# nginx.conf for production deployment
worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /tmp/nginx.pid;

events {
    worker_connections 1024;
    use epoll;
    multi_accept on;
}

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

    # Logging
    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;

    # Basic Settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    client_max_body_size 100m;

    # Gzip Settings
    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/atom+xml
        image/svg+xml;

    # Security Headers
    add_header X-Frame-Options DENY always;
    add_header X-Content-Type-Options nosniff always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    server {
        listen 80;
        server_name _;
        root /usr/share/nginx/html;
        index index.html;

        # Security: Hide nginx version
        server_tokens off;

        # Main application
        location / {
            try_files $uri $uri/ /index.html;
            
            # Cache control for HTML files (no cache)
            location ~* \.html$ {
                add_header Cache-Control "no-cache, no-store, must-revalidate";
                add_header Pragma "no-cache";
                add_header Expires "0";
            }
        }

        # Static assets with long-term caching
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
            add_header Access-Control-Allow-Origin "*";
        }

        # Proxy for Docker Registry API (configurable via environment)
        location /api/ {
            # Remove /api prefix and forward to registry
            rewrite ^/api/(.*)$ /$1 break;
            
            # Default to localhost:5000, but can be overridden
            proxy_pass http://host.docker.internal:5000;
            
            # Proxy headers
            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;
            
            # CORS headers for registry API
            add_header Access-Control-Allow-Origin "*" always;
            add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS" always;
            add_header Access-Control-Allow-Headers "DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization" always;
            
            # Handle preflight requests
            if ($request_method = 'OPTIONS') {
                add_header Access-Control-Allow-Origin "*";
                add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS";
                add_header Access-Control-Allow-Headers "DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization";
                add_header Access-Control-Max-Age 1728000;
                add_header Content-Type "text/plain charset=UTF-8";
                add_header Content-Length 0;
                return 204;
            }
            
            # Timeouts
            proxy_connect_timeout 30s;
            proxy_send_timeout 30s;
            proxy_read_timeout 30s;
        }

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

        # 404 error handling
        error_page 404 /index.html;

        # 50x error handling
        error_page 500 502 503 504 /50x.html;
        location = /50x.html {
            root /usr/share/nginx/html;
        }
    }
}