const prisma = require('../../../config/prisma');
const ApiError = require('../../../utils/ApiError');
const auditLog = require('../../../utils/auditLog');
const { getPagination, isDropdownCall } = require('../../../utils/pagination');
const { parseId } = require('../../../utils/parseId');
const { rowsToCsv } = require('../../../utils/csv');
const {
  LOCATION_TYPES,
  toPlantResponse,
  toWarehouseResponse,
  toLocationResponse,
} = require('../../../utils/locations');
const { LOCATION_STATE_OPTIONS } = require('./locations.constants');

const TABLE_NAME = 'locations';

const normalizeString = (value) => {
  if (value === null || value === undefined) return value;
  return String(value).trim();
};

const buildPlantData = (payload) => ({
  type: LOCATION_TYPES.PLANT,
  code: payload.code ? String(payload.code).trim().toUpperCase() : undefined,
  name: normalizeString(payload.name),
  gstin: normalizeString(payload.gstin),
  address: normalizeString(payload.address),
  city: normalizeString(payload.city),
  state: normalizeString(payload.state),
  pincode: normalizeString(payload.pincode),
  phone: normalizeString(payload.phone),
  is_active: payload.is_active,
  location: null,
});

const buildWarehouseData = (payload) => ({
  type: LOCATION_TYPES.WAREHOUSE,
  code: payload.code ? String(payload.code).trim().toUpperCase() : undefined,
  name: normalizeString(payload.name),
  location: normalizeString(payload.location),
  is_active: payload.is_active,
  gstin: null,
  address: null,
  city: null,
  state: null,
  pincode: null,
  phone: null,
});

const assertUniqueCode = async (code, excludeId = null) => {
  if (!code) return;
  const existing = await prisma.locations.findFirst({
    where: {
      code,
      deleted_at: null,
      ...(excludeId ? { id: { not: parseId(excludeId) } } : {}),
    },
  });
  if (existing) throw new ApiError(409, 'Location code already exists');
};

const createLocation = async (type, payload, userId, requestId) => {
  const data =
    type === LOCATION_TYPES.PLANT ? buildPlantData(payload) : buildWarehouseData(payload);

  if (!data.code || !data.name) throw new ApiError(422, 'code and name are required');
  await assertUniqueCode(data.code);

  data.created_by = userId ? BigInt(userId) : null;
  data.updated_by = userId ? BigInt(userId) : null;

  const created = await prisma.locations.create({ data });

  const response =
    type === LOCATION_TYPES.PLANT ? toPlantResponse(created) : toWarehouseResponse(created);

  await auditLog({
    tableName: TABLE_NAME,
    recordId: created.id,
    action: 'CREATE',
    oldValue: null,
    newValue: response,
    userId,
    requestId,
  });

  return response;
};

const buildLocationsWhere = (query, type = null) => {
  const effectiveType = type || query.type || null;
  const where = {
    deleted_at: null,
    ...(effectiveType ? { type: effectiveType } : {}),
    ...(query.is_active !== undefined ? { is_active: query.is_active } : {}),
    ...(query.search
      ? {
          OR: [
            { code: { contains: query.search, mode: 'insensitive' } },
            { name: { contains: query.search, mode: 'insensitive' } },
          ],
        }
      : {}),
  };
  return { where, effectiveType };
};

const listLocations = async (query, type = null) => {
  const { where, effectiveType } = buildLocationsWhere(query, type);

  const mapRow = (row) => {
    if (effectiveType === LOCATION_TYPES.PLANT) return toPlantResponse(row);
    if (effectiveType === LOCATION_TYPES.WAREHOUSE) return toWarehouseResponse(row);
    return toLocationResponse(row);
  };

  if (isDropdownCall(query)) {
    where.is_active = true;
    const rows = await prisma.locations.findMany({
      where,
      orderBy: { created_at: 'desc' },
    });
    const data = rows.map(mapRow);
    return { data, meta: { page: 1, limit: data.length, total: data.length, dropdown: true } };
  }

  const { page, limit, skip } = getPagination(query);

  const [rows, total] = await Promise.all([
    prisma.locations.findMany({
      where,
      orderBy: { created_at: 'desc' },
      skip,
      take: limit,
    }),
    prisma.locations.count({ where }),
  ]);

  return { data: rows.map(mapRow), meta: { page, limit, total } };
};

const exportLocations = async (query, type = null) => {
  const { where, effectiveType } = buildLocationsWhere(query, type);
  const rows = await prisma.locations.findMany({
    where,
    orderBy: { created_at: 'desc' },
  });

  const mapRow = (row) => {
    if (effectiveType === LOCATION_TYPES.PLANT) return toPlantResponse(row);
    if (effectiveType === LOCATION_TYPES.WAREHOUSE) return toWarehouseResponse(row);
    return toLocationResponse(row);
  };

  const columns =
    effectiveType === LOCATION_TYPES.WAREHOUSE
      ? [
          { key: 'code', header: 'Code' },
          { key: 'name', header: 'Name' },
          { key: 'location', header: 'Location' },
          { key: 'is_active', header: 'Is Active' },
          { key: 'created_at', header: 'Created At', type: 'datetime' },
        ]
      : effectiveType === LOCATION_TYPES.PLANT
        ? [
            { key: 'code', header: 'Code' },
            { key: 'name', header: 'Name' },
            { key: 'gstin', header: 'GSTIN' },
            { key: 'city', header: 'City' },
            { key: 'state', header: 'State' },
            { key: 'is_active', header: 'Is Active' },
            { key: 'created_at', header: 'Created At', type: 'datetime' },
          ]
        : [
            { key: 'type', header: 'Type' },
            { key: 'code', header: 'Code' },
            { key: 'name', header: 'Name' },
            { key: 'is_active', header: 'Is Active' },
            { key: 'created_at', header: 'Created At', type: 'datetime' },
          ];

  return rowsToCsv(columns, rows.map(mapRow));
};

const getLocationById = async (id, type = null) => {
  const row = await prisma.locations.findFirst({
    where: {
      id: parseId(id),
      deleted_at: null,
      ...(type ? { type } : {}),
    },
  });
  if (!row) throw new ApiError(404, type ? `${type} not found` : 'Location not found');

  if (type === LOCATION_TYPES.PLANT) return toPlantResponse(row);
  if (type === LOCATION_TYPES.WAREHOUSE) return toWarehouseResponse(row);
  return toLocationResponse(row);
};

const updateLocation = async (id, type, payload, userId, requestId) => {
  const idBigInt = parseId(id);
  const existing = await prisma.locations.findFirst({
    where: { id: idBigInt, deleted_at: null, type },
  });
  if (!existing) throw new ApiError(404, `${type} not found`);

  const data =
    type === LOCATION_TYPES.PLANT ? buildPlantData(payload) : buildWarehouseData(payload);
  Object.keys(data).forEach((key) => {
    if (data[key] === undefined) delete data[key];
  });

  if (data.code) await assertUniqueCode(data.code, id);

  data.updated_by = userId ? BigInt(userId) : null;

  const updated = await prisma.locations.update({
    where: { id: idBigInt },
    data,
  });

  const oldValue =
    type === LOCATION_TYPES.PLANT ? toPlantResponse(existing) : toWarehouseResponse(existing);
  const newValue =
    type === LOCATION_TYPES.PLANT ? toPlantResponse(updated) : toWarehouseResponse(updated);

  await auditLog({
    tableName: TABLE_NAME,
    recordId: id,
    action: 'UPDATE',
    oldValue,
    newValue,
    userId,
    requestId,
  });

  return newValue;
};

const deleteLocation = async (id, type, userId, requestId) => {
  const idBigInt = parseId(id);
  const existing = await prisma.locations.findFirst({
    where: { id: idBigInt, deleted_at: null, type },
  });
  if (!existing) throw new ApiError(404, `${type} not found`);

  await prisma.locations.update({
    where: { id: idBigInt },
    data: { deleted_at: new Date(), updated_by: userId ? BigInt(userId) : null },
  });

  const oldValue =
    type === LOCATION_TYPES.PLANT ? toPlantResponse(existing) : toWarehouseResponse(existing);

  await auditLog({
    tableName: TABLE_NAME,
    recordId: id,
    action: 'DELETE',
    oldValue,
    newValue: { deleted_at: new Date() },
    userId,
    requestId,
  });
};

const deleteLocationById = async (id, userId, requestId) => {
  const existing = await prisma.locations.findFirst({
    where: { id: parseId(id), deleted_at: null },
  });
  if (!existing) throw new ApiError(404, 'Location not found');
  return deleteLocation(id, existing.type, userId, requestId);
};

const updateLocationById = async (id, payload, userId, requestId) => {
  const existing = await prisma.locations.findFirst({
    where: { id: parseId(id), deleted_at: null },
  });
  if (!existing) throw new ApiError(404, 'Location not found');
  return updateLocation(id, existing.type, payload, userId, requestId);
};

module.exports = {
  LOCATION_TYPES,
  createPlant: (payload, userId, requestId) =>
    createLocation(LOCATION_TYPES.PLANT, payload, userId, requestId),
  listPlants: (query) => listLocations(query, LOCATION_TYPES.PLANT),
  exportPlants: (query) => exportLocations(query, LOCATION_TYPES.PLANT),
  getPlantById: (id) => getLocationById(id, LOCATION_TYPES.PLANT),
  updatePlant: (id, payload, userId, requestId) =>
    updateLocation(id, LOCATION_TYPES.PLANT, payload, userId, requestId),
  deletePlant: (id, userId, requestId) =>
    deleteLocation(id, LOCATION_TYPES.PLANT, userId, requestId),
  createWarehouse: (payload, userId, requestId) =>
    createLocation(LOCATION_TYPES.WAREHOUSE, payload, userId, requestId),
  listWarehouses: (query) => listLocations(query, LOCATION_TYPES.WAREHOUSE),
  exportWarehouses: (query) => exportLocations(query, LOCATION_TYPES.WAREHOUSE),
  getWarehouseById: (id) => getLocationById(id, LOCATION_TYPES.WAREHOUSE),
  updateWarehouse: (id, payload, userId, requestId) =>
    updateLocation(id, LOCATION_TYPES.WAREHOUSE, payload, userId, requestId),
  deleteWarehouse: (id, userId, requestId) =>
    deleteLocation(id, LOCATION_TYPES.WAREHOUSE, userId, requestId),
  createLocation: (payload, userId, requestId) => {
    if (!payload.type) throw new ApiError(422, 'type is required');
    if (![LOCATION_TYPES.PLANT, LOCATION_TYPES.WAREHOUSE].includes(payload.type)) {
      throw new ApiError(422, 'type must be plant or warehouse');
    }
    return createLocation(payload.type, payload, userId, requestId);
  },
  listLocations: (query) => listLocations(query),
  exportLocations: (query) => exportLocations(query),
  getLocationById: (id) => getLocationById(id),
  updateLocationById,
  deleteLocationById,
  listStateOptions: () => LOCATION_STATE_OPTIONS,
};