# ©AngelaMos | 2025
# Production Nginx Configuration
# - Serves static frontend from /usr/share/nginx/html
# - Proxies /api and /ws to FastAPI backend
# - Caching, compression, security headers, rate limiting

user nginx;
worker_processes auto;
worker_rlimit_nofile 100000;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 4096;
    use epoll;
    multi_accept on;
}

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

    # WebSocket upgrade handling
    map $http_upgrade $connection_upgrade {
        default upgrade;
        ''      close;
    }

    upstream backend {
        server backend:8000 max_fails=3 fail_timeout=30s;
        keepalive 32;
    }

    # Rate limit zones
    limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
    limit_conn_zone $binary_remote_addr zone=conn_limit:10m;

    # Logging with timing and buffering
    log_format main_timed '$remote_addr - $remote_user [$time_local] '
                          '"$request" $status $body_bytes_sent '
                          '"$http_referer" "$http_user_agent" '
                          'rt=$request_time urt="$upstream_response_time"';

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

    # Performance
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    keepalive_requests 100;
    types_hash_max_size 2048;
    server_tokens off;

    # File cache
    open_file_cache max=10000 inactive=20s;
    open_file_cache_valid 30s;
    open_file_cache_min_uses 2;
    open_file_cache_errors on;

    # Buffer sizes
    client_body_buffer_size 128k;
    client_header_buffer_size 16k;
    client_max_body_size 10m;
    large_client_header_buffers 4 16k;

    # Timeouts
    client_body_timeout 12s;
    client_header_timeout 12s;
    send_timeout 10s;

    # 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
        text/javascript
        application/json
        application/javascript
        application/xml+rss
        application/atom+xml
        font/truetype
        font/opentype
        application/vnd.ms-fontobject
        image/svg+xml;

    server {
        listen 80;
        listen [::]:80;
        server_name _;

        root /usr/share/nginx/html;
        index index.html;

        # 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 Permissions-Policy "geolocation=(), microphone=(), camera=()" always;

        # WebSocket to backend
        location /ws {
            proxy_pass http://backend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $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_read_timeout 3600s;
            proxy_send_timeout 3600s;
            proxy_connect_timeout 75s;
            proxy_buffering off;
        }

        # API routes with rate limiting
        location /api {
            limit_req zone=api_limit burst=20 nodelay;
            limit_conn conn_limit 20;

            proxy_pass http://backend;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
            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_buffering on;
            proxy_buffers 8 24k;
            proxy_buffer_size 2k;

            proxy_connect_timeout 75s;
            proxy_send_timeout 30s;
            proxy_read_timeout 30s;
        }

        # Static assets - aggressive caching
        location ~* \.(jpg|jpeg|png|gif|ico|svg|webp|avif)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
            access_log off;
        }

        location ~* \.(css|js)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
            access_log off;
        }

        location ~* \.(woff|woff2|ttf|eot|otf)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
            access_log off;
        }

        # index.html - never cache
        location = /index.html {
            add_header Cache-Control "no-cache, no-store, must-revalidate";
        }

        # SPA fallback
        location / {
            try_files $uri $uri/ /index.html;
        }

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

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