import { Injectable } from '@nestjs/common';
import type { BackupConnectionTestResult, BackupSettingsView } from '@dorfteich/shared';
import { webdavCheck, type WebDavTarget } from '@dorfteich/shared/webdav';

import { SecretStoreService } from '../config/secret-store.service';
import { InstanceSettingsService } from '../settings/instance-settings.service';

/**
 * The api's view of the Nextcloud backup target (issue #103): instance
 * settings hold everything non-secret, the app password lives in the
 * wizard-written secret store (security.md §Secrets) under the key the
 * backup sidecar reads. This service resolves, tests, and persists the
 * combination — it never returns the password.
 */
export const NEXTCLOUD_PASSWORD_SECRET_KEY = 'BACKUP_NEXTCLOUD_PASSWORD';

@Injectable()
export class BackupTargetService {
  constructor(
    private readonly settings: InstanceSettingsService,
    private readonly secretStore: SecretStoreService,
  ) {}

  async settingsView(): Promise<BackupSettingsView> {
    return {
      localRetentionDays: await this.settings.get('backup.localRetentionDays'),
      remoteRetentionDays: await this.settings.get('backup.remoteRetentionDays'),
      nextcloud: {
        enabled: await this.settings.get('backup.nextcloud.enabled'),
        baseUrl: await this.settings.get('backup.nextcloud.baseUrl'),
        username: await this.settings.get('backup.nextcloud.username'),
        folder: await this.settings.get('backup.nextcloud.folder'),
        uploadSchedule: await this.settings.get('backup.nextcloud.uploadSchedule'),
        passwordSet: Boolean(this.storedPassword()),
      },
    };
  }

  /**
   * The effective WebDAV target, or null when disabled or not fully
   * configured — the exact resolution the sidecar applies on its side.
   */
  async resolveTarget(): Promise<WebDavTarget | null> {
    const view = await this.settingsView();
    const password = this.storedPassword();
    const { enabled, baseUrl, username, folder } = view.nextcloud;
    if (!enabled || !baseUrl || !username || !password) return null;
    return { baseUrl, username, password, folder };
  }

  /**
   * Live connection test (credentials + folder, creating missing folder
   * segments) for the admin "test connection" button. An empty password
   * falls back to the stored one, so a saved configuration can be re-tested
   * without re-entering the secret.
   */
  async testConnection(candidate: {
    baseUrl: string;
    username: string;
    folder: string;
    password?: string;
  }): Promise<BackupConnectionTestResult> {
    const password = candidate.password || this.storedPassword();
    if (!password) return { ok: false, error: 'no app password provided or stored' };
    const result = await webdavCheck({
      baseUrl: candidate.baseUrl,
      username: candidate.username,
      folder: candidate.folder,
      password,
    });
    return result.ok ? { ok: true } : { ok: false, error: result.error };
  }

  /** Stores a new app password; empty input keeps the current one. */
  async storePassword(password: string): Promise<void> {
    if (!password) return;
    await this.secretStore.set({ [NEXTCLOUD_PASSWORD_SECRET_KEY]: password });
  }

  storedPassword(): string {
    return this.secretStore.read()[NEXTCLOUD_PASSWORD_SECRET_KEY] ?? '';
  }
}