import { ConflictException, Injectable, Logger, NotFoundException } from '@nestjs/common';
import { OnEvent } from '@nestjs/event-emitter';
import { DataSource, EntityManager } from 'typeorm';
import { ExchangeService } from '@edr/api-common';
import { Freight, NotificationAudience, NotificationType } from '@edr/types';

import { BillingService, InvoiceEventPayload } from '../billing/billing.service';
import { Invoice } from '../billing/entities/invoice.entity';
import { FilesService } from '../files/files.service';
import { NotificationsService } from '../notifications/notifications.service';
import { NotificationInboxService } from '../notification-inbox/notification-inbox.service';
import { sendCompanyChannels } from '../notifications/notify-company.util';
import { FREIGHT_PERMS } from '../../seed/freight-permissions.registry';
import { BookingsService } from './bookings.service';
import { BookingsRepository } from './bookings.repository';
import { AdditionalChargeRepository } from './additional-charge.repository';
import { AdditionalCharge } from './entities/additional-charge.entity';
import { CreateAdditionalChargeDto } from './dto/additional-charge.dto';

const FILE_RESOURCE = 'additional_charges';

/**
 * Ad-hoc extra charges finance raises against a booking, independent of
 * `BookingClearanceCharge` (which is capped at one PORT_CHARGES/MISCELLANEOUS
 * row per booking). Any number per booking, free-text reason. DRAFT until
 * sent; sending issues the payable invoice and notifies the customer
 * (in-app + SMS + email). Settles via `additional_charge.invoice.paid`,
 * same event-driven pattern as every other invoice source.
 */
@Injectable()
export class AdditionalChargeService {
  private readonly logger = new Logger(AdditionalChargeService.name);

  constructor(
    private readonly dataSource: DataSource,
    private readonly repository: AdditionalChargeRepository,
    private readonly bookingsRepository: BookingsRepository,
    private readonly filesService: FilesService,
    private readonly exchangeService: ExchangeService,
    private readonly billing: BillingService,
    private readonly bookingsService: BookingsService,
    private readonly notifications: NotificationsService,
    private readonly inbox: NotificationInboxService,
  ) {}

  private async findOwned(bookingId: string, chargeId: string): Promise<AdditionalCharge> {
    const charge = await this.repository.findById(chargeId);
    if (!charge || charge.bookingId !== bookingId) {
      throw new NotFoundException('Additional charge not found');
    }
    return charge;
  }

  async list(bookingId: string): Promise<Freight.AdditionalCharge[]> {
    const rows = await this.repository.findAll({
      where: { bookingId },
      order: { createdAt: 'DESC' },
    });
    return this.toDtoList(rows);
  }

  async create(
    bookingId: string,
    dto: CreateAdditionalChargeDto,
    staffId: string,
    file?: Express.Multer.File,
  ): Promise<Freight.AdditionalCharge[]> {
    const booking = await this.bookingsService.findById(bookingId);
    const shouldSend = dto.action === 'send';

    const chargeId = await this.dataSource.transaction(async (manager) => {
      const repo = manager.getRepository(AdditionalCharge);
      let saved = await repo.save(
        repo.create({
          bookingId,
          reason: dto.reason.trim(),
          amount: dto.amount.toFixed(2),
          currency: dto.currency.trim().toUpperCase(),
          dueAt: dto.dueDate ? new Date(dto.dueDate) : null,
          status: 'DRAFT',
          createdByStaffId: staffId,
        }),
      );

      if (file) {
        const record = await this.filesService.upload({
          resourceId: saved.id,
          resource: FILE_RESOURCE,
          code: FILE_RESOURCE,
          file,
          uploadedByUserId: staffId,
        });
        await repo.update(saved.id, { fileRecordId: record.id });
      }

      if (shouldSend) {
        saved = await this.issueInvoice(manager, saved.id, booking, staffId);
      }
      return saved.id;
    });

    if (shouldSend) await this.notifyCustomerSent(chargeId);
    return this.list(bookingId);
  }

  async send(bookingId: string, chargeId: string, staffId: string): Promise<Freight.AdditionalCharge[]> {
    const charge = await this.findOwned(bookingId, chargeId);
    if (charge.status !== 'DRAFT') {
      throw new ConflictException('Only a draft charge can be sent.');
    }
    const booking = await this.bookingsService.findById(bookingId);

    await this.dataSource.transaction((manager) =>
      this.issueInvoice(manager, charge.id, booking, staffId),
    );
    await this.notifyCustomerSent(charge.id);
    return this.list(bookingId);
  }

  /** Issues the invoice and flips DRAFT → SENT. Notification happens after commit — never inside the transaction. */
  private async issueInvoice(
    manager: EntityManager,
    chargeId: string,
    booking: { id: string; companyId?: string | null; companyProfileId?: string | null; reference?: string | null },
    staffId: string,
  ): Promise<AdditionalCharge> {
    const repo = manager.getRepository(AdditionalCharge);
    const charge = await repo.findOneByOrFail({ id: chargeId });

    const invoice = await this.billing.generateInvoice(
      {
        source: Freight.InvoiceSource.AdditionalCharge,
        sourceId: charge.id,
        type: 'ADDITIONAL_CHARGE',
        companyId: booking.companyId,
        companyProfileId: booking.companyProfileId,
        currency: charge.currency,
        // Unset falls through to BillingService's own DEFAULT_DUE_DAYS (14).
        dueAt: charge.dueAt ?? undefined,
        lines: [
          {
            chargeType: 'ADDITIONAL_CHARGE',
            description: `${charge.reason} — ${booking.reference ?? booking.id}`,
            amount: Number(charge.amount),
          },
        ],
      },
      manager,
    );

    await repo.update(charge.id, {
      status: 'SENT',
      invoiceId: invoice.id,
      sentByStaffId: staffId,
      sentAt: new Date(),
    });
    this.logger.log(
      `Additional charge ${charge.id} on booking ${booking.id} sent as invoice ${invoice.invoiceNumber}`,
    );
    return repo.findOneByOrFail({ id: charge.id });
  }

  private async notifyCustomerSent(chargeId: string): Promise<void> {
    try {
      const charge = await this.repository.findById(chargeId);
      if (!charge) return;
      const booking = await this.bookingsService.findById(charge.bookingId);
      if (!booking.companyId) return;
      const body = `A new charge of ${charge.amount} ${charge.currency} has been added to booking ${booking.reference ?? charge.bookingId}: ${charge.reason}. Pay via the portal.`;
      await this.inbox.notify({
        recipients: { companyId: booking.companyId },
        audience: NotificationAudience.PORTAL,
        type: NotificationType.INVOICE_ISSUED,
        title: 'New charge on your booking',
        body,
        link: `/bookings/${charge.bookingId}`,
        data: {
          bookingId: charge.bookingId,
          chargeId: charge.id,
          amount: Number(charge.amount),
          currency: charge.currency,
        },
      });
      await sendCompanyChannels(this.dataSource, this.notifications, booking.companyId, body);
    } catch (err) {
      this.logger.warn(`Additional charge sent-notify failed for ${chargeId}: ${(err as Error).message}`);
    }
  }

  async cancel(
    bookingId: string,
    chargeId: string,
    staffId: string,
    reason?: string,
  ): Promise<Freight.AdditionalCharge[]> {
    const charge = await this.findOwned(bookingId, chargeId);
    if (charge.status !== 'DRAFT' && charge.status !== 'SENT') {
      throw new ConflictException('Only a draft or unpaid charge can be cancelled.');
    }
    if (charge.status === 'SENT' && charge.invoiceId) {
      await this.billing.cancelInvoice(charge.invoiceId);
    }
    await this.repository.update(charge.id, {
      status: 'CANCELLED',
      cancelledByStaffId: staffId,
      cancelledAt: new Date(),
      cancelReason: reason ?? null,
    });
    return this.list(bookingId);
  }

  /** Gateway and manual settlements both land here (`${source}.invoice.paid`). */
  @OnEvent('additional_charge.invoice.paid')
  async onChargeInvoicePaid(payload: InvoiceEventPayload): Promise<void> {
    const charge = await this.repository.findById(payload.sourceId);
    if (!charge || charge.status === 'PAID') return;
    await this.repository.update(charge.id, { status: 'PAID', paidAt: new Date() });

    try {
      const booking = await this.bookingsService.findById(charge.bookingId);
      if (!booking.companyId) return;
      const body = `Payment received for ${charge.amount} ${charge.currency} on booking ${booking.reference ?? charge.bookingId}: ${charge.reason}.`;
      await this.inbox.notify({
        recipients: { companyId: booking.companyId },
        audience: NotificationAudience.PORTAL,
        type: NotificationType.PAYMENT_RECEIVED,
        title: 'Charge payment received',
        body,
        link: `/bookings/${charge.bookingId}`,
        data: { bookingId: charge.bookingId, chargeId: charge.id },
      });
      await this.inbox.notify({
        recipients: { permissionKeys: [FREIGHT_PERMS.additionalCharges.getNotification] },
        audience: NotificationAudience.BACKOFFICE,
        type: NotificationType.PAYMENT_RECEIVED,
        title: 'Additional charge paid',
        body,
        link: `/bookings/${charge.bookingId}`,
        data: { bookingId: charge.bookingId, chargeId: charge.id },
      });
    } catch (err) {
      this.logger.warn(`Additional charge paid-notify failed for ${charge.id}: ${(err as Error).message}`);
    }
  }

  private async toDtoList(rows: AdditionalCharge[]): Promise<Freight.AdditionalCharge[]> {
    if (!rows.length) return [];

    const filesByCharge = await this.filesService.findByResourceIdsGrouped(
      rows.map((r) => r.id),
      FILE_RESOURCE,
    );
    const names = await this.bookingsRepository.resolveStaffNames(
      rows.flatMap((r) => [r.createdByStaffId, r.sentByStaffId]),
    );

    const invoiceIds = rows.map((r) => r.invoiceId).filter((id): id is string => Boolean(id));
    const invoices = invoiceIds.length
      ? await this.dataSource.getRepository(Invoice).find({ where: invoiceIds.map((id) => ({ id })) })
      : [];
    const invoiceById = new Map(invoices.map((i) => [i.id, i]));
    const converted = await Promise.all(rows.map((r) => this.convertAmount(r)));
    const convertedById = new Map(rows.map((r, i) => [r.id, converted[i]]));

    return rows.map((r) => {
      const file = filesByCharge.get(r.id)?.[0];
      const fx = convertedById.get(r.id) ?? null;
      return {
        id: r.id,
        bookingId: r.bookingId,
        reason: r.reason,
        status: r.status,
        amount: Number(r.amount),
        currency: r.currency,
        convertedAmount: fx?.amount ?? null,
        convertedCurrency: fx?.currency ?? null,
        dueAt: r.dueAt?.toISOString() ?? null,
        file: file ? { id: file.id, name: file.name, url: file.url } : null,
        invoiceId: r.invoiceId ?? null,
        invoiceNumber: r.invoiceId ? (invoiceById.get(r.invoiceId)?.invoiceNumber ?? null) : null,
        paymentReference: r.paymentReference ?? null,
        createdByName: r.createdByStaffId ? (names.get(r.createdByStaffId) ?? null) : null,
        createdAt: r.createdAt.toISOString(),
        sentByName: r.sentByStaffId ? (names.get(r.sentByStaffId) ?? null) : null,
        sentAt: r.sentAt?.toISOString() ?? null,
        paidAt: r.paidAt?.toISOString() ?? null,
        cancelledAt: r.cancelledAt?.toISOString() ?? null,
        cancelReason: r.cancelReason ?? null,
      };
    });
  }

  /**
   * Amount converted to the other of ETB/USD, via the existing shared
   * `ExchangeService` (CBE rate, falls back to the stored `exchange_settings`
   * rate) — same mechanism `booking-wagon-cancellation.service.ts` and
   * warehouse fee pricing already use. Null on anything but ETB/USD, or if
   * the rate feed is down — this is a display convenience, not the payable
   * amount, so a failure here must never break the charge list.
   */
  private async convertAmount(
    charge: AdditionalCharge,
  ): Promise<{ amount: number; currency: string } | null> {
    if (charge.currency !== 'ETB' && charge.currency !== 'USD') return null;
    const target = charge.currency === 'ETB' ? 'USD' : 'ETB';
    try {
      const amount = await this.exchangeService.convert(Number(charge.amount), charge.currency, target);
      return { amount: Math.round(amount * 100) / 100, currency: target };
    } catch (err) {
      this.logger.warn(`Rate conversion failed for charge ${charge.id}: ${(err as Error).message}`);
      return null;
    }
  }
}