import * as plugins from '../plugins.js';

/**
 * Base provider entry for tracking provider state
 */
export interface IBaseProviderEntry<TProvider> {
  provider: TProvider;
  config: IBaseProviderConfig;
  lastError?: Error;
  lastErrorTime?: Date;
  successCount: number;
  errorCount: number;
}

/**
 * Base provider configuration
 */
export interface IBaseProviderConfig {
  enabled: boolean;
  priority: number;
  timeout?: number;
  retryAttempts?: number;
  retryDelay?: number;
  cacheTTL?: number;
}

/**
 * Base provider interface
 */
export interface IBaseProvider {
  name: string;
  priority: number;
  isAvailable(): Promise<boolean>;
  readonly requiresAuth: boolean;
  readonly rateLimit?: {
    requestsPerMinute: number;
    requestsPerDay?: number;
  };
}

/**
 * Cache entry for any data type
 */
export interface IBaseCacheEntry<TData> {
  data: TData;
  timestamp: Date;
  ttl: number;
}

/**
 * Base service for managing data providers with caching
 * Shared logic extracted from StockPriceService and FundamentalsService
 */
export abstract class BaseProviderService<TProvider extends IBaseProvider, TData> {
  protected providers = new Map<string, IBaseProviderEntry<TProvider>>();
  protected cache = new Map<string, IBaseCacheEntry<TData>>();
  protected logger = console;

  protected cacheConfig = {
    ttl: 60000, // Default 60 seconds
    maxEntries: 10000
  };

  constructor(cacheConfig?: { ttl?: number; maxEntries?: number }) {
    if (cacheConfig) {
      this.cacheConfig = { ...this.cacheConfig, ...cacheConfig };
    }
  }

  /**
   * Register a provider
   */
  public register(provider: TProvider, config?: Partial<IBaseProviderConfig>): void {
    const defaultConfig: IBaseProviderConfig = {
      enabled: true,
      priority: provider.priority,
      timeout: 30000,
      retryAttempts: 2,
      retryDelay: 1000,
      cacheTTL: this.cacheConfig.ttl
    };

    const mergedConfig = { ...defaultConfig, ...config };

    this.providers.set(provider.name, {
      provider,
      config: mergedConfig,
      successCount: 0,
      errorCount: 0
    });

    console.log(`Registered provider: ${provider.name}`);
  }

  /**
   * Unregister a provider
   */
  public unregister(providerName: string): void {
    this.providers.delete(providerName);
    console.log(`Unregistered provider: ${providerName}`);
  }

  /**
   * Get a specific provider by name
   */
  public getProvider(name: string): TProvider | undefined {
    return this.providers.get(name)?.provider;
  }

  /**
   * Get all registered providers
   */
  public getAllProviders(): TProvider[] {
    return Array.from(this.providers.values()).map(entry => entry.provider);
  }

  /**
   * Get enabled providers sorted by priority
   */
  public getEnabledProviders(): TProvider[] {
    return Array.from(this.providers.values())
      .filter(entry => entry.config.enabled)
      .sort((a, b) => (b.config.priority || 0) - (a.config.priority || 0))
      .map(entry => entry.provider);
  }

  /**
   * Check health of all providers
   */
  public async checkProvidersHealth(): Promise<Map<string, boolean>> {
    const health = new Map<string, boolean>();

    for (const [name, entry] of this.providers) {
      if (!entry.config.enabled) {
        health.set(name, false);
        continue;
      }

      try {
        const isAvailable = await entry.provider.isAvailable();
        health.set(name, isAvailable);
      } catch (error) {
        health.set(name, false);
        console.error(`Health check failed for ${name}:`, error);
      }
    }

    return health;
  }

  /**
   * Get provider statistics
   */
  public getProviderStats(): Map<
    string,
    {
      successCount: number;
      errorCount: number;
      lastError?: string;
      lastErrorTime?: Date;
    }
  > {
    const stats = new Map();

    for (const [name, entry] of this.providers) {
      stats.set(name, {
        successCount: entry.successCount,
        errorCount: entry.errorCount,
        lastError: entry.lastError?.message,
        lastErrorTime: entry.lastErrorTime
      });
    }

    return stats;
  }

  /**
   * Clear all cached data
   */
  public clearCache(): void {
    this.cache.clear();
    console.log('Cache cleared');
  }

  /**
   * Set cache TTL
   */
  public setCacheTTL(ttl: number): void {
    this.cacheConfig.ttl = ttl;
    console.log(`Cache TTL set to ${ttl}ms`);
  }

  /**
   * Get cache statistics
   */
  public getCacheStats(): {
    size: number;
    maxEntries: number;
    ttl: number;
  } {
    return {
      size: this.cache.size,
      maxEntries: this.cacheConfig.maxEntries,
      ttl: this.cacheConfig.ttl
    };
  }

  /**
   * Fetch with retry logic
   */
  protected async fetchWithRetry<T>(
    fetchFn: () => Promise<T>,
    config: IBaseProviderConfig
  ): Promise<T> {
    const maxAttempts = config.retryAttempts || 1;
    let lastError: Error | undefined;

    for (let attempt = 1; attempt <= maxAttempts; attempt++) {
      try {
        return await fetchFn();
      } catch (error) {
        lastError = error as Error;

        if (attempt < maxAttempts) {
          const delay = (config.retryDelay || 1000) * attempt;
          console.log(`Retry attempt ${attempt} after ${delay}ms`);
          await plugins.smartdelay.delayFor(delay);
        }
      }
    }

    throw lastError || new Error('Unknown error during fetch');
  }

  /**
   * Get from cache if not expired
   */
  protected getFromCache(key: string): TData | null {
    const entry = this.cache.get(key);

    if (!entry) {
      return null;
    }

    // Check if cache entry has expired
    const age = Date.now() - entry.timestamp.getTime();
    if (entry.ttl !== Infinity && age > entry.ttl) {
      this.cache.delete(key);
      return null;
    }

    return entry.data;
  }

  /**
   * Add to cache with TTL
   */
  protected addToCache(key: string, data: TData, ttl?: number): void {
    // Enforce max entries limit
    if (this.cache.size >= this.cacheConfig.maxEntries) {
      // Remove oldest entry
      const oldestKey = this.cache.keys().next().value;
      if (oldestKey) {
        this.cache.delete(oldestKey);
      }
    }

    this.cache.set(key, {
      data,
      timestamp: new Date(),
      ttl: ttl || this.cacheConfig.ttl
    });
  }

  /**
   * Track successful fetch for provider
   */
  protected trackSuccess(providerName: string): void {
    const entry = this.providers.get(providerName);
    if (entry) {
      entry.successCount++;
    }
  }

  /**
   * Track failed fetch for provider
   */
  protected trackError(providerName: string, error: Error): void {
    const entry = this.providers.get(providerName);
    if (entry) {
      entry.errorCount++;
      entry.lastError = error;
      entry.lastErrorTime = new Date();
    }
  }
}