import { Module, DynamicModule, Provider } from '@nestjs/common';
import {
  TelegrafModuleAsyncOptions,
  TelegrafOptionsFactory
} from './interfaces';
import {
  TELEGRAF_MODULE_OPTIONS,
  TokenInjectionToken
} from './telegraf.constants';
import { TelegrafService, TelegrafTelegramService } from './';

@Module({})
export class TelegrafModule {
  static fromFactory(options: TelegrafModuleAsyncOptions): DynamicModule {
    return {
      module: TelegrafModule,
      imports: options.imports || [],
      providers: [
        ...this.createAsyncProviders(options),
        TelegrafService,
        TelegrafTelegramService,
        {
          provide: TokenInjectionToken,
          useClass: options.useClass
        }
      ],
      exports: [TelegrafService, TelegrafTelegramService]
    };
  }

  private static createAsyncProviders(
    options: TelegrafModuleAsyncOptions
  ): Provider[] {
    if (options.useExisting || options.useFactory) {
      return [this.createAsyncOptionsProvider(options)];
    }
    return [
      this.createAsyncOptionsProvider(options),
      {
        provide: options.useClass,
        useClass: options.useClass
      }
    ];
  }

  private static createAsyncOptionsProvider(
    options: TelegrafModuleAsyncOptions
  ): Provider {
    if (options.useFactory) {
      return {
        provide: TELEGRAF_MODULE_OPTIONS,
        useFactory: options.useFactory,
        inject: options.inject || []
      };
    }
    return {
      provide: TELEGRAF_MODULE_OPTIONS,
      useFactory: async (optionsFactory: TelegrafOptionsFactory) =>
        await optionsFactory.createTelegrafOptions(),
      inject: [options.useExisting || options.useClass]
    };
  }
}