import {
  BadRequestException,
  Inject,
  Injectable,
  NotFoundException,
  forwardRef,
} from '@nestjs/common';
import { Decimal } from '../../../common/value-objects/decimal/decimal';
import { Status } from '../../../common/value-objects/status/status';
import { PackingSlipsRepository } from '../packing-slips/packing-slips.repository';
import { PackingSlipsService } from '../packing-slips/packing-slips.service';
import type { PackingSlip } from '../packing-slips/packing-slip';
import { SalesInvoicesRepository } from '../sales-invoices/sales-invoices.repository';
import { SalesInvoicesService } from '../sales-invoices/sales-invoices.service';
import { SalesOrdersService } from '../sales-orders/sales-orders.service';
import { PACKING_SLIP_STATUSES, SALES_INVOICE_STATUSES } from './sales-fields';

export type DeliveredLineBody = {
  readonly productId: string;
  readonly quantity: string;
};

@Injectable()
export class SalesDocumentFlowService {
  constructor(
    @Inject(forwardRef(() => SalesOrdersService))
    private readonly salesOrdersService: SalesOrdersService,
    @Inject(forwardRef(() => PackingSlipsService))
    private readonly packingSlipsService: PackingSlipsService,
    @Inject(forwardRef(() => SalesInvoicesService))
    private readonly salesInvoicesService: SalesInvoicesService,
    private readonly packingSlipsRepository: PackingSlipsRepository,
    private readonly salesInvoicesRepository: SalesInvoicesRepository,
  ) {}

  async relatedDocumentIds(orderId: string): Promise<{
    packingSlipIds: string[];
    invoiceIds: string[];
  }> {
    const [packing, invoices] = await Promise.all([
      this.packingSlipsRepository.listBySalesOrderId(orderId),
      this.salesInvoicesRepository.listBySalesOrderId(orderId),
    ]);
    return {
      packingSlipIds: packing.map((item) => item.id),
      invoiceIds: invoices.map((item) => item.id),
    };
  }

  async onOrderProcessed(
    orderId: string,
    userId: string,
    generatePackingSlip: boolean,
  ): Promise<void> {
    const existing =
      await this.salesInvoicesRepository.listBySalesOrderId(orderId);
    if (existing.length > 0) {
      throw new BadRequestException('Sales order already has an invoice');
    }
    await this.salesInvoicesService.create({
      salesOrderId: orderId,
      userId,
    });
    if (generatePackingSlip) {
      await this.packingSlipsService.create({
        salesOrderId: orderId,
        status: 'processed',
        userId,
      });
      return;
    }
    await this.salesOrdersService.completeFromSystem(orderId, userId);
  }

  async cancelOrderDocuments(orderId: string, userId: string): Promise<void> {
    const [packing, invoices] = await Promise.all([
      this.packingSlipsRepository.listBySalesOrderId(orderId),
      this.salesInvoicesRepository.listBySalesOrderId(orderId),
    ]);
    for (const slip of packing) {
      if (slip.status.value !== 'cancelled') {
        await this.packingSlipsRepository.updateStatus(
          slip.id,
          Status.create('cancelled', PACKING_SLIP_STATUSES),
          userId,
        );
      }
    }
    for (const invoice of invoices) {
      if (invoice.status.value !== 'cancelled') {
        await this.salesInvoicesRepository.updateStatus(
          invoice.id,
          Status.create('cancelled', SALES_INVOICE_STATUSES),
          userId,
        );
      }
    }
  }

  async completePacking(
    id: string,
    userId: string,
    products?: DeliveredLineBody[],
  ): Promise<ReturnType<PackingSlipsService['toDetail']>> {
    const packing = await this.packingSlipsRepository.findById(id);
    if (!packing) {
      throw new NotFoundException('Packing slip not found');
    }
    const delivered = this.splitDelivered(packing, products);
    if (delivered.remaining.length > 0) {
      await this.packingSlipsRepository.update(id, {
        products: delivered.delivered,
        userId,
      });
    }
    await this.packingSlipsRepository.updateStatus(
      id,
      Status.create('completed', PACKING_SLIP_STATUSES),
      userId,
    );
    if (delivered.remaining.length > 0) {
      await this.packingSlipsService.create({
        salesOrderId: packing.salesOrderId ?? undefined,
        date: packing.date.format(),
        customerId: packing.customerId,
        address: packing.address,
        latitude: packing.latitude,
        longitude: packing.longitude,
        notes: packing.notes,
        products: delivered.remaining.map((line) => ({
          productId: line.productId,
          quantity: line.quantity.value,
          price: line.price.value,
        })),
        status: 'processed',
        userId,
      });
    }
    if (packing.salesOrderId) {
      await this.completeOrderIfPackingDone(packing.salesOrderId, userId);
    }
    return this.packingSlipsService.findById(id);
  }

  async completeOrderIfPackingDone(
    orderId: string,
    userId: string,
  ): Promise<void> {
    const slips = await this.packingSlipsRepository.listBySalesOrderId(orderId);
    const blocking = slips.filter(
      (item) =>
        item.status.value !== 'cancelled' && item.status.value !== 'completed',
    );
    if (blocking.length === 0) {
      await this.salesOrdersService.completeFromSystem(orderId, userId);
    }
  }

  private splitDelivered(
    packing: PackingSlip,
    products?: DeliveredLineBody[],
  ): {
    delivered: Array<{
      productId: string;
      quantity: Decimal;
      price: Decimal;
    }>;
    remaining: Array<{
      productId: string;
      quantity: Decimal;
      price: Decimal;
    }>;
  } {
    const requested = new Map<string, Decimal>();
    for (const line of products ?? []) {
      let quantity: Decimal;
      try {
        quantity = Decimal.create(line.quantity);
      } catch {
        throw new BadRequestException('Invalid delivered quantity');
      }
      requested.set(line.productId, quantity);
    }
    for (const productId of requested.keys()) {
      if (!packing.products.some((line) => line.productId === productId)) {
        throw new BadRequestException('Invalid delivered quantity');
      }
    }
    const delivered: Array<{
      productId: string;
      quantity: Decimal;
      price: Decimal;
    }> = [];
    const remaining: Array<{
      productId: string;
      quantity: Decimal;
      price: Decimal;
    }> = [];
    for (const line of packing.products) {
      const qty = requested.get(line.productId) ?? line.quantity;
      if (!qty.isPositive() || qty.compare(line.quantity) > 0) {
        throw new BadRequestException('Invalid delivered quantity');
      }
      delivered.push({
        productId: line.productId,
        quantity: qty,
        price: line.price,
      });
      const leftover = line.quantity.subtract(qty);
      if (leftover.isPositive()) {
        remaining.push({
          productId: line.productId,
          quantity: leftover,
          price: line.price,
        });
      }
    }
    return { delivered, remaining };
  }
}