import { BadRequestException, ForbiddenException, Injectable, UnauthorizedException } from '@nestjs/common';
import { isNumber, isString } from 'class-validator';
import cookieParser from 'cookie';
import { DateTime } from 'luxon';
import { IncomingHttpHeaders } from 'node:http';
import { LOGIN_URL, MOBILE_REDIRECT, SALT_ROUNDS } from 'src/constants';
import { OnEvent } from 'src/decorators';
import {
  AuthDto,
  ChangePasswordDto,
  ImmichCookie,
  ImmichHeader,
  ImmichQuery,
  LoginCredentialDto,
  LogoutResponseDto,
  OAuthAuthorizeResponseDto,
  OAuthCallbackDto,
  OAuthConfigDto,
  SignUpDto,
  mapLoginResponse,
} from 'src/dtos/auth.dto';
import { UserAdminResponseDto, mapUserAdmin } from 'src/dtos/user.dto';
import { UserEntity } from 'src/entities/user.entity';
import { AuthType, Permission } from 'src/enum';
import { OAuthProfile } from 'src/interfaces/oauth.interface';
import { BaseService } from 'src/services/base.service';
import { isGranted } from 'src/utils/access';
import { HumanReadableSize } from 'src/utils/bytes';
import { createUser } from 'src/utils/user';

export interface LoginDetails {
  isSecure: boolean;
  clientIp: string;
  deviceType: string;
  deviceOS: string;
}

interface ClaimOptions<T> {
  key: string;
  default: T;
  isValid: (value: unknown) => boolean;
}

export type ValidateRequest = {
  headers: IncomingHttpHeaders;
  queryParams: Record<string, string>;
  metadata: {
    sharedLinkRoute: boolean;
    adminRoute: boolean;
    permission?: Permission;
    uri: string;
  };
};

@Injectable()
export class AuthService extends BaseService {
  @OnEvent({ name: 'app.bootstrap' })
  onBootstrap() {
    this.oauthRepository.init();
  }

  async login(dto: LoginCredentialDto, details: LoginDetails) {
    const config = await this.getConfig({ withCache: false });
    if (!config.passwordLogin.enabled) {
      throw new UnauthorizedException('Password login has been disabled');
    }

    let user = await this.userRepository.getByEmail(dto.email, true);
    if (user) {
      const isAuthenticated = this.validatePassword(dto.password, user);
      if (!isAuthenticated) {
        user = null;
      }
    }

    if (!user) {
      this.logger.warn(`Failed login attempt for user ${dto.email} from ip address ${details.clientIp}`);
      throw new UnauthorizedException('Incorrect email or password');
    }

    return this.createLoginResponse(user, details);
  }

  async logout(auth: AuthDto, authType: AuthType): Promise<LogoutResponseDto> {
    if (auth.session) {
      await this.sessionRepository.delete(auth.session.id);
      await this.eventRepository.emit('session.delete', { sessionId: auth.session.id });
    }

    return {
      successful: true,
      redirectUri: await this.getLogoutEndpoint(authType),
    };
  }

  async changePassword(auth: AuthDto, dto: ChangePasswordDto): Promise<UserAdminResponseDto> {
    const { password, newPassword } = dto;
    const user = await this.userRepository.getByEmail(auth.user.email, true);
    if (!user) {
      throw new UnauthorizedException();
    }

    const valid = this.validatePassword(password, user);
    if (!valid) {
      throw new BadRequestException('Wrong password');
    }

    const hashedPassword = await this.cryptoRepository.hashBcrypt(newPassword, SALT_ROUNDS);

    const updatedUser = await this.userRepository.update(user.id, { password: hashedPassword });

    return mapUserAdmin(updatedUser);
  }

  async adminSignUp(dto: SignUpDto): Promise<UserAdminResponseDto> {
    const adminUser = await this.userRepository.getAdmin();
    if (adminUser) {
      throw new BadRequestException('The server already has an admin');
    }

    const admin = await createUser(
      { userRepo: this.userRepository, cryptoRepo: this.cryptoRepository },
      {
        isAdmin: true,
        email: dto.email,
        name: dto.name,
        password: dto.password,
        storageLabel: 'admin',
      },
    );

    return mapUserAdmin(admin);
  }

  async authenticate({ headers, queryParams, metadata }: ValidateRequest): Promise<AuthDto> {
    const authDto = await this.validate({ headers, queryParams });
    const { adminRoute, sharedLinkRoute, permission, uri } = metadata;

    if (!authDto.user.isAdmin && adminRoute) {
      this.logger.warn(`Denied access to admin only route: ${uri}`);
      throw new ForbiddenException('Forbidden');
    }

    if (authDto.sharedLink && !sharedLinkRoute) {
      this.logger.warn(`Denied access to non-shared route: ${uri}`);
      throw new ForbiddenException('Forbidden');
    }

    if (authDto.apiKey && permission && !isGranted({ requested: [permission], current: authDto.apiKey.permissions })) {
      throw new ForbiddenException(`Missing required permission: ${permission}`);
    }

    return authDto;
  }

  private async validate({ headers, queryParams }: Omit<ValidateRequest, 'metadata'>): Promise<AuthDto> {
    const shareKey = (headers[ImmichHeader.SHARED_LINK_KEY] || queryParams[ImmichQuery.SHARED_LINK_KEY]) as string;
    const session = (headers[ImmichHeader.USER_TOKEN] ||
      headers[ImmichHeader.SESSION_TOKEN] ||
      queryParams[ImmichQuery.SESSION_KEY] ||
      this.getBearerToken(headers) ||
      this.getCookieToken(headers)) as string;
    const apiKey = (headers[ImmichHeader.API_KEY] || queryParams[ImmichQuery.API_KEY]) as string;

    if (shareKey) {
      return this.validateSharedLink(shareKey);
    }

    if (session) {
      return this.validateSession(session);
    }

    if (apiKey) {
      return this.validateApiKey(apiKey);
    }

    throw new UnauthorizedException('Authentication required');
  }

  getMobileRedirect(url: string) {
    return `${MOBILE_REDIRECT}?${url.split('?')[1] || ''}`;
  }

  async authorize(dto: OAuthConfigDto): Promise<OAuthAuthorizeResponseDto> {
    const { oauth } = await this.getConfig({ withCache: false });

    if (!oauth.enabled) {
      throw new BadRequestException('OAuth is not enabled');
    }

    const url = await this.oauthRepository.authorize(oauth, dto.redirectUri);
    return { url };
  }

  async callback(dto: OAuthCallbackDto, loginDetails: LoginDetails) {
    const { oauth } = await this.getConfig({ withCache: false });
    const profile = await this.oauthRepository.getProfile(oauth, dto.url, this.normalize(oauth, dto.url.split('?')[0]));
    const { autoRegister, defaultStorageQuota, storageLabelClaim, storageQuotaClaim } = oauth;
    this.logger.debug(`Logging in with OAuth: ${JSON.stringify(profile)}`);
    let user = await this.userRepository.getByOAuthId(profile.sub);

    // link by email
    if (!user && profile.email) {
      const emailUser = await this.userRepository.getByEmail(profile.email);
      if (emailUser) {
        if (emailUser.oauthId) {
          throw new BadRequestException('User already exists, but is linked to another account.');
        }
        user = await this.userRepository.update(emailUser.id, { oauthId: profile.sub });
      }
    }

    // register new user
    if (!user) {
      if (!autoRegister) {
        this.logger.warn(
          `Unable to register ${profile.sub}/${profile.email || '(no email)'}. To enable set OAuth Auto Register to true in admin settings.`,
        );
        throw new BadRequestException(`User does not exist and auto registering is disabled.`);
      }

      if (!profile.email) {
        throw new BadRequestException('OAuth profile does not have an email address');
      }

      this.logger.log(`Registering new user: ${profile.sub}/${profile.email}`);

      const storageLabel = this.getClaim(profile, {
        key: storageLabelClaim,
        default: '',
        isValid: isString,
      });
      const storageQuota = this.getClaim(profile, {
        key: storageQuotaClaim,
        default: defaultStorageQuota,
        isValid: (value: unknown) => isNumber(value) && value >= 0,
      });

      const userName = profile.name ?? `${profile.given_name || ''} ${profile.family_name || ''}`;
      user = await createUser(
        { userRepo: this.userRepository, cryptoRepo: this.cryptoRepository },
        {
          name: userName,
          email: profile.email,
          oauthId: profile.sub,
          quotaSizeInBytes: storageQuota * HumanReadableSize.GiB || null,
          storageLabel: storageLabel || null,
        },
      );
    }

    return this.createLoginResponse(user, loginDetails);
  }

  async link(auth: AuthDto, dto: OAuthCallbackDto): Promise<UserAdminResponseDto> {
    const { oauth } = await this.getConfig({ withCache: false });
    const { sub: oauthId } = await this.oauthRepository.getProfile(
      oauth,
      dto.url,
      this.normalize(oauth, dto.url.split('?')[0]),
    );
    const duplicate = await this.userRepository.getByOAuthId(oauthId);
    if (duplicate && duplicate.id !== auth.user.id) {
      this.logger.warn(`OAuth link account failed: sub is already linked to another user (${duplicate.email}).`);
      throw new BadRequestException('This OAuth account has already been linked to another user.');
    }

    const user = await this.userRepository.update(auth.user.id, { oauthId });
    return mapUserAdmin(user);
  }

  async unlink(auth: AuthDto): Promise<UserAdminResponseDto> {
    const user = await this.userRepository.update(auth.user.id, { oauthId: '' });
    return mapUserAdmin(user);
  }

  private async getLogoutEndpoint(authType: AuthType): Promise<string> {
    if (authType !== AuthType.OAUTH) {
      return LOGIN_URL;
    }

    const config = await this.getConfig({ withCache: false });
    if (!config.oauth.enabled) {
      return LOGIN_URL;
    }

    return (await this.oauthRepository.getLogoutEndpoint(config.oauth)) || LOGIN_URL;
  }

  private getBearerToken(headers: IncomingHttpHeaders): string | null {
    const [type, token] = (headers.authorization || '').split(' ');
    if (type.toLowerCase() === 'bearer') {
      return token;
    }

    return null;
  }

  private getCookieToken(headers: IncomingHttpHeaders): string | null {
    const cookies = cookieParser.parse(headers.cookie || '');
    return cookies[ImmichCookie.ACCESS_TOKEN] || null;
  }

  async validateSharedLink(key: string | string[]): Promise<AuthDto> {
    key = Array.isArray(key) ? key[0] : key;

    const bytes = Buffer.from(key, key.length === 100 ? 'hex' : 'base64url');
    const sharedLink = await this.sharedLinkRepository.getByKey(bytes);
    if (sharedLink && (!sharedLink.expiresAt || new Date(sharedLink.expiresAt) > new Date())) {
      const user = sharedLink.user;
      if (user) {
        return { user, sharedLink };
      }
    }
    throw new UnauthorizedException('Invalid share key');
  }

  private async validateApiKey(key: string): Promise<AuthDto> {
    const hashedKey = this.cryptoRepository.hashSha256(key);
    const apiKey = await this.keyRepository.getKey(hashedKey);
    if (apiKey?.user) {
      return { user: apiKey.user, apiKey };
    }

    throw new UnauthorizedException('Invalid API key');
  }

  private validatePassword(inputPassword: string, user: UserEntity): boolean {
    if (!user || !user.password) {
      return false;
    }
    return this.cryptoRepository.compareBcrypt(inputPassword, user.password);
  }

  private async validateSession(tokenValue: string): Promise<AuthDto> {
    const hashedToken = this.cryptoRepository.hashSha256(tokenValue);
    const session = await this.sessionRepository.getByToken(hashedToken);

    if (session?.user) {
      const now = DateTime.now();
      const updatedAt = DateTime.fromJSDate(session.updatedAt);
      const diff = now.diff(updatedAt, ['hours']);
      if (diff.hours > 1) {
        await this.sessionRepository.update({ id: session.id, updatedAt: new Date() });
      }

      return { user: session.user, session };
    }

    throw new UnauthorizedException('Invalid user token');
  }

  private async createLoginResponse(user: UserEntity, loginDetails: LoginDetails) {
    const key = this.cryptoRepository.newPassword(32);
    const token = this.cryptoRepository.hashSha256(key);

    await this.sessionRepository.create({
      token,
      user,
      deviceOS: loginDetails.deviceOS,
      deviceType: loginDetails.deviceType,
    });

    return mapLoginResponse(user, key);
  }

  private getClaim<T>(profile: OAuthProfile, options: ClaimOptions<T>): T {
    const value = profile[options.key as keyof OAuthProfile];
    return options.isValid(value) ? (value as T) : options.default;
  }

  private normalize(
    { mobileRedirectUri, mobileOverrideEnabled }: { mobileRedirectUri: string; mobileOverrideEnabled: boolean },
    redirectUri: string,
  ) {
    const isMobile = redirectUri.startsWith('app.immich:/');
    if (isMobile && mobileOverrideEnabled && mobileRedirectUri) {
      return mobileRedirectUri;
    }
    return redirectUri;
  }
}