import 'package:freezed_annotation/freezed_annotation.dart';

part 'grn_model.freezed.dart';
part 'grn_model.g.dart';

String _idFromJson(Object? value) => value?.toString() ?? '';

int? _intFromJsonNullable(Object? value) {
  if (value == null) return null;
  if (value is int) return value;
  if (value is num) return value.toInt();
  return int.tryParse(value.toString());
}

double? _doubleFromJsonNullable(Object? value) {
  if (value == null) return null;
  if (value is double) return value;
  if (value is num) return value.toDouble();
  return double.tryParse(value.toString());
}

DateTime? _dateFromJsonNullable(Object? value) {
  if (value == null) return null;
  if (value is DateTime) return value;
  return DateTime.tryParse(value.toString());
}

Object? _readNestedName(Map<dynamic, dynamic> json, String flatKey, String nestedKey) {
  final flat = json[flatKey];
  if (flat is String && flat.isNotEmpty) return flat;
  final nested = json[nestedKey];
  if (nested is Map) {
    return nested['name'] ?? nested['vendor_name'];
  }
  return null;
}

Object? _readVendorName(Map<dynamic, dynamic> json, String key) =>
    _readNestedName(json, 'vendor_name', 'vendor');

Object? _readWarehouseName(Map<dynamic, dynamic> json, String key) =>
    _readNestedName(json, 'warehouse_name', 'warehouse');

Object? _readPoNumber(Map<dynamic, dynamic> json, String key) {
  final grnNumber = json['grn_number'];
  if (grnNumber != null && grnNumber.toString().trim().isNotEmpty) {
    return grnNumber.toString();
  }
  final grnNo = json['grn_no'];
  if (grnNo != null && grnNo.toString().trim().isNotEmpty) {
    return grnNo.toString();
  }
  return null;
}

Object? _readPoRefNumber(Map<dynamic, dynamic> json, String key) {
  final flat = json['po_number'];
  if (flat is String && flat.isNotEmpty) return flat;
  final nested = json['purchase_order'] ?? json['po'];
  if (nested is Map) {
    return nested['po_number'] ?? nested['po_no'];
  }
  return null;
}

Object? _readItemName(Map<dynamic, dynamic> json, String key) {
  final flat = json['item_name'];
  if (flat is String && flat.isNotEmpty) return flat;
  final nested = json['item'];
  if (nested is Map) return nested['name'] ?? nested['item_name'];
  return null;
}

Object? _readItemCode(Map<dynamic, dynamic> json, String key) {
  final flat = json['item_code'];
  if (flat is String && flat.isNotEmpty) return flat;
  final nested = json['item'];
  if (nested is Map) return nested['code'] ?? nested['item_code'];
  return null;
}

Object? _readUomName(Map<dynamic, dynamic> json, String key) {
  final flat = json['uom_name'];
  if (flat is String && flat.isNotEmpty) return flat;
  final nested = json['uom'];
  if (nested is Map) return nested['name'];
  return null;
}

Object? _readGrnItemCategoryId(Map<dynamic, dynamic> json, String key) {
  for (final flatKey in ['item_category_id', 'asset_category_id']) {
    final flat = json[flatKey];
    if (flat != null) return flat;
  }
  final nested = json['item_category'] ?? json['asset_category'];
  if (nested is Map) return nested['id'];
  return null;
}

Object? _readGrnItemSubcategoryId(Map<dynamic, dynamic> json, String key) {
  for (final flatKey in ['item_subcategory_id', 'asset_subcategory_id']) {
    final flat = json[flatKey];
    if (flat != null) return flat;
  }
  final nested = json['item_subcategory'] ?? json['asset_subcategory'];
  if (nested is Map) return nested['id'];
  return null;
}

Object? _readUploadedByName(Map<dynamic, dynamic> json, String key) {
  final flat = json['uploaded_by_name'];
  if (flat is String && flat.trim().isNotEmpty) return flat;
  final nested = json['uploaded_by_user'] ?? json['uploaded_by'];
  if (nested is Map) {
    return nested['full_name'] ?? nested['name'];
  }
  return null;
}

@freezed
class GrnModel with _$GrnModel {
  const GrnModel._();

  const factory GrnModel({
    @JsonKey(fromJson: _idFromJson) required String id,
    @JsonKey(name: 'grn_number', readValue: _readPoNumber) String? grnNumber,
    @JsonKey(name: 'grn_date', fromJson: _dateFromJsonNullable) DateTime? grnDate,
    @Default('POSTED') String status,
    @JsonKey(name: 'po_id', fromJson: _intFromJsonNullable) int? poId,
    @JsonKey(name: 'po_number', readValue: _readPoRefNumber) String? poNumber,
    @JsonKey(name: 'vendor_id', fromJson: _intFromJsonNullable) int? vendorId,
    @JsonKey(name: 'vendor_name', readValue: _readVendorName) String? vendorName,
    @JsonKey(name: 'warehouse_id', fromJson: _intFromJsonNullable) int? warehouseId,
    @JsonKey(name: 'warehouse_name', readValue: _readWarehouseName) String? warehouseName,
    @JsonKey(name: 'vendor_invoice_no') String? vendorInvoiceNo,
    @JsonKey(name: 'vendor_invoice_date', fromJson: _dateFromJsonNullable)
    DateTime? vendorInvoiceDate,
    @JsonKey(name: 'vendor_invoice_amount', fromJson: _doubleFromJsonNullable)
    double? vendorInvoiceAmount,
    @JsonKey(name: 'vehicle_no') String? vehicleNo,
    @JsonKey(name: 'lr_no') String? lrNo,
    @JsonKey(name: 'lr_date', fromJson: _dateFromJsonNullable) DateTime? lrDate,
    @JsonKey(name: 'received_by', fromJson: _intFromJsonNullable) int? receivedBy,
    @JsonKey(name: 'quality_checked_by', fromJson: _intFromJsonNullable)
    int? qualityCheckedBy,
    String? remarks,
    @JsonKey(name: 'cancellation_reason') String? cancellationReason,
    @JsonKey(name: 'created_at', fromJson: _dateFromJsonNullable) DateTime? createdAt,
    @JsonKey(name: 'updated_at', fromJson: _dateFromJsonNullable) DateTime? updatedAt,
    @Default([]) List<GrnItemModel> items,
    @Default([]) List<GrnAttachmentModel> attachments,
  }) = _GrnModel;

  factory GrnModel.fromJson(Map<String, dynamic> json) => _$GrnModelFromJson(json);

  bool get canEdit => status.toUpperCase() == 'POSTED';

  bool get canCancel => status.toUpperCase() == 'POSTED';

  /// Upload/delete attachments only while GRN is POSTED.
  bool get canManageAttachments => status.toUpperCase() == 'POSTED';
}

@freezed
class GrnAttachmentModel with _$GrnAttachmentModel {
  const GrnAttachmentModel._();

  const factory GrnAttachmentModel({
    @JsonKey(fromJson: _idFromJson) required String id,
    @JsonKey(name: 'grn_id', fromJson: _idFromJson) String? grnId,
    @JsonKey(name: 'file_name') String? fileName,
    @JsonKey(name: 'file_type') String? fileType,
    @JsonKey(name: 'file_size', fromJson: _intFromJsonNullable) int? fileSize,
    @JsonKey(name: 'uploaded_by_name', readValue: _readUploadedByName)
    String? uploadedByName,
    @JsonKey(name: 'created_at', fromJson: _dateFromJsonNullable) DateTime? createdAt,
  }) = _GrnAttachmentModel;

  factory GrnAttachmentModel.fromJson(Map<String, dynamic> json) =>
      _$GrnAttachmentModelFromJson(json);

  bool get isPdf =>
      (fileType ?? '').toLowerCase().contains('pdf') ||
      (fileName ?? '').toLowerCase().endsWith('.pdf');

  bool get isImage {
    final type = (fileType ?? '').toLowerCase();
    final name = (fileName ?? '').toLowerCase();
    return type.startsWith('image/') ||
        name.endsWith('.jpg') ||
        name.endsWith('.jpeg') ||
        name.endsWith('.png') ||
        name.endsWith('.webp');
  }
}

@freezed
class GrnItemModel with _$GrnItemModel {
  const factory GrnItemModel({
    @JsonKey(fromJson: _idFromJson) required String id,
    @JsonKey(name: 'grn_id', fromJson: _idFromJson) String? grnId,
    @JsonKey(name: 'po_item_id', fromJson: _intFromJsonNullable) int? poItemId,
    @JsonKey(name: 'item_id', fromJson: _intFromJsonNullable) int? itemId,
    @JsonKey(name: 'item_code', readValue: _readItemCode) String? itemCode,
    @JsonKey(name: 'item_name', readValue: _readItemName) String? itemName,
    @JsonKey(name: 'line_no', fromJson: _intFromJsonNullable) int? lineNo,
    @JsonKey(name: 'current_qty', fromJson: _doubleFromJsonNullable) double? currentQty,
    @JsonKey(name: 'accepted_qty', fromJson: _doubleFromJsonNullable) double? acceptedQty,
    @JsonKey(name: 'damaged_qty', fromJson: _doubleFromJsonNullable) double? damagedQty,
    @JsonKey(name: 'short_qty', fromJson: _doubleFromJsonNullable) double? shortQty,
    @JsonKey(name: 'excess_qty', fromJson: _doubleFromJsonNullable) double? excessQty,
    @JsonKey(name: 'rejected_qty', fromJson: _doubleFromJsonNullable) double? rejectedQty,
    @JsonKey(name: 'rejection_reason') String? rejectionReason,
    @JsonKey(fromJson: _doubleFromJsonNullable) double? rate,
    @JsonKey(name: 'batch_no') String? batchNo,
    @JsonKey(name: 'mfg_date', fromJson: _dateFromJsonNullable) DateTime? mfgDate,
    @JsonKey(name: 'expiry_date', fromJson: _dateFromJsonNullable) DateTime? expiryDate,
    @JsonKey(name: 'storage_location') String? storageLocation,
    @JsonKey(
      name: 'item_category_id',
      readValue: _readGrnItemCategoryId,
      fromJson: _intFromJsonNullable,
    )
    int? itemCategoryId,
    @JsonKey(
      name: 'item_subcategory_id',
      readValue: _readGrnItemSubcategoryId,
      fromJson: _intFromJsonNullable,
    )
    int? itemSubcategoryId,
    @JsonKey(name: 'uom_id', fromJson: _intFromJsonNullable) int? uomId,
    @JsonKey(name: 'uom_name', readValue: _readUomName) String? uomName,
    String? remarks,
  }) = _GrnItemModel;

  factory GrnItemModel.fromJson(Map<String, dynamic> json) =>
      _$GrnItemModelFromJson(json);
}

@freezed
class GrnListQuery with _$GrnListQuery {
  const factory GrnListQuery({
    @Default(1) int page,
    @Default(20) int limit,
    String? search,
    String? status,
    int? poId,
    int? vendorId,
    int? warehouseId,
    String? dateFrom,
    String? dateTo,
  }) = _GrnListQuery;
}

const grnStatusOptions = [
  ('POSTED', 'Posted'),
  ('CANCELLED', 'Cancelled'),
];

String grnStatusLabel(String? value) {
  if (value == null) return '—';
  return grnStatusOptions
          .where((e) => e.$1 == value.toUpperCase())
          .map((e) => e.$2)
          .firstOrNull ??
      value.replaceAll('_', ' ');
}