using System;
using System.Collections.Generic;
using System.Text;

namespace Pack89KData
{
    public class ApplicationFile
    {
        #region Declarations

        private byte[] _signature;
        private ushort _revisionNumber;
        private byte _flags;
        private byte _objectType;
        private uint _fileDate;
        private string _applicationName;
        private byte _deviceType;
        private byte _dataType;
        private List<ApplicationField> _fields;

        #endregion

        #region Constructors/Teardown

        public ApplicationFile()
        {
            _signature = new byte[8];
            _fields = new List<ApplicationField>();
        }

        #endregion

        #region Public Properties

        public string ApplicationName
        {
            get
            {
                return _applicationName;
            }
            set
            {
                _applicationName = value;
            }
        }

        public List<ApplicationField> Fields
        {
            get
            {
                return _fields;
            }
        }

        #endregion

        #region Public Methods

        public void Load(string fileName)
        {
            const int BUFFER_SIZE = 9;
            byte[] buffer = new byte[BUFFER_SIZE];
            var file = new System.IO.FileStream(fileName, System.IO.FileMode.Open);

            //Get the signature
            file.Read(_signature, 0, 8);

            //Get the revision number
            file.Read(buffer, 0, 2);
            _revisionNumber = (ushort)((buffer[0] & 0xFF) | (buffer[1] << 8));

            //Get flags and object type
            _flags = (byte)file.ReadByte();
            _objectType = (byte)file.ReadByte();

            //Get date
            file.Read(buffer, 0, 4);
            _fileDate = (uint)((buffer[0] & 0xFF) | (buffer[1] << 8) | (buffer[2] << 16) | (buffer[3] << 24));

            //Get the name
            char[] name = new char[9];
            file.Read(buffer, 0, 9);
            for (int i = 0; i < 8; i++)
                name[i] = (char)buffer[i+1];
            _applicationName = new string(name).Trim('\0');

            //Get device/data types
            file.Seek(0x30, System.IO.SeekOrigin.Begin);
            _deviceType = (byte)file.ReadByte();
            _dataType = (byte)file.ReadByte();

            //Get total file size
            int fileSize;
            file.Seek(0x4A, System.IO.SeekOrigin.Begin);
            file.Read(buffer, 0, 4);
            fileSize = (buffer[0] & 0xFF) | (buffer[1] << 8) | (buffer[2] << 16) | (buffer[3] << 24);

            //Read in the data
            byte[] data = new byte[fileSize];
            file.Read(data, 0, fileSize);

            _fields = ApplicationField.ParseContents(data);

            file.Close();
        }

        public void Save(string fileName)
        {
            const int BUFFER_SIZE = 9;
            byte[] buffer = new byte[BUFFER_SIZE];
            var file = new System.IO.FileStream(fileName, System.IO.FileMode.Create);

            //Write signature
            file.Write(_signature, 0, _signature.Length);

            //Write revision number
            buffer[0] = (byte)(_revisionNumber & 0xFF);
            buffer[1] = (byte)(_revisionNumber >> 8);
            file.Write(buffer, 0, 2);

            //Write flags and object type
            file.WriteByte(_flags);
            file.WriteByte(_objectType);

            //Write date
            file.WriteByte((byte)(_fileDate & 0xFF));
            file.WriteByte((byte)((_fileDate >> 8) & 0xFF));
            file.WriteByte((byte)((_fileDate >> 16) & 0xFF));
            file.WriteByte((byte)((_fileDate >> 24) & 0xFF));

            //Write the name
            for (int i = 1; i < 9; i++)
                buffer[i] = 0x00;
            buffer[0] = 0x08;
            for (int i = 0; i < _applicationName.Length; i++)
                buffer[i + 1] = (byte)_applicationName[i];
            file.Write(buffer, 0, 9);

            file.Seek(0x30, System.IO.SeekOrigin.Begin);

            //Write device/data types
            file.WriteByte(_deviceType);
            file.WriteByte(_dataType);

            file.Seek(0x4A, System.IO.SeekOrigin.Begin);

            //Write total file size
            int size = 0;
            for (int i = 0; i < _fields.Count; i++)
                size += _fields[i].Count;
            file.WriteByte((byte)(size & 0xFF));
            file.WriteByte((byte)((size >> 8) & 0xFF));
            file.WriteByte((byte)((size >> 16) & 0xFF));
            file.WriteByte((byte)((size >> 24) & 0xFF));

            //Write out the data
            for (int i = 0; i < _fields.Count; i++)
            {
                byte[] d = _fields[i].ToByteArray();
                file.Write(d, 0, d.Length);
            }

            file.Close();
        }

        #endregion
    }
}