using LibXom.Data;
using LibXom.Streams;
using LibXom;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using LibW4M.Data.Stats;

namespace LibW4M.PS2
{
    public static class Ps2Save
    {
        private const int PS2_MAX_SZ = 0x20000;

        private static void createPs2SaveXOM(W4SaveFile save, Stream output)
        {
            // Remove all stats ...
            foreach (StatsContainerData stat in save.StatsCollective.ToArray())
                save.StatsCollective.Delete(stat);

            // Save changes
            save.saveData();
            XomWriter.WriteXom(save.OriginalXom,output);
            Ps2Save.CalcAndWriteChecksum(output);
        }
        public static void CalcAndWriteChecksum(Stream s)
        {
            XomStreamReader reader = new XomStreamReader(s);
            XomStreamWriter writer = new XomStreamWriter(s);

            // Set size to ps2 save size.

            s.SetLength(PS2_MAX_SZ);
            s.Seek(0, SeekOrigin.Begin);

            // Calculate checksum

            Int64 chk = 0;

            for (int i = 0; i < (PS2_MAX_SZ - 4); i += 4)
            {
                int c = reader.ReadInt32();
                chk = (chk + c) & UInt32.MaxValue;
            }

            writer.WriteUInt32(Convert.ToUInt32(chk));

            s.Seek(0, SeekOrigin.Begin);
        }

        public static W4SaveFile ReadPS2Save(string filename)
        {
            return new W4SaveFile(XomReader.ReadXomFile(PsuFile.ReadPSU(filename).GetFileByName("BESLES-53096W4MA").FileData));
        }

        public static void CreateSaveFile(W4SaveFile save, Stream output)
        {
            PsuFile psuFile = new PsuFile();
            psuFile.InitalizePSU("BESLES-53096W4MA");
            psuFile.CreateFile("Icon1.ico", SaveResources.IconFile);
            psuFile.CreateFile("icon.sys", SaveResources.IconSys);

            using(MemoryStream ms = new MemoryStream())
            {
                createPs2SaveXOM(save, ms);
                ms.Seek(0, SeekOrigin.Begin);
                psuFile.CreateFile("BESLES-53096W4MA", ms.ToArray());
            }

            psuFile.WritePSU(output);
        }


    }
}