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

    root /var/lib/arma-tiles;
    etag on;

    # Public API is x/y/z. try_files performs an internal lookup at z/x/y.png.
    location ~ ^/tiles/(?<tile_x>[0-9]+)/(?<tile_y>[0-9]+)/(?<tile_z>[0-9]+)$ {
        if ($request_method = OPTIONS) {
            add_header Access-Control-Allow-Origin "*" always;
            add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS" always;
            add_header Access-Control-Allow-Headers "Origin, Range, Accept" always;
            add_header Content-Length 0;
            return 204;
        }
        try_files /tiles/$tile_z/$tile_x/$tile_y.png @callback_provider_tile;
        add_header Cache-Control "public, max-age=86400, stale-while-revalidate=604800" always;
        add_header Access-Control-Allow-Origin "*" always;
        add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS" always;
        add_header Access-Control-Allow-Headers "Origin, Range, Accept" always;
    }

    # A callback-provider base layer fills transparent edges when configured.
    location ~ ^/base/(?<base_x>[0-9]+)/(?<base_y>[0-9]+)/(?<base_z>[0-9]+)$ {
        try_files /__callback_provider_base__ @callback_provider_base;
    }

    include /etc/nginx/includes/callback-provider.conf;

    # metadata.json and internal z/x/y.png paths are intentionally not public.
    location / {
        return 404;
    }
}