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

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

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;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_min_length 256;
    gzip_types text/plain text/css text/xml application/json application/javascript 
               application/xml application/xml+rss text/javascript application/x-javascript;

    upstream api {
        server api1:5000 max_fails=2 fail_timeout=10s;
        server api2:5000 max_fails=2 fail_timeout=10s;
    }

    server {
        listen 80;
        server_name localhost;

        # Health check endpoint
        location /health {
            proxy_pass http://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_set_header X-Forwarded-Host $host;
            proxy_connect_timeout 30s;
            proxy_send_timeout 30s;
            proxy_read_timeout 30s;
        }

        # API routes
        location /api/ {
            proxy_pass http://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_set_header X-Forwarded-Host $host;
            proxy_connect_timeout 120s;
            proxy_send_timeout 120s;
            proxy_read_timeout 120s;
            
            # Increase buffer for larger responses
            proxy_buffering on;
            proxy_buffer_size 4k;
            proxy_buffers 8 16k;
            proxy_busy_buffers_size 24k;
        }

        # Catch-all proxy (for any other routes)
        location / {
            proxy_pass http://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_set_header X-Forwarded-Host $host;
            proxy_connect_timeout 120s;
            proxy_send_timeout 120s;
            proxy_read_timeout 120s;
        }

        # 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;
    }
}