import { ForbiddenException, Injectable, UnauthorizedException } from '@nestjs/common';
import { Client } from 'ldapts';
import { AuthConfigService } from '../auth.config';
import { AuthTokenService } from '../auth-token.service';
import { AuthResult, LoginData } from '../auth.types';

@Injectable()
export class LdapAuthProvider {
  constructor(
    private readonly authConfig: AuthConfigService,
    private readonly authToken: AuthTokenService,
  ) {}

  async authenticate({ username, password }: LoginData): Promise<AuthResult> {
    const config = this.authConfig.getConfig();

    if (!config.ldap.enabled) {
      throw new ForbiddenException('Login AD/LDAP desabilitado');
    }

    if (!config.ldap.url) {
      throw new Error('LDAP_URL nao configurado');
    }

    if (!username || !password) {
      throw new UnauthorizedException('Usuario e senha sao obrigatorios');
    }

    const client = new Client({
      url: config.ldap.url,
      timeout: config.ldap.timeoutMs,
      connectTimeout: config.ldap.timeoutMs,
    });

    try {
      if (config.ldap.bindDn && config.ldap.bindPassword) {
        await client.bind(config.ldap.bindDn, config.ldap.bindPassword);
      }

      const userPrincipal = this.buildUserPrincipal(username);
      await client.bind(userPrincipal, password);

      const directoryUser = await this.searchUser(client, username);
      const user = {
        id: directoryUser?.email || userPrincipal,
        name: directoryUser?.name || username,
        email:
          directoryUser?.email ||
          (config.ldap.domain ? `${username}@${config.ldap.domain}` : null),
        username: directoryUser?.username || username,
        provider: 'ldap' as const,
      };

      return {
        token: this.authToken.issueToken(user),
        user,
      };
    } catch (_error) {
      throw new UnauthorizedException('Autenticacao AD/LDAP falhou');
    } finally {
      await client.unbind().catch(() => undefined);
    }
  }

  private buildUserPrincipal(username: string) {
    const config = this.authConfig.getConfig();

    if (config.ldap.userDnTemplate) {
      return config.ldap.userDnTemplate.replaceAll('{{username}}', username);
    }

    if (config.ldap.domain) {
      return `${username}@${config.ldap.domain}`;
    }

    return username;
  }

  private async searchUser(client: Client, username: string) {
    const config = this.authConfig.getConfig();

    if (!config.ldap.searchBase) {
      return null;
    }

    const filter = config.ldap.searchFilter.replaceAll('{{username}}', username);
    const { searchEntries } = await client.search(config.ldap.searchBase, {
      scope: 'sub',
      filter,
      attributes: [
        'cn',
        'displayName',
        'givenName',
        'sn',
        'mail',
        'userPrincipalName',
        'sAMAccountName',
      ],
      sizeLimit: 1,
    });

    const entry = searchEntries[0] as Record<string, unknown> | undefined;

    if (!entry) {
      return null;
    }

    const givenName = this.getFirstValue(entry.givenName);
    const surname = this.getFirstValue(entry.sn);
    const fullName = [givenName, surname].filter(Boolean).join(' ');

    return {
      name:
        this.getFirstValue(entry.displayName) ||
        fullName ||
        this.getFirstValue(entry.cn) ||
        username,
      email: this.getFirstValue(entry.mail) || this.getFirstValue(entry.userPrincipalName) || null,
      username: this.getFirstValue(entry.sAMAccountName) || username,
    };
  }

  private getFirstValue(value: unknown): string | null {
    if (Array.isArray(value)) {
      return String(value[0] || '') || null;
    }

    return value ? String(value) : null;
  }
}