# Rate limiting
limit_req_zone $binary_remote_addr zone=api:10m rate=10r/s;
limit_req_zone $binary_remote_addr zone=login:10m rate=5r/m;

# Upstream backends
upstream backend {
    server backend:8000;
    keepalive 32;
}

upstream frontend {
    server frontend:80;
    keepalive 32;
}

# HTTP server - redirect to HTTPS
server {
    listen 80;
    listen [::]:80;
    server_name ${DOMAIN_NAME};

    # Allow Let's Encrypt challenges
    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    # Health check
    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }

    # Redirect all other traffic to HTTPS
    location / {
        return 301 https://$server_name$request_uri;
    }
}

# HTTPS server
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name ${DOMAIN_NAME};

    # SSL configuration
    ssl_certificate /etc/letsencrypt/live/${DOMAIN_NAME}/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/${DOMAIN_NAME}/privkey.pem;
    
    # Include SSL and security configurations
    include /etc/nginx/conf.d/ssl.conf;
    include /etc/nginx/conf.d/security.conf;

    # Logging
    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    # Frontend - React app
    location / {
        proxy_pass http://frontend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_cache_bypass $http_upgrade;
        
        # CORS headers for frontend
        add_header Access-Control-Allow-Origin $http_origin;
        add_header Access-Control-Allow-Credentials true;
    }

    # Backend API
    location /api {
        # Rate limiting
        limit_req zone=api burst=20 nodelay;
        
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_cache_bypass $http_upgrade;
        
        # Timeout settings
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
        
        # CORS headers
        add_header Access-Control-Allow-Origin $http_origin;
        add_header Access-Control-Allow-Credentials true;
        add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
        add_header Access-Control-Allow-Headers "Authorization, Content-Type, Accept, Origin, User-Agent, DNT, Cache-Control, X-Mx-ReqToken, Keep-Alive, X-Requested-With, If-Modified-Since";
        
        # Handle preflight requests
        if ($request_method = 'OPTIONS') {
            add_header Access-Control-Allow-Origin $http_origin;
            add_header Access-Control-Allow-Credentials true;
            add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
            add_header Access-Control-Allow-Headers "Authorization, Content-Type, Accept, Origin, User-Agent, DNT, Cache-Control, X-Mx-ReqToken, Keep-Alive, X-Requested-With, If-Modified-Since";
            add_header Access-Control-Max-Age 1728000;
            add_header Content-Type 'text/plain charset=UTF-8';
            add_header Content-Length 0;
            return 204;
        }
    }

    # Login endpoint with stricter rate limiting
    location /api/login {
        limit_req zone=login burst=5 nodelay;
        
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    # WebSocket support
    location /ws {
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        
        # WebSocket timeout settings
        proxy_read_timeout 86400s;
        proxy_send_timeout 86400s;
    }

    # Health check
    location /health {
        access_log off;
        return 200 "healthy\n";
        add_header Content-Type text/plain;
    }
}