using Invercargill;
using Invercargill.DataStructures;
using Astralis;

namespace Statum {

    /**
     * A precompressed, named resource served from the Statum resource endpoint
     * (`/_statum/resource/{name}`).
     *
     * Mirrors the old Spry 0.1 `StaticResource` (removed in Spry 0.2): each
     * concrete resource exposes
     * the encodings it was precompressed with (identity/gzip/zstd/br), an ETag
     * per encoding, and the ability to render itself as an {@link HttpResult}.
     */
    public interface StatumResource : Object {

        /** The name the resource is served under (the `{name}` path segment). */
        public abstract string name { get; }

        /**
         * Selects the best supported encoding for a request given the set of
         * `Accept-Encoding` values the client advertised.
         */
        public abstract string get_best_encoding(Set<string> supported);

        /** The ETag to send for a given encoding. */
        public abstract string get_etag_for(string encoding);

        /** Renders the resource for the given encoding as an {@link HttpResult}. */
        public abstract HttpResult to_result(string encoding, StatusCode status = StatusCode.OK) throws GLib.Error;

    }

    /**
     * A {@link StatumResource} whose bytes are baked in at compile time.
     *
     * Concrete subclasses (typically generated by `statum-mkres`) provide the
     * precompressed byte arrays and the abstract metadata/encoding members; this
     * base supplies the {@link get_etag_for}/{@link to_result} implementation.
     */
    public abstract class ConstantStatumResource : Object, StatumResource {

        public abstract string name { get; }
        public abstract string file_hash { get; }
        public abstract string content_type { get; }

        public abstract string get_best_encoding(Set<string> supported);
        public abstract unowned uint8[] get_encoding(string encoding);

        public string get_etag_for(string encoding) {
            return @"\"$encoding-$file_hash\"";
        }

        public HttpResult to_result(string encoding, StatusCode status = StatusCode.OK) throws GLib.Error {
            var result = new HttpDataResult(Wrap.byte_array(get_encoding(encoding)), status);
            result.set_header("Content-Type", content_type);
            result.set_header("Content-Encoding", encoding);
            result.set_header("ETag", get_etag_for(encoding));
            return result;
        }

    }

}