/**
 * Service Order Service
 * Mecánicas Diesel - ERP Suite
 *
 * Business logic for service orders management.
 */

import { Repository, DataSource, FindOptionsWhere, ILike } from 'typeorm';
import {
  ServiceOrder,
  ServiceOrderStatus,
  ServiceOrderPriority,
} from '../entities/service-order.entity';
import { OrderItem, OrderItemType, OrderItemStatus } from '../entities/order-item.entity';
import { Customer } from '../../customers/entities/customer.entity';
import { Vehicle } from '../../vehicle-management/entities/vehicle.entity';
import { User, UserRole } from '../../auth/entities/user.entity';
import { Service } from '../entities/service.entity';

// DTOs
export interface CreateServiceOrderDto {
  customerId: string;
  vehicleId: string;
  customerSymptoms?: string;
  priority?: ServiceOrderPriority;
  promisedAt?: Date;
  assignedTo?: string;
  bayId?: string;
  odometerIn?: number;
  internalNotes?: string;
}

export interface UpdateServiceOrderDto {
  status?: ServiceOrderStatus;
  priority?: ServiceOrderPriority;
  assignedTo?: string;
  bayId?: string;
  promisedAt?: Date;
  odometerOut?: number;
  customerSymptoms?: string;
  internalNotes?: string;
  customerNotes?: string;
}

export interface AddOrderItemDto {
  itemType: OrderItemType;
  description: string;
  quantity: number;
  unitPrice: number;
  discountPct?: number;
  serviceId?: string;
  partId?: string;
  estimatedHours?: number;
  notes?: string;
}

export interface ServiceOrderFilters {
  status?: ServiceOrderStatus;
  priority?: ServiceOrderPriority;
  customerId?: string;
  vehicleId?: string;
  assignedTo?: string;
  bayId?: string;
  search?: string;
  fromDate?: Date;
  toDate?: Date;
}

export interface PaginationOptions {
  page: number;
  limit: number;
}

export interface PaginatedResult<T> {
  data: T[];
  total: number;
  page: number;
  limit: number;
  totalPages: number;
}

export interface ServiceContext {
  tenantId: string;
  userId?: string;
}

export interface CostBreakdown {
  laborSubtotal: number;
  partsSubtotal: number;
  subtotal: number;
  discountPercent: number;
  discountAmount: number;
  taxableAmount: number;
  taxRate: number;
  taxAmount: number;
  grandTotal: number;
  items: {
    id: string;
    itemType: OrderItemType;
    description: string;
    quantity: number;
    unitPrice: number;
    discountPct: number;
    subtotal: number;
    status: OrderItemStatus;
  }[];
}

export interface OrderHistoryEntry {
  field: string;
  oldValue: unknown;
  newValue: unknown;
  changedAt: Date;
  changedBy?: string;
}

// Estimated completion times by service type (in hours)
const SERVICE_ESTIMATION_HOURS: Record<string, number> = {
  diagnostico: 2,
  cambio_aceite: 1,
  frenos: 4,
  suspension: 6,
  motor: 24,
  transmision: 16,
  electrico: 4,
  turbo: 8,
  inyectores: 6,
  bomba_diesel: 8,
  mantenimiento_general: 4,
  default: 4,
};

export class ServiceOrderService {
  private orderRepository: Repository<ServiceOrder>;
  private itemRepository: Repository<OrderItem>;
  private customerRepository: Repository<Customer>;
  private vehicleRepository: Repository<Vehicle>;
  private userRepository: Repository<User>;
  private serviceRepository: Repository<Service>;

  constructor(private dataSource: DataSource) {
    this.orderRepository = dataSource.getRepository(ServiceOrder);
    this.itemRepository = dataSource.getRepository(OrderItem);
    this.customerRepository = dataSource.getRepository(Customer);
    this.vehicleRepository = dataSource.getRepository(Vehicle);
    this.userRepository = dataSource.getRepository(User);
    this.serviceRepository = dataSource.getRepository(Service);
  }

  /**
   * Generate next order number for tenant
   */
  private async generateOrderNumber(tenantId: string): Promise<string> {
    const year = new Date().getFullYear();
    const prefix = `OS-${year}-`;

    const lastOrder = await this.orderRepository.findOne({
      where: { tenantId },
      order: { createdAt: 'DESC' },
    });

    let sequence = 1;
    if (lastOrder?.orderNumber?.startsWith(prefix)) {
      const lastSeq = parseInt(lastOrder.orderNumber.replace(prefix, ''), 10);
      sequence = isNaN(lastSeq) ? 1 : lastSeq + 1;
    }

    return `${prefix}${sequence.toString().padStart(5, '0')}`;
  }

  /**
   * Create a new service order with full validation
   *
   * Validates:
   * - Customer exists and is active
   * - Vehicle exists, belongs to customer, and has complete data
   * - Generates sequential order number (OS-YYYY-NNNNN)
   * - Sets initial status to RECEIVED
   * - Calculates estimated completion date based on service type
   */
  async createOrder(dto: CreateServiceOrderDto, ctx: ServiceContext): Promise<ServiceOrder> {
    const { tenantId, userId } = ctx;

    // Validate customer exists and is active
    const customer = await this.customerRepository.findOne({
      where: { id: dto.customerId, tenantId },
    });

    if (!customer) {
      throw new Error(`Customer not found: ${dto.customerId}`);
    }

    if (!customer.isActive) {
      throw new Error(`Customer is inactive: ${customer.name}`);
    }

    // Validate vehicle exists and has complete data
    const vehicle = await this.vehicleRepository.findOne({
      where: { id: dto.vehicleId, tenantId },
    });

    if (!vehicle) {
      throw new Error(`Vehicle not found: ${dto.vehicleId}`);
    }

    // Verify vehicle belongs to the customer
    if (vehicle.customerId !== dto.customerId) {
      throw new Error(`Vehicle ${vehicle.licensePlate} does not belong to customer ${customer.name}`);
    }

    // Check vehicle has complete required data
    if (!vehicle.make || !vehicle.model || !vehicle.year) {
      throw new Error(
        `Vehicle ${vehicle.licensePlate} has incomplete data. ` +
        `Required: make, model, year. Please update vehicle information first.`
      );
    }

    // Generate sequential order number
    const orderNumber = await this.generateOrderNumber(tenantId);

    // Calculate estimated completion date if not provided
    let promisedAt = dto.promisedAt;
    if (!promisedAt) {
      promisedAt = this.calculateEstimatedDate(dto.priority || ServiceOrderPriority.NORMAL);
    }

    // Validate technician if provided
    if (dto.assignedTo) {
      const technician = await this.userRepository.findOne({
        where: { id: dto.assignedTo, tenantId, isActive: true },
      });

      if (!technician) {
        throw new Error(`Technician not found or inactive: ${dto.assignedTo}`);
      }
    }

    // Create the order within a transaction
    const order = await this.dataSource.transaction(async (manager) => {
      const orderRepo = manager.getRepository(ServiceOrder);

      const newOrder = orderRepo.create({
        tenantId,
        orderNumber,
        customerId: dto.customerId,
        vehicleId: dto.vehicleId,
        customerSymptoms: dto.customerSymptoms,
        priority: dto.priority || ServiceOrderPriority.NORMAL,
        status: ServiceOrderStatus.RECEIVED,
        promisedAt,
        assignedTo: dto.assignedTo,
        bayId: dto.bayId,
        odometerIn: dto.odometerIn,
        internalNotes: dto.internalNotes,
        createdBy: userId,
        receivedAt: new Date(),
      });

      return orderRepo.save(newOrder);
    });

    return order;
  }

  /**
   * Create a new service order (legacy method for backward compatibility)
   */
  async create(tenantId: string, dto: CreateServiceOrderDto, userId?: string): Promise<ServiceOrder> {
    return this.createOrder(dto, { tenantId, userId });
  }

  /**
   * Calculate estimated completion date based on priority
   */
  private calculateEstimatedDate(priority: ServiceOrderPriority): Date {
    const now = new Date();
    let hoursToAdd: number;

    switch (priority) {
      case ServiceOrderPriority.URGENT:
        hoursToAdd = 8; // Same day
        break;
      case ServiceOrderPriority.HIGH:
        hoursToAdd = 24; // Next day
        break;
      case ServiceOrderPriority.NORMAL:
        hoursToAdd = 48; // 2 business days
        break;
      case ServiceOrderPriority.LOW:
        hoursToAdd = 96; // 4 business days
        break;
      default:
        hoursToAdd = 48;
    }

    const estimatedDate = new Date(now.getTime() + hoursToAdd * 60 * 60 * 1000);
    return estimatedDate;
  }

  /**
   * Find order by ID
   */
  async findById(tenantId: string, id: string): Promise<ServiceOrder | null> {
    return this.orderRepository.findOne({
      where: { id, tenantId },
    });
  }

  /**
   * Find order by order number
   */
  async findByOrderNumber(tenantId: string, orderNumber: string): Promise<ServiceOrder | null> {
    return this.orderRepository.findOne({
      where: { tenantId, orderNumber },
    });
  }

  /**
   * List orders with filters and pagination
   */
  async findAll(
    tenantId: string,
    filters: ServiceOrderFilters = {},
    pagination: PaginationOptions = { page: 1, limit: 20 }
  ): Promise<PaginatedResult<ServiceOrder>> {
    const where: FindOptionsWhere<ServiceOrder> = { tenantId };

    if (filters.status) where.status = filters.status;
    if (filters.priority) where.priority = filters.priority;
    if (filters.customerId) where.customerId = filters.customerId;
    if (filters.vehicleId) where.vehicleId = filters.vehicleId;
    if (filters.assignedTo) where.assignedTo = filters.assignedTo;
    if (filters.bayId) where.bayId = filters.bayId;

    const queryBuilder = this.orderRepository.createQueryBuilder('order')
      .where('order.tenant_id = :tenantId', { tenantId });

    if (filters.status) {
      queryBuilder.andWhere('order.status = :status', { status: filters.status });
    }
    if (filters.priority) {
      queryBuilder.andWhere('order.priority = :priority', { priority: filters.priority });
    }
    if (filters.customerId) {
      queryBuilder.andWhere('order.customer_id = :customerId', { customerId: filters.customerId });
    }
    if (filters.vehicleId) {
      queryBuilder.andWhere('order.vehicle_id = :vehicleId', { vehicleId: filters.vehicleId });
    }
    if (filters.assignedTo) {
      queryBuilder.andWhere('order.assigned_to = :assignedTo', { assignedTo: filters.assignedTo });
    }
    if (filters.fromDate) {
      queryBuilder.andWhere('order.received_at >= :fromDate', { fromDate: filters.fromDate });
    }
    if (filters.toDate) {
      queryBuilder.andWhere('order.received_at <= :toDate', { toDate: filters.toDate });
    }
    if (filters.search) {
      queryBuilder.andWhere(
        '(order.order_number ILIKE :search OR order.customer_symptoms ILIKE :search)',
        { search: `%${filters.search}%` }
      );
    }

    const skip = (pagination.page - 1) * pagination.limit;

    const [data, total] = await queryBuilder
      .orderBy('order.received_at', 'DESC')
      .skip(skip)
      .take(pagination.limit)
      .getManyAndCount();

    return {
      data,
      total,
      page: pagination.page,
      limit: pagination.limit,
      totalPages: Math.ceil(total / pagination.limit),
    };
  }

  /**
   * Update service order with validation and history tracking
   *
   * Validates:
   * - Order exists
   * - Status transitions are valid
   * - Fields are modifiable based on current status
   * - Records history of changes
   */
  async updateOrder(
    id: string,
    dto: UpdateServiceOrderDto,
    ctx: ServiceContext
  ): Promise<{ order: ServiceOrder; changes: OrderHistoryEntry[] }> {
    const { tenantId, userId } = ctx;

    const order = await this.findById(tenantId, id);
    if (!order) {
      throw new Error(`Service order not found: ${id}`);
    }

    const changes: OrderHistoryEntry[] = [];
    const now = new Date();

    // Handle status transitions with validation
    if (dto.status && dto.status !== order.status) {
      this.validateStatusTransition(order.status, dto.status);

      // Check if modifications are allowed based on status
      if (order.status === ServiceOrderStatus.DELIVERED) {
        throw new Error('Cannot modify a delivered order');
      }

      if (order.status === ServiceOrderStatus.CANCELLED) {
        throw new Error('Cannot modify a cancelled order');
      }

      changes.push({
        field: 'status',
        oldValue: order.status,
        newValue: dto.status,
        changedAt: now,
        changedBy: userId,
      });

      this.applyStatusSideEffects(order, dto.status);
    }

    // Check field modification restrictions based on status
    const restrictedStatuses = [
      ServiceOrderStatus.COMPLETED,
      ServiceOrderStatus.DELIVERED,
      ServiceOrderStatus.CANCELLED,
    ];

    if (restrictedStatuses.includes(order.status)) {
      // Only allow updating notes and odometer on completed orders
      const allowedFields = ['customerNotes', 'internalNotes', 'odometerOut'];
      const attemptedFields = Object.keys(dto).filter(k => k !== 'status');
      const disallowedFields = attemptedFields.filter(f => !allowedFields.includes(f));

      if (disallowedFields.length > 0) {
        throw new Error(
          `Cannot modify fields [${disallowedFields.join(', ')}] on order with status ${order.status}`
        );
      }
    }

    // Track changes for audit
    const trackableFields: (keyof UpdateServiceOrderDto)[] = [
      'priority', 'assignedTo', 'bayId', 'promisedAt', 'odometerOut',
      'customerSymptoms', 'internalNotes', 'customerNotes',
    ];

    for (const field of trackableFields) {
      if (dto[field] !== undefined && dto[field] !== order[field as keyof ServiceOrder]) {
        changes.push({
          field,
          oldValue: order[field as keyof ServiceOrder],
          newValue: dto[field],
          changedAt: now,
          changedBy: userId,
        });
      }
    }

    // Validate technician if changing assignment
    if (dto.assignedTo && dto.assignedTo !== order.assignedTo) {
      const technician = await this.userRepository.findOne({
        where: { id: dto.assignedTo, tenantId, isActive: true },
      });

      if (!technician) {
        throw new Error(`Technician not found or inactive: ${dto.assignedTo}`);
      }
    }

    // Apply updates
    Object.assign(order, dto);

    const savedOrder = await this.orderRepository.save(order);

    return { order: savedOrder, changes };
  }

  /**
   * Update service order (legacy method for backward compatibility)
   */
  async update(
    tenantId: string,
    id: string,
    dto: UpdateServiceOrderDto
  ): Promise<ServiceOrder | null> {
    try {
      const result = await this.updateOrder(id, dto, { tenantId });
      return result.order;
    } catch {
      return null;
    }
  }

  /**
   * Validate status transition
   */
  private validateStatusTransition(from: ServiceOrderStatus, to: ServiceOrderStatus): void {
    const validTransitions: Record<ServiceOrderStatus, ServiceOrderStatus[]> = {
      [ServiceOrderStatus.RECEIVED]: [ServiceOrderStatus.DIAGNOSED, ServiceOrderStatus.CANCELLED],
      [ServiceOrderStatus.DIAGNOSED]: [ServiceOrderStatus.QUOTED, ServiceOrderStatus.IN_PROGRESS, ServiceOrderStatus.CANCELLED],
      [ServiceOrderStatus.QUOTED]: [ServiceOrderStatus.APPROVED, ServiceOrderStatus.CANCELLED],
      [ServiceOrderStatus.APPROVED]: [ServiceOrderStatus.IN_PROGRESS, ServiceOrderStatus.CANCELLED],
      [ServiceOrderStatus.IN_PROGRESS]: [ServiceOrderStatus.WAITING_PARTS, ServiceOrderStatus.COMPLETED, ServiceOrderStatus.CANCELLED],
      [ServiceOrderStatus.WAITING_PARTS]: [ServiceOrderStatus.IN_PROGRESS, ServiceOrderStatus.CANCELLED],
      [ServiceOrderStatus.COMPLETED]: [ServiceOrderStatus.DELIVERED],
      [ServiceOrderStatus.DELIVERED]: [],
      [ServiceOrderStatus.CANCELLED]: [],
    };

    if (!validTransitions[from].includes(to)) {
      throw new Error(`Invalid status transition from ${from} to ${to}`);
    }
  }

  /**
   * Apply side effects when status changes
   */
  private applyStatusSideEffects(order: ServiceOrder, newStatus: ServiceOrderStatus): void {
    const now = new Date();

    switch (newStatus) {
      case ServiceOrderStatus.IN_PROGRESS:
        if (!order.startedAt) order.startedAt = now;
        break;
      case ServiceOrderStatus.COMPLETED:
        order.completedAt = now;
        break;
      case ServiceOrderStatus.DELIVERED:
        order.deliveredAt = now;
        break;
    }
  }

  /**
   * Assign a technician to a service order
   *
   * Validates:
   * - Technician exists and is active
   * - Technician has appropriate role (MECANICO or JEFE_TALLER)
   * - Order is in an assignable status (RECEIVED or DIAGNOSED)
   * - Updates order status to IN_PROGRESS if appropriate
   */
  async assignTechnician(
    orderId: string,
    technicianId: string,
    ctx: ServiceContext
  ): Promise<ServiceOrder> {
    const { tenantId, userId } = ctx;

    const order = await this.findById(tenantId, orderId);
    if (!order) {
      throw new Error(`Service order not found: ${orderId}`);
    }

    // Validate order is in an assignable status
    const assignableStatuses = [
      ServiceOrderStatus.RECEIVED,
      ServiceOrderStatus.DIAGNOSED,
      ServiceOrderStatus.QUOTED,
      ServiceOrderStatus.APPROVED,
    ];

    if (!assignableStatuses.includes(order.status)) {
      throw new Error(
        `Cannot assign technician to order with status '${order.status}'. ` +
        `Order must be in status: ${assignableStatuses.join(', ')}`
      );
    }

    // Validate technician exists and is active
    const technician = await this.userRepository.findOne({
      where: { id: technicianId, tenantId, isActive: true },
    });

    if (!technician) {
      throw new Error(`Technician not found or inactive: ${technicianId}`);
    }

    // Validate technician has appropriate role
    const allowedRoles = [UserRole.MECANICO, UserRole.JEFE_TALLER, UserRole.ADMIN];
    if (!allowedRoles.includes(technician.role)) {
      throw new Error(
        `User ${technician.fullName} does not have technician role. ` +
        `Required roles: ${allowedRoles.join(', ')}`
      );
    }

    // Check technician workload (optional business logic)
    const activeOrders = await this.orderRepository.count({
      where: {
        tenantId,
        assignedTo: technicianId,
        status: ServiceOrderStatus.IN_PROGRESS,
      },
    });

    // Warn if technician has many active orders (threshold: 5)
    if (activeOrders >= 5) {
      console.warn(
        `Technician ${technician.fullName} has ${activeOrders} active orders. ` +
        `Consider load balancing.`
      );
    }

    // Perform the assignment within a transaction
    return this.dataSource.transaction(async (manager) => {
      const orderRepo = manager.getRepository(ServiceOrder);

      const previousAssignee = order.assignedTo;
      order.assignedTo = technicianId;

      // If order is in APPROVED status and being assigned, move to IN_PROGRESS
      if (order.status === ServiceOrderStatus.APPROVED) {
        order.status = ServiceOrderStatus.IN_PROGRESS;
        order.startedAt = new Date();
      }

      // Record internal note about assignment
      const assignmentNote = previousAssignee
        ? `Reassigned from ${previousAssignee} to ${technician.fullName}`
        : `Assigned to ${technician.fullName}`;

      order.internalNotes = order.internalNotes
        ? `${order.internalNotes}\n[${new Date().toISOString()}] ${assignmentNote}`
        : `[${new Date().toISOString()}] ${assignmentNote}`;

      return orderRepo.save(order);
    });
  }

  /**
   * Calculate detailed cost breakdown for a service order
   *
   * Returns:
   * - Labor subtotal (sum of all service items)
   * - Parts subtotal (sum of all part items)
   * - Discount calculation
   * - IVA (16%) calculation
   * - Grand total
   * - Itemized breakdown
   */
  async calculateCosts(orderId: string, ctx: ServiceContext): Promise<CostBreakdown> {
    const { tenantId } = ctx;

    const order = await this.findById(tenantId, orderId);
    if (!order) {
      throw new Error(`Service order not found: ${orderId}`);
    }

    const items = await this.getItems(orderId);

    let laborSubtotal = 0;
    let partsSubtotal = 0;

    const itemizedBreakdown = items.map((item) => {
      const itemSubtotal = Number(item.subtotal);

      if (item.itemType === OrderItemType.SERVICE) {
        laborSubtotal += itemSubtotal;
      } else {
        partsSubtotal += itemSubtotal;
      }

      return {
        id: item.id,
        itemType: item.itemType,
        description: item.description,
        quantity: Number(item.quantity),
        unitPrice: Number(item.unitPrice),
        discountPct: Number(item.discountPct),
        subtotal: itemSubtotal,
        status: item.status,
      };
    });

    const subtotal = laborSubtotal + partsSubtotal;
    const discountPercent = Number(order.discountPercent) || 0;
    const discountAmount = subtotal * (discountPercent / 100);
    const taxableAmount = subtotal - discountAmount;
    const taxRate = 0.16; // 16% IVA Mexico
    const taxAmount = taxableAmount * taxRate;
    const grandTotal = taxableAmount + taxAmount;

    return {
      laborSubtotal,
      partsSubtotal,
      subtotal,
      discountPercent,
      discountAmount,
      taxableAmount,
      taxRate,
      taxAmount,
      grandTotal,
      items: itemizedBreakdown,
    };
  }

  /**
   * Close a service order (mark as COMPLETED)
   *
   * Validates:
   * - All work items are completed
   * - No pending parts items
   * - Order is in a closeable status
   *
   * Actions:
   * - Sets status to COMPLETED
   * - Records completion timestamp
   * - Updates customer stats
   * - Prepares order for invoicing
   */
  async closeOrder(orderId: string, ctx: ServiceContext): Promise<ServiceOrder> {
    const { tenantId, userId } = ctx;

    const order = await this.findById(tenantId, orderId);
    if (!order) {
      throw new Error(`Service order not found: ${orderId}`);
    }

    // Validate order is in a closeable status
    const closeableStatuses = [ServiceOrderStatus.IN_PROGRESS, ServiceOrderStatus.WAITING_PARTS];
    if (!closeableStatuses.includes(order.status)) {
      throw new Error(
        `Cannot close order with status '${order.status}'. ` +
        `Order must be in status: ${closeableStatuses.join(' or ')}`
      );
    }

    // Get all order items
    const items = await this.getItems(orderId);

    if (items.length === 0) {
      throw new Error('Cannot close order without any work items');
    }

    // Check all items are completed
    const pendingItems = items.filter(
      (item) => item.status !== OrderItemStatus.COMPLETED
    );

    if (pendingItems.length > 0) {
      const pendingDescriptions = pendingItems
        .map((item) => `- ${item.description} (${item.status})`)
        .join('\n');
      throw new Error(
        `Cannot close order. The following items are not completed:\n${pendingDescriptions}`
      );
    }

    // Check for pending parts (items marked as PART type with PENDING status)
    const pendingParts = items.filter(
      (item) => item.itemType === OrderItemType.PART && item.status === OrderItemStatus.PENDING
    );

    if (pendingParts.length > 0) {
      throw new Error(
        `Cannot close order. There are ${pendingParts.length} pending parts that need to be resolved.`
      );
    }

    // Close the order within a transaction
    return this.dataSource.transaction(async (manager) => {
      const orderRepo = manager.getRepository(ServiceOrder);
      const customerRepo = manager.getRepository(Customer);

      const now = new Date();

      // Update order status
      order.status = ServiceOrderStatus.COMPLETED;
      order.completedAt = now;

      // Add completion note
      const closureNote = `Order closed by ${userId || 'system'} at ${now.toISOString()}`;
      order.internalNotes = order.internalNotes
        ? `${order.internalNotes}\n${closureNote}`
        : closureNote;

      // Recalculate final totals
      await this.recalculateTotals(orderId);

      // Reload order with updated totals
      const updatedOrder = await orderRepo.findOne({ where: { id: orderId } });
      if (!updatedOrder) {
        throw new Error('Failed to reload order after total recalculation');
      }

      // Update customer statistics
      const customer = await customerRepo.findOne({
        where: { id: order.customerId, tenantId },
      });

      if (customer) {
        customer.totalOrders = (customer.totalOrders || 0) + 1;
        customer.totalSpent = Number(customer.totalSpent || 0) + Number(updatedOrder.grandTotal);
        customer.lastVisitAt = now;
        await customerRepo.save(customer);
      }

      // Save and return the completed order
      return orderRepo.save(updatedOrder);
    });
  }

  /**
   * Deliver a completed order to customer
   *
   * Final step in the order lifecycle:
   * - Validates order is completed
   * - Records delivery timestamp
   * - Updates vehicle odometer if provided
   */
  async deliverOrder(
    orderId: string,
    odometerOut?: number,
    ctx?: ServiceContext
  ): Promise<ServiceOrder> {
    const tenantId = ctx?.tenantId;
    if (!tenantId) {
      throw new Error('Tenant ID is required');
    }

    const order = await this.findById(tenantId, orderId);
    if (!order) {
      throw new Error(`Service order not found: ${orderId}`);
    }

    if (order.status !== ServiceOrderStatus.COMPLETED) {
      throw new Error(
        `Cannot deliver order with status '${order.status}'. Order must be completed first.`
      );
    }

    return this.dataSource.transaction(async (manager) => {
      const orderRepo = manager.getRepository(ServiceOrder);
      const vehicleRepo = manager.getRepository(Vehicle);

      const now = new Date();

      order.status = ServiceOrderStatus.DELIVERED;
      order.deliveredAt = now;

      if (odometerOut !== undefined) {
        if (order.odometerIn && odometerOut < order.odometerIn) {
          throw new Error(
            `Odometer out (${odometerOut}) cannot be less than odometer in (${order.odometerIn})`
          );
        }
        order.odometerOut = odometerOut;

        // Update vehicle's current odometer
        const vehicle = await vehicleRepo.findOne({
          where: { id: order.vehicleId, tenantId },
        });

        if (vehicle) {
          vehicle.currentOdometer = odometerOut;
          vehicle.odometerUpdatedAt = now;
          await vehicleRepo.save(vehicle);
        }
      }

      return orderRepo.save(order);
    });
  }

  /**
   * Get technician workload summary
   */
  async getTechnicianWorkload(
    technicianId: string,
    ctx: ServiceContext
  ): Promise<{
    activeOrders: number;
    completedToday: number;
    pendingItems: number;
    estimatedHoursRemaining: number;
  }> {
    const { tenantId } = ctx;

    const today = new Date();
    today.setHours(0, 0, 0, 0);

    const [activeOrders, completedToday] = await Promise.all([
      this.orderRepository.count({
        where: {
          tenantId,
          assignedTo: technicianId,
          status: ServiceOrderStatus.IN_PROGRESS,
        },
      }),
      this.orderRepository
        .createQueryBuilder('order')
        .where('order.tenant_id = :tenantId', { tenantId })
        .andWhere('order.assigned_to = :technicianId', { technicianId })
        .andWhere('order.status = :status', { status: ServiceOrderStatus.COMPLETED })
        .andWhere('order.completed_at >= :today', { today })
        .getCount(),
    ]);

    // Get pending items for active orders
    const activeOrderIds = await this.orderRepository
      .createQueryBuilder('order')
      .select('order.id')
      .where('order.tenant_id = :tenantId', { tenantId })
      .andWhere('order.assigned_to = :technicianId', { technicianId })
      .andWhere('order.status = :status', { status: ServiceOrderStatus.IN_PROGRESS })
      .getMany();

    let pendingItems = 0;
    let estimatedHoursRemaining = 0;

    for (const order of activeOrderIds) {
      const items = await this.itemRepository.find({
        where: {
          orderId: order.id,
          status: OrderItemStatus.PENDING,
        },
      });

      pendingItems += items.length;
      estimatedHoursRemaining += items.reduce(
        (sum, item) => sum + (Number(item.estimatedHours) || 0),
        0
      );
    }

    return {
      activeOrders,
      completedToday,
      pendingItems,
      estimatedHoursRemaining,
    };
  }

  /**
   * Add item to order
   */
  async addItem(tenantId: string, orderId: string, dto: AddOrderItemDto): Promise<OrderItem | null> {
    const order = await this.findById(tenantId, orderId);
    if (!order) return null;

    const subtotal = dto.quantity * dto.unitPrice * (1 - (dto.discountPct || 0) / 100);

    const item = this.itemRepository.create({
      orderId,
      itemType: dto.itemType,
      description: dto.description,
      quantity: dto.quantity,
      unitPrice: dto.unitPrice,
      discountPct: dto.discountPct || 0,
      subtotal,
      serviceId: dto.serviceId,
      partId: dto.partId,
      estimatedHours: dto.estimatedHours,
      notes: dto.notes,
      status: OrderItemStatus.PENDING,
    });

    const savedItem = await this.itemRepository.save(item);

    // Recalculate totals
    await this.recalculateTotals(orderId);

    return savedItem;
  }

  /**
   * Get order items
   */
  async getItems(orderId: string): Promise<OrderItem[]> {
    return this.itemRepository.find({
      where: { orderId },
      order: { sortOrder: 'ASC', createdAt: 'ASC' },
    });
  }

  /**
   * Update order item
   */
  async updateItem(
    itemId: string,
    dto: Partial<AddOrderItemDto>
  ): Promise<OrderItem | null> {
    const item = await this.itemRepository.findOne({ where: { id: itemId } });
    if (!item) return null;

    if (dto.quantity !== undefined || dto.unitPrice !== undefined || dto.discountPct !== undefined) {
      const quantity = dto.quantity ?? item.quantity;
      const unitPrice = dto.unitPrice ?? item.unitPrice;
      const discountPct = dto.discountPct ?? item.discountPct;
      item.subtotal = quantity * unitPrice * (1 - discountPct / 100);
    }

    Object.assign(item, dto);
    const savedItem = await this.itemRepository.save(item);

    // Recalculate totals
    await this.recalculateTotals(item.orderId);

    return savedItem;
  }

  /**
   * Remove order item
   */
  async removeItem(itemId: string): Promise<boolean> {
    const item = await this.itemRepository.findOne({ where: { id: itemId } });
    if (!item) return false;

    const orderId = item.orderId;
    await this.itemRepository.remove(item);

    // Recalculate totals
    await this.recalculateTotals(orderId);

    return true;
  }

  /**
   * Recalculate order totals
   */
  private async recalculateTotals(orderId: string): Promise<void> {
    const items = await this.getItems(orderId);

    let laborTotal = 0;
    let partsTotal = 0;

    for (const item of items) {
      if (item.itemType === OrderItemType.SERVICE) {
        laborTotal += Number(item.subtotal);
      } else {
        partsTotal += Number(item.subtotal);
      }
    }

    const order = await this.orderRepository.findOne({ where: { id: orderId } });
    if (!order) return;

    order.laborTotal = laborTotal;
    order.partsTotal = partsTotal;

    const subtotal = laborTotal + partsTotal;
    const discountAmount = subtotal * (Number(order.discountPercent) / 100);
    order.discountAmount = discountAmount;

    const taxableAmount = subtotal - discountAmount;
    order.tax = taxableAmount * 0.16; // 16% IVA México

    order.grandTotal = taxableAmount + order.tax;

    await this.orderRepository.save(order);
  }

  /**
   * Get orders by status (for Kanban board)
   */
  async getOrdersByStatus(tenantId: string): Promise<Record<ServiceOrderStatus, ServiceOrder[]>> {
    const orders = await this.orderRepository.find({
      where: { tenantId },
      order: { receivedAt: 'DESC' },
    });

    const grouped: Record<ServiceOrderStatus, ServiceOrder[]> = {
      [ServiceOrderStatus.RECEIVED]: [],
      [ServiceOrderStatus.DIAGNOSED]: [],
      [ServiceOrderStatus.QUOTED]: [],
      [ServiceOrderStatus.APPROVED]: [],
      [ServiceOrderStatus.IN_PROGRESS]: [],
      [ServiceOrderStatus.WAITING_PARTS]: [],
      [ServiceOrderStatus.COMPLETED]: [],
      [ServiceOrderStatus.DELIVERED]: [],
      [ServiceOrderStatus.CANCELLED]: [],
    };

    for (const order of orders) {
      grouped[order.status].push(order);
    }

    return grouped;
  }

  /**
   * Get dashboard statistics
   */
  async getDashboardStats(tenantId: string): Promise<{
    totalOrders: number;
    pendingOrders: number;
    inProgressOrders: number;
    completedToday: number;
    totalRevenue: number;
    averageTicket: number;
  }> {
    const today = new Date();
    today.setHours(0, 0, 0, 0);

    const [
      totalOrders,
      pendingOrders,
      inProgressOrders,
      completedToday,
      revenueResult,
    ] = await Promise.all([
      this.orderRepository.count({ where: { tenantId } }),
      this.orderRepository.count({
        where: { tenantId, status: ServiceOrderStatus.RECEIVED },
      }),
      this.orderRepository.count({
        where: { tenantId, status: ServiceOrderStatus.IN_PROGRESS },
      }),
      this.orderRepository.createQueryBuilder('order')
        .where('order.tenant_id = :tenantId', { tenantId })
        .andWhere('order.status = :status', { status: ServiceOrderStatus.COMPLETED })
        .andWhere('order.completed_at >= :today', { today })
        .getCount(),
      this.orderRepository.createQueryBuilder('order')
        .select('SUM(order.grand_total)', 'total')
        .where('order.tenant_id = :tenantId', { tenantId })
        .andWhere('order.status IN (:...statuses)', {
          statuses: [ServiceOrderStatus.COMPLETED, ServiceOrderStatus.DELIVERED],
        })
        .getRawOne(),
    ]);

    const totalRevenue = parseFloat(revenueResult?.total) || 0;
    const completedCount = await this.orderRepository.count({
      where: {
        tenantId,
        status: ServiceOrderStatus.COMPLETED,
      },
    });

    return {
      totalOrders,
      pendingOrders,
      inProgressOrders,
      completedToday,
      totalRevenue,
      averageTicket: completedCount > 0 ? totalRevenue / completedCount : 0,
    };
  }
}