import {
  BadRequestException,
  ConflictException,
  Injectable,
  Logger,
  NotFoundException,
  UnauthorizedException,
} from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { JwtService } from '@nestjs/jwt';
import * as bcrypt from 'bcryptjs';
import * as path from 'path';
import type { AuthUserDto, LoginResponse } from '@mento/shared';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.service';
import { SmsService } from '../common/sms.service';
import { LocalFileStorage } from '../storage/local-file.storage';
import {
  LoginDto,
  LoginOtpRequestDto,
  LoginOtpVerifyDto,
  RegisterOrganizationDto,
  RegisterVerifyOtpDto,
  UpdateProfileDto,
} from './dto';

const OTP_LENGTH = 6;
const OTP_TTL_SECONDS = 5 * 60;
const AVATAR_MAX_BYTES = 2 * 1024 * 1024;
const AVATAR_EXT: Record<string, string> = {
  'image/jpeg': 'jpg',
  'image/jpg': 'jpg',
  'image/png': 'png',
  'image/webp': 'webp',
  'image/gif': 'gif',
};

function slugify(input: string): string {
  return (
    input
      .trim()
      .toLowerCase()
      .replace(/[^\w\u0600-\u06FF]+/g, '-')
      .replace(/^-+|-+$/g, '')
      .slice(0, 48) || `org-${Date.now()}`
  );
}

/** نرمال‌سازی موبایل ایران به 09xxxxxxxxx */
export function normalizeMobile(raw: string): string | null {
  let s = raw.replace(/[\s\-()]/g, '');
  if (s.startsWith('+98')) s = `0${s.slice(3)}`;
  if (s.startsWith('98') && s.length === 12) s = `0${s.slice(2)}`;
  if (/^9\d{9}$/.test(s)) s = `0${s}`;
  if (/^09\d{9}$/.test(s)) return s;
  return null;
}

function looksLikeEmail(value: string): boolean {
  return value.includes('@');
}

function maskEmail(email: string): string {
  const [local, domain] = email.split('@');
  if (!domain) return '***';
  const head = local.slice(0, Math.min(2, local.length));
  return `${head}***@${domain}`;
}

function maskMobile(mobile: string): string {
  if (mobile.length < 4) return '****';
  return `${mobile.slice(0, 4)}***${mobile.slice(-2)}`;
}

function generateOtp(): string {
  return String(
    Math.floor(10 ** (OTP_LENGTH - 1) + Math.random() * 9 * 10 ** (OTP_LENGTH - 1)),
  );
}

type RegisterPayload = {
  organizationName: string;
  fullName: string;
  businessField: string;
  referralCode?: string;
};

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

  constructor(
    private readonly prisma: PrismaService,
    private readonly jwt: JwtService,
    private readonly config: ConfigService,
    private readonly sms: SmsService,
    private readonly files: LocalFileStorage,
  ) {}

  /**
   * ثبت‌نام مرحله ۱:
   * - همیشه OTP موبایل
   * - OTP ایمیل فقط وقتی AUTH_EMAIL_OTP_ENABLED=true
   */
  async startRegister(dto: RegisterOrganizationDto) {
    if (dto.password !== dto.passwordConfirm) {
      throw new BadRequestException('تکرار رمز عبور مطابقت ندارد');
    }
    if (dto.acceptedTerms === false) {
      throw new BadRequestException('پذیرش شرایط و قوانین الزامی است');
    }

    const email = dto.email.trim().toLowerCase();
    const mobile = normalizeMobile(dto.mobile);
    if (!mobile) {
      throw new BadRequestException('شماره موبایل معتبر نیست');
    }

    const existingEmail = await this.prisma.user.findFirst({ where: { email } });
    if (existingEmail) {
      throw new ConflictException('این ایمیل قبلاً ثبت شده است');
    }
    const existingMobile = await this.prisma.user.findFirst({ where: { mobile } });
    if (existingMobile) {
      throw new ConflictException('این شماره موبایل قبلاً ثبت شده است');
    }

    await this.throttleChallenges('register', email, mobile);

    const returnOtp = this.shouldReturnOtp();
    const emailOtpEnabled = this.isEmailOtpConfigured();
    const mobileCode = generateOtp();
    const emailCode = emailOtpEnabled ? generateOtp() : null;
    const passwordHash = await bcrypt.hash(dto.password, 10);
    const payload: RegisterPayload = {
      organizationName: dto.organizationName.trim(),
      fullName: dto.fullName.trim(),
      businessField: dto.businessField,
      ...(dto.referralCode?.trim()
        ? { referralCode: dto.referralCode.trim() }
        : {}),
    };

    const challenge = await this.prisma.authChallenge.create({
      data: {
        kind: 'register',
        email,
        mobile,
        passwordHash,
        payload: payload as Prisma.InputJsonValue,
        emailCode,
        mobileCode,
        expiresAt: new Date(Date.now() + OTP_TTL_SECONDS * 1000),
      },
    });

    if (emailOtpEnabled && emailCode) {
      await this.dispatchEmailOtp(email, emailCode, returnOtp);
    }
    await this.dispatchMobileOtp(mobile, mobileCode, returnOtp);

    return {
      challengeId: challenge.id,
      expiresInSeconds: OTP_TTL_SECONDS,
      maskedEmail: maskEmail(email),
      maskedMobile: maskMobile(mobile),
      emailOtpRequired: emailOtpEnabled,
      ...(returnOtp
        ? {
            ...(emailCode ? { devEmailCode: emailCode } : {}),
            devMobileCode: mobileCode,
          }
        : {}),
    };
  }

  /** ثبت‌نام مرحله ۲: تأیید OTP و ساخت سازمان */
  async verifyRegister(dto: RegisterVerifyOtpDto): Promise<LoginResponse> {
    const challenge = await this.prisma.authChallenge.findUnique({
      where: { id: dto.challengeId },
    });
    if (
      !challenge ||
      challenge.kind !== 'register' ||
      challenge.consumedAt ||
      challenge.expiresAt <= new Date()
    ) {
      throw new UnauthorizedException('کد تأیید نامعتبر یا منقضی است');
    }

    const mobileOk = challenge.mobileCode === dto.mobileCode.trim();
    if (!mobileOk) {
      throw new UnauthorizedException('کد تأیید موبایل نادرست است');
    }

    const emailRequired = Boolean(challenge.emailCode);
    if (emailRequired) {
      const emailOk = challenge.emailCode === (dto.emailCode ?? '').trim();
      if (!emailOk) {
        throw new UnauthorizedException('کد تأیید ایمیل نادرست است');
      }
    }

    const email = (challenge.email ?? '').toLowerCase();
    const mobile = challenge.mobile ?? '';
    if (!email || !mobile || !challenge.passwordHash) {
      throw new BadRequestException('چالش ثبت‌نام ناقص است');
    }

    const payload = (challenge.payload ?? {}) as RegisterPayload;
    if (!payload.organizationName || !payload.fullName || !payload.businessField) {
      throw new BadRequestException('اطلاعات ثبت‌نام ناقص است');
    }

    const existingEmail = await this.prisma.user.findFirst({ where: { email } });
    if (existingEmail) {
      throw new ConflictException('این ایمیل قبلاً ثبت شده است');
    }
    const existingMobile = await this.prisma.user.findFirst({ where: { mobile } });
    if (existingMobile) {
      throw new ConflictException('این شماره موبایل قبلاً ثبت شده است');
    }

    const baseSlug = slugify(payload.organizationName);
    let slug = baseSlug;
    let i = 1;
    while (await this.prisma.organization.findUnique({ where: { slug } })) {
      slug = `${baseSlug}-${i++}`;
    }

    const now = new Date();
    const organization = await this.prisma.organization.create({
      data: {
        name: payload.organizationName,
        slug,
        businessField: payload.businessField,
        users: {
          create: {
            email,
            mobile,
            fullName: payload.fullName,
            passwordHash: challenge.passwordHash,
            role: 'owner',
            emailVerifiedAt: emailRequired ? now : null,
            mobileVerifiedAt: now,
          },
        },
      },
      include: { users: true },
    });

    await this.prisma.authChallenge.update({
      where: { id: challenge.id },
      data: {
        consumedAt: now,
        emailVerified: emailRequired,
        mobileVerified: true,
      },
    });

    return this.buildLoginResponse(organization.users[0]);
  }

  /** ورود با رمز: ایمیل یا موبایل + رمز → JWT (بدون OTP) */
  async loginWithPassword(dto: LoginDto): Promise<LoginResponse> {
    const identifier = (dto.identifier ?? dto.email ?? '').trim();
    const isEmail = looksLikeEmail(identifier);
    const email = isEmail ? identifier.toLowerCase() : null;
    const mobile = isEmail ? null : normalizeMobile(identifier);

    if (!identifier || (!email && !mobile)) {
      throw new BadRequestException('ایمیل یا شماره موبایل معتبر وارد کنید');
    }

    const user = await this.prisma.user.findFirst({
      where: email ? { email } : { mobile: mobile! },
    });
    if (!user) {
      throw new UnauthorizedException('اطلاعات ورود نادرست است');
    }

    const ok = await bcrypt.compare(dto.password, user.passwordHash);
    if (!ok) {
      throw new UnauthorizedException('اطلاعات ورود نادرست است');
    }

    return this.buildLoginResponse(user);
  }

  /** ورود اختیاری با موبایل + OTP (بدون رمز) — فقط کاربران ثبت‌شده */
  async requestLoginOtp(dto: LoginOtpRequestDto) {
    const mobile = normalizeMobile(dto.mobile);
    if (!mobile) {
      throw new BadRequestException('شماره موبایل معتبر نیست');
    }

    const user = await this.prisma.user.findFirst({ where: { mobile } });
    if (!user) {
      throw new UnauthorizedException('حسابی با این موبایل یافت نشد');
    }

    await this.throttleChallenges('login', user.email, mobile);

    const code = generateOtp();
    const returnOtp = this.shouldReturnOtp();
    const challenge = await this.prisma.authChallenge.create({
      data: {
        kind: 'login',
        channel: 'mobile',
        email: user.email,
        mobile,
        payload: { userId: user.id } as Prisma.InputJsonValue,
        mobileCode: code,
        expiresAt: new Date(Date.now() + OTP_TTL_SECONDS * 1000),
      },
    });

    await this.dispatchMobileOtp(mobile, code, returnOtp);

    return {
      challengeId: challenge.id,
      channel: 'mobile' as const,
      expiresInSeconds: OTP_TTL_SECONDS,
      maskedDestination: maskMobile(mobile),
      ...(returnOtp ? { devCode: code } : {}),
    };
  }

  async verifyLoginOtp(dto: LoginOtpVerifyDto): Promise<LoginResponse> {
    const challenge = await this.prisma.authChallenge.findUnique({
      where: { id: dto.challengeId },
    });
    if (
      !challenge ||
      challenge.kind !== 'login' ||
      challenge.consumedAt ||
      challenge.expiresAt <= new Date()
    ) {
      throw new UnauthorizedException('کد تأیید نامعتبر یا منقضی است');
    }

    if (!challenge.mobileCode || challenge.mobileCode !== dto.code.trim()) {
      throw new UnauthorizedException('کد تأیید نادرست است');
    }

    const payload = (challenge.payload ?? {}) as { userId?: string };
    if (!payload.userId) {
      throw new BadRequestException('چالش ورود ناقص است');
    }

    const user = await this.prisma.user.findUnique({ where: { id: payload.userId } });
    if (!user) {
      throw new UnauthorizedException();
    }

    const now = new Date();
    await this.prisma.authChallenge.update({
      where: { id: challenge.id },
      data: { consumedAt: now, mobileVerified: true },
    });
    if (!user.mobileVerifiedAt) {
      await this.prisma.user.update({
        where: { id: user.id },
        data: { mobileVerifiedAt: now },
      });
    }

    return this.buildLoginResponse(user);
  }

  async me(userId: string): Promise<AuthUserDto> {
    const user = await this.prisma.user.findUnique({ where: { id: userId } });
    if (!user) {
      throw new UnauthorizedException();
    }
    return this.toAuthUserDto(user);
  }

  async updateMe(userId: string, dto: UpdateProfileDto): Promise<AuthUserDto> {
    const fullName = dto.fullName.trim();
    if (fullName.length < 2) {
      throw new BadRequestException('نام باید حداقل دو حرف باشد');
    }
    const email = dto.email.trim().toLowerCase();
    const mobile = normalizeMobile(dto.mobile);
    if (!mobile) {
      throw new BadRequestException('شماره موبایل معتبر نیست');
    }

    const existing = await this.prisma.user.findUnique({ where: { id: userId } });
    if (!existing) {
      throw new UnauthorizedException();
    }

    if (email !== existing.email) {
      const taken = await this.prisma.user.findFirst({
        where: { organizationId: existing.organizationId, email, id: { not: userId } },
      });
      if (taken) {
        throw new ConflictException('این ایمیل قبلاً ثبت شده است');
      }
    }
    if (mobile !== existing.mobile) {
      const taken = await this.prisma.user.findFirst({
        where: { mobile, id: { not: userId } },
      });
      if (taken) {
        throw new ConflictException('این شماره موبایل قبلاً ثبت شده است');
      }
    }

    try {
      const user = await this.prisma.user.update({
        where: { id: userId },
        data: { fullName, email, mobile },
      });
      return this.toAuthUserDto(user);
    } catch (error) {
      if (
        error instanceof Prisma.PrismaClientKnownRequestError &&
        error.code === 'P2002'
      ) {
        throw new ConflictException('این ایمیل یا شماره موبایل قبلاً ثبت شده است');
      }
      throw error;
    }
  }

  async saveAvatar(
    userId: string,
    organizationId: string,
    file: Express.Multer.File | undefined,
  ): Promise<AuthUserDto> {
    if (!file?.buffer?.length) {
      throw new BadRequestException('فایل تصویر ارسال نشده');
    }
    if (file.size > AVATAR_MAX_BYTES) {
      throw new BadRequestException('حجم تصویر باید کمتر از ۲ مگابایت باشد');
    }
    const mime = (file.mimetype || '').toLowerCase();
    const ext = AVATAR_EXT[mime];
    if (!ext) {
      throw new BadRequestException('فقط تصویر JPG، PNG، WebP یا GIF مجاز است');
    }
    const existing = await this.prisma.user.findUnique({ where: { id: userId } });
    if (!existing) {
      throw new UnauthorizedException();
    }
    const prevKey = await this.readAvatarKey(userId);
    const storageKey = path
      .join(organizationId, 'users', userId, `avatar.${ext}`)
      .replace(/\\/g, '/');
    await this.files.save(storageKey, file.buffer);
    if (prevKey && prevKey !== storageKey) {
      await this.files.remove(prevKey);
    }
    await this.writeAvatarKey(userId, storageKey);
    return this.toAuthUserDto(existing);
  }

  async removeAvatar(userId: string): Promise<AuthUserDto> {
    const existing = await this.prisma.user.findUnique({ where: { id: userId } });
    if (!existing) {
      throw new UnauthorizedException();
    }
    const prevKey = await this.readAvatarKey(userId);
    if (prevKey) await this.files.remove(prevKey);
    await this.writeAvatarKey(userId, null);
    return this.toAuthUserDto(existing);
  }

  async openAvatar(userId: string) {
    const user = await this.prisma.user.findUnique({ where: { id: userId } });
    if (!user) {
      throw new UnauthorizedException();
    }
    const storageKey = await this.readAvatarKey(userId);
    if (!storageKey) {
      throw new NotFoundException('عکس پروفایل تنظیم نشده');
    }
    const ext = path.extname(storageKey).slice(1).toLowerCase();
    const mime =
      Object.entries(AVATAR_EXT).find(([, value]) => value === ext)?.[0] ??
      'image/jpeg';
    return {
      stream: this.files.openReadStream(storageKey),
      mimeType: mime,
    };
  }

  private async readAvatarKey(userId: string): Promise<string | null> {
    const rows = await this.prisma.$queryRaw<Array<{ avatarStorageKey: string | null }>>`
      SELECT "avatarStorageKey" FROM "User" WHERE "id" = ${userId}
    `;
    return rows[0]?.avatarStorageKey ?? null;
  }

  private async writeAvatarKey(userId: string, storageKey: string | null) {
    await this.prisma.$executeRaw`
      UPDATE "User" SET "avatarStorageKey" = ${storageKey} WHERE "id" = ${userId}
    `;
  }

  private async toAuthUserDto(user: {
    id: string;
    email: string;
    mobile?: string | null;
    fullName: string;
    role: AuthUserDto['role'];
    organizationId: string;
  }): Promise<AuthUserDto> {
    return this.toAuthUser({
      ...user,
      avatarStorageKey: await this.readAvatarKey(user.id),
    });
  }

  private async throttleChallenges(
    kind: string,
    email: string | null | undefined,
    mobile: string | null | undefined,
  ) {
    const since = new Date(Date.now() - 60 * 60 * 1000);
    const count = await this.prisma.authChallenge.count({
      where: {
        kind,
        createdAt: { gte: since },
        OR: [
          ...(email ? [{ email }] : []),
          ...(mobile ? [{ mobile }] : []),
        ],
      },
    });
    if (count >= 12) {
      throw new BadRequestException(
        'درخواست زیاد است؛ کمی بعد دوباره تلاش کنید',
      );
    }
  }

  private shouldReturnOtp(): boolean {
    return (
      this.config.get<string>('AUTH_RETURN_OTP') === 'true' ||
      this.config.get<string>('PORTAL_SHOW_OTP') === 'true' ||
      (this.config.get<string>('NODE_ENV') !== 'production' &&
        this.config.get<string>('AUTH_RETURN_OTP') !== 'false')
    );
  }

  private isEmailOtpConfigured(): boolean {
    return this.config.get<string>('AUTH_EMAIL_OTP_ENABLED') === 'true';
  }

  private async dispatchEmailOtp(
    email: string,
    code: string,
    returnOtp: boolean,
  ) {
    this.logger.log(`[auth-otp-email] ${email} => ${code}`);
    if (!this.isEmailOtpConfigured() && !returnOtp) {
      throw new BadRequestException(
        'ارسال ایمیل پیکربندی نشده است؛ با پشتیبانی تماس بگیرید',
      );
    }
  }

  private async dispatchMobileOtp(
    mobile: string,
    code: string,
    returnOtp: boolean,
  ) {
    if (this.sms.isConfigured()) {
      const sent = await this.sms.sendOtpSms(mobile, code);
      if (!sent && !returnOtp) {
        throw new BadRequestException(
          'ارسال پیامک ناموفق بود؛ کمی بعد دوباره تلاش کنید',
        );
      }
      if (!sent) {
        this.logger.warn(`[auth-otp-sms-fallback] ${mobile} => ${code}`);
      }
      return;
    }
    if (!returnOtp) {
      throw new BadRequestException('سامانه پیامک پیکربندی نشده است');
    }
    this.logger.log(`[auth-otp-sms] ${mobile} => ${code}`);
  }

  private async buildLoginResponse(user: {
    id: string;
    email: string;
    mobile?: string | null;
    fullName: string;
    role: AuthUserDto['role'];
    organizationId: string;
  }): Promise<LoginResponse> {
    const payload = {
      sub: user.id,
      organizationId: user.organizationId,
      role: user.role,
    };
    return {
      accessToken: this.jwt.sign(payload),
      user: await this.toAuthUserDto(user),
    };
  }

  private toAuthUser(user: {
    id: string;
    email: string;
    mobile?: string | null;
    fullName: string;
    role: AuthUserDto['role'];
    organizationId: string;
    avatarStorageKey?: string | null;
  }): AuthUserDto {
    return {
      id: user.id,
      email: user.email,
      fullName: user.fullName,
      role: user.role,
      organizationId: user.organizationId,
      hasAvatar: Boolean(user.avatarStorageKey),
      ...(user.mobile ? { mobile: user.mobile } : {}),
    };
  }
}