/**
 * API CLIENT SYSTEM
 * Professional REST API Client
 */

class APIClient {
  constructor(baseURL, options = {}) {
    this.baseURL = baseURL;
    this.options = {
      timeout: 10000,
      retries: 3,
      retryDelay: 1000,
      headers: {
        'Content-Type': 'application/json',
        'Accept': 'application/json'
      },
      ...options
    };
    
    this.requestInterceptors = [];
    this.responseInterceptors = [];
    this.authToken = null;
  }

  // Request Interceptors
  useRequestInterceptor(interceptor) {
    this.requestInterceptors.push(interceptor);
  }

  // Response Interceptors
  useResponseInterceptor(interceptor) {
    this.responseInterceptors.push(interceptor);
  }

  // Authentication
  setAuthToken(token) {
    this.authToken = token;
    this.options.headers['Authorization'] = `Bearer ${token}`;
  }

  // HTTP Methods
  async get(url, options = {}) {
    return this.request('GET', url, null, options);
  }

  async post(url, data = null, options = {}) {
    return this.request('POST', url, data, options);
  }

  async put(url, data = null, options = {}) {
    return this.request('PUT', url, data, options);
  }

  async patch(url, data = null, options = {}) {
    return this.request('PATCH', url, data, options);
  }

  async delete(url, options = {}) {
    return this.request('DELETE', url, null, options);
  }

  // Main Request Method
  async request(method, url, data = null, options = {}) {
    const config = {
      method,
      headers: { ...this.options.headers },
      ...options
    };

    // Add auth token if available
    if (this.authToken) {
      config.headers['Authorization'] = `Bearer ${this.authToken}`;
    }

    // Add data for POST/PUT/PATCH requests
    if (data && ['POST', 'PUT', 'PATCH'].includes(method)) {
      config.body = JSON.stringify(data);
    }

    // Apply request interceptors
    let finalUrl = this.baseURL + url;
    for (const interceptor of this.requestInterceptors) {
      const result = interceptor({
        url: finalUrl,
        method,
        headers: config.headers,
        body: config.body
      });
      if (result) {
        finalUrl = result.url || finalUrl;
        config.headers = result.headers || config.headers;
        config.body = result.body || config.body;
      }
    }

    let attempt = 0;
    const maxAttempts = options.retries || this.options.retries;

    while (attempt <= maxAttempts) {
      try {
        const controller = new AbortController();
        const timeoutId = setTimeout(() => controller.abort(), this.options.timeout);

        const response = await fetch(finalUrl, {
          ...config,
          signal: controller.signal
        });

        clearTimeout(timeoutId);

        // Handle HTTP errors
        if (!response.ok) {
          throw new HTTPError(response.status, response.statusText, await response.text());
        }

        // Parse response
        const contentType = response.headers.get('content-type');
        let result;

        if (contentType && contentType.includes('application/json')) {
          result = await response.json();
        } else {
          result = await response.text();
        }

        // Apply response interceptors
        for (const interceptor of this.responseInterceptors) {
          result = interceptor(result, response) || result;
        }

        return result;

      } catch (error) {
        attempt++;
        
        // Don't retry on certain errors
        if (error instanceof HTTPError && [400, 401, 403, 422].includes(error.status)) {
          throw error;
        }

        // Retry logic
        if (attempt <= maxAttempts) {
          console.warn(`Request failed (attempt ${attempt}/${maxAttempts}), retrying...`, error);
          await this.delay(this.options.retryDelay * attempt);
          continue;
        }

        throw error;
      }
    }
  }

  delay(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
  }

  // Utility Methods
  setHeader(key, value) {
    this.options.headers[key] = value;
  }

  removeHeader(key) {
    delete this.options.headers[key];
  }

  // File Upload
  async upload(url, file, onProgress = null) {
    const formData = new FormData();
    formData.append('file', file);

    const config = {
      method: 'POST',
      headers: {
        // Don't set Content-Type for FormData, let browser set it with boundary
      }
    };

    if (onProgress) {
      return this.uploadWithProgress(url, formData, onProgress, config);
    }

    return this.request('POST', url, formData, config);
  }

  async uploadWithProgress(url, formData, onProgress, config) {
    return new Promise((resolve, reject) => {
      const xhr = new XMLHttpRequest();
      
      xhr.upload.addEventListener('progress', (event) => {
        if (event.lengthComputable) {
          const percentComplete = (event.loaded / event.total) * 100;
          onProgress(percentComplete);
        }
      });

      xhr.addEventListener('load', () => {
        if (xhr.status >= 200 && xhr.status < 300) {
          try {
            const result = JSON.parse(xhr.responseText);
            resolve(result);
          } catch (e) {
            resolve(xhr.responseText);
          }
        } else {
          reject(new HTTPError(xhr.status, xhr.statusText, xhr.responseText));
        }
      });

      xhr.addEventListener('error', () => {
        reject(new Error('Upload failed'));
      });

      xhr.open('POST', this.baseURL + url);
      
      // Add auth header
      if (this.authToken) {
        xhr.setRequestHeader('Authorization', `Bearer ${this.authToken}`);
      }
      
      xhr.send(formData);
    });
  }
}

// HTTP Error Class
class HTTPError extends Error {
  constructor(status, statusText, body) {
    super(`${status} ${statusText}`);
    this.status = status;
    this.statusText = statusText;
    this.body = body;
    this.name = 'HTTPError';
  }
}

// Specialized API Classes
class PatrolAPI extends APIClient {
  constructor() {
    super('/api/v1');
    this.setupInterceptors();
  }

  setupInterceptors() {
    // Add auth token from storage
    this.useRequestInterceptor((config) => {
      const token = localStorage.getItem('authToken');
      if (token) {
        config.headers['Authorization'] = `Bearer ${token}`;
      }
      return config;
    });

    // Handle token refresh on 401
    this.useResponseInterceptor(async (response, originalResponse) => {
      if (originalResponse.status === 401) {
        const refreshed = await this.refreshToken();
        if (refreshed) {
          // Retry original request
          return this.request('GET', '/health');
        }
      }
      return response;
    });
  }

  // Control Points
  async getControlPoints(filters = {}) {
    const params = new URLSearchParams(filters);
    return this.get(`/control-points?${params}`);
  }

  async getControlPoint(id) {
    return this.get(`/control-points/${id}`);
  }

  async createControlPoint(data) {
    return this.post('/control-points', data);
  }

  async updateControlPoint(id, data) {
    return this.put(`/control-points/${id}`, data);
  }

  async deleteControlPoint(id) {
    return this.delete(`/control-points/${id}`);
  }

  // Rounds
  async getRounds(filters = {}) {
    const params = new URLSearchParams(filters);
    return this.get(`/rounds?${params}`);
  }

  async getRound(id) {
    return this.get(`/rounds/${id}`);
  }

  async createRound(data) {
    return this.post('/rounds', data);
  }

  async updateRound(id, data) {
    return this.put(`/rounds/${id}`, data);
  }

  async startRound(id) {
    return this.post(`/rounds/${id}/start`);
  }

  async completeRound(id) {
    return this.post(`/rounds/${id}/complete`);
  }

  // Guards
  async getGuards(filters = {}) {
    const params = new URLSearchParams(filters);
    return this.get(`/guards?${params}`);
  }

  async getGuard(id) {
    return this.get(`/guards/${id}`);
  }

  async createGuard(data) {
    return this.post('/guards', data);
  }

  async updateGuard(id, data) {
    return this.put(`/guards/${id}`, data);
  }

  // Companies
  async getCompanies(filters = {}) {
    const params = new URLSearchParams(filters);
    return this.get(`/companies?${params}`);
  }

  async getCompany(id) {
    return this.get(`/companies/${id}`);
  }

  async createCompany(data) {
    return this.post('/companies', data);
  }

  // Reports
  async generateReport(type, params = {}) {
    return this.post('/reports/generate', { type, params });
  }

  async getReports(filters = {}) {
    const params = new URLSearchParams(filters);
    return this.get(`/reports?${params}`);
  }

  // NFC Scanning
  async scanNFC(nfcId, roundId) {
    return this.post('/nfc/scan', { nfcId, roundId });
  }

  // Incidents
  async getIncidents(filters = {}) {
    const params = new URLSearchParams(filters);
    return this.get(`/incidents?${params}`);
  }

  async createIncident(data) {
    return this.post('/incidents', data);
  }

  async updateIncident(id, data) {
    return this.put(`/incidents/${id}`, data);
  }

  // Authentication
  async login(credentials) {
    const response = await this.post('/auth/login', credentials);
    if (response.token) {
      this.setAuthToken(response.token);
      localStorage.setItem('authToken', response.token);
    }
    return response;
  }

  async logout() {
    try {
      await this.post('/auth/logout');
    } finally {
      this.clearAuth();
    }
  }

  async refreshToken() {
    try {
      const response = await this.post('/auth/refresh');
      if (response.token) {
        this.setAuthToken(response.token);
        localStorage.setItem('authToken', response.token);
        return true;
      }
    } catch (error) {
      this.clearAuth();
      return false;
    }
  }

  clearAuth() {
    this.authToken = null;
    localStorage.removeItem('authToken');
    delete this.options.headers['Authorization'];
  }
}

// Real-time API for WebSocket connections
class RealtimeAPI {
  constructor(url) {
    this.url = url;
    this.ws = null;
    this.reconnectAttempts = 0;
    this.maxReconnectAttempts = 5;
    this.reconnectInterval = 1000;
    this.listeners = new Map();
  }

  connect() {
    if (this.ws?.readyState === WebSocket.OPEN) return;

    this.ws = new WebSocket(this.url);

    this.ws.onopen = () => {
      console.log('WebSocket connected');
      this.reconnectAttempts = 0;
      this.emit('connected');
    };

    this.ws.onmessage = (event) => {
      try {
        const data = JSON.parse(event.data);
        this.emit(data.type, data);
      } catch (error) {
        console.error('Failed to parse WebSocket message:', error);
      }
    };

    this.ws.onclose = () => {
      console.log('WebSocket disconnected');
      this.emit('disconnected');
      this.reconnect();
    };

    this.ws.onerror = (error) => {
      console.error('WebSocket error:', error);
      this.emit('error', error);
    };
  }

  reconnect() {
    if (this.reconnectAttempts < this.maxReconnectAttempts) {
      this.reconnectAttempts++;
      const delay = this.reconnectInterval * Math.pow(2, this.reconnectAttempts - 1);
      
      setTimeout(() => {
        console.log(`Reconnecting... (attempt ${this.reconnectAttempts})`);
        this.connect();
      }, delay);
    } else {
      console.error('Max reconnection attempts reached');
      this.emit('maxReconnectAttemptsReached');
    }
  }

  send(type, data) {
    if (this.ws?.readyState === WebSocket.OPEN) {
      this.ws.send(JSON.stringify({ type, data }));
    }
  }

  on(event, callback) {
    if (!this.listeners.has(event)) {
      this.listeners.set(event, new Set());
    }
    this.listeners.get(event).add(callback);
  }

  off(event, callback) {
    const listeners = this.listeners.get(event);
    if (listeners) {
      listeners.delete(callback);
    }
  }

  emit(event, data) {
    const listeners = this.listeners.get(event);
    if (listeners) {
      listeners.forEach(callback => callback(data));
    }
  }

  disconnect() {
    if (this.ws) {
      this.ws.close();
      this.ws = null;
    }
  }
}

// Export classes
if (typeof module !== 'undefined' && module.exports) {
  module.exports = {
    APIClient,
    HTTPError,
    PatrolAPI,
    RealtimeAPI
  };
}