# Honour the outer reverse proxy's X-Forwarded-Proto when present (e.g. NPM,
# Traefik, Caddy in front of PicPeak). Falls back to nginx's own $scheme when
# the header is absent (direct access / no outer proxy). Without this the
# inner nginx was always forwarding "http" to the backend because the outer
# proxy → inner nginx hop is plain HTTP, breaking Secure cookies and HTTPS
# URL generation in the backend. See issue #547.
map $http_x_forwarded_proto $real_proto {
    default $http_x_forwarded_proto;
    ""      $scheme;
}

server {
    listen 80;
    server_name localhost;
    server_tokens off;
    root /usr/share/nginx/html;
    index index.html;

    # Docker DNS resolver for dynamic service discovery (required for Swarm/Compose)
    resolver 127.0.0.11 valid=10s ipv6=off;
    resolver_timeout 5s;

    # Allow larger file uploads (up to 1GB for video support)
    client_max_body_size 1G;
    client_body_timeout 300s;

    # Defensive header buffer bump (#591). Default `4 8k` is too tight when
    # an outer Cloudflare / corp-proxy sits in front and injects long
    # Set-Cookie / X-Forwarded-* headers, or when a power-user accumulates
    # many per-gallery `gallery_token_<slug>` cookies over the 24h maxAge
    # in tokenUtils.js. Either way users hit "400 Request Header Or Cookie
    # Too Large" and clearing cookies is the only fix. 4×32k is cheap RAM
    # and matches what most reverse proxies already do upstream.
    large_client_header_buffers 4 32k;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_types text/plain text/css text/xml text/javascript application/javascript application/xml+rss application/json;

    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=(), payment=()" always;
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' https://www.google.com https://www.gstatic.com; style-src 'self' 'unsafe-inline' https:; img-src 'self' data: https: blob:; connect-src 'self' https://www.google.com https://www.gstatic.com; font-src 'self' https: data:; object-src 'none'; media-src 'self'; frame-src 'self' https://www.google.com" always;

    # Strip the same headers when emitted by the upstream backend so nginx
    # is the single source. Without this, helmet (in the Express app) and
    # nginx both emit the headers and clients see duplicates — testssl
    # flagged "Multiple X-Frame-Options / X-Content-Type-Options / CSP /
    # Permissions-Policy / Referrer-Policy headers" on the live origin.
    # proxy_hide_header at server level applies to every proxy_pass below.
    proxy_hide_header X-Frame-Options;
    proxy_hide_header X-Content-Type-Options;
    proxy_hide_header Referrer-Policy;
    proxy_hide_header Content-Security-Policy;
    proxy_hide_header Permissions-Policy;
    proxy_hide_header Strict-Transport-Security;

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

    # Cache static assets
    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
        # Re-apply security headers (add_header in location block overrides server-level)
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
        add_header Content-Security-Policy "default-src 'self'; script-src 'self' https://www.google.com https://www.gstatic.com; style-src 'self' 'unsafe-inline' https:; img-src 'self' data: https: blob:; connect-src 'self' https://www.google.com https://www.gstatic.com; font-src 'self' https: data:; object-src 'none'; media-src 'self'; frame-src 'self' https://www.google.com" always;
    }

    # Cache index.html with revalidation
    location = /index.html {
        add_header Cache-Control "no-cache, no-store, must-revalidate";
        add_header Pragma "no-cache";
        add_header Expires "0";
        # Re-apply security headers
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
        add_header Content-Security-Policy "default-src 'self'; script-src 'self' https://www.google.com https://www.gstatic.com; style-src 'self' 'unsafe-inline' https:; img-src 'self' data: https: blob:; connect-src 'self' https://www.google.com https://www.gstatic.com; font-src 'self' https: data:; object-src 'none'; media-src 'self'; frame-src 'self' https://www.google.com" always;
    }

    # API proxy
    location /api {
        # Use variable to force DNS resolution per request (required for Docker Swarm)
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000;
        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 $real_proto;
        proxy_cache_bypass $http_upgrade;
        proxy_read_timeout 86400;

        # Allow larger uploads for API endpoints (up to 1GB for video support)
        client_max_body_size 1G;
        client_body_timeout 300s;
    }

    # Photo serving proxy
    location /photos {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000;
        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 $real_proto;

        # Cache photos
        proxy_cache_valid 200 302 1d;
        proxy_cache_valid 404 1m;
    }

    # Thumbnail serving proxy
    location /thumbnails {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000;
        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 $real_proto;

        # Cache thumbnails
        proxy_cache_valid 200 302 7d;
        proxy_cache_valid 404 1m;
    }

    # Uploads serving proxy (logos, favicons, watermarks)
    # ^~ modifier stops regex matching, ensuring uploads are proxied not served locally
    location ^~ /uploads {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000;
        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 $real_proto;

        # Cache uploads
        proxy_cache_valid 200 302 7d;
        proxy_cache_valid 404 1m;
    }

    # Self-hosted webfonts proxy (bundled families + admin user additions).
    # ^~ modifier stops regex matching, ensuring fonts are proxied to the
    # backend (which scans backend/assets/fonts and STORAGE_PATH/fonts) and
    # NOT served locally — the .woff2 files do not exist in the frontend image.
    location ^~ /fonts {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000;
        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 $real_proto;

        # Fonts rarely change; cache aggressively (matches backend Cache-Control).
        proxy_cache_valid 200 302 7d;
        proxy_cache_valid 404 1m;
    }

    # Dynamic robots.txt served by backend
    location = /robots.txt {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000/robots.txt;
        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 $real_proto;
    }

    # Dynamic favicon / apple-touch-icon served by backend (resolves the
    # admin-configured branding favicon, falls back to the bundled asset).
    # Exact-match (=) wins over the static-asset regex below, so these reach
    # the backend instead of the build dir. Browsers (especially Safari)
    # request these at the site root regardless of any JS-injected
    # <link rel="icon">.
    location = /favicon.ico {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000/favicon.ico;
        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 $real_proto;
    }
    location = /apple-touch-icon.png {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000/apple-touch-icon.png;
        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 $real_proto;
    }
    location = /apple-touch-icon-precomposed.png {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000/apple-touch-icon-precomposed.png;
        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 $real_proto;
    }

    # Delegate root requests to backend for public landing page handling
    location = / {
        # Use variable to force DNS resolution per request (required for Docker Swarm)
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000/;
        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 $real_proto;
        proxy_read_timeout 60s;
    }

    # Social-crawler detection for gallery share URLs. Crawlers (WhatsApp,
    # Facebook, Slack, Twitter, etc.) don't run JS, so the SPA's client-side
    # meta tags never reach them. Route those UAs to backend's /og handler
    # via internal rewrite; humans fall through to the SPA via try_files.
    location ~ ^/gallery/(?<gallery_slug>[A-Za-z0-9_-]+)(?:/[^/]+)?/?$ {
        # Keep this list in sync with SOCIAL_CRAWLER_PATTERNS in
        # backend/src/services/galleryOgService.js. WhatsAppBot / wa-bot
        # and LinkPreview / Slack-ImgProxy added in #521 to catch
        # business-API preview fetchers that aren't the main WhatsApp app.
        if ($http_user_agent ~* "(facebookexternalhit|facebot|Twitterbot|WhatsApp|WhatsAppBot|wa-bot|Slackbot|Slack-ImgProxy|TelegramBot|SkypeUriPreview|Discordbot|LinkedInBot|Pinterest|vkShare|redditbot|Embedly|iframely|Snapchat|Applebot|Mastodon|Bluesky|OpenGraph|LinkPreview)") {
            rewrite ^ /og/gallery/$gallery_slug last;
        }
        try_files $uri $uri/ /index.html;
    }

    # OG preview endpoint (proxied to backend). Public endpoint by design —
    # only exposes event_name + branding logo, no protected photo content.
    location ^~ /og/gallery/ {
        set $backend_upstream backend;
        proxy_pass http://$backend_upstream:3000;
        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 $real_proto;
    }

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

    # Deny access to hidden files
    location ~ /\. {
        deny all;
    }
}