/**
 * Rate Limit Metrics API
 * 
 * Exposes rate limiting metrics for monitoring and analysis.
 * Requires admin/moderator authentication.
 */

import { createClient } from 'jsr:@supabase/supabase-js@2';
import { withRateLimit, rateLimiters } from '../_shared/rateLimiter.ts';
import {
  getRecentMetrics,
  getMetricsStats,
  getFunctionMetrics,
  getUserMetrics,
  getIPMetrics,
  clearMetrics,
} from '../_shared/rateLimitMetrics.ts';

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
};

interface QueryParams {
  action?: string;
  limit?: string;
  timeWindow?: string;
  functionName?: string;
  userId?: string;
  clientIP?: string;
}

async function handler(req: Request): Promise<Response> {
  // Handle CORS preflight
  if (req.method === 'OPTIONS') {
    return new Response(null, { headers: corsHeaders });
  }

  try {
    // Verify authentication
    const authHeader = req.headers.get('Authorization');
    if (!authHeader) {
      return new Response(
        JSON.stringify({ error: 'Authentication required' }),
        { status: 401, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    }

    const supabaseUrl = Deno.env.get('SUPABASE_URL')!;
    const supabaseServiceKey = Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!;
    const supabase = createClient(supabaseUrl, supabaseServiceKey, {
      global: {
        headers: { Authorization: authHeader },
      },
    });

    // Get authenticated user
    const { data: { user }, error: authError } = await supabase.auth.getUser();
    if (authError || !user) {
      return new Response(
        JSON.stringify({ error: 'Invalid authentication' }),
        { status: 401, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    }

    // Check if user has admin or moderator role
    const { data: roles } = await supabase
      .from('user_roles')
      .select('role')
      .eq('user_id', user.id);

    const userRoles = roles?.map(r => r.role) || [];
    const isAuthorized = userRoles.some(role => 
      ['admin', 'moderator', 'superuser'].includes(role)
    );

    if (!isAuthorized) {
      return new Response(
        JSON.stringify({ error: 'Insufficient permissions' }),
        { status: 403, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
      );
    }

    // Parse query parameters
    const url = new URL(req.url);
    const action = url.searchParams.get('action') || 'stats';
    const limit = parseInt(url.searchParams.get('limit') || '100', 10);
    const timeWindow = parseInt(url.searchParams.get('timeWindow') || '60000', 10);
    const functionName = url.searchParams.get('functionName');
    const userId = url.searchParams.get('userId');
    const clientIP = url.searchParams.get('clientIP');

    let responseData: any;

    // Route to appropriate metrics handler
    switch (action) {
      case 'recent':
        responseData = {
          metrics: getRecentMetrics(limit),
          count: getRecentMetrics(limit).length,
        };
        break;

      case 'stats':
        responseData = getMetricsStats(timeWindow);
        break;

      case 'function':
        if (!functionName) {
          return new Response(
            JSON.stringify({ error: 'functionName parameter required for function action' }),
            { status: 400, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
          );
        }
        responseData = {
          functionName,
          metrics: getFunctionMetrics(functionName, limit),
          count: getFunctionMetrics(functionName, limit).length,
        };
        break;

      case 'user':
        if (!userId) {
          return new Response(
            JSON.stringify({ error: 'userId parameter required for user action' }),
            { status: 400, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
          );
        }
        responseData = {
          userId,
          metrics: getUserMetrics(userId, limit),
          count: getUserMetrics(userId, limit).length,
        };
        break;

      case 'ip':
        if (!clientIP) {
          return new Response(
            JSON.stringify({ error: 'clientIP parameter required for ip action' }),
            { status: 400, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
          );
        }
        responseData = {
          clientIP,
          metrics: getIPMetrics(clientIP, limit),
          count: getIPMetrics(clientIP, limit).length,
        };
        break;

      case 'clear':
        // Only superusers can clear metrics
        const isSuperuser = userRoles.includes('superuser');
        if (!isSuperuser) {
          return new Response(
            JSON.stringify({ error: 'Only superusers can clear metrics' }),
            { status: 403, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
          );
        }
        clearMetrics();
        responseData = { success: true, message: 'Metrics cleared' };
        break;

      default:
        return new Response(
          JSON.stringify({ 
            error: 'Invalid action',
            validActions: ['recent', 'stats', 'function', 'user', 'ip', 'clear']
          }),
          { status: 400, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
        );
    }

    return new Response(
      JSON.stringify(responseData),
      { 
        status: 200, 
        headers: { 
          ...corsHeaders, 
          'Content-Type': 'application/json',
        } 
      }
    );

  } catch (error) {
    console.error('Error in rate-limit-metrics function:', error);
    return new Response(
      JSON.stringify({ 
        error: 'Internal server error',
        message: error instanceof Error ? error.message : 'Unknown error'
      }),
      { 
        status: 500, 
        headers: { ...corsHeaders, 'Content-Type': 'application/json' } 
      }
    );
  }
}

// Apply rate limiting (lenient tier for admin monitoring)
Deno.serve(withRateLimit(handler, rateLimiters.lenient, corsHeaders, 'rate-limit-metrics'));