using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using Wms.Screen.Service.IService;

namespace Wms.Screen.Service.Service
{
    /// <summary>
    /// INI文件操作方法
    /// </summary>
    /// creater  maya
    /// createon 2020-09-08
    public class FileService : IFileService
    {
        public string IniPath { get; set; }
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct STRINGBUFFER
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string szText;
        }

        //读写INI文件的API函数 
        [DllImport("kernel32", CharSet = CharSet.Auto)]
        private static extern long WritePrivateProfileString(string section, string key, string val, string filePath);

        [DllImport("kernel32", CharSet = CharSet.Auto)]
        private static extern int GetPrivateProfileString(string section, string key, string def, out STRINGBUFFER retVal, int size, string filePath);

        [DllImport("kernel32")]
        private static extern int GetPrivateProfileString(string section, string key, string def, byte[] retVal, int size, string filePath);

        /// 读取INI文件中指定的Key的值

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern uint GetPrivateProfileString(string lpAppName, string lpKeyName, string lpDefault, [In, Out] char[] lpReturnedString, uint nSize, string lpFileName);

        //另一种声明方式,使用 StringBuilder 作为缓冲区类型的缺点是不能接受\0字符，会将\0及其后的字符截断,
        //所以对于lpAppName或lpKeyName为null的情况就不适用
        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern uint GetPrivateProfileString(string lpAppName, string lpKeyName, string lpDefault, StringBuilder lpReturnedString, uint nSize, string lpFileName);

        //再一种声明，使用string作为缓冲区的类型同char[]
        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern uint GetPrivateProfileString(string lpAppName, string lpKeyName, string lpDefault, string lpReturnedString, uint nSize, string lpFileName);

         

        //类的构造函数，传递INI档案名 
        public FileService()
        { 
            IniPath = $@"{Directory.GetCurrentDirectory()}\ZhongTian.ini";
            if (!File.Exists(IniPath))
            {
                CreateIniFile();
            }
        }

        //写INI文件 
        public void IniWriteValue(string Section, string Key, string Value)
        {
            WritePrivateProfileString(Section, Key, Value, this.IniPath);
        }

        //读取INI文件指定 
        public string IniReadValue(string Section, string Key)
        {
            //int i;
            //const int SIZE = 1024 * 10;
            //STRINGBUFFER RetVal;
            //i = GetPrivateProfileString(Section, Key, null, out RetVal, SIZE, this.IniPath);
            //string temp = RetVal.szText;
            //return temp.Trim();

            string value = "";
            const int SIZE = 1024 * 10;

            
            StringBuilder sb = new StringBuilder(SIZE); 
            uint bytesReturned = GetPrivateProfileString(Section, Key, "", sb, SIZE, IniPath);

            if (bytesReturned != 0)
            {
                value = sb.ToString();
            } 
            return value; 
             
        }

        /// <summary>
        /// 创建INI文件
        /// </summary>
        public void CreateIniFile()
        {
            StreamWriter w = File.CreateText(IniPath);
            w.Write("");
            w.Flush();
            w.Close();
        }

        #region 读取Section下的所有Key
        /// <summary>
        /// 读取Section下的所有Key,section为ini文件中的项目，通过该函数将对应项目中的变量都提取出来保存到KeyList中
        /// </summary>
        /// <param name="Section"></param> 
        public List<string> ReadKeyList(string Section)
        {
            List<string> StrList = new List<string>();
            byte[] TmpBuf = new byte[40960];
            int Len = GetPrivateProfileString(Section, null, null, TmpBuf, TmpBuf.Length, this.IniPath);
            StrList = SplitBufToStrList(TmpBuf, Len);
            return StrList;
        }
        private List<string> SplitBufToStrList(byte[] Buffer, int bufLen)
        {
            List<string> StrList = new List<string>();

            if (bufLen != 0)
            {
                int start = 0;
                for (int i = 0; i < bufLen; i++)
                {
                    if ((Buffer[i] == 0) && ((i - start) > 0))
                    {
                        string TmpStr = Encoding.GetEncoding(0).GetString(Buffer, start, i - start);
                        StrList.Add(TmpStr);
                        start = i + 1;
                    }
                }
            }
            return StrList;
        }
        #endregion

    }
}