import {
  Injectable,
  NotFoundException,
  BadRequestException,
  Logger,
} from '@nestjs/common';
import { PrismaService } from '../../common/prisma.service';
import { PaymentClientService } from '../payments/payment-client.service';
import { NotificationsService } from '../notifications/notifications.service';
import {
  LogExcessBaggageDto,
  WaiveChargeDto,
  InitiateExcessPaymentDto,
} from './excess-baggage.dto';
import {
  PaymentService as PaymentServiceEnum,
  PaymentReferenceType,
  ProviderMethod,
  ProviderPaymentStatus,
} from '@edr/types';
import { PaymentMethodType, PaymentIntentStatus } from '@prisma/client';

const CHARGE_TTL_MS = 30 * 60 * 1000; // 30 minutes

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

  constructor(
    private prisma: PrismaService,
    private paymentClient: PaymentClientService,
    private notifications: NotificationsService,
  ) {}

  async logCharge(dto: LogExcessBaggageDto) {
    const booking = await this.prisma.booking.findUnique({
      where: { id: dto.bookingId },
      include: {
        seats: { take: 1, include: { seat: { include: { coach: { include: { coachType: true } } } } } },
        passenger: { include: { user: true } },
      },
    });
    if (!booking) throw new NotFoundException('Booking not found');
    if (!['CONFIRMED', 'BOARDED'].includes(booking.status)) {
      throw new BadRequestException('Booking must be CONFIRMED or BOARDED to log excess baggage');
    }

    // Resolve fee per kg from BaggageAllowance via seat class
    const coachTypeId = booking.seats[0]?.seat?.coach?.coachTypeId;
    let feePerKgMinor = 5000; // 50 ETB default fallback (in minor)
    if (coachTypeId) {
      const seatClass = await this.prisma.seatClass.findFirst({
        where: { coachTypeId },
      });
      if (seatClass) {
        const allowance = await this.prisma.baggageAllowance.findFirst({
          where: { seatClassId: seatClass.id },
        });
        if (allowance) feePerKgMinor = allowance.excessFeePerKg;
      }
    }

    const totalMinor = feePerKgMinor * dto.excessWeightKg;
    const expiresAt = new Date(Date.now() + CHARGE_TTL_MS);
    const contactPhone = booking.contactPhone ?? booking.passenger?.user?.phone ?? null;
    const contactEmail = booking.contactEmail ?? booking.passenger?.user?.email ?? null;

    const status = dto.collectCash ? 'CASH_COLLECTED' : 'PENDING';
    const paidAt = dto.collectCash ? new Date() : null;

    const charge = await this.prisma.excessBaggageCharge.create({
      data: {
        bookingId: dto.bookingId,
        agentId: dto.agentId,
        excessWeightKg: dto.excessWeightKg,
        feePerKgMinor,
        totalMinor,
        status,
        expiresAt,
        paidAt,
        contactPhone,
        contactEmail,
      },
    });

    if (!dto.collectCash) {
      await this.sendPaymentLink(charge, booking, contactPhone, contactEmail);
    }

    return charge;
  }

  private async sendPaymentLink(
    charge: any,
    booking: any,
    phone: string | null,
    email: string | null,
  ) {
    const portalUrl = process.env.PORTAL_URL ?? 'http://localhost:5174';
    const payUrl = `${portalUrl}/excess-baggage/pay/${charge.paymentToken}`;
    const amountStr = (charge.totalMinor / 100).toFixed(2);
    const msg = `EDR: Excess baggage charge of ${amountStr} ETB for booking ${booking.bookingRef}. Pay here: ${payUrl} (valid 30 min)`;

    const recipient = phone ?? email ?? booking.passengerId;
    try {
      await this.notifications['deliverSms'](recipient, msg);
    } catch (err) {
      this.logger.warn(`SMS send failed for excess baggage charge ${charge.id}: ${err}`);
    }
    if (email) {
      try {
        await this.notifications['deliverEmail'](
          recipient,
          `EDR — Excess baggage payment required (${booking.bookingRef})`,
          msg,
        );
      } catch (err) {
        this.logger.warn(`Email send failed for excess baggage charge ${charge.id}: ${err}`);
      }
    }
  }

  async getCharge(id: string) {
    const charge = await this.prisma.excessBaggageCharge.findUnique({
      where: { id },
      include: { booking: { select: { bookingRef: true, status: true } } },
    });
    if (!charge) throw new NotFoundException('Charge not found');
    return charge;
  }

  async getByToken(token: string) {
    const charge = await this.prisma.excessBaggageCharge.findUnique({
      where: { paymentToken: token },
      include: { booking: { select: { bookingRef: true, scheduleId: true } } },
    });
    if (!charge) throw new NotFoundException('Payment link not found');
    if (charge.status === 'EXPIRED' || new Date() > charge.expiresAt) {
      if (charge.status === 'PENDING') {
        await this.prisma.excessBaggageCharge.update({
          where: { id: charge.id },
          data: { status: 'EXPIRED' },
        });
      }
      throw new BadRequestException('This payment link has expired');
    }
    if (charge.status === 'PAID' || charge.status === 'CASH_COLLECTED') {
      throw new BadRequestException('This charge has already been paid');
    }
    if (charge.status === 'WAIVED') {
      throw new BadRequestException('This charge has been waived');
    }
    return charge;
  }

  async initiatePayment(token: string, dto: InitiateExcessPaymentDto) {
    const charge = await this.getByToken(token);

    const portalUrl = process.env.PORTAL_URL ?? 'http://localhost:5174';
    const returnUrl = `${portalUrl}/excess-baggage/pay/${token}/result`;

    const snapshot = await this.paymentClient.initiate({
      service: PaymentServiceEnum.PASSENGER,
      referenceType: 'EXCESS_BAGGAGE' as PaymentReferenceType,
      referenceId: charge.id,
      orderRef: `EXB-${charge.id.substring(0, 8).toUpperCase()}`,
      amountMinor: charge.totalMinor / 100,
      currency: charge.currency,
      provider: dto.method as unknown as ProviderMethod,
      platform: dto.platform as any,
      returnUrl,
      failureUrl: returnUrl,
    });

    if (snapshot.status === ProviderPaymentStatus.SUCCEEDED) {
      await this.markPaid(charge.id, snapshot.providerTxnId);
    }

    return {
      chargeId: charge.id,
      status: snapshot.status,
      clientAction: snapshot.clientAction,
      merchantOrderId: snapshot.merchantOrderId,
    };
  }

  async markPaid(chargeId: string, providerTxnId?: string) {
    const charge = await this.prisma.excessBaggageCharge.findUnique({ where: { id: chargeId } });
    if (!charge) throw new NotFoundException('Charge not found');
    if (charge.status === 'PAID') return charge;
    return this.prisma.excessBaggageCharge.update({
      where: { id: chargeId },
      data: { status: 'PAID', paidAt: new Date() },
    });
  }

  async waiveCharge(id: string, dto: WaiveChargeDto) {
    const charge = await this.prisma.excessBaggageCharge.findUnique({ where: { id } });
    if (!charge) throw new NotFoundException('Charge not found');
    if (['PAID', 'CASH_COLLECTED'].includes(charge.status)) {
      throw new BadRequestException('Cannot waive a charge that has already been paid');
    }
    return this.prisma.excessBaggageCharge.update({
      where: { id },
      data: { status: 'WAIVED', waivedBy: dto.waivedBy, waivedReason: dto.waivedReason },
    });
  }

  async resendLink(id: string) {
    const charge = await this.prisma.excessBaggageCharge.findUnique({
      where: { id },
      include: { booking: { select: { bookingRef: true, passengerId: true } } },
    });
    if (!charge) throw new NotFoundException('Charge not found');
    if (charge.status !== 'PENDING') {
      throw new BadRequestException('Can only resend link for PENDING charges');
    }
    // Extend expiry by 30 minutes from now
    const updatedCharge = await this.prisma.excessBaggageCharge.update({
      where: { id },
      data: { expiresAt: new Date(Date.now() + CHARGE_TTL_MS) },
    });
    await this.sendPaymentLink(updatedCharge, charge.booking, charge.contactPhone, charge.contactEmail);
    return { sent: true };
  }

  async getAll(filters: {
    status?: string;
    bookingRef?: string;
    page?: number;
    pageSize?: number;
  }) {
    const { status, bookingRef, page = 1, pageSize = 20 } = filters;
    const skip = (page - 1) * pageSize;
    const where: any = {};
    if (status) where.status = status;
    if (bookingRef) where.booking = { bookingRef: { contains: bookingRef, mode: 'insensitive' } };

    const [items, total] = await Promise.all([
      this.prisma.excessBaggageCharge.findMany({
        where,
        include: { booking: { select: { bookingRef: true, status: true } } },
        orderBy: { createdAt: 'desc' },
        skip,
        take: pageSize,
      }),
      this.prisma.excessBaggageCharge.count({ where }),
    ]);

    return { items, total, page, pageSize };
  }

  async getAllowances() {
    const [allowances, seatClasses] = await Promise.all([
      this.prisma.baggageAllowance.findMany({ orderBy: { createdAt: 'asc' } }),
      this.prisma.seatClass.findMany({ select: { id: true, name: true } }),
    ]);
    const scMap = new Map(seatClasses.map(s => [s.id, s]));
    return allowances.map(a => ({ ...a, seatClass: scMap.get(a.seatClassId) ?? null }));
  }

  async upsertAllowance(dto: { seatClassId: string; maxWeightKg: number; maxPiecesCount: number; excessFeePerKg: number }) {
    return this.prisma.baggageAllowance.upsert({
      where: { seatClassId: dto.seatClassId } as any,
      update: { maxWeightKg: dto.maxWeightKg, maxPiecesCount: dto.maxPiecesCount, excessFeePerKg: dto.excessFeePerKg },
      create: { seatClassId: dto.seatClassId, maxWeightKg: dto.maxWeightKg, maxPiecesCount: dto.maxPiecesCount, excessFeePerKg: dto.excessFeePerKg },
    });
  }

  async updateAllowance(id: string, dto: Partial<{ maxWeightKg: number; maxPiecesCount: number; excessFeePerKg: number }>) {
    return this.prisma.baggageAllowance.update({ where: { id }, data: dto });
  }

  async deleteAllowance(id: string) {
    await this.prisma.baggageAllowance.delete({ where: { id } });
    return { deleted: true };
  }
}