import { Request, Response, NextFunction } from 'express';
import UserActivity, { ActivityAction, ActivityCategory } from '../model/userActivity.model';
import UserStats from '../model/userStats.model';
import UAParser from 'ua-parser-js';


// Extend Express Request type to include custom properties
declare global {
  namespace Express {
    interface Request {
      user?: any;
      activityLogged?: boolean;
      startTime?: number;
    }
  }
}

interface ActivityLogOptions {
  action: ActivityAction;
  category: ActivityCategory;
  description: string;
  metadata?: Record<string, any>;
  skipLog?: boolean;
}

/**
 * Helper function to extract device and browser info from user agent
 */
const parseUserAgent = (userAgent: string) => {
  const parser = new (UAParser as any)(userAgent);
  const result = parser.getResult();
  
  return {
    device: `${result.device.vendor || 'Unknown'} ${result.device.model || 'Device'}`,
    browser: `${result.browser.name || 'Unknown'} ${result.browser.version || ''}`
  };
};

/**
 * Main activity logger middleware
 * Automatically logs all authenticated API calls
 */
export const activityLogger = async (
  req: Request,
  res: Response,
  next: NextFunction
) => {
  // Skip if no user (unauthenticated routes)
  if (!req.user) {
    return next();
  }

  // Track request start time for duration calculation
  req.startTime = Date.now();

  // Store original res.json to intercept response
  const originalJson = res.json.bind(res);
  
  res.json = function (body: any) {
    // Calculate request duration
    const duration = req.startTime ? Date.now() - req.startTime : 0;
    
    // Don't log if already logged (prevents double logging)
    if (!req.activityLogged) {
      // Map route to activity action
      const activityInfo = mapRouteToActivity(req);
      
      if (activityInfo && !activityInfo.skipLog) {
        logActivity(req, res, duration, activityInfo, body).catch(err => {
          console.error('Error logging activity:', err);
        });
      }
    }
    
    return originalJson(body);
  };

  next();
};

/**
 * Manual activity logging for custom events
 */
export const logCustomActivity = async (
  req: Request,
  options: ActivityLogOptions
) => {
  if (!req.user) return;

  const duration = req.startTime ? Date.now() - req.startTime : 0;
  await logActivity(req, null, duration, options, null);
  req.activityLogged = true;
};

/**
 * Map API routes to activity actions
 */
const mapRouteToActivity = (req: Request): ActivityLogOptions | null => {
  const { method, path } = req;
  const route = `${method} ${path}`;

  // Authentication routes
  if (route.includes('/login')) {
    return {
      action: ActivityAction.LOGIN,
      category: ActivityCategory.AUTH,
      description: 'User logged in'
    };
  }
  
  if (route.includes('/signup')) {
    return {
      action: ActivityAction.SIGNUP,
      category: ActivityCategory.AUTH,
      description: 'User signed up'
    };
  }
  
  if (route.includes('/logout')) {
    return {
      action: ActivityAction.LOGOUT,
      category: ActivityCategory.AUTH,
      description: 'User logged out'
    };
  }

  // Profile routes
  if (route.includes('/me') && method === 'PUT') {
    return {
      action: ActivityAction.PROFILE_UPDATE,
      category: ActivityCategory.PROFILE,
      description: 'User updated profile',
      metadata: { changes: req.body }
    };
  }

  if (route.includes('/upload-photo')) {
    return {
      action: ActivityAction.PROFILE_PHOTO_UPLOAD,
      category: ActivityCategory.PROFILE,
      description: 'User uploaded profile photo'
    };
  }

  if (route.includes('/change-password')) {
    return {
      action: ActivityAction.PASSWORD_CHANGE,
      category: ActivityCategory.AUTH,
      description: 'User changed password'
    };
  }

  // Event routes
  if (route.includes('/events/create')) {
    return {
      action: ActivityAction.EVENT_CREATE,
      category: ActivityCategory.EVENT,
      description: 'User created an event',
      metadata: { eventData: req.body }
    };
  }

  if (route.match(/PUT .*\/events\/[^/]+$/)) {
    return {
      action: ActivityAction.EVENT_UPDATE,
      category: ActivityCategory.EVENT,
      description: 'User updated an event',
      metadata: { eventId: req.params.eventId, changes: req.body }
    };
  }

  if (route.match(/DELETE .*\/events\/[^/]+$/)) {
    return {
      action: ActivityAction.EVENT_DELETE,
      category: ActivityCategory.EVENT,
      description: 'User deleted an event',
      metadata: { eventId: req.params.eventId }
    };
  }

  if (route.includes('/events/join')) {
    return {
      action: ActivityAction.EVENT_JOIN,
      category: ActivityCategory.EVENT,
      description: 'User joined an event',
      metadata: { joinData: req.body }
    };
  }

  if (route.includes('/events/search') || route.includes('/events/nearby')) {
    return {
      action: ActivityAction.EVENT_SEARCH,
      category: ActivityCategory.EVENT,
      description: 'User searched for events',
      metadata: { searchParams: req.query }
    };
  }

  if (route.match(/GET .*\/events\/[^/]+$/) && !route.includes('my-events')) {
    return {
      action: ActivityAction.EVENT_VIEW,
      category: ActivityCategory.EVENT,
      description: 'User viewed an event',
      metadata: { eventId: req.params.eventId }
    };
  }

  // Form routes
  if (route.includes('/forms/create')) {
    return {
      action: ActivityAction.FORM_CREATE,
      category: ActivityCategory.FORM,
      description: 'User created a form',
      metadata: { formData: req.body }
    };
  }

  if (route.match(/PUT .*\/forms\/[^/]+$/)) {
    return {
      action: ActivityAction.FORM_UPDATE,
      category: ActivityCategory.FORM,
      description: 'User updated a form',
      metadata: { formId: req.params.formId, changes: req.body }
    };
  }

  if (route.match(/DELETE .*\/forms\/[^/]+$/)) {
    return {
      action: ActivityAction.FORM_DELETE,
      category: ActivityCategory.FORM,
      description: 'User deleted a form',
      metadata: { formId: req.params.formId }
    };
  }

  if (route.includes('/forms/') && route.includes('/submit')) {
    return {
      action: ActivityAction.FORM_SUBMIT,
      category: ActivityCategory.FORM,
      description: 'User submitted a form',
      metadata: { formId: req.params.formId }
    };
  }

  if (route.includes('/forms/') && route.includes('/export')) {
    return {
      action: ActivityAction.FORM_EXPORT,
      category: ActivityCategory.FORM,
      description: 'User exported form responses',
      metadata: { formId: req.params.formId }
    };
  }

  // Verification routes
  if (route.includes('/verify-trainer')) {
    return {
      action: ActivityAction.TRAINER_VERIFY,
      category: ActivityCategory.VERIFICATION,
      description: 'Organization verified a trainer',
      metadata: { trainerId: req.body.trainerId }
    };
  }

  if (route.includes('/verify-organization')) {
    return {
      action: ActivityAction.ORG_VERIFY,
      category: ActivityCategory.VERIFICATION,
      description: 'Admin verified an organization',
      metadata: { organizationId: req.body.organizationId }
    };
  }

  // Location updates
  if (route.includes('/location/update')) {
    return {
      action: ActivityAction.LOCATION_UPDATE,
      category: ActivityCategory.PROFILE,
      description: 'User updated location',
      skipLog: true // Too frequent, skip individual logs
    };
  }

  // Analytics routes
  if (route.includes('/analytics')) {
    return {
      action: ActivityAction.ANALYTICS_VIEW,
      category: ActivityCategory.ANALYTICS,
      description: 'User viewed analytics',
      metadata: { endpoint: path, params: req.query }
    };
  }

  // Skip logging for health checks and static resources
  if (route.includes('/health') || route.includes('/my-events') || route.includes('/my-forms')) {
    return { 
      action: ActivityAction.API_ERROR, 
      category: ActivityCategory.SYSTEM, 
      description: '', 
      skipLog: true 
    };
  }

  return null;
};

/**
 * Core function to save activity to database
 */
const logActivity = async (
  req: Request,
  res: Response | null,
  duration: number,
  options: ActivityLogOptions,
  responseBody: any
) => {
  try {
    const userAgent = req.headers['user-agent'] || '';
    const { device, browser } = parseUserAgent(userAgent);
    
    const activityData: any = {
      user: req.user!._id,
      action: options.action,
      category: options.category,
      description: options.description,
      timestamp: new Date(),
      success: res ? res.statusCode < 400 : true,
      metadata: {
        ipAddress: req.ip || req.headers['x-forwarded-for'] || req.socket.remoteAddress,
        userAgent,
        device,
        browser,
        method: req.method,
        endpoint: req.path,
        queryParams: req.query,
        duration,
        statusCode: res?.statusCode,
        responseSize: responseBody ? JSON.stringify(responseBody).length : 0,
        ...options.metadata
      }
    };

    // Save activity log
    await UserActivity.create(activityData);

    // Update user stats asynchronously (don't wait)
    updateUserStats(req.user!._id, options.action).catch(err => {
      console.error('Error updating user stats:', err);
    });

  } catch (error) {
    console.error('Failed to log activity:', error);
  }
};

/**
 * Update aggregated user statistics
 */
const updateUserStats = async (userId: string, action: ActivityAction) => {
  const updateFields: Record<string, any> = {
    lastActivityDate: new Date(),
    lastActivityType: action
  };

  // Increment specific counters based on action
  switch (action) {
    case ActivityAction.LOGIN:
      updateFields.$inc = { loginCount: 1, totalSessions: 1 };
      updateFields.lastLoginDate = new Date();
      // Calculate login streak logic here
      break;
    
    case ActivityAction.EVENT_CREATE:
      updateFields.$inc = { eventsCreated: 1 };
      break;
    
    case ActivityAction.EVENT_JOIN:
      updateFields.$inc = { eventsJoined: 1 };
      break;
    
    case ActivityAction.FORM_CREATE:
      updateFields.$inc = { formsCreated: 1 };
      break;
    
    case ActivityAction.FORM_SUBMIT:
      updateFields.$inc = { formsSubmitted: 1 };
      break;
    
    case ActivityAction.PROFILE_UPDATE:
      updateFields.$inc = { profileUpdates: 1 };
      break;
    
    case ActivityAction.LOCATION_UPDATE:
      updateFields.$inc = { locationUpdates: 1 };
      break;
    
    case ActivityAction.TRAINER_VERIFY:
      updateFields.$inc = { trainersVerified: 1 };
      break;
    
    case ActivityAction.ORG_VERIFY:
      updateFields.$inc = { organizationsVerified: 1 };
      break;
  }

  // Upsert user stats
  await UserStats.findOneAndUpdate(
    { user: userId },
    updateFields,
    { upsert: true, new: true }
  );
};

export default activityLogger;