import { Injectable, Logger } from '@nestjs/common';
import { InjectDataSource } from '@nestjs/typeorm';
import { DataSource } from 'typeorm';
import { AuditService } from '../audit/audit.service';
import { AuditAction } from '../audit/entities/audit-log.entity';
import { ApiError } from '../common/errors/api-error';
import { ErrorCode } from '../common/errors/error-codes';
import { AppConfigService } from '../config/config.service';
import { RolesService } from '../roles/roles.service';
import { UserEntity } from '../users/entities/user.entity';
import {
  UserRoleAssignmentEntity,
  UserRoleAssignmentSource,
} from '../users/entities/user-role-assignment.entity';
import { OidcRoleExtractorService } from './oidc-role-extractor.service';

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

  constructor(
    private readonly config: AppConfigService,
    private readonly extractor: OidcRoleExtractorService,
    private readonly roles: RolesService,
    private readonly audit: AuditService,
    @InjectDataSource() private readonly dataSource: DataSource,
  ) {}

  async synchronize(
    userId: string,
    claims: Readonly<Record<string, unknown>>,
  ): Promise<UserEntity> {
    const adminRoleName = this.config.oidc.adminRole;
    if (!adminRoleName) return this.reloadUser(userId);
    const claimPath = this.config.oidc.rolesClaim;
    if (!claimPath)
      throw new Error(
        'OIDC_ROLES_CLAIM fehlt trotz validierter Konfiguration.',
      );
    console.log(claims, claimPath)
    const extracted = this.extractor.extract(claims, claimPath);
    if (!extracted.readable) {
      this.logger.error(
        { userId, claimPath, reason: extracted.reason },
        'OIDC-Administrator-Synchronisierung: Rollenclaim konnte nicht gelesen werden',
      );
      throw new ApiError(
        ErrorCode.Unauthorized,
        'Die OIDC-Rollen konnten nicht sicher validiert werden.',
        401,
      );
    }
    const normalize = (value: string) =>
      this.config.oidc.roleMatchCaseSensitive
        ? value
        : value.toLocaleLowerCase('en-US');
    const hasAdminRole = extracted.roles.some(
      (role) => normalize(role) === normalize(adminRoleName),
    );

    await this.dataSource.transaction(async (manager) => {
      const { admin } = await this.roles.ensureSystemRoles(manager);
      const assignments = manager.getRepository(UserRoleAssignmentEntity);
      const existing = await assignments.findOneBy({
        userId,
        roleId: admin.id,
        source: UserRoleAssignmentSource.Oidc,
      });
      if (hasAdminRole) {
        if (existing) {
          existing.lastSynchronizedAt = new Date();
          await assignments.save(existing);
        } else {
          await manager.query(
            `INSERT INTO user_role_assignments
               (id, user_id, role_id, source, last_synchronized_at, created_at, updated_at)
             VALUES (UUID(), ?, ?, ?, CURRENT_TIMESTAMP(3), CURRENT_TIMESTAMP(3), CURRENT_TIMESTAMP(3))
             ON DUPLICATE KEY UPDATE last_synchronized_at = CURRENT_TIMESTAMP(3), updated_at = CURRENT_TIMESTAMP(3)`,
            [userId, admin.id, UserRoleAssignmentSource.Oidc],
          );
          await manager.query(
            'INSERT IGNORE INTO user_roles (user_id, role_id) VALUES (?, ?)',
            [userId, admin.id],
          );
          await this.audit.record(
            userId,
            AuditAction.OidcAdminAssigned,
            'user',
            userId,
            {
              roleId: admin.id,
              oidcRole: adminRoleName,
              source: UserRoleAssignmentSource.Oidc,
            },
            manager,
          );
        }
      } else if (existing) {
        await assignments.remove(existing);
        const remaining = await assignments.countBy({
          userId,
          roleId: admin.id,
        });
        if (remaining === 0) {
          await manager.query(
            'DELETE FROM user_roles WHERE user_id = ? AND role_id = ?',
            [userId, admin.id],
          );
        }
        await this.audit.record(
          userId,
          AuditAction.OidcAdminRemoved,
          'user',
          userId,
          {
            roleId: admin.id,
            oidcRole: adminRoleName,
            source: UserRoleAssignmentSource.Oidc,
          },
          manager,
        );
      }
    });
    return this.reloadUser(userId);
  }

  private async reloadUser(userId: string): Promise<UserEntity> {
    const user = await this.dataSource.getRepository(UserEntity).findOne({
      where: { id: userId },
      relations: { roles: { permissions: true }, settings: true },
    });
    if (!user)
      throw new ApiError(
        ErrorCode.UserNotFound,
        'Der Benutzer wurde nicht gefunden.',
        404,
      );
    return user;
  }
}