import {
  Injectable,
  ConflictException,
  InternalServerErrorException,
  UnauthorizedException,
} from '@nestjs/common';
import { ModuleRef, ContextIdFactory } from '@nestjs/core';
import { InjectDataSource } from '@nestjs/typeorm';
import { DataSource } from 'typeorm';
import { EventEmitter2 } from '@nestjs/event-emitter';
import { AuthService as IamAuthService } from '@tria-plc/iamapi-common/module/auth/services/auth.service';
import { EUserType } from '@tria-plc/api-common/utils/enums/user.enum';
import { PrismaService } from '../../common/prisma.service';
import { RegisterDto, LoginDto } from './auth.dto';

type IamUserRow = { id: string; name: { en: string; am: string } | null; phone_number: string | null };

@Injectable()
export class PassengerAuthService {
  constructor(
    private readonly prisma: PrismaService,
    @InjectDataSource() private readonly dataSource: DataSource,
    private readonly moduleRef: ModuleRef,
    private readonly eventEmitter: EventEmitter2,
  ) {}

  private async resolveIamAuthService(req: any): Promise<IamAuthService> {
    const contextId = ContextIdFactory.getByRequest(req);
    this.moduleRef.registerRequestByContextId(req, contextId);
    return this.moduleRef.resolve(IamAuthService, contextId, { strict: false });
  }

  async register(dto: RegisterDto, req: any) {
    const existing = await this.prisma.user.findFirst({
      where: { OR: [{ email: dto.email }, { phone: dto.phone }] },
    });
    if (existing) throw new ConflictException('Email or phone already registered');

    const iamAuthService = await this.resolveIamAuthService(req);

    const { token, refreshToken } = await iamAuthService.signupWithPassword({
      email: dto.email,
      username: dto.email,
      phoneNumber: dto.phone,
      userType: EUserType.INDIVIDUAL,
      name: { en: dto.fullName, am: dto.fullName },
      password: dto.password,
      confirmPassword: dto.confirmPassword ?? dto.password,
    });

    const iamRows = await this.dataSource.query<IamUserRow[]>(
      `SELECT id, name, phone_number FROM iam.users WHERE email = $1 LIMIT 1`,
      [dto.email],
    );
    if (!iamRows.length) {
      await this.compensateIamSignup(dto.email);
      throw new InternalServerErrorException('Account creation failed. Please try again.');
    }
    const iamUserId = iamRows[0].id;

    let passengerId: string;
    try {
      const result = await this.provisionPassengerSatellite({
        iamUserId,
        email: dto.email,
        fullName: dto.fullName,
        phone: dto.phone,
        nationality: dto.nationality,
        nationalId: dto.nationalId,
        passportNumber: dto.passportNumber,
        auditAction: 'USER_REGISTERED',
      });
      passengerId = result.passengerId;
    } catch {
      await this.compensateIamSignup(dto.email);
      throw new InternalServerErrorException('Account creation failed. Please try again.');
    }

    return {
      token,
      refreshToken,
      user: { id: iamUserId, iamUserId, email: dto.email, fullName: dto.fullName, passengerId },
    };
  }

  async login(dto: LoginDto, req: any) {
    const iamAuthService = await this.resolveIamAuthService(req);

    let iamResult: { token: string; refreshToken: string } | { mfaRequired: boolean };
    try {
      iamResult = await iamAuthService.login({ email: dto.email, password: dto.password });
    } catch {
      this.eventEmitter.emit('auth.login.failed', { email: dto.email });
      throw new UnauthorizedException('Invalid credentials');
    }

    if ('mfaRequired' in iamResult && iamResult.mfaRequired) {
      return iamResult;
    }

    const { token, refreshToken } = iamResult as { token: string; refreshToken: string };

    const iamRows = await this.dataSource.query<IamUserRow[]>(
      `SELECT id, name, phone_number FROM iam.users WHERE email = $1 LIMIT 1`,
      [dto.email],
    );
    const iamUser = iamRows[0];
    if (!iamUser) {
      throw new InternalServerErrorException('IAM user not found after successful authentication');
    }

    // Find existing Passenger record or lazy-provision one on first login
    let passenger = await this.prisma.passenger.findUnique({
      where: { iamUserId: iamUser.id },
      select: { id: true },
    });

    if (!passenger) {
      const fullName = iamUser.name?.en ?? iamUser.name?.am ?? dto.email;
      const result = await this.provisionPassengerSatellite({
        iamUserId: iamUser.id,
        email: dto.email,
        fullName,
        phone: iamUser.phone_number ?? '',
        auditAction: 'USER_AUTO_PROVISIONED',
      });
      passenger = { id: result.passengerId };
    }

    return {
      token,
      refreshToken,
      user: { id: iamUser.id, iamUserId: iamUser.id, email: dto.email, passengerId: passenger.id },
    };
  }

  private async provisionPassengerSatellite(data: {
    iamUserId: string;
    email: string;
    fullName: string;
    phone: string;
    nationality?: string;
    nationalId?: string;
    passportNumber?: string;
    auditAction: string;
  }): Promise<{ passengerId: string }> {
    return this.prisma.$transaction(async (tx) => {
      // Check if a local User already exists (pre-IAM registration)
      const existingUser = await tx.user.findFirst({
        where: { OR: [{ email: data.email }, { phone: data.phone }] },
        select: { id: true },
      });

      if (existingUser) {
        // User already exists — find their Passenger and stamp iamUserId
        const existingPassenger = await tx.passenger.findFirst({
          where: { userId: existingUser.id },
          select: { id: true },
        });

        if (existingPassenger) {
          await tx.passenger.update({
            where: { id: existingPassenger.id },
            data: { iamUserId: data.iamUserId },
          });
          return { passengerId: existingPassenger.id };
        }

        // User exists but no Passenger yet — create just the Passenger + sub-records
        const passenger = await tx.passenger.create({
          data: { userId: existingUser.id, iamUserId: data.iamUserId },
        });
        await tx.loyaltyAccount.create({ data: { passengerId: passenger.id } });
        await tx.walletAccount.create({ data: { passengerId: passenger.id } });
        return { passengerId: passenger.id };
      }

      // Brand new user — create the full satellite set
      const user = await tx.user.create({
        data: {
          email: data.email,
          phone: data.phone,
          fullName: data.fullName,
          passwordHash: 'IAM_MANAGED',
          nationality: data.nationality,
          nationalId: data.nationalId,
          passportNumber: data.passportNumber,
        },
      });
      const passenger = await tx.passenger.create({
        data: { userId: user.id, iamUserId: data.iamUserId },
      });
      await tx.loyaltyAccount.create({ data: { passengerId: passenger.id } });
      await tx.walletAccount.create({ data: { passengerId: passenger.id } });
      await tx.userPreferences.create({ data: { userId: user.id } });
      await tx.auditLog.create({
        data: {
          userId: user.id,
          action: data.auditAction,
          entityType: 'User',
          entityId: user.id,
          newData: { email: data.email, iamUserId: data.iamUserId },
        },
      });
      return { passengerId: passenger.id };
    });
  }

  async logout(user: any, req: any) {
    const iamAuthService = await this.resolveIamAuthService(req);
    await iamAuthService.logout(user);
    return { success: true, message: 'Logged out successfully' };
  }

  async getProfile(iamUserId: string) {
    const passenger = await this.prisma.passenger.findUnique({
      where: { iamUserId },
      include: {
        user: true,
        loyalty: true,
        wallet: true,
      },
    });
    if (!passenger) {
      throw new Error('Passenger not found');
    }
    return {
      iamUserId,
      email: passenger.user?.email,
      phone: passenger.user?.phone,
      fullName: passenger.user?.fullName,
      nationality: passenger.user?.nationality,
      nationalId: passenger.user?.nationalId,
      passportNumber: passenger.user?.passportNumber,
      faydaVerified: passenger.user?.faydaVerified,
      createdAt: passenger.createdAt,
      passenger: {
        id: passenger.id,
        preferredLanguage: passenger.preferredLanguage,
        loyalty: passenger.loyalty
          ? { tier: passenger.loyalty.tier, pointsBalance: passenger.loyalty.pointsBalance, lifetimePoints: passenger.loyalty.lifetimePoints }
          : null,
        wallet: passenger.wallet
          ? { balanceMinor: passenger.wallet.balanceMinor, currency: passenger.wallet.currency }
          : null,
      },
    };
  }

  private async compensateIamSignup(email: string): Promise<void> {
    try {
      await this.dataSource.query(`DELETE FROM iam.sessions WHERE email = $1`, [email]);
      await this.dataSource.query(`DELETE FROM iam.users WHERE email = $1`, [email]);
    } catch (err) {
      console.error('[PassengerAuthService] IAM compensating cleanup failed for', email, (err as Error).message);
    }
  }
}