user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
    use epoll;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for"';

    access_log /var/log/nginx/access.log main;

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    client_max_body_size 10M;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml text/javascript 
               application/json application/javascript application/xml+rss 
               application/rss+xml font/truetype font/opentype 
               application/vnd.ms-fontobject image/svg+xml;

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=general_limit:10m rate=20r/s;

    # Upstream backend
    upstream abdm_gateway {
        server abdm-gateway:3000;
        keepalive 32;
    }

    # HTTP redirect to HTTPS
    server {
        listen 80;
        server_name abdm-bridge.e-atria.in;

        location /.well-known/acme-challenge/ {
            root /var/www/certbot;
        }

        location / {
            return 301 https://$server_name$request_uri;
        }
    }

    # HTTPS Server
    server {
        listen 443 ssl http2;
        server_name abdm-bridge.e-atria.in;

        # SSL Certificates (Certbot managed)
        ssl_certificate /etc/letsencrypt/live/abdm-bridge.e-atria.in/fullchain.pem;
        ssl_certificate_key /etc/letsencrypt/live/abdm-bridge.e-atria.in/privkey.pem;

        # SSL Configuration
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers on;
        ssl_session_cache shared:SSL:10m;
        ssl_session_timeout 10m;

        # Security Headers
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header X-Frame-Options "DENY" always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
        add_header Permissions-Policy "geolocation=(), microphone=(), camera=()" always;

        # API Proxy
        location /api/ {
            limit_req zone=api_limit burst=20 nodelay;

            proxy_pass http://abdm_gateway;
            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_set_header X-Request-ID $request_id;
            proxy_buffering off;
            proxy_request_buffering off;
            proxy_connect_timeout 60s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
        }

        # Health check endpoint (no rate limit)
        location /api/v3/health {
            proxy_pass http://abdm_gateway;
            proxy_http_version 1.1;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            access_log off;
        }

        # Status page (admin only)
        location /nginx-status {
            stub_status on;
            access_log off;
            allow 127.0.0.1;
            allow ::1;
            deny all;
        }

        # Catch all other requests
        location / {
            limit_req zone=general_limit burst=30 nodelay;
            proxy_pass http://abdm_gateway;
        }
    }
}