stock-bot/libs/core/di/src/service-container.ts

import { getLogger, type Logger } from '@stock-bot/logger';
import type { ConnectionFactory } from './connection-factory';

export interface ServiceRegistration<T = any> {
  name: string;
  factory: () => T | Promise<T>;
  singleton?: boolean;
  dispose?: (instance: T) => Promise<void>;
}

export interface ServiceResolver {
  resolve<T>(name: string, options?: any): T;
  resolveAsync<T>(name: string, options?: any): Promise<T>;
}

export class ServiceContainer implements ServiceResolver {
  private readonly logger: Logger;
  private readonly registrations = new Map<string, ServiceRegistration>();
  private readonly instances = new Map<string, any>();
  private readonly scopedInstances = new Map<string, any>();
  private readonly parent?: ServiceContainer;

  constructor(name: string, parent?: ServiceContainer) {
    this.logger = getLogger(`service-container:${name}`);
    this.parent = parent;
  }

  register<T>(registration: ServiceRegistration<T>): void {
    this.registrations.set(registration.name, registration);
    this.logger.debug('Service registered', { name: registration.name, singleton: registration.singleton });
  }

  resolve<T>(name: string, _options?: any): T {
    // Check scoped instances first
    if (this.scopedInstances.has(name)) {
      return this.scopedInstances.get(name);
    }

    // Check singleton instances
    if (this.instances.has(name)) {
      return this.instances.get(name);
    }

    // Get registration from this container or parent
    const registration = this.getRegistration(name);
    if (!registration) {
      throw new Error(`Service ${name} not registered`);
    }

    // Create instance synchronously
    const instance = registration.factory();
    
    // Check if factory returned a promise
    if (instance instanceof Promise) {
      throw new Error(`Service ${name} is async. Use resolveAsync() instead.`);
    }

    // Store based on singleton flag
    if (registration.singleton) {
      this.instances.set(name, instance);
    } else {
      this.scopedInstances.set(name, instance);
    }

    return instance as T;
  }

  async resolveAsync<T>(name: string, _options?: any): Promise<T> {
    // Check scoped instances first
    if (this.scopedInstances.has(name)) {
      return this.scopedInstances.get(name);
    }

    // Check singleton instances
    if (this.instances.has(name)) {
      return this.instances.get(name);
    }

    // Get registration from this container or parent
    const registration = this.getRegistration(name);
    if (!registration) {
      throw new Error(`Service ${name} not registered`);
    }

    // Create instance
    const instance = await Promise.resolve(registration.factory());

    // Store based on singleton flag
    if (registration.singleton) {
      this.instances.set(name, instance);
    } else {
      this.scopedInstances.set(name, instance);
    }

    return instance as T;
  }

  createScope(): ServiceContainer {
    return new ServiceContainer('scoped', this);
  }

  async dispose(): Promise<void> {
    // Dispose scoped instances
    for (const [name, instance] of this.scopedInstances.entries()) {
      const registration = this.getRegistration(name);
      if (registration?.dispose) {
        await registration.dispose(instance);
      }
    }
    this.scopedInstances.clear();

    // Only dispose singletons if this is the root container
    if (!this.parent) {
      for (const [name, instance] of this.instances.entries()) {
        const registration = this.registrations.get(name);
        if (registration?.dispose) {
          await registration.dispose(instance);
        }
      }
      this.instances.clear();
    }
  }

  private getRegistration(name: string): ServiceRegistration | undefined {
    return this.registrations.get(name) || this.parent?.getRegistration(name);
  }
}

// Enhanced service container factory with infrastructure services
export function createServiceContainer(
  serviceName: string,
  connectionFactory: ConnectionFactory,
  config?: any
): ServiceContainer {
  const container = new ServiceContainer(serviceName);
  
  // Register configuration if provided
  if (config) {
    container.register({
      name: 'config',
      factory: () => config,
      singleton: true,
    });
  }

  // Register connection factories
  container.register({
    name: 'mongodb',
    factory: async () => {
      const pool = await connectionFactory.createMongoDB({
        name: 'default',
        config: {} as any, // Config injected by factory
      });
      return pool.client;
    },
    singleton: true,
  });

  container.register({
    name: 'postgres',
    factory: async () => {
      const pool = await connectionFactory.createPostgreSQL({
        name: 'default',
        config: {} as any, // Config injected by factory
      });
      return pool.client;
    },
    singleton: true,
  });

  container.register({
    name: 'cache',
    factory: async () => {
      const pool = await connectionFactory.createCache({
        name: 'default',
        config: {} as any, // Config injected by factory
      });
      return pool.client;
    },
    singleton: true,
  });

  container.register({
    name: 'queue',
    factory: async () => {
      const pool = await connectionFactory.createQueue({
        name: 'default',
        config: {} as any, // Config injected by factory
      });
      return pool.client;
    },
    singleton: true,
  });

  // Note: Additional services can be registered by individual applications as needed:
  // - ProxyManager: container.register({ name: 'proxyManager', factory: () => ProxyManager.getInstance() })
  // - Browser: container.register({ name: 'browser', factory: () => Browser })  
  // - HttpClient: container.register({ name: 'httpClient', factory: () => createHttpClient(...) })

  return container;
}