using Invercargill;
using Invercargill.DataStructures;
using Inversion;
using Astralis;

namespace Statum {

    /**
     * `GET /_statum/resource/{name}` — serves precompressed {@link StatumResource}s.
     *
     * Mirrors the old Spry 0.1 `StaticResourceProvider` (removed in Spry
     * 0.2): all registered
     * {@link StatumResource}s are collected at construction, the `{name}` segment
     * selects one, the best encoding is chosen from `Accept-Encoding`, and
     * `ETag`/`If-None-Match` is honoured.
     */
    public class ResourceEndpoint : Object, Endpoint {

        private Dictionary<string, StatumResource> resource_map = inject_all<StatumResource>().to_dictionary<string>(r => r.name);

        public async HttpResult handle_request(HttpContext http_context, RouteContext route_context) throws GLib.Error {
            var name = route_context.mapped_parameters.get_or_default("name");
            if (name == null) {
                return new HttpStringResult("No such resource.", StatusCode.NOT_FOUND);
            }

            StatumResource resource;
            if (!resource_map.try_get((!)name, out resource)) {
                return new HttpStringResult(@"No such resource \"$((!)name)\".", StatusCode.NOT_FOUND);
            }

            var accepts = new HashSet<string>();
            foreach (var header in http_context.request.headers.get_or_empty("Accept-Encoding")) {
                foreach (var token in header.split(",")) {
                    var encoding = token.strip();
                    if (encoding.length > 0) {
                        accepts.add(encoding);
                    }
                }
            }

            var best = resource.get_best_encoding(accepts);
            var etag = resource.get_etag_for(best);
            foreach (var header in http_context.request.headers.get_or_empty("If-None-Match")) {
                if (header.contains(etag)) {
                    return new HttpEmptyResult(StatusCode.NOT_MODIFIED);
                }
            }

            return resource.to_result(best);
        }

    }

}