using Invercargill;
using Gee;

namespace Ppub {

    public class Builder {

        private Invercargill.Sequence<BuilderAsset> assets {get; set;}

        private uint64 position = 0;

        public void add_metadata(Metadata metadata) {
            var data = (uint8[])metadata.to_string().to_utf8();
            var mis = new MemoryInputStream.from_data(data);
            add_asset("metadata", "application/x-ppub-metadata", mis, data.length);
        }

        public void add_asset(string name, string mimetype, InputStream stream, uint64 size) {

            lock(assets) {
                var asset = new BuilderAsset();
                asset.name = name;
                asset.start_location = position;
                asset.end_location = position + size;
                asset.mimetype = mimetype;
                asset.stream = stream;
    
                position += size;
                assets.add(asset);
            }

        }

        public void write(OutputStream stream) throws IOError {

            var index_entries = assets.select<string>(a => a.to_string() + "\n").to_array();
            var index_data = (uint8[])string.join("", index_entries).to_utf8();
            var header_data = (uint8[])(@"$(index_data.length)\n".to_utf8());

            stream.write(header_data);
            stream.write(index_data);

            foreach (var asset in assets.as_iterable()) {
                stream.splice(asset.stream, OutputStreamSpliceFlags.CLOSE_SOURCE);
            }

        }



    }

    public class BuilderAsset : Asset {
        
        public InputStream stream {get; set;}

    }

}