# SPARKNET Production Nginx Configuration
# Reverse proxy for API and Demo services

user nginx;
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;

    # Logging format
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent" "$http_x_forwarded_for" '
                    'rt=$request_time uct="$upstream_connect_time" '
                    'uht="$upstream_header_time" urt="$upstream_response_time"';

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

    # Performance optimizations
    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_types text/plain text/css text/xml application/json application/javascript
               application/xml application/xml+rss text/javascript application/x-javascript;
    gzip_min_length 1000;

    # Rate limiting zones
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=30r/s;
    limit_req_zone $binary_remote_addr zone=upload_limit:10m rate=5r/s;
    limit_conn_zone $binary_remote_addr zone=conn_limit:10m;

    # Security headers map
    map $sent_http_content_type $security_headers {
        default "always";
    }

    # Upstream servers
    upstream sparknet_api {
        server sparknet-api:8000;
        keepalive 32;
    }

    upstream sparknet_demo {
        server sparknet-demo:4000;
        keepalive 32;
    }

    # HTTP redirect to HTTPS (uncomment for production with SSL)
    # server {
    #     listen 80;
    #     listen [::]:80;
    #     server_name _;
    #     return 301 https://$host$request_uri;
    # }

    # Main HTTP server (development/internal)
    server {
        listen 80;
        listen [::]:80;
        server_name _;

        # Connection limits
        limit_conn conn_limit 20;

        # 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 "strict-origin-when-cross-origin" always;

        # Client body size for file uploads
        client_max_body_size 100M;
        client_body_buffer_size 128k;
        client_body_timeout 300s;

        # Proxy timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 300s;
        proxy_read_timeout 300s;

        # Health check endpoint (no rate limiting)
        location /api/health {
            proxy_pass http://sparknet_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;
        }

        # API endpoints
        location /api/ {
            # Rate limiting
            limit_req zone=api_limit burst=50 nodelay;

            proxy_pass http://sparknet_api;
            proxy_http_version 1.1;

            # 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;
            proxy_set_header Connection "";

            # CORS headers (if not handled by FastAPI)
            # add_header Access-Control-Allow-Origin "*" always;
            # add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS" always;
            # add_header Access-Control-Allow-Headers "Authorization, Content-Type" always;

            # Handle OPTIONS for CORS preflight
            if ($request_method = 'OPTIONS') {
                add_header Access-Control-Allow-Origin "*";
                add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
                add_header Access-Control-Allow-Headers "Authorization, Content-Type";
                add_header Access-Control-Max-Age 3600;
                add_header Content-Length 0;
                add_header Content-Type text/plain;
                return 204;
            }
        }

        # Document upload endpoint (lower rate limit)
        location /api/documents/upload {
            limit_req zone=upload_limit burst=10 nodelay;

            proxy_pass http://sparknet_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;

            # Increased timeout for large uploads
            proxy_connect_timeout 120s;
            proxy_send_timeout 600s;
            proxy_read_timeout 600s;
        }

        # RAG streaming endpoint (SSE support)
        location /api/rag/query/stream {
            proxy_pass http://sparknet_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 Connection "";

            # SSE-specific settings
            proxy_buffering off;
            proxy_cache off;
            chunked_transfer_encoding off;
            proxy_read_timeout 3600s;
        }

        # Streamlit Demo (with WebSocket support)
        location / {
            proxy_pass http://sparknet_demo;
            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 for Streamlit
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";

            # Streamlit specific
            proxy_read_timeout 86400;
        }

        # Streamlit WebSocket endpoint
        location /_stcore/stream {
            proxy_pass http://sparknet_demo;
            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;

            # WebSocket
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection "upgrade";

            proxy_read_timeout 86400;
            proxy_buffering off;
        }

        # Streamlit static files
        location /static {
            proxy_pass http://sparknet_demo;
            proxy_http_version 1.1;
            proxy_set_header Host $host;

            # Cache static assets
            expires 1d;
            add_header Cache-Control "public, immutable";
        }

        # Error pages
        error_page 502 503 504 /50x.html;
        location = /50x.html {
            root /usr/share/nginx/html;
            internal;
        }
    }

    # HTTPS server (uncomment and configure for production)
    # server {
    #     listen 443 ssl http2;
    #     listen [::]:443 ssl http2;
    #     server_name sparknet.example.com;
    #
    #     # SSL configuration
    #     ssl_certificate /etc/nginx/ssl/fullchain.pem;
    #     ssl_certificate_key /etc/nginx/ssl/privkey.pem;
    #     ssl_session_timeout 1d;
    #     ssl_session_cache shared:SSL:50m;
    #     ssl_session_tickets off;
    #
    #     # Modern SSL configuration
    #     ssl_protocols TLSv1.2 TLSv1.3;
    #     ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384;
    #     ssl_prefer_server_ciphers off;
    #
    #     # HSTS
    #     add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    #
    #     # Include same location blocks as HTTP server above
    #     # ...
    # }
}