# BackgroundFX Pro Nginx Configuration
# Production-ready configuration with caching, compression, and security

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

# Load dynamic modules
load_module modules/ngx_http_image_filter_module.so;

events {
    worker_connections 4096;
    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" '
                    'rt=$request_time uct="$upstream_connect_time" '
                    'uht="$upstream_header_time" urt="$upstream_response_time"';

    access_log /var/log/nginx/access.log main buffer=32k flush=5s;

    # Basic Settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    server_tokens off;
    client_max_body_size 100M;

    # SSL Settings
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK;
    ssl_prefer_server_ciphers on;
    ssl_session_cache shared:SSL:50m;
    ssl_session_timeout 1d;
    ssl_stapling on;
    ssl_stapling_verify on;

    # 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/rss+xml application/atom+xml image/svg+xml 
               text/x-js text/x-cross-domain-policy application/x-font-ttf 
               application/x-font-opentype application/vnd.ms-fontobject 
               image/x-icon;

    # Cache Settings
    proxy_cache_path /var/cache/nginx/proxy levels=1:2 keys_zone=proxy_cache:100m 
                     max_size=10g inactive=60m use_temp_path=off;
    
    proxy_cache_path /var/cache/nginx/images levels=1:2 keys_zone=images:100m 
                     max_size=50g inactive=30d use_temp_path=off;

    # Rate Limiting
    limit_req_zone $binary_remote_addr zone=api:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=upload:10m rate=1r/s;
    limit_conn_zone $binary_remote_addr zone=addr:10m;

    # Upstream Servers
    upstream api_backend {
        least_conn;
        server api1:8000 max_fails=3 fail_timeout=30s;
        server api2:8000 max_fails=3 fail_timeout=30s backup;
        keepalive 32;
    }

    upstream web_backend {
        least_conn;
        server web1:3000 max_fails=3 fail_timeout=30s;
        server web2:3000 max_fails=3 fail_timeout=30s backup;
        keepalive 32;
    }

    upstream websocket_backend {
        ip_hash;
        server ws1:8001;
        server ws2:8001;
    }

    # Redirect HTTP to HTTPS
    server {
        listen 80;
        listen [::]:80;
        server_name backgroundfx.pro www.backgroundfx.pro;
        return 301 https://$server_name$request_uri;
    }

    # Main HTTPS Server
    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name backgroundfx.pro www.backgroundfx.pro;

        # SSL Certificate
        ssl_certificate /etc/nginx/ssl/fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/privkey.pem;
        ssl_trusted_certificate /etc/nginx/ssl/chain.pem;

        # 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;
        add_header Content-Security-Policy "default-src 'self' https:; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net https://unpkg.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com; img-src 'self' data: https:; connect-src 'self' https://api.backgroundfx.pro wss://ws.backgroundfx.pro" always;
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;

        # Root and Index
        root /var/www/html;
        index index.html;

        # API Endpoints
        location /api/ {
            limit_req zone=api burst=20 nodelay;
            limit_conn addr 10;

            proxy_pass http://api_backend;
            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 "";
            
            # Timeouts
            proxy_connect_timeout 60s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
            
            # Buffering
            proxy_buffering on;
            proxy_buffer_size 4k;
            proxy_buffers 8 4k;
            proxy_busy_buffers_size 8k;
            
            # Cache for GET requests
            proxy_cache proxy_cache;
            proxy_cache_valid 200 1m;
            proxy_cache_valid 404 1m;
            proxy_cache_use_stale error timeout http_500 http_502 http_503 http_504;
            proxy_cache_bypass $http_cache_control;
            add_header X-Cache-Status $upstream_cache_status;
        }

        # Upload Endpoint
        location /api/upload {
            limit_req zone=upload burst=5 nodelay;
            client_max_body_size 100M;
            client_body_buffer_size 1M;
            
            proxy_pass http://api_backend;
            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;
            
            # Longer timeout for uploads
            proxy_connect_timeout 120s;
            proxy_send_timeout 300s;
            proxy_read_timeout 300s;
        }

        # WebSocket Endpoint
        location /ws/ {
            proxy_pass http://websocket_backend;
            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;
        }

        # Static Files
        location /static/ {
            alias /var/www/static/;
            expires 30d;
            add_header Cache-Control "public, immutable";
            
            # Enable gzip for static files
            gzip_static on;
            
            # CORS for fonts
            location ~* \.(eot|ttf|woff|woff2)$ {
                add_header Access-Control-Allow-Origin *;
                expires 30d;
            }
        }

        # Processed Images with Caching
        location /images/ {
            alias /var/www/images/;
            expires 7d;
            add_header Cache-Control "public, max-age=604800";
            
            # Image processing on the fly
            location ~ ^/images/resize/(\d+)x(\d+)/(.+)$ {
                alias /var/www/images/$3;
                image_filter resize $1 $2;
                image_filter_jpeg_quality 85;
                image_filter_buffer 20M;
                error_page 415 = /empty;
            }
            
            # Cache processed images
            proxy_cache images;
            proxy_cache_valid 200 30d;
            proxy_cache_valid 404 1h;
        }

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

        # Metrics Endpoint (internal only)
        location /metrics {
            allow 10.0.0.0/8;
            deny all;
            proxy_pass http://api_backend/metrics;
        }

        # Web Application
        location / {
            proxy_pass http://web_backend;
            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 "";
            
            # Next.js specific
            proxy_set_header X-Forwarded-Host $host;
            proxy_set_header X-Forwarded-Port $server_port;
        }

        # Error Pages
        error_page 404 /404.html;
        error_page 500 502 503 504 /50x.html;
        
        location = /404.html {
            root /var/www/error;
            internal;
        }
        
        location = /50x.html {
            root /var/www/error;
            internal;
        }
        
        location = /empty {
            empty_gif;
        }
    }

    # CDN Server
    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name cdn.backgroundfx.pro;

        ssl_certificate /etc/nginx/ssl/cdn-fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/cdn-privkey.pem;

        root /var/www/cdn;

        location / {
            expires 1y;
            add_header Cache-Control "public, immutable";
            add_header Access-Control-Allow-Origin "*";
            
            # Enable gzip
            gzip_static on;
            
            # Serve pre-compressed files if available
            gzip_types *;
        }
    }
}