import { Injectable, BadRequestException, Logger, NotFoundException, ForbiddenException } from '@nestjs/common';
import { EntityManager } from '@mikro-orm/postgresql';
import { OrderRepository } from '../repositories/order.repository';
import { FindOrdersDto } from '../dto/find-orders.dto';
import { EventEmitter2 } from '@nestjs/event-emitter';
import {
  CreateOrderAsAdminDto,
} from '../dto/create-order.dto';
import { UserService } from 'src/modules/user/providers/user.service';
import { OrderStatusEnum, IOrderPrintResponse } from '../interface/order.interface';
import { Order } from '../entities/order.entity';
import { AdminService } from 'src/modules/admin/providers/admin.service';
import { UpdateOrderAsAdminDto } from '../dto/update-order.dto';
import { PermissionEnum } from 'src/common/enums/permission.enum';
import { User } from 'src/modules/user/entities/user.entity';
import { Product } from 'src/modules/product/entities/product.entity';
import { Category } from 'src/modules/product/entities/category.entity';
import { InvoiceItem } from 'src/modules/invoice/entities/invoice-item.entity';
import { PaginatedResult } from 'src/common/interfaces/pagination.interface';
import { UpdateStatusDto } from '../dto/update-status.dto';
import { CreateOrderPrintDto } from '../dto/create-order-print.dto';
import { OrderPrintValueDto } from '../dto/order-print-value.dto';
import { OrderPrint } from '../entities/order-print.entity';
import { OrderPrintValue } from '../entities/order-print-value.entity';
import { OrderPrintRepository } from '../repositories/order-print.repository';
import { Field } from 'src/modules/form-builder/entities/field.entity';
import { Request } from 'src/modules/request/entities/request.entity';
import { Invoice } from 'src/modules/invoice/entities/invoice.entity';
import { OrderCreatedEvent } from '../events/order.events';
import { InvoiceConfirmStatusEnum } from 'src/modules/invoice/enum/invoice-confirm-status.enum';

@Injectable()
export class OrderService {
  private readonly logger = new Logger(OrderService.name);

  constructor(
    private readonly em: EntityManager,
    private readonly orderRepository: OrderRepository,
    private readonly userService: UserService,
    private readonly adminService: AdminService,
    private readonly orderPrintRepository: OrderPrintRepository,
    private readonly eventEmitter: EventEmitter2,
  ) {}

  async createOrderAsAdmin(adminId: string, dto: CreateOrderAsAdminDto): Promise<Order> {
    let invoiceItem: null | InvoiceItem = null
    let user: User | null = null

    if (dto.invoiceItemId) {
      invoiceItem = await this.em.findOne(InvoiceItem, { id: dto.invoiceItemId }, { populate: ['invoice', 'invoice.user', 'product'] });
      if (!invoiceItem) {
        throw new NotFoundException(`Invoice item with ID ${dto.invoiceItemId} not found.`);
      }

      if (!invoiceItem.confirmedAt ) {
        throw new BadRequestException(`Invoice item is not confirmed`);
      }

      user = invoiceItem.invoice.user
    }

    if (!dto.invoiceItemId) {

      if (!dto.userId) {
        throw new NotFoundException(`UserId is required`);
      }

      user = await this.userService.findById(dto.userId);

      if (!user) {
        throw new NotFoundException(`User with ID ${dto.userId} not found.`);
      }
    }

    if (!user) {
      throw new NotFoundException(`User not found`);
    }

    const creator = await this.adminService.findOrFail(adminId);

    const type = await this.em.findOne(Category, { id: dto.typeId });
    if (!type) {
      throw new NotFoundException(`Order type with ID ${dto.typeId} not found.`);
    }

    let product: Product | null = null;
    if (dto.productId) {
      product = await this.em.findOne(Product, { id: dto.productId });
      if (!product) {
        throw new NotFoundException(`Product with ID ${dto.productId} not found.`);
      }
    } else if (invoiceItem?.product) {
      product = invoiceItem.product;
    }

    let designer = null;
    if (dto.designerId) {
      designer = await this.adminService.findOrFail(dto.designerId);
    }

    const order = this.em.create(Order, {
      user,
      creator,
      designer,
      type,
      product: product ?? null,
      title: dto.title,
      status: OrderStatusEnum.CREATED,
      estimatedDays: dto.estimatedDays,
      invoiceItem,
      attachments: dto.attachments,

    });

    await this.em.persistAndFlush(order);

    this.eventEmitter.emit(
      OrderCreatedEvent.name,
      new OrderCreatedEvent(order.id, user.id, order.orderNumber),
    );

    return order;
  }

  async findOrdersAsUser(userId: string, dto: FindOrdersDto): Promise<PaginatedResult<Order>> {
    return this.orderRepository.findAllPaginated({
      userId,
      ...dto
    })
  }

  async findOrdersAsAdmin(adminId: string, dto: FindOrdersDto): Promise<PaginatedResult<Order>> {
    const permissions = await this.adminService.ownedPermissions(adminId,
      [PermissionEnum.VIEW_ORDERS, PermissionEnum.VIEW_ASSIGNED_ORDERS])
 
    if (permissions.includes(PermissionEnum.VIEW_ORDERS)) {

      return this.orderRepository.findAllPaginated(dto)

    } else if (permissions.includes(PermissionEnum.VIEW_ASSIGNED_ORDERS)) {
       return this.orderRepository.findAllPaginated({
        ...dto,
        designerId: adminId,
      })

    } else {

      throw new ForbiddenException("You don't have permission to view orders")

    }
  }

  async getOrderAsUser(userId: string, orderId: string): Promise<Order> {
    const order = await this.findOrderOrFail(orderId)
    if (order.user.id !== userId) {
      throw new BadRequestException("this order doesnt belongs to you")
    }
    return order
  }


  async updateOrderAsAdmin(id: string, dto: UpdateOrderAsAdminDto): Promise<Order> {
    const order = await this.findOrderOrFail(id);

    if (dto.userId !== undefined) {
      const user = await this.userService.findById(dto.userId);
      if (!user) {
        throw new NotFoundException(`User with ID ${dto.userId} not found.`);
      }
      order.user = user as User;
    }
    if (dto.typeId !== undefined) {
      const type = await this.em.findOne(Category, { id: dto.typeId });
      if (!type) {
        throw new NotFoundException(`Order type with ID ${dto.typeId} not found.`);
      }
      order.type = type;
    }
    if (dto.estimatedDays !== undefined) {
      order.estimatedDays = dto.estimatedDays;
    }
    if (dto.title !== undefined) {
      order.title = dto.title;
    }
    if (dto.productId !== undefined) {
      if (dto.productId == null || dto.productId === '') {
        order.product = null;
      } else {
        const product = await this.em.findOne(Product, { id: dto.productId });
        if (!product) {
          throw new NotFoundException(`Product with ID ${dto.productId} not found.`);
        }
        order.product = product;
      }
    }

    await this.em.flush();
    return order;
  }

  async softDeleteOrder(orderId: string): Promise<void> {
    const order = await this.findOrderOrFail(orderId);
    order.deletedAt = new Date();
    await this.em.flush();
  }



  async updateStatus(orderId: string, adminId: string, dto: UpdateStatusDto): Promise<Order> {
    const permissions = await this.adminService.ownedPermissions(adminId,
      [PermissionEnum.VIEW_ORDERS, PermissionEnum.VIEW_ASSIGNED_ORDERS])

    if (permissions.includes(PermissionEnum.VIEW_ORDERS)) {
      const order = await this.findOrderOrFail(orderId);
      order.status = dto.status;
      await this.em.flush();
      return order
    }

    if (permissions.includes(PermissionEnum.VIEW_ASSIGNED_ORDERS)) {
      //TODO
      const order = await this.findOrderOrFailAssignedOrder(orderId, adminId);
      order.status = dto.status;
      await this.em.flush();
      return order
    }

    throw new ForbiddenException("You don't have permission to update order status")
  }

  async assignDesigner(orderId: string, designerId: string) {
    const order = await this.findOrderOrFail(orderId)
    const designer = await this.adminService.findOrFail(designerId)

    order.designer = designer
    await this.em.flush()
    return order
  }

  async createPrint(orderId: string, dto: CreateOrderPrintDto): Promise<IOrderPrintResponse> {
    const order = await this.em.findOne(Order, { id: orderId }, { populate: ['print'] });
    if (!order) {
      throw new NotFoundException(`Order with ID ${orderId} not found.`);
    }

    const fieldMap = await this.resolvePrintFields(dto.fields);

    let print = order.print;
    if (print) {
      await this.em.populate(print, ['values']);
      print.values.removeAll();
    } else {
      print = this.em.create(OrderPrint, { order });
    }

    this.assignPrintValues(print, dto.fields, fieldMap);
    await this.em.persistAndFlush(print);
    await this.em.populate(print, ['values', 'values.field']);
    return this.serializeOrderPrint(print);
  }

  async getPrint(orderId: string): Promise<IOrderPrintResponse> {
    const orderPrint = await this.orderPrintRepository.findOne(
      { order: { id: orderId } },
      { populate: ['values', 'values.field'] },
    );
    if (!orderPrint) {
      throw new NotFoundException(`Print with ID ${orderId} not found.`);
    }
    return this.serializeOrderPrint(orderPrint);
  }

  private serializeOrderPrint(print: OrderPrint): IOrderPrintResponse {
    return {
      id: print.id,
      createdAt: print.createdAt,
      deletedAt: print.deletedAt,
      fileds: print.values.getItems().map((item) => ({
        fieldId: item.field.id,
        value: item.value,
      })),
    };
  }

  private async resolvePrintFields(dtoFields: OrderPrintValueDto[]): Promise<Map<string, Field>> {
    const fieldIds = [...new Set(dtoFields.map((field) => field.fieldId))];
    const fields = await this.em.find(Field, { id: { $in: fieldIds } });
    if (fields.length !== fieldIds.length) {
      throw new NotFoundException('One or more fields not found.');
    }
    return new Map(fields.map((field) => [field.id, field]));
  }

  private assignPrintValues(
    print: OrderPrint,
    dtoFields: OrderPrintValueDto[],
    fieldMap: Map<string, Field>,
  ): void {
    for (const dtoField of dtoFields) {
      print.values.add(
        this.em.create(OrderPrintValue, {
          orderPrint: print,
          field: fieldMap.get(dtoField.fieldId)!,
          value: dtoField.value,
        }),
      );
    }
  }

  // -----------Hrlper Methods -----------
  async findOrderOrFail(id: string): Promise<Order> {
    const order = await this.em.findOne(Order, { id }, { populate: ['user', 'type', 'product', 'creator', 'designer'] });
    if (!order) {
      throw new NotFoundException(`Order with ID ${id} not found.`);
    }
    return order;
  }

  async findOrderOrFailAssignedOrder(id: string, adminId: string): Promise<Order> {
    const order = await this.em.findOne(Order, { id }, { populate: ['user', 'type', 'product', 'creator'] });
    if (!order) {
      throw new NotFoundException(`Order with ID ${id} not found.`);
    }
    if (order?.designer?.id !== adminId) {
      throw new ForbiddenException("You don't have permission to view this order")
    }
    return order;
  }

  async getStats(userId: string) {
    const [requestsCount, invoicesCount, inProgressOrdersCount, completedOrdersCount] =
      await Promise.all([
        this.em.count(Request, { user: { id: userId } }),
        this.em.count(Invoice, { user: { id: userId } }),
        this.em.count(Order, {
          user: { id: userId },
          status: { $nin: [OrderStatusEnum.FINISHED, OrderStatusEnum.CANCELED] },
        }),
        this.em.count(Order, { user: { id: userId }, status: OrderStatusEnum.FINISHED }),
      ]);

    return {
      requestsCount,
      invoicesCount,
      inProgressOrdersCount,
      completedOrdersCount,
    };
  }

  async getAdminStats() {
    const [requestsCount, invoicesCount, inProgressOrdersCount, completedOrdersCount] =
      await Promise.all([
        this.em.count(Request),
        this.em.count(Invoice),
        this.em.count(Order, {
          status: { $nin: [OrderStatusEnum.FINISHED, OrderStatusEnum.CANCELED] },
        }),
        this.em.count(Order, { status: OrderStatusEnum.FINISHED }),
      ]);

    return {
      requestsCount,
      invoicesCount,
      inProgressOrdersCount,
      completedOrdersCount,
    };
  }
}