import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
import { InjectDataSource } from '@nestjs/typeorm';
import { DataSource } from 'typeorm';
import { PrismaService } from '../../common/prisma.service';
import { CreateTravelerProfileDto, CreateSavedRouteDto, RegisterPassengerDto } from './passengers.dto';
import { VerifaydaService } from '../verifayda/verifayda.service';

interface PassengerFilters {
  search?: string;
  verified?: boolean;
  page?: number;
  pageSize?: number;
}

type IamUserRow = {
  id: string;
  email: string;
  name: { en: string; am: string } | null;
  phone_number: string | null;
  metadata: Record<string, any> | null;
};

@Injectable()
export class PassengersService {
  constructor(
    private readonly prisma: PrismaService,
    @InjectDataSource() private readonly dataSource: DataSource,
    private readonly verifaydaService: VerifaydaService,
  ) {}

  async findAll(filters: PassengerFilters = {}) {
    const { search, verified, page = 1, pageSize = 20 } = filters;
    const skip = (page - 1) * pageSize;

    const where: any = {};

    if (search) {
      where.user = {
        OR: [
          { email: { contains: search, mode: 'insensitive' } },
          { phone: { contains: search, mode: 'insensitive' } },
          { fullName: { contains: search, mode: 'insensitive' } },
        ],
      };
    }

    if (verified !== undefined) {
      where.user = { ...(where.user ?? {}), faydaVerified: verified };
    }

    const [items, total] = await Promise.all([
      this.prisma.passenger.findMany({
        where,
        skip,
        take: pageSize,
        orderBy: { createdAt: 'desc' },
        include: {
          user: true,
          loyalty: true,
          wallet: true,
          _count: { select: { bookings: true } },
          bookings: {
            orderBy: { createdAt: 'desc' },
            take: 1,
            select: {
              contactEmail: true,
              contactPhone: true,
              seats: { take: 1, orderBy: { id: 'asc' }, select: {
                passengerName: true, dateOfBirth: true, passportNumber: true,
                passportCountry: true, idDocumentType: true, verifaydaVerified: true, faydaVerifiedAt: true,
              }},
            },
          },
        },
      }),
      this.prisma.passenger.count({ where }),
    ]);

    const iamUserIds = items.map(p => p.iamUserId).filter(Boolean) as string[];
    const iamRows = iamUserIds.length > 0
      ? await this.dataSource.query<IamUserRow[]>(
          `SELECT id, email, name, phone_number, metadata FROM iam.users WHERE id = ANY($1)`,
          [iamUserIds],
        )
      : [];
    const iamMap = new Map(iamRows.map(r => [r.id, r]));

    // Collect guest contact details for bulk SavedPassengerProfile lookup
    const guestContacts = items
      .filter(p => !(p as any).user && !p.iamUserId)
      .map(p => (p as any).bookings?.[0])
      .filter(Boolean);
    const guestEmails = guestContacts.map((b: any) => b.contactEmail).filter(Boolean) as string[];
    const guestPhones = guestContacts.map((b: any) => b.contactPhone).filter(Boolean) as string[];

    const savedProfiles = (guestEmails.length || guestPhones.length)
      ? await this.prisma.savedPassengerProfile.findMany({
          where: { OR: [
            ...(guestEmails.length ? [{ email: { in: guestEmails } }] : []),
            ...(guestPhones.length ? [{ phone: { in: guestPhones } }] : []),
          ]},
          orderBy: { createdAt: 'desc' },
        })
      : [];

    // Index by email then phone for O(1) lookup
    const profileByEmail = new Map(savedProfiles.filter(s => s.email).map(s => [s.email!, s]));
    const profileByPhone = new Map(savedProfiles.filter(s => s.phone).map(s => [s.phone!, s]));

    return {
      items: items.map(passenger => {
        const localUser = (passenger as any).user ?? null;
        const iam = passenger.iamUserId ? iamMap.get(passenger.iamUserId) : undefined;
        const faydaVerified = localUser?.faydaVerified === true
          || iam?.metadata?.faydaVerified === true
          || iam?.metadata?.faydaVerified === 'true';
        const guestBooking = !localUser && !iam ? (passenger as any).bookings?.[0] : null;
        const guestSeat = guestBooking?.seats?.[0] ?? null;
        const savedProfile = guestBooking
          ? (profileByEmail.get(guestBooking.contactEmail) ?? profileByPhone.get(guestBooking.contactPhone) ?? null)
          : null;
        return {
          id: passenger.id,
          fullName: localUser?.fullName ?? iam?.name?.en ?? iam?.name?.am ?? savedProfile?.passengerName ?? guestSeat?.passengerName ?? null,
          email: localUser?.email ?? iam?.email ?? savedProfile?.email ?? guestBooking?.contactEmail ?? null,
          phone: localUser?.phone ?? iam?.phone_number ?? savedProfile?.phone ?? guestBooking?.contactPhone ?? null,
          gender: localUser?.gender ?? iam?.metadata?.gender ?? null,
          dateOfBirth: localUser?.dateOfBirth
            ? (localUser.dateOfBirth instanceof Date ? localUser.dateOfBirth.toISOString().split('T')[0] : localUser.dateOfBirth)
            : (iam?.metadata?.dateOfBirth ?? (savedProfile?.dateOfBirth
                ? new Date(savedProfile.dateOfBirth).toISOString().split('T')[0]
                : (guestSeat?.dateOfBirth ? new Date(guestSeat.dateOfBirth).toISOString().split('T')[0] : null))),
          nationality: localUser?.nationality ?? iam?.metadata?.nationality ?? savedProfile?.nationality ?? null,
          nationalityCode: localUser?.nationalityCode ?? iam?.metadata?.nationalityCode ?? null,
          faydaVerified,
          faydaVerifiedAt: localUser?.faydaVerifiedAt ?? iam?.metadata?.faydaVerifiedAt ?? guestSeat?.faydaVerifiedAt ?? null,
          passportNumber: localUser?.passportNumber ?? iam?.metadata?.passportNumber ?? savedProfile?.passportNumber ?? guestSeat?.passportNumber ?? null,
          passportCountry: localUser?.passportCountry ?? iam?.metadata?.passportCountry ?? savedProfile?.passportCountry ?? guestSeat?.passportCountry ?? null,
          passportExpiryDate: localUser?.passportExpiryDate ?? iam?.metadata?.passportExpiryDate ?? null,
          idDocumentType: savedProfile?.idDocumentType ?? guestSeat?.idDocumentType ?? null,
          verified: faydaVerified,
          lastLoginAt: localUser?.lastLoginAt ?? null,
          role: localUser?.role ?? null,
          loyalty: passenger.loyalty
            ? { tier: passenger.loyalty.tier, pointsBalance: passenger.loyalty.pointsBalance, lifetimePoints: (passenger.loyalty as any).lifetimePoints ?? 0 }
            : null,
          wallet: (passenger as any).wallet
            ? { balanceMinor: (passenger as any).wallet.balanceMinor, currency: (passenger as any).wallet.currency ?? 'ETB' }
            : null,
          loyaltyTier: passenger.loyalty?.tier || 'BRONZE',
          loyaltyPoints: passenger.loyalty?.pointsBalance || 0,
          totalBookings: passenger._count.bookings,
          createdAt: passenger.createdAt,
        };
      }),
      meta: {
        page,
        pageSize,
        total,
        totalPages: Math.ceil(total / pageSize),
      },
    };
  }

  async getProfile(passengerId: string) {
    const passenger = await this.prisma.passenger.findUnique({
      where: { id: passengerId },
      include: {
        bookings: {
          orderBy: { createdAt: 'desc' },
          take: 10,
          include: {
            schedule: { include: { originStation: true, destinationStation: true, train: true } },
            seats: { include: { seat: { include: { coach: true } } } },
          },
        },
        loyalty: true,
        wallet: true,
        travelerProfiles: true,
        savedRoutes: true,
      },
    });
    if (!passenger) throw new NotFoundException('Passenger not found');

    let iamUser: IamUserRow | null = null;
    if (passenger.iamUserId) {
      const rows = await this.dataSource.query<IamUserRow[]>(
        `SELECT id, email, name, phone_number, metadata FROM iam.users WHERE id = $1 LIMIT 1`,
        [passenger.iamUserId],
      );
      iamUser = rows[0] ?? null;
    }

    return {
      id: passenger.id,
      fullName: iamUser?.name?.en ?? iamUser?.name?.am ?? null,
      email: iamUser?.email ?? null,
      phone: iamUser?.phone_number ?? null,
      createdAt: passenger.createdAt,
      bookings: passenger.bookings.map((b) => ({
        id: b.id,
        bookingRef: b.bookingRef,
        status: b.status,
        totalFare: b.totalMinor / 100,
        createdAt: b.createdAt,
        trip: {
          number: b.schedule.train.number,
          origin: { 
            id: b.schedule.originStation.id, 
            name: b.schedule.originStation.name, 
            code: b.schedule.originStation.code, 
            city: b.schedule.originStation.city 
          },
          destination: { 
            id: b.schedule.destinationStation.id, 
            name: b.schedule.destinationStation.name, 
            code: b.schedule.destinationStation.code, 
            city: b.schedule.destinationStation.city 
          },
          departureAt: b.schedule.departureAt,
        },
        passengers: b.seats.map((bs) => ({
          fullName: bs.passengerName,
          seat: { number: bs.seat.seatNumber, coach: bs.seat.coach.number, class: 'N/A' },
        })),
      })),
    };
  }

  async getStats(passengerId: string) {
    const [totalTrips, totalSpendResult, loyalty] = await Promise.all([
      this.prisma.booking.count({ where: { passengerId, status: 'BOARDED' as any } }),
      this.prisma.booking.aggregate({ where: { passengerId, status: 'BOARDED' as any }, _sum: { totalMinor: true } }),
      this.prisma.loyaltyAccount.findUnique({ where: { passengerId } }),
    ]);
    const totalSpend = ((totalSpendResult._sum?.totalMinor ?? 0) as number) / 100;
    return { totalTrips, totalSpend, loyaltyPoints: loyalty?.pointsBalance ?? 0, co2Saved: totalTrips * 6 };
  }

  async savePassengers(passengers: any[], userId?: string, deviceId?: string) {
    if (!passengers || !Array.isArray(passengers)) {
      throw new BadRequestException('Passengers array is required');
    }

    if (passengers.length === 0) {
      throw new BadRequestException('At least one passenger is required');
    }

    const savedProfiles = await Promise.all(
      passengers.map((p) =>
        this.prisma.savedPassengerProfile.create({
          data: {
            userId,
            deviceId,
            passengerName: p.name || p.passengerName,
            dateOfBirth: new Date(p.dateOfBirth),
            idDocumentType: p.nationalId ? 'NATIONAL_ID' : 'PASSPORT',
            passportNumber: p.passportNumber,
            passportCountry: p.passportCountry,
            nationality: p.nationality,
            phone: p.phone,
            email: p.email,
          },
        })
      )
    );
    return {
      count: savedProfiles.length,
      passengerIds: savedProfiles.map(p => p.id),
      passengers: savedProfiles.map(p => ({
        id: p.id,
        passengerName: p.passengerName,
        dateOfBirth: p.dateOfBirth,
        nationality: p.nationality,
      })),
      message: 'Passenger details saved successfully',
    };
  }

  createTravelerProfile(dto: CreateTravelerProfileDto) {
    return this.prisma.travelerProfile.create({ 
      data: { 
        ...dto, 
        dateOfBirth: dto.dateOfBirth ? new Date(dto.dateOfBirth) : null 
      } 
    });
  }

  getTravelerProfiles(passengerId: string) { 
    return this.prisma.travelerProfile.findMany({ where: { passengerId } }); 
  }

  createSavedRoute(dto: CreateSavedRouteDto) { 
    return this.prisma.savedRoute.create({ data: dto }); 
  }

  getSavedRoutes(passengerId: string) { 
    return this.prisma.savedRoute.findMany({ where: { passengerId }, orderBy: { tripCount: 'desc' } }); 
  }

  async updatePassenger(id: string, dto: any) {
    const passenger = await this.prisma.passenger.findUnique({ where: { id } });
    if (!passenger) throw new NotFoundException('Passenger not found');

    if (passenger.iamUserId && (dto.fullName || dto.email || dto.phone)) {
      const updates: string[] = [];
      const params: any[] = [];
      let idx = 1;

      if (dto.fullName) {
        updates.push(`name = COALESCE(name, '{}') || jsonb_build_object('en', $${idx}::text, 'am', $${idx}::text)`);
        params.push(dto.fullName);
        idx++;
      }
      if (dto.email) {
        updates.push(`email = $${idx}`);
        params.push(dto.email);
        idx++;
      }
      if (dto.phone) {
        updates.push(`phone_number = $${idx}`);
        params.push(dto.phone);
        idx++;
      }

      params.push(passenger.iamUserId);
      await this.dataSource.query(
        `UPDATE iam.users SET ${updates.join(', ')} WHERE id = $${idx}`,
        params,
      );
    }

    const [updated, iamRows] = await Promise.all([
      this.prisma.passenger.findUnique({ where: { id }, include: { loyalty: true } }),
      passenger.iamUserId
        ? this.dataSource.query<IamUserRow[]>(
            `SELECT id, email, name, phone_number, metadata FROM iam.users WHERE id = $1 LIMIT 1`,
            [passenger.iamUserId],
          )
        : Promise.resolve([] as IamUserRow[]),
    ]);

    const iamUser = iamRows[0] ?? null;
    return {
      id: updated!.id,
      fullName: iamUser?.name?.en ?? iamUser?.name?.am ?? null,
      email: iamUser?.email ?? null,
      phone: iamUser?.phone_number ?? null,
      loyalty: updated!.loyalty,
    };
  }

  async registerPassenger(dto: RegisterPassengerDto) {
    const isEthiopian = !!dto.nationalId;
    const isLoggedIn = !!dto.userId;
    let verifiedData: any = null;

    if (isEthiopian && dto.verifyWithFayda !== false) {
      try {
        const verification = await this.verifaydaService.verifyNationalId(dto.nationalId!);
        if (verification.verified && verification.passengerData) {
          verifiedData = verification.passengerData;
        }
      } catch (error) {
        console.warn('Fayda verification failed, using manual data:', error);
      }
    }

    const finalData = {
      passengerName: verifiedData?.fullName || dto.passengerName,
      dateOfBirth: verifiedData?.dateOfBirth || new Date(dto.dateOfBirth),
      nationality: verifiedData?.nationality || dto.nationality || (isEthiopian ? 'Ethiopian' : null),
      gender: verifiedData?.gender || dto.gender,
      phone: dto.phone,
      email: dto.email,
    };

    if (isLoggedIn) {
      const linkedPassenger = await this.prisma.passenger.findUnique({
        where: { iamUserId: dto.userId },
      });

      if (!linkedPassenger) {
        throw new BadRequestException('Passenger not found');
      }

      return {
        id: linkedPassenger.id,
        passengerName: finalData.passengerName,
        dateOfBirth: finalData.dateOfBirth,
        nationality: finalData.nationality,
        verified: !!verifiedData,
        linked: true,
        message: 'Passenger details saved and linked to user account',
      };
    }

    const profile = await this.prisma.savedPassengerProfile.create({
      data: {
        deviceId: dto.deviceId,
        passengerName: finalData.passengerName,
        dateOfBirth: finalData.dateOfBirth,
        idDocumentType: isEthiopian ? 'NATIONAL_ID' : 'PASSPORT',
        passportNumber: dto.passportNumber,
        passportCountry: dto.passportCountry,
        nationality: finalData.nationality,
        phone: dto.phone,
        email: dto.email,
      },
    });

    return {
      id: profile.id,
      passengerName: finalData.passengerName,
      dateOfBirth: finalData.dateOfBirth,
      nationality: finalData.nationality,
      verified: !!verifiedData,
      linked: false,
      message: 'Passenger details saved for guest booking',
    };
  }

  async deletePassenger(id: string) {
    const passenger = await this.prisma.passenger.findUnique({ where: { id } });
    if (!passenger) throw new NotFoundException('Passenger not found');

    await this.prisma.$transaction([
      this.prisma.loyaltyLedgerEntry.deleteMany({ where: { account: { passengerId: id } } }),
      this.prisma.loyaltyAccount.deleteMany({ where: { passengerId: id } }),
      this.prisma.walletLedgerEntry.deleteMany({ where: { wallet: { passengerId: id } } }),
      this.prisma.walletAccount.deleteMany({ where: { passengerId: id } }),
      this.prisma.notification.deleteMany({ where: { passengerId: id } }),
      this.prisma.travelerProfile.deleteMany({ where: { passengerId: id } }),
      this.prisma.savedRoute.deleteMany({ where: { passengerId: id } }),
      this.prisma.packageBooking.deleteMany({ where: { passengerId: id } }),
      this.prisma.ticket.deleteMany({ where: { booking: { passengerId: id } } }),
      this.prisma.bookingSeat.deleteMany({ where: { booking: { passengerId: id } } }),
      this.prisma.booking.deleteMany({ where: { passengerId: id } }),
      this.prisma.journeySegment.deleteMany({ where: { journey: { passengerId: id } } }),
      this.prisma.journey.deleteMany({ where: { passengerId: id } }),
      this.prisma.passenger.delete({ where: { id } }),
    ]);

    return { deleted: true, passengerId: id };
  }

  async checkPassengerUsage(id: string) {
    const [bookingCount, loyaltyAccount, walletAccount] = await Promise.all([
      this.prisma.booking.count({ where: { passengerId: id } }),
      this.prisma.loyaltyAccount.findUnique({ where: { passengerId: id } }),
      this.prisma.walletAccount.findUnique({ where: { passengerId: id } }),
    ]);

    const usage = [];
    if (bookingCount > 0) usage.push(`${bookingCount} booking(s)`);
    if (loyaltyAccount) usage.push('Loyalty account');
    if (walletAccount) usage.push('Wallet account');

    return {
      isInUse: usage.length > 0,
      affectedModules: usage,
    };
  }
}