# ==============================================================================
# Dashfront + Dashback Production NGINX Server Configuration
# ==============================================================================

map $http_upgrade $connection_upgrade {
    default upgrade;
    ''      close;
}

# ------------------------------------------------------------------------------
# 1. HTTP -> HTTPS Redirect
# ------------------------------------------------------------------------------
server {
    listen 80;
    listen [::]:80;
    server_name dashdev.quixpos.com;

    location ^~ /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    location / {
        return 301 https://$host$request_uri;
    }
}

# ------------------------------------------------------------------------------
# 2. Main HTTPS Server Block
# ------------------------------------------------------------------------------
server {
    listen 443 ssl;
    listen [::]:443 ssl;
    http2 on;

    server_name dashdev.quixpos.com;

    # --- SSL / TLS Certificates ---
    ssl_certificate     /etc/letsencrypt/live/dashdev.quixpos.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/dashdev.quixpos.com/privkey.pem;

    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:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305;
    ssl_prefer_server_ciphers off;
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:10m;
    ssl_session_tickets off;

    # --- Header Buffer Limits (prevents HTTP/2 RST_STREAM / ERR_HTTP2_PROTOCOL_ERROR) ---
    large_client_header_buffers 4 128k;

    # --- Static File Root ---
    root /home/seb/src/dashfront/dist;
    index index.html;

    # --- Request Body & Uploads (PDF receipts, AVIF photos) ---
    client_max_body_size 100m;
    client_body_timeout 300s;

    # --- Compression (Gzip) ---
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 5;
    gzip_min_length 256;
    gzip_types
        text/plain
        text/css
        text/xml
        text/javascript
        application/javascript
        application/x-javascript
        application/json
        application/xml
        application/manifest+json
        application/wasm
        image/svg+xml;

    # --- Security Headers ---
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "camera=(self), microphone=(), geolocation=()" always;

    # ==========================================================================
    # API & Backend Routing (Dashback on port 4208)
    # ==========================================================================

    # Dedicated SSE route: Real-time broadcast events
    location = /api/events {
        proxy_pass http://127.0.0.1:4208;
        proxy_http_version 1.1;

        # Clear Connection & Accept-Encoding to prevent upstream gzip/chunk buffering
        proxy_set_header Connection        "";
        proxy_set_header Accept-Encoding   "";
        proxy_set_header Host              $http_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;

        # Disable buffering and compression completely for immediate push
        proxy_buffering off;
        proxy_cache off;
        chunked_transfer_encoding off;
        gzip off;

        # Prevent premature disconnections; keep SSE open for 24 hours
        proxy_read_timeout 86400s;
        proxy_send_timeout 86400s;
    }

    # General API endpoints (REST)
    location /api/ {
        proxy_pass http://127.0.0.1:4208;
        proxy_http_version 1.1;

        proxy_set_header Upgrade           $http_upgrade;
        proxy_set_header Connection        $connection_upgrade;
        proxy_set_header Host              $http_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_cookie_path / /;

        proxy_request_buffering off;
        proxy_connect_timeout 60s;
        proxy_send_timeout    300s;
        proxy_read_timeout    300s;
    }

    # ==========================================================================
    # PWA & Service Worker Rules (Zero Caching)
    # ==========================================================================

    location ~* ^/(sw\.js|registerSW\.js|workbox-[a-f0-9]+\.js)$ {
        add_header Cache-Control "no-cache, no-store, must-revalidate";
        add_header Pragma "no-cache";
        add_header Expires "0";
        access_log off;
    }

    location ~* ^/(manifest\.webmanifest|favicon\.svg|icons/.*)$ {
        add_header Cache-Control "public, max-age=3600";
        add_header Vary "Accept-Encoding";
        access_log off;
    }

    # ==========================================================================
    # Static Assets & Hashed Bundles (Aggressive Immutable Caching)
    # ==========================================================================

    location /assets/ {
        add_header Cache-Control "public, max-age=31536000, immutable";
        add_header Vary "Accept-Encoding";
        access_log off;
    }

    location ~* \.wasm$ {
        default_type application/wasm;
        add_header Cache-Control "public, max-age=31536000, immutable";
        access_log off;
    }

    # ==========================================================================
    # HTML5 SPA Entry Point & Navigation Fallback
    # ==========================================================================

    location = /index.html {
        add_header Cache-Control "no-cache, no-store, must-revalidate";
        add_header Pragma "no-cache";
        add_header Expires "0";
    }

    location / {
        try_files $uri $uri/ /index.html;
    }
}