import { CosmosClient, Database, Container } from '@azure/cosmos';
import { SecretClient } from '@azure/keyvault-secrets';
import { DefaultAzureCredential } from '@azure/identity';

export interface ServiceContainer {
  cosmosClient: CosmosClient;
  database: Database;
  donationsContainer: Container;
  volunteersContainer: Container;
  programsContainer: Container;
  secretClient: SecretClient;
}

class DIContainer {
  private static instance: DIContainer;
  private services: ServiceContainer | null = null;

  private constructor() {}

  public static getInstance(): DIContainer {
    if (!DIContainer.instance) {
      DIContainer.instance = new DIContainer();
    }
    return DIContainer.instance;
  }

  public async initializeServices(): Promise<ServiceContainer> {
    if (this.services) {
      return this.services;
    }

    try {
      // Initialize Cosmos DB
      const cosmosConnectionString = process.env.COSMOS_CONNECTION_STRING;
      if (!cosmosConnectionString) {
        throw new Error('COSMOS_CONNECTION_STRING is not configured');
      }

      const cosmosClient = new CosmosClient(cosmosConnectionString);
      const databaseName = process.env.COSMOS_DATABASE_NAME || 'MiraclesInMotion';
      const database = cosmosClient.database(databaseName);

      // Get containers
      const donationsContainer = database.container('donations');
      const volunteersContainer = database.container('volunteers');
      const programsContainer = database.container('programs');

      // Initialize Key Vault
      const keyVaultUrl = process.env.KEY_VAULT_URL;
      if (!keyVaultUrl) {
        throw new Error('KEY_VAULT_URL is not configured');
      }

      const credential = new DefaultAzureCredential();
      const secretClient = new SecretClient(keyVaultUrl, credential);

      this.services = {
        cosmosClient,
        database,
        donationsContainer,
        volunteersContainer,
        programsContainer,
        secretClient
      };

      console.log('✅ Services initialized successfully');
      return this.services;
    } catch (error) {
      console.error('❌ Failed to initialize services:', error);
      throw error;
    }
  }

  public getServices(): ServiceContainer {
    if (!this.services) {
      throw new Error('Services not initialized. Call initializeServices() first.');
    }
    return this.services;
  }
}

export default DIContainer;