using System;
using System.IO;
using System.Diagnostics;

namespace TwlBackupBlock
{
    /// <summary>
    /// ヘッダブロック中のTMDReserved。
    /// Normal, Legacy 共に共通。
    /// </summary>
    public class TmdReserved
    {
        private const int TMD_RESERVED_SIZE = 62;

        public const int RESERVED8_SIZE = 3;
        public const int PARENTAL_CONTROL_SIZE = 16;
        public const int RESERVED_SIZE = 30;

        public UInt32 publicSaveSize;
        public UInt32 privateSaveSize;
        public UInt32 reserved32;
        public Byte flags;
        public readonly Byte[] reserved8;
        public readonly Byte[] parentalControl;
        public readonly Byte[] reserved;

        public TmdReserved()
        {
            reserved8 = new Byte[RESERVED8_SIZE];
            parentalControl = new Byte[PARENTAL_CONTROL_SIZE];
            reserved = new Byte[RESERVED_SIZE];
        }

        public byte[] GetBytes()
        {
            byte[] bytes = new byte[TMD_RESERVED_SIZE];

            using (var ms = new MemoryStream(bytes))
            using (var bw = new BinaryWriter(ms))
            {
                bw.Write(publicSaveSize);
                bw.Write(privateSaveSize);
                bw.Write(reserved32);
                bw.Write(flags);
                bw.Write(reserved8);
                bw.Write(parentalControl);
                bw.Write(reserved);

                Debug.Assert(ms.Position == TMD_RESERVED_SIZE);
            }

            return bytes;
        }

        public void SetBytes(byte[] bytes)
        {
            if (bytes == null)
            {
                throw new ArgumentNullException("bytes");
            }
            if (bytes.Length != TMD_RESERVED_SIZE)
            {
                string message = string.Format("bytes.Length != {0} (bytes.Length:{1})", TMD_RESERVED_SIZE, bytes.Length);
                throw new ArgumentException("bytes", message);
            }

            using (var ms = new MemoryStream(bytes))
            using (var br = new ExtBinaryReader(ms))
            {
                br.Read(ref publicSaveSize);
                br.Read(ref privateSaveSize);
                br.Read(ref reserved32);
                br.Read(ref flags);
                br.Read(reserved8);
                br.Read(parentalControl);
                br.Read(reserved);

                Debug.Assert(ms.Position == TMD_RESERVED_SIZE);
            }
        }
    }
}