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 100M;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1000;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml text/javascript 
               application/json application/javascript application/xml+rss;

    # Upstream services
    upstream agents_ui {
        least_conn;
        server agents-ui:3000 max_fails=3 fail_timeout=30s;
        keepalive 32;
    }

    upstream claude_api {
        least_conn;
        server claude-code-backend:5000 max_fails=3 fail_timeout=30s;
        keepalive 32;
    }

    # Rate limiting zones
    limit_req_zone $binary_remote_addr zone=general:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=api:10m rate=100r/s;
    limit_req_zone $binary_remote_addr zone=ws:10m rate=1000r/s;

    # HTTP redirect to HTTPS (uncomment when SSL is configured)
    # server {
    #     listen 80;
    #     server_name _;
    #     return 301 https://$host$request_uri;
    # }

    # Main server block
    server {
        listen 80;
        server_name _;

        # SSL configuration (uncomment when certificates are available)
        # listen 443 ssl http2;
        # ssl_certificate /etc/nginx/certs/cert.pem;
        # ssl_key /etc/nginx/certs/key.pem;
        # ssl_protocols TLSv1.2 TLSv1.3;
        # ssl_ciphers HIGH:!aNULL:!MD5;
        # ssl_prefer_server_ciphers on;

        # Security headers
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header Referrer-Policy "no-referrer-when-downgrade" always;
        add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline'" always;

        # Root location
        location / {
            limit_req zone=general burst=20 nodelay;
            proxy_pass http://agents_ui;
            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_redirect off;
            
            # Timeouts
            proxy_connect_timeout 60s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
        }

        # WebSocket support for real-time agent updates
        location /ws {
            limit_req zone=ws burst=50 nodelay;
            proxy_pass http://agents_ui;
            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 timeouts
            proxy_connect_timeout 7d;
            proxy_send_timeout 7d;
            proxy_read_timeout 7d;
        }

        # Claude Code API backend
        location /api/claude {
            limit_req zone=api burst=50 nodelay;
            proxy_pass http://claude_api;
            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;
            proxy_redirect off;
            
            # Allow larger payloads for code uploads
            client_max_body_size 500M;
            
            # Timeouts for long-running operations
            proxy_connect_timeout 300s;
            proxy_send_timeout 300s;
            proxy_read_timeout 300s;
        }

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

        # Status endpoint (nginx metrics)
        location /nginx-status {
            stub_status on;
            access_log off;
            allow 127.0.0.1;
            deny all;
        }

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

        # Deny access to hidden files
        location ~ /\. {
            deny all;
            access_log off;
            log_not_found off;
        }
    }
}