import type { Logger } from '@stock-bot/logger';
import type {
  HttpClientConfig,
  RequestConfig,
  HttpResponse,
} from './types.js';
import {
  HttpError,
  TimeoutError,
  validateHttpClientConfig,
  validateRequestConfig,
} from './types.js';
import { RateLimiter } from './rate-limiter.js';
import { ProxyManager } from './proxy-manager.js';

export class HttpClient {
  private readonly config: HttpClientConfig;
  private readonly rateLimiter?: RateLimiter;
  private readonly logger?: Logger;
  constructor(config: Partial<HttpClientConfig> = {}, logger?: Logger) {
    // Validate and set default configuration
    this.config = validateHttpClientConfig(config);
    this.logger = logger;

    // Initialize rate limiter if configured
    if (this.config.rateLimit) {
      this.rateLimiter = new RateLimiter(this.config.rateLimit);
    }

    // Validate proxy configuration if provided
    if (this.config.proxy) {
      ProxyManager.validateConfig(this.config.proxy);
    }
  }

  /**
   * Make an HTTP request
   */  async request<T = any>(config: RequestConfig): Promise<HttpResponse<T>> {
    // Validate request configuration
    const validatedConfig = validateRequestConfig(config);
    
    // Merge with default configuration
    const finalConfig = this.mergeConfig(validatedConfig);

    // Check rate limiting
    if (this.rateLimiter) {
      await this.rateLimiter.checkRateLimit();
    }

    this.logger?.debug('Making HTTP request', { 
      method: finalConfig.method, 
      url: finalConfig.url 
    });    let lastError: Error | undefined;
    const maxRetries = finalConfig.retries ?? 3;

    for (let attempt = 0; attempt <= maxRetries; attempt++) {
      try {
        const response = await this.executeRequest<T>(finalConfig);
        
        // Record successful request for rate limiting
        if (this.rateLimiter) {
          this.rateLimiter.recordRequest(true);
        }

        this.logger?.debug('HTTP request successful', {
          method: finalConfig.method,
          url: finalConfig.url,
          status: response.status,
          attempt: attempt + 1,
        });

        return response;
      } catch (error) {
        lastError = error as Error;
        
        // Record failed request for rate limiting
        if (this.rateLimiter) {
          this.rateLimiter.recordRequest(false);
        }

        this.logger?.warn('HTTP request failed', {
          method: finalConfig.method,
          url: finalConfig.url,
          attempt: attempt + 1,
          error: lastError.message,
        });

        // Don't retry on certain errors
        if (error instanceof TimeoutError || 
            (error instanceof HttpError && error.status && error.status < 500)) {
          break;
        }

        // Wait before retrying (except on last attempt)
        if (attempt < maxRetries) {
          const delay = finalConfig.retryDelay ?? 1000;
          await this.sleep(delay * Math.pow(2, attempt)); // Exponential backoff
        }
      }
    }

    throw lastError;
  }

  /**
   * Convenience methods for common HTTP methods
   */
  async get<T = any>(url: string, config: Omit<RequestConfig, 'method' | 'url'> = {}): Promise<HttpResponse<T>> {
    return this.request<T>({ ...config, method: 'GET', url });
  }

  async post<T = any>(url: string, body?: any, config: Omit<RequestConfig, 'method' | 'url' | 'body'> = {}): Promise<HttpResponse<T>> {
    return this.request<T>({ ...config, method: 'POST', url, body });
  }

  async put<T = any>(url: string, body?: any, config: Omit<RequestConfig, 'method' | 'url' | 'body'> = {}): Promise<HttpResponse<T>> {
    return this.request<T>({ ...config, method: 'PUT', url, body });
  }

  async delete<T = any>(url: string, config: Omit<RequestConfig, 'method' | 'url'> = {}): Promise<HttpResponse<T>> {
    return this.request<T>({ ...config, method: 'DELETE', url });
  }

  async patch<T = any>(url: string, body?: any, config: Omit<RequestConfig, 'method' | 'url' | 'body'> = {}): Promise<HttpResponse<T>> {
    return this.request<T>({ ...config, method: 'PATCH', url, body });
  }

  /**
   * Execute the actual HTTP request
   */  private async executeRequest<T>(config: RequestConfig): Promise<HttpResponse<T>> {
    const url = this.buildUrl(config.url);
    const timeout = config.timeout ?? 30000;
    
    // Create abort controller for timeout
    const abortController = new AbortController();
    const timeoutId = setTimeout(() => {
      abortController.abort();
    }, timeout);

    try {      // Prepare request options
      const requestOptions: RequestInit = {
        method: config.method,
        headers: config.headers ? {...config.headers} : {},
        signal: abortController.signal,
      };
      
      // Add basic auth if provided
      if (config.auth) {
        const authValue = `Basic ${Buffer.from(`${config.auth.username}:${config.auth.password}`).toString('base64')}`;
        requestOptions.headers = {
          ...requestOptions.headers,
          'Authorization': authValue
        };
      }

      // Add body for non-GET requests
      if (config.body && config.method !== 'GET' && config.method !== 'HEAD') {
        if (typeof config.body === 'object') {
          requestOptions.body = JSON.stringify(config.body);
          requestOptions.headers = {
            'Content-Type': 'application/json',
            ...requestOptions.headers,
          };
        } else {
          requestOptions.body = config.body;
        }
      }

      // Add proxy agent if configured
      if (this.config.proxy) {
        const agent = ProxyManager.createAgent(this.config.proxy);
        (requestOptions as any).agent = agent;
      }

      // Make the request
      const response = await fetch(url, requestOptions);

      // Clear timeout
      clearTimeout(timeoutId);

      // Check if response status is valid
      const validateStatus = config.validateStatus ?? this.config.validateStatus ?? this.defaultValidateStatus;
      if (!validateStatus(response.status)) {
        throw new HttpError(
          `Request failed with status ${response.status}`,
          response.status,
          undefined,
          config
        );
      }

      // Parse response
      const responseHeaders: Record<string, string> = {};
      response.headers.forEach((value, key) => {
        responseHeaders[key] = value;
      });

      let data: T;
      const contentType = response.headers.get('content-type') || '';
      
      if (contentType.includes('application/json')) {
        data = await response.json();
      } else if (contentType.includes('text/')) {
        data = await response.text() as any;
      } else {
        data = await response.arrayBuffer() as any;
      }

      return {
        data,
        status: response.status,
        statusText: response.statusText,
        headers: responseHeaders,
        config,
      };
    } catch (error) {
      clearTimeout(timeoutId);
      
      if (abortController.signal.aborted) {
        throw new TimeoutError(config, timeout);
      }
      
      if (error instanceof HttpError) {
        throw error;
      }
      
      throw new HttpError(`Request failed: ${(error as Error).message}`, undefined, undefined, config);
    }
  }

  /**
   * Merge request config with default config
   */  private mergeConfig(config: RequestConfig): RequestConfig {
    return {
      ...config,
      headers: {
        ...this.config.defaultHeaders,
        ...config.headers,
      },
      timeout: config.timeout ?? this.config.timeout ?? 30000,
      retries: config.retries ?? this.config.retries ?? 3,
      retryDelay: config.retryDelay ?? this.config.retryDelay ?? 1000,
      validateStatus: config.validateStatus ?? this.config.validateStatus ?? this.defaultValidateStatus,
    };
  }
  /**
   * Build full URL from base URL and request URL
   */
  private buildUrl(url: string): string {
    // If it's already a full URL, return it as is
    if (url.startsWith('http://') || url.startsWith('https://')) {
      return url;
    }
    
    // If we have a baseURL, combine them
    if (this.config.baseURL) {
      try {
        // Try to use URL constructor
        return new URL(url, this.config.baseURL).toString();
      } catch (e) {
        // Fall back to string concatenation if URL constructor fails
        const base = this.config.baseURL.endsWith('/') ? this.config.baseURL : `${this.config.baseURL}/`;
        const path = url.startsWith('/') ? url.substring(1) : url;
        return `${base}${path}`;
      }
    }
    
    // No baseURL, so prepend https:// if it's a domain-like string
    if (!url.includes('://') && url.includes('.')) {
      return `https://${url}`;
    }
    
    return url;
  }

  /**
   * Default status validator
   */
  private defaultValidateStatus(status: number): boolean {
    return status >= 200 && status < 300;
  }

  /**
   * Sleep utility for retries
   */
  private sleep(ms: number): Promise<void> {
    return new Promise(resolve => setTimeout(resolve, ms));
  }

  /**
   * Get current rate limiting status
   */
  getRateLimitStatus() {
    if (!this.rateLimiter) {
      return null;
    }

    return {
      currentCount: this.rateLimiter.getCurrentCount(),
      maxRequests: this.config.rateLimit!.maxRequests,
      windowMs: this.config.rateLimit!.windowMs,
      timeUntilReset: this.rateLimiter.getTimeUntilReset(),
    };
  }
}