/**
 * OperationContext - Unified context for handler operations
 * 
 * Provides streamlined access to:
 * - Child loggers with hierarchical context
 * - Database clients (MongoDB, PostgreSQL) 
 * - Contextual cache with automatic key prefixing
 * - Shared resource management
 */

import { createCache, type CacheProvider } from '@stock-bot/cache';
import { getLogger, type Logger } from '@stock-bot/logger';
import { getDatabaseConfig } from '@stock-bot/config';
import type { ServiceResolver } from './service-container';
import type { MongoDBClient } from '@stock-bot/mongodb';
import type { PostgreSQLClient } from '@stock-bot/postgres';

export interface OperationContextOptions {
  handlerName: string;
  operationName: string;
  parentLogger?: Logger;
  container?: ServiceResolver;
}

export class OperationContext {
  public readonly logger: Logger;
  private readonly container?: ServiceResolver;
  private _mongodb?: MongoDBClient;
  private _postgres?: PostgreSQLClient;
  private _cache?: CacheProvider;
  private _queue?: any; // Type will be QueueManager but we avoid import for circular deps
  
  private static sharedCache: CacheProvider | null = null;
  private static parentLoggers = new Map<string, Logger>();
  private static databaseConfig: any = null;
  
  constructor(
    public readonly handlerName: string,
    public readonly operationName: string,
    parentLoggerOrOptions?: Logger | OperationContextOptions
  ) {
    // Handle both old and new constructor signatures
    if (parentLoggerOrOptions && 'container' in parentLoggerOrOptions) {
      const options = parentLoggerOrOptions;
      this.container = options.container;
      const parent = options.parentLogger || this.getOrCreateParentLogger();
      this.logger = parent.child(operationName, {
        handler: handlerName,
        operation: operationName
      });
    } else {
      // Legacy support
      const parentLogger = parentLoggerOrOptions as Logger | undefined;
      const parent = parentLogger || this.getOrCreateParentLogger();
      this.logger = parent.child(operationName, {
        handler: handlerName,
        operation: operationName
      });
    }
  }
  
  // Lazy load MongoDB client
  get mongodb(): MongoDBClient {
    if (!this._mongodb) {
      if (this.container) {
        try {
          this._mongodb = this.container.resolve<MongoDBClient>('mongodb');
        } catch (error) {
          this.logger.warn('Failed to resolve MongoDB from container, falling back to singleton', { error });
          this._mongodb = this.getLegacyDatabaseClient('mongodb') as MongoDBClient;
        }
      } else {
        this._mongodb = this.getLegacyDatabaseClient('mongodb') as MongoDBClient;
      }
    }
    return this._mongodb!;
  }
  
  // Lazy load PostgreSQL client
  get postgres(): PostgreSQLClient {
    if (!this._postgres) {
      if (this.container) {
        try {
          this._postgres = this.container.resolve<PostgreSQLClient>('postgres');
        } catch (error) {
          this.logger.warn('Failed to resolve PostgreSQL from container, falling back to singleton', { error });
          this._postgres = this.getLegacyDatabaseClient('postgres') as PostgreSQLClient;
        }
      } else {
        this._postgres = this.getLegacyDatabaseClient('postgres') as PostgreSQLClient;
      }
    }
    return this._postgres!;
  }
  
  // Lazy load QueueManager
  get queue(): any {
    if (!this._queue) {
      if (this.container) {
        try {
          this._queue = this.container.resolve('queue');
        } catch (error) {
          this.logger.warn('Failed to resolve QueueManager from container, falling back to singleton', { error });
          this._queue = this.getLegacyQueueManager();
        }
      } else {
        this._queue = this.getLegacyQueueManager();
      }
    }
    return this._queue!;
  }
  
  // Legacy method for QueueManager
  private getLegacyQueueManager(): any {
    try {
      // Dynamic import to avoid TypeScript issues during build
      const { QueueManager } = require('@stock-bot/queue');
      return QueueManager.getInstance();
    } catch (error) {
      this.logger.warn('QueueManager not initialized, queue operations may fail', { error });
      throw new Error('QueueManager not available');
    }
  }
  
  // Legacy method for backward compatibility
  private getLegacyDatabaseClient(type: 'mongodb' | 'postgres'): any {
    try {
      if (type === 'mongodb') {
        // Dynamic import to avoid TypeScript issues during build
        const { getMongoDBClient } = require('@stock-bot/mongodb');
        return getMongoDBClient();
      } else {
        // Dynamic import to avoid TypeScript issues during build
        const { getPostgreSQLClient } = require('@stock-bot/postgres');
        return getPostgreSQLClient();
      }
    } catch (error) {
      this.logger.warn(`${type} client not initialized, operations may fail`, { error });
      return null;
    }
  }
  
  private getOrCreateParentLogger(): Logger {
    const parentKey = `${this.handlerName}-handler`;
    
    if (!OperationContext.parentLoggers.has(parentKey)) {
      const parentLogger = getLogger(parentKey);
      OperationContext.parentLoggers.set(parentKey, parentLogger);
    }
    
    return OperationContext.parentLoggers.get(parentKey)!;
  }
  
  /**
   * Get contextual cache with automatic key prefixing
   * Keys are automatically prefixed as: "operations:handlerName:operationName:key"
   */
  get cache(): CacheProvider {
    if (!this._cache) {
      if (this.container) {
        try {
          const baseCache = this.container.resolve<CacheProvider>('cache');
          this._cache = this.createContextualCache(baseCache);
        } catch (error) {
          this.logger.warn('Failed to resolve cache from container, using shared cache', { error });
          this._cache = this.getOrCreateSharedCache();
        }
      } else {
        this._cache = this.getOrCreateSharedCache();
      }
    }
    return this._cache!;
  }
  
  private getOrCreateSharedCache(): CacheProvider {
    if (!OperationContext.sharedCache) {
      // Get Redis configuration from database config
      if (!OperationContext.databaseConfig) {
        OperationContext.databaseConfig = getDatabaseConfig();
      }
      
      const redisConfig = OperationContext.databaseConfig.dragonfly || {
        host: 'localhost',
        port: 6379,
        db: 1
      };
      
      OperationContext.sharedCache = createCache({
        keyPrefix: 'operations:',
        shared: true, // Use singleton Redis connection
        enableMetrics: true,
        ttl: 3600, // Default 1 hour TTL
        redisConfig
      });
    }
    return this.createContextualCache(OperationContext.sharedCache);
  }
  
  private createContextualCache(baseCache: CacheProvider): CacheProvider {
    const contextPrefix = `${this.handlerName}:${this.operationName}:`;
    
    // Return a proxy that automatically prefixes keys with context
    return {
      async get<T>(key: string): Promise<T | null> {
        return baseCache.get(`${contextPrefix}${key}`);
      },
      
      async set<T>(key: string, value: T, options?: any): Promise<T | null> {
        return baseCache.set(`${contextPrefix}${key}`, value, options);
      },
      
      async del(key: string): Promise<void> {
        return baseCache.del(`${contextPrefix}${key}`);
      },
      
      async exists(key: string): Promise<boolean> {
        return baseCache.exists(`${contextPrefix}${key}`);
      },
      
      async clear(): Promise<void> {
        // Not implemented for contextual cache - use del() for specific keys
        throw new Error('clear() not implemented for contextual cache - use del() for specific keys');
      },
      
      async keys(pattern: string): Promise<string[]> {
        const fullPattern = `${contextPrefix}${pattern}`;
        return baseCache.keys(fullPattern);
      },
      
      getStats() {
        return baseCache.getStats();
      },
      
      async health(): Promise<boolean> {
        return baseCache.health();
      },
      
      async waitForReady(timeout?: number): Promise<void> {
        return baseCache.waitForReady(timeout);
      },
      
      isReady(): boolean {
        return baseCache.isReady();
      }
    } as CacheProvider;
  }
  
  /**
   * Factory method to create OperationContext
   */
  static create(handlerName: string, operationName: string, parentLoggerOrOptions?: Logger | OperationContextOptions): OperationContext {
    if (parentLoggerOrOptions && 'container' in parentLoggerOrOptions) {
      return new OperationContext(handlerName, operationName, {
        ...parentLoggerOrOptions,
        handlerName,
        operationName
      });
    }
    return new OperationContext(handlerName, operationName, parentLoggerOrOptions as Logger | undefined);
  }
  
  /**
   * Get cache key prefix for this operation context
   */
  getCacheKeyPrefix(): string {
    return `operations:${this.handlerName}:${this.operationName}:`;
  }
  
  /**
   * Create a child context for sub-operations
   */
  createChild(subOperationName: string): OperationContext {
    if (this.container) {
      return new OperationContext(
        this.handlerName,
        `${this.operationName}:${subOperationName}`,
        { 
          handlerName: this.handlerName,
          operationName: `${this.operationName}:${subOperationName}`,
          parentLogger: this.logger, 
          container: this.container 
        }
      );
    }
    return new OperationContext(
      this.handlerName,
      `${this.operationName}:${subOperationName}`,
      this.logger
    );
  }
  
  /**
   * Dispose of resources if using container-based connections
   * This is a no-op for legacy singleton connections
   */
  async dispose(): Promise<void> {
    // If using container, it will handle cleanup
    // For singleton connections, they persist
    this.logger.debug('OperationContext disposed', {
      handler: this.handlerName,
      operation: this.operationName,
      hasContainer: !!this.container
    });
  }
}

export default OperationContext;