# Honour outer reverse-proxy's X-Forwarded-Proto when present (see #547 /
# frontend/nginx.conf for full rationale).
map $http_x_forwarded_proto $real_proto {
    default $http_x_forwarded_proto;
    ""      $scheme;
}

server {
    listen 80;
    server_name localhost;
    root /usr/share/nginx/html;

    # API proxy to backend
    location /api {
        proxy_pass http://backend: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;
    }

    # Photos proxy to backend
    location /photos {
        proxy_pass http://backend:3000;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
    }

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

    # Gallery share URLs: route social-crawler UAs to backend OG handler.
    location ~ ^/gallery/(?<gallery_slug>[A-Za-z0-9_-]+)(?:/[^/]+)?/?$ {
        if ($http_user_agent ~* "(facebookexternalhit|facebot|Twitterbot|WhatsApp|Slackbot|TelegramBot|SkypeUriPreview|Discordbot|LinkedInBot|Pinterest|vkShare|redditbot|Embedly|iframely|Snapchat|Applebot|Mastodon|Bluesky|OpenGraph)") {
            rewrite ^ /og/gallery/$gallery_slug last;
        }
        try_files $uri $uri/ /index.html;
    }

    location ^~ /og/gallery/ {
        proxy_pass http://backend: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;
    }
}