/', authorize('MASTERS', 'view'), validate(listQuerySchema, 'query'), controller.list);
-router.get('/:id', authorize('MASTERS', 'view'), controller.getOne);
-router.post('/', authorize('MASTERS', 'create'), validate(createSchema), controller.create);
-router.put('/:id', authorize('MASTERS', 'edit'), validate(updateSchema), controller.update);
-router.delete('/:id', authorize('MASTERS', 'delete'), controller.remove);
-
-module.exports = router;
diff --git a/src/modules/masters/asset-categories/asset-categories.service.js b/src/modules/masters/asset-categories/asset-categories.service.js
deleted file mode 100644
index eafcd5f..0000000
--- a/src/modules/masters/asset-categories/asset-categories.service.js
+++ /dev/null
@@ -1,68 +0,0 @@
-const { buildMasterService } = require('../_shared/master.factory');
-
-const config = {
-  modelName: 'asset_categories',
-  tableName: 'asset_categories',
-  uniqueField: 'code',
-  softDelete: true,
-  fields: [
-    {
-      name: 'code',
-      type: 'string',
-      uppercase: true,
-      searchable: true,
-    },
-    {
-      name: 'name',
-      type: 'string',
-      uppercase: false,
-      searchable: true,
-    },
-    {
-      name: 'code_prefix',
-      type: 'string',
-      uppercase: true,
-      searchable: false,
-    },
-    {
-      name: 'default_useful_life_years',
-      type: 'int',
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'default_depreciation_method',
-      type: 'string',
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'is_active',
-      type: 'boolean',
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'created_by',
-      type: 'int',
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'updated_by',
-      type: 'int',
-      uppercase: false,
-      searchable: false,
-    },
-  ],
-};
-
-const service = buildMasterService(config);
-
-module.exports = {
-  createAssetCategories: service.createOne,
-  listAssetCategories: service.list,
-  getAssetCategoriesById: service.getOne,
-  updateAssetCategories: service.updateOne,
-  deleteAssetCategories: service.removeOne,
-};
diff --git a/src/modules/masters/asset-categories/asset-categories.validation.js b/src/modules/masters/asset-categories/asset-categories.validation.js
deleted file mode 100644
index 7e34fe6..0000000
--- a/src/modules/masters/asset-categories/asset-categories.validation.js
+++ /dev/null
@@ -1,29 +0,0 @@
-const Joi = require('joi');
-const { masterCode, masterName, listQuerySchema } = require('../_shared/masters.validation');
-const { DEPRECIATION_METHODS } = require('../../assets/assets.constants');
-
-const createSchema = Joi.object({
-  code: masterCode({ max: 30 }),
-  name: masterName({ max: 150 }),
-  code_prefix: masterCode({ max: 20 }),
-  default_useful_life_years: Joi.number().integer().optional(),
-  default_depreciation_method: Joi.string()
-    .valid(...DEPRECIATION_METHODS)
-    .allow(null, '')
-    .optional(),
-  is_active: Joi.boolean().optional(),
-});
-
-const updateSchema = Joi.object({
-  code: masterCode({ max: 30 }),
-  name: masterName({ max: 150 }),
-  code_prefix: masterCode({ max: 20 }),
-  default_useful_life_years: Joi.number().integer().optional(),
-  default_depreciation_method: Joi.string()
-    .valid(...DEPRECIATION_METHODS)
-    .allow(null, '')
-    .optional(),
-  is_active: Joi.boolean().optional(),
-}).min(1);
-
-module.exports = { createSchema, updateSchema, listQuerySchema };
diff --git a/src/modules/masters/asset-subcategories/asset-subcategories.controller.js b/src/modules/masters/asset-subcategories/asset-subcategories.controller.js
deleted file mode 100644
index 6308aab..0000000
--- a/src/modules/masters/asset-subcategories/asset-subcategories.controller.js
+++ /dev/null
@@ -1,35 +0,0 @@
-const asyncHandler = require('../../../utils/asyncHandler');
-const ApiResponse = require('../../../utils/ApiResponse');
-const service = require('./asset-subcategories.service');
-
-const create = asyncHandler(async (req, res) => {
-  const data = await service.createAssetSubcategories(req.body, req.user?.id, req.id);
-  res.status(201).json(new ApiResponse(201, data, 'asset_subcategories created successfully'));
-});
-
-const list = asyncHandler(async (req, res) => {
-  const result = await service.listAssetSubcategories(req.query);
-  res.json(new ApiResponse(200, result.data, 'asset_subcategories list fetched', result.meta));
-});
-
-const getOne = asyncHandler(async (req, res) => {
-  const data = await service.getAssetSubcategoriesById(req.params.id);
-  res.json(new ApiResponse(200, data, 'asset_subcategories fetched'));
-});
-
-const update = asyncHandler(async (req, res) => {
-  const data = await service.updateAssetSubcategories(
-    req.params.id,
-    req.body,
-    req.user?.id,
-    req.id
-  );
-  res.json(new ApiResponse(200, data, 'asset_subcategories updated successfully'));
-});
-
-const remove = asyncHandler(async (req, res) => {
-  await service.deleteAssetSubcategories(req.params.id, req.user?.id, req.id);
-  res.json(new ApiResponse(200, null, 'asset_subcategories deleted successfully'));
-});
-
-module.exports = { create, list, getOne, update, remove };
diff --git a/src/modules/masters/asset-subcategories/asset-subcategories.routes.js b/src/modules/masters/asset-subcategories/asset-subcategories.routes.js
deleted file mode 100644
index 7c5dad1..0000000
--- a/src/modules/masters/asset-subcategories/asset-subcategories.routes.js
+++ /dev/null
@@ -1,17 +0,0 @@
-const express = require('express');
-const authenticate = require('../../../middlewares/auth.middleware');
-const authorize = require('../../../middlewares/rbac.middleware');
-const validate = require('../../../middlewares/validate.middleware');
-const controller = require('./asset-subcategories.controller');
-const { createSchema, updateSchema, listQuerySchema } = require('./asset-subcategories.validation');
-
-const router = express.Router();
-
-router.use(authenticate);
-router.get('/', authorize('MASTERS', 'view'), validate(listQuerySchema, 'query'), controller.list);
-router.get('/:id', authorize('MASTERS', 'view'), controller.getOne);
-router.post('/', authorize('MASTERS', 'create'), validate(createSchema), controller.create);
-router.put('/:id', authorize('MASTERS', 'edit'), validate(updateSchema), controller.update);
-router.delete('/:id', authorize('MASTERS', 'delete'), controller.remove);
-
-module.exports = router;
diff --git a/src/modules/masters/asset-subcategories/asset-subcategories.service.js b/src/modules/masters/asset-subcategories/asset-subcategories.service.js
deleted file mode 100644
index cf15f93..0000000
--- a/src/modules/masters/asset-subcategories/asset-subcategories.service.js
+++ /dev/null
@@ -1,158 +0,0 @@
-const prisma = require('../../../config/prisma');
-const ApiError = require('../../../utils/ApiError');
-const { getPagination } = require('../../../utils/pagination');
-const { buildMasterService } = require('../_shared/master.factory');
-
-const config = {
-  modelName: 'asset_subcategories',
-  tableName: 'asset_subcategories',
-  uniqueField: 'code',
-  softDelete: true,
-  fields: [
-    {
-      name: 'asset_category_id',
-      type: 'int',
-      asBigInt: true,
-      filterable: true,
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'code',
-      type: 'string',
-      uppercase: true,
-      searchable: true,
-    },
-    {
-      name: 'name',
-      type: 'string',
-      uppercase: false,
-      searchable: true,
-    },
-    {
-      name: 'is_active',
-      type: 'boolean',
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'created_by',
-      type: 'int',
-      uppercase: false,
-      searchable: false,
-    },
-    {
-      name: 'updated_by',
-      type: 'int',
-      uppercase: false,
-      searchable: false,
-    },
-  ],
-};
-
-const service = buildMasterService(config);
-
-const categoryInclude = {
-  asset_categories: { select: { id: true, code: true, name: true } },
-};
-
-const sanitizeSubcategory = (row) => {
-  if (!row) return null;
-  const { asset_categories, ...rest } = row;
-  return {
-    ...rest,
-    asset_category: asset_categories || null,
-    asset_category_name: asset_categories?.name || null,
-    asset_categories: undefined,
-  };
-};
-
-const assertAssetCategory = async (assetCategoryId) => {
-  const category = await prisma.asset_categories.findFirst({
-    where: { id: BigInt(assetCategoryId), deleted_at: null },
-  });
-  if (!category) throw new ApiError(422, 'Invalid asset_category_id');
-  if (category.is_active === false) throw new ApiError(422, 'asset_category_id is inactive');
-  return category;
-};
-
-const withCategory = async (row) => {
-  if (!row) return null;
-  const full = await prisma.asset_subcategories.findFirst({
-    where: { id: row.id },
-    include: categoryInclude,
-  });
-  return sanitizeSubcategory(full || row);
-};
-
-const listAssetSubcategories = async (query) => {
-  const { page, limit, skip } = getPagination(query);
-
-  const where = {
-    deleted_at: null,
-    ...(query.is_active !== undefined ? { is_active: query.is_active } : {}),
-    ...(query.asset_category_id
-      ? { asset_category_id: BigInt(query.asset_category_id) }
-      : {}),
-    ...(query.search
-      ? {
-          OR: [
-            { code: { contains: query.search, mode: 'insensitive' } },
-            { name: { contains: query.search, mode: 'insensitive' } },
-            {
-              asset_categories: {
-                name: { contains: query.search, mode: 'insensitive' },
-              },
-            },
-          ],
-        }
-      : {}),
-  };
-
-  const [rows, total] = await Promise.all([
-    prisma.asset_subcategories.findMany({
-      where,
-      include: categoryInclude,
-      orderBy: { created_at: 'desc' },
-      skip,
-      take: limit,
-    }),
-    prisma.asset_subcategories.count({ where }),
-  ]);
-
-  return {
-    data: rows.map(sanitizeSubcategory),
-    meta: { page, limit, total },
-  };
-};
-
-const getAssetSubcategoriesById = async (id) => {
-  const row = await prisma.asset_subcategories.findFirst({
-    where: { id: BigInt(id), deleted_at: null },
-    include: categoryInclude,
-  });
-  if (!row) throw new ApiError(404, 'asset_subcategories not found');
-  return sanitizeSubcategory(row);
-};
-
-const createAssetSubcategories = async (payload, userId, requestId) => {
-  await assertAssetCategory(payload.asset_category_id);
-  const created = await service.createOne(payload, userId, requestId);
-  return withCategory(created);
-};
-
-const updateAssetSubcategories = async (id, payload, userId, requestId) => {
-  if (payload.asset_category_id !== undefined) {
-    await assertAssetCategory(payload.asset_category_id);
-  }
-  const updated = await service.updateOne(id, payload, userId, requestId);
-  return withCategory(updated);
-};
-
-module.exports = {
-  createAssetSubcategories,
-  listAssetSubcategories,
-  getAssetSubcategoriesById,
-  updateAssetSubcategories,
-  deleteAssetSubcategories: service.removeOne,
-};
diff --git a/src/modules/masters/asset-subcategories/asset-subcategories.validation.js b/src/modules/masters/asset-subcategories/asset-subcategories.validation.js
deleted file mode 100644
index 480dc26..0000000
--- a/src/modules/masters/asset-subcategories/asset-subcategories.validation.js
+++ /dev/null
@@ -1,26 +0,0 @@
-const Joi = require('joi');
-const { masterCode, masterName, listQuerySchema } = require('../_shared/masters.validation');
-
-const createSchema = Joi.object({
-  asset_category_id: Joi.number().integer().positive().required(),
-  code: masterCode({ max: 30, required: true }),
-  name: masterName({ max: 150, required: true }),
-  is_active: Joi.boolean().optional(),
-});
-
-const updateSchema = Joi.object({
-  asset_category_id: Joi.number().integer().positive().optional(),
-  code: masterCode({ max: 30 }),
-  name: masterName({ max: 150 }),
-  is_active: Joi.boolean().optional(),
-}).min(1);
-
-const listAssetSubcategoriesQuerySchema = listQuerySchema.keys({
-  asset_category_id: Joi.number().integer().positive().optional(),
-});
-
-module.exports = {
-  createSchema,
-  updateSchema,
-  listQuerySchema: listAssetSubcategoriesQuerySchema,
-};
diff --git a/src/modules/masters/index.js b/src/modules/masters/index.js
index 62e0ab1..3f202e3 100644
--- a/src/modules/masters/index.js
+++ b/src/modules/masters/index.js
@@ -8,8 +8,6 @@ router.use('/brands', require('./brands/brands.routes'));
 router.use('/gst-rates', require('./gst-rates/gst-rates.routes'));
 router.use('/payment-terms', require('./payment-terms/payment-terms.routes'));
 router.use('/delivery-terms', require('./delivery-terms/delivery-terms.routes'));
-router.use('/asset-categories', require('./asset-categories/asset-categories.routes'));
-router.use('/asset-subcategories', require('./asset-subcategories/asset-subcategories.routes'));
 router.use('/departments', require('./departments/departments.routes'));
 router.use('/designations', require('./designations/designations.routes'));
 router.use('/document-series', require('./document-series/document-series.routes'));
diff --git a/src/modules/masters/item-categories/item-categories.service.js b/src/modules/masters/item-categories/item-categories.service.js
index 10844ad..daa0318 100644
--- a/src/modules/masters/item-categories/item-categories.service.js
+++ b/src/modules/masters/item-categories/item-categories.service.js
@@ -1,5 +1,7 @@
 const { buildMasterService } = require('../_shared/master.factory');
 
+const emptyToNull = (value) => (value === '' ? null : value);
+
 const config = {
   modelName: 'item_categories',
   tableName: 'item_categories',
@@ -18,6 +20,24 @@ const config = {
       uppercase: false,
       searchable: true,
     },
+    {
+      name: 'code_prefix',
+      type: 'string',
+      uppercase: true,
+      searchable: false,
+    },
+    {
+      name: 'default_useful_life_years',
+      type: 'int',
+      uppercase: false,
+      searchable: false,
+    },
+    {
+      name: 'default_depreciation_method',
+      type: 'string',
+      uppercase: false,
+      searchable: false,
+    },
     {
       name: 'is_active',
       type: 'boolean',
@@ -41,10 +61,24 @@ const config = {
 
 const service = buildMasterService(config);
 
+const normalizeAssetDefaults = (payload) => {
+  if (!payload || typeof payload !== 'object') return payload;
+  const out = { ...payload };
+  if (Object.prototype.hasOwnProperty.call(out, 'code_prefix')) {
+    out.code_prefix = emptyToNull(out.code_prefix);
+  }
+  if (Object.prototype.hasOwnProperty.call(out, 'default_depreciation_method')) {
+    out.default_depreciation_method = emptyToNull(out.default_depreciation_method);
+  }
+  return out;
+};
+
 module.exports = {
-  createItemCategories: service.createOne,
+  createItemCategories: (payload, userId, requestId) =>
+    service.createOne(normalizeAssetDefaults(payload), userId, requestId),
   listItemCategories: service.list,
   getItemCategoriesById: service.getOne,
-  updateItemCategories: service.updateOne,
+  updateItemCategories: (id, payload, userId, requestId) =>
+    service.updateOne(id, normalizeAssetDefaults(payload), userId, requestId),
   deleteItemCategories: service.removeOne,
 };
diff --git a/src/modules/masters/item-categories/item-categories.validation.js b/src/modules/masters/item-categories/item-categories.validation.js
index c90ee1a..84f3e48 100644
--- a/src/modules/masters/item-categories/item-categories.validation.js
+++ b/src/modules/masters/item-categories/item-categories.validation.js
@@ -1,15 +1,28 @@
 const Joi = require('joi');
 const { masterCode, masterName, listQuerySchema } = require('../_shared/masters.validation');
+const { DEPRECIATION_METHODS } = require('../../assets/assets.constants');
 
 const createSchema = Joi.object({
   code: masterCode({ max: 30 }),
   name: masterName({ max: 150 }),
+  code_prefix: masterCode({ max: 10 }).allow(null, ''),
+  default_useful_life_years: Joi.number().integer().min(0).allow(null).optional(),
+  default_depreciation_method: Joi.string()
+    .valid(...DEPRECIATION_METHODS)
+    .allow(null, '')
+    .optional(),
   is_active: Joi.boolean().optional(),
 });
 
 const updateSchema = Joi.object({
   code: masterCode({ max: 30 }),
   name: masterName({ max: 150 }),
+  code_prefix: masterCode({ max: 10 }).allow(null, ''),
+  default_useful_life_years: Joi.number().integer().min(0).allow(null).optional(),
+  default_depreciation_method: Joi.string()
+    .valid(...DEPRECIATION_METHODS)
+    .allow(null, '')
+    .optional(),
   is_active: Joi.boolean().optional(),
 }).min(1);