using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace ConsoleGetPLCData.CS
{

    /// <summary> 
    /// 通讯编码格式提供者,为通讯服务提供编码和解码服务 
    /// 你可以在继承类中定制自己的编码方式如:数据加密传输等 
    /// </summary> 
    public class Coder
    {
        /// <summary> 
        /// 编码方式 
        /// </summary> 
        private EncodingMothord _encodingMothord;

        protected Coder()
        {

        }

        public Coder(EncodingMothord encodingMothord)
        {
            _encodingMothord = encodingMothord;
        }

        public enum EncodingMothord
        {
            Default = 0,
            Unicode,
            UTF8,
            ASCII,
        }

        /// <summary> 
        /// 通讯数据解码 
        /// </summary> 
        /// <param name="dataBytes">需要解码的数据</param> 
        /// <returns>编码后的数据</returns> 
        public virtual string GetEncodingString(byte[] dataBytes, int start, int size)
        {
            switch (_encodingMothord)
            {
                case EncodingMothord.Default:
                    {
                        return Encoding.Default.GetString(dataBytes, start, size);
                    }
                case EncodingMothord.Unicode:
                    {
                        return Encoding.Unicode.GetString(dataBytes, start, size);
                    }
                case EncodingMothord.UTF8:
                    {
                        return Encoding.UTF8.GetString(dataBytes, start, size);
                    }
                case EncodingMothord.ASCII:
                    {
                        return Encoding.ASCII.GetString(dataBytes, start, size);
                    }
                default:
                    {
                        throw (new Exception("未定义的编码格式"));
                    }
            }

        }

        /// <summary>
        /// Saves the file.
        /// </summary>
        /// <param name="FileName">Name of the file.</param>
        /// <param name="Result">The result.</param>
        public void SaveFile(string FileName, byte[] Result)
        {
            try
            {
                FileStream fs = new FileStream(FileName, FileMode.OpenOrCreate);
                fs.Write(Result, 5 + Result[1], Result[2] * 65536 + Result[3] * 256 + Result[4]);
                fs.Flush();
                fs.Close();
            }
            catch
            {

            }

        }

        StreamWriter writer = null;
        /// <summary>
        /// Saves the file.
        /// </summary>
        /// <param name="FileName">Name of the file.</param>
        /// <param name="Result">The result.</param>
        public void WriteFile(string FileName, string Result)
        {
            try
            {
                if (writer == null)
                {
                    writer = new StreamWriter(FileName);
                }
                writer.Write(string.Concat(Result.ToString(), Environment.NewLine));
                writer.Flush();
            }
            catch
            {

            }

        }

        /// <summary> 
        /// 数据编码 
        /// </summary> 
        /// <param name="datagram">需要编码的报文</param> 
        /// <returns>编码后的数据</returns> 
        public virtual byte[] GetTextBytes(string datagram)
        {
            byte[] rbyte = new byte[Encoding.UTF8.GetBytes(datagram).Length + 1];
            rbyte[0] = 0x55;
            switch (_encodingMothord)
            {
                case EncodingMothord.Default:
                    {
                        Encoding.Default.GetBytes(datagram, 0, datagram.Length, rbyte, 1);
                        return rbyte;
                    }
                case EncodingMothord.Unicode:
                    {
                        Encoding.Unicode.GetBytes(datagram, 0, datagram.Length, rbyte, 1);
                        return rbyte;
                    }
                case EncodingMothord.UTF8:
                    {
                        Encoding.UTF8.GetBytes(datagram, 0, datagram.Length, rbyte, 1);
                        return rbyte;
                    }
                case EncodingMothord.ASCII:
                    {
                        Encoding.ASCII.GetBytes(datagram, 0, datagram.Length, rbyte, 1);
                        return rbyte;
                    }
                default:
                    {
                        throw (new Exception("未定义的编码格式"));
                    }
            }

        }

        public virtual byte[] GetFileBytes(string FilePath)
        {
            if (File.Exists(FilePath))
            {
                string fileName = Path.GetFileName(FilePath);
                byte[] bytFileName = this.GetTextBytes(fileName);
                FileStream fs = new FileStream(FilePath, FileMode.Open);
                Byte[] RByte = new byte[fs.Length + 5 + bytFileName.Length];
                RByte[0] = 0x66;
                RByte[1] = (byte)(bytFileName.Length);
                RByte[2] = (byte)(fs.Length / 65536);
                RByte[3] = (byte)(fs.Length / 256);
                RByte[4] = (byte)(fs.Length % 256);
                bytFileName.CopyTo(RByte, 5);
                fs.Read(RByte, 5 + bytFileName.Length, (int)fs.Length);
                return RByte;
            }
            else
            {
                throw (new Exception("文件不存在"));
            }
        }

    } 
}