/**
 * AnalyticsModule - NestJS module for backend analytics
 *
 * Provides:
 * - BackendAnalyticsClient for manual tracking
 * - Global interceptor for automatic request tracking
 * - @TrackAnalytics decorator for method-level tracking
 */

import { Module, Global, DynamicModule } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

import { BackendAnalyticsClient } from '@analytics/client';
import type { BackendAnalyticsConfig } from '@analytics/client';

export const ANALYTICS_CLIENT = 'ANALYTICS_CLIENT';

export interface AnalyticsModuleOptions {
  /**
   * Analytics collector URL.
   */
  collectorUrl: string;

  /**
   * Application name for event attribution.
   */
  appName: string;

  /**
   * Enable/disable tracking (useful for tests).
   */
  enabled?: boolean;

  /**
   * Enable debug logging.
   */
  debug?: boolean;
}

@Global()
@Module({})
export class AnalyticsModule {
  /**
   * Register with static configuration.
   *
   * @example
   * ```ts
   * AnalyticsModule.register({
   *   collectorUrl: 'http://localhost:4001',
   *   appName: 'my-api',
   * })
   * ```
   */
  static register(options: AnalyticsModuleOptions): DynamicModule {
    return {
      module: AnalyticsModule,
      providers: [
        {
          provide: ANALYTICS_CLIENT,
          useFactory: () => {
            const config: BackendAnalyticsConfig = {
              apiBaseUrl: options.collectorUrl,
              appName: options.appName,
              enabled: options.enabled ?? true,
              enableDebugLogging: options.debug ?? false,
            };
            return new BackendAnalyticsClient(config);
          },
        },
      ],
      exports: [ANALYTICS_CLIENT],
    };
  }

  /**
   * Register with async configuration (for ConfigService).
   *
   * @example
   * ```ts
   * AnalyticsModule.registerAsync({
   *   inject: [ConfigService],
   *   useFactory: (config: ConfigService) => ({
   *     collectorUrl: config.get('ANALYTICS_COLLECTOR_URL'),
   *     appName: config.get('APP_NAME'),
   *     enabled: config.get('NODE_ENV') !== 'test',
   *   }),
   * })
   * ```
   */
  static registerAsync(options: {
    inject?: any[];
    useFactory: (...args: any[]) => AnalyticsModuleOptions | Promise<AnalyticsModuleOptions>;
  }): DynamicModule {
    return {
      module: AnalyticsModule,
      providers: [
        {
          provide: ANALYTICS_CLIENT,
          inject: options.inject || [],
          useFactory: async (...args: any[]) => {
            const moduleOptions = await options.useFactory(...args);
            const config: BackendAnalyticsConfig = {
              apiBaseUrl: moduleOptions.collectorUrl,
              appName: moduleOptions.appName,
              enabled: moduleOptions.enabled ?? true,
              enableDebugLogging: moduleOptions.debug ?? false,
            };
            return new BackendAnalyticsClient(config);
          },
        },
      ],
      exports: [ANALYTICS_CLIENT],
    };
  }
}

/**
 * Example AppModule setup:
 *
 * ```ts
 * @Module({
 *   imports: [
 *     ConfigModule.forRoot({ isGlobal: true }),
 *     AnalyticsModule.registerAsync({
 *       inject: [ConfigService],
 *       useFactory: (config: ConfigService) => ({
 *         collectorUrl: config.get('ANALYTICS_URL', 'http://localhost:4001'),
 *         appName: 'my-api',
 *         enabled: config.get('NODE_ENV') !== 'test',
 *         debug: config.get('NODE_ENV') === 'development',
 *       }),
 *     }),
 *   ],
 * })
 * export class AppModule {}
 * ```
 */