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

namespace IStation.Untity
{
    /// <summary>
    /// 文件辅助类
    /// </summary>
    public class FileHelper
    {
        /// <summary>
        ///文件夹中不能包含的字符列表
        /// </summary>
        public static List<string> DisableStrList = new List<string> { "\\", "/", "*", "?", "\"", "<", ">", "|", ":" };

        // 私有变量
        private List<FileInfo> _lst = null;

        /// <summary>
        /// 获得目录下所有文件或指定文件类型文件(包含所有子文件夹)
        /// </summary>
        /// <param name="path"></param>
        /// <param name="extName">扩展名可以多个 例如 .mp3.wma.rm</param>
        /// <returns></returns>
        public List<FileInfo> GetFile(string path, string extName)
        {
            _lst = new List<FileInfo>();
            getdir2(path, extName);
            return _lst;
        }

        /// <summary>
        /// 获得目录下所有文件或指定文件类型文件(包含所有子文件夹)
        /// </summary>
        /// <param name="path"></param>
        /// <returns></returns>
        public List<FileInfo> GetFile(string path)
        {
            _lst = new List<FileInfo>();
            getdir1(path);
            return _lst;
        }

        // 私有方法,递归获取指定类型文件,包含子文件夹
        private void getdir2(string path, string extName)
        {
            try
            {
                string[] dir = Directory.GetDirectories(path); //文件夹列表   
                DirectoryInfo fdir = new DirectoryInfo(path);
                FileInfo[] file = fdir.GetFiles();
                //FileInfo[] file = Directory.GetFiles(path); //文件列表   
                if (file.Length != 0 || dir.Length != 0) //当前目录文件或文件夹不为空                   
                {
                    foreach (FileInfo f in file) //显示当前目录所有文件   
                    {
                        if (extName.ToLower().IndexOf(f.Extension.ToLower()) >= 0)
                        {
                            _lst.Add(f);
                        }
                    }
                    foreach (string d in dir)
                    {
                        getdir2(d, extName);//递归   
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        // 私有方法,递归获取指定类型文件,包含子文件夹
        private void getdir1(string path)
        {
            try
            {
                string[] dir = Directory.GetDirectories(path); //文件夹列表   
                DirectoryInfo fdir = new DirectoryInfo(path);
                FileInfo[] file = fdir.GetFiles();
                //FileInfo[] file = Directory.GetFiles(path); //文件列表   
                if (file.Length != 0 || dir.Length != 0) //当前目录文件或文件夹不为空                   
                {
                    foreach (FileInfo f in file) //显示当前目录所有文件   
                    {
                        _lst.Add(f);
                    }
                    foreach (string d in dir)
                    {
                        getdir1(d);//递归   
                    }
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// 获取文件夹下的所有文件夹（包含子文件夹）
        /// </summary>
        public static List<DirectoryInfo> GetFolders(string path)
        {
            try
            {
                List<DirectoryInfo> list = new List<DirectoryInfo>();
                var dir_root = new DirectoryInfo(path);
                var dir_root_subs = dir_root.GetDirectories();
                if (dir_root_subs != null && dir_root_subs.Length > 0)
                {
                    foreach (var dir in dir_root_subs)
                    {
                        list.Add(dir);
                        var folders_sub = GetFolders(dir);
                        if (folders_sub != null && folders_sub.Count > 0)
                            list.AddRange(folders_sub);
                    }
                }
                return list;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        //递归获取
        private static List<DirectoryInfo> GetFolders(DirectoryInfo directoryInfo)
        {
            List<DirectoryInfo> list = new List<DirectoryInfo>();
            var dir_subs = directoryInfo.GetDirectories();
            if (dir_subs != null && dir_subs.Length > 0)
            {
                foreach (var dir in dir_subs)
                {
                    list.Add(dir);
                    var folders_sub = GetFolders(dir);
                    if (folders_sub != null && folders_sub.Count > 0)
                        list.AddRange(folders_sub);
                }
            }
            return list;
        }

        /// 给定文件的路径，读取文件的二进制数据，判断文件的编码类型
        /// <param name="FILE_NAME">文件路径</param>
        /// <returns>文件的编码类型</returns>
        public static System.Text.Encoding GetEncoding(string FILE_NAME)
        {
            System.IO.FileStream fs = new System.IO.FileStream(FILE_NAME, System.IO.FileMode.Open,
                System.IO.FileAccess.Read);
            System.Text.Encoding r = GetEncoding(fs);
            fs.Close();
            return r;
        }

        /// 通过给定的文件流，判断文件的编码类型
        /// <param name="fs">文件流</param>
        /// <returns>文件的编码类型</returns>
        public static System.Text.Encoding GetEncoding(System.IO.FileStream fs)
        {
            byte[] Unicode = new byte[] { 0xFF, 0xFE, 0x41 };
            byte[] UnicodeBIG = new byte[] { 0xFE, 0xFF, 0x00 };
            byte[] UTF8 = new byte[] { 0xEF, 0xBB, 0xBF }; //带BOM
            System.Text.Encoding reVal = System.Text.Encoding.Default;

            System.IO.BinaryReader r = new System.IO.BinaryReader(fs, System.Text.Encoding.Default);
            int i;
            int.TryParse(fs.Length.ToString(), out i);
            byte[] ss = r.ReadBytes(i);
            if (IsUTF8Bytes(ss) || (ss[0] == 0xEF && ss[1] == 0xBB && ss[2] == 0xBF))
            {
                reVal = System.Text.Encoding.UTF8;
            }
            else if (ss[0] == 0xFE && ss[1] == 0xFF && ss[2] == 0x00)
            {
                reVal = System.Text.Encoding.BigEndianUnicode;
            }
            else if (ss[0] == 0xFF && ss[1] == 0xFE && ss[2] == 0x41)
            {
                reVal = System.Text.Encoding.Unicode;
            }
            r.Close();
            return reVal;
        }

        /// 判断是否是不带 BOM 的 UTF8 格式
        /// <param name="data"></param>
        /// <returns></returns>
        private static bool IsUTF8Bytes(byte[] data)
        {
            int charByteCounter = 1;  //计算当前正分析的字符应还有的字节数
            byte curByte; //当前分析的字节.
            for (int i = 0; i < data.Length; i++)
            {
                curByte = data[i];
                if (charByteCounter == 1)
                {
                    if (curByte >= 0x80)
                    {
                        //判断当前
                        while (((curByte <<= 1) & 0x80) != 0)
                        {
                            charByteCounter++;
                        }
                        //标记位首位若为非0 则至少以2个1开始 如:110XXXXX...........1111110X　
                        if (charByteCounter == 1 || charByteCounter > 6)
                        {
                            return false;
                        }
                    }
                }
                else
                {
                    //若是UTF-8 此时第一位必须为1
                    if ((curByte & 0xC0) != 0x80)
                    {
                        return false;
                    }
                    charByteCounter--;
                }
            }
            if (charByteCounter > 1)
            {
                throw new Exception("非预期的byte格式");
            }
            return true;
        }

        /// <summary>
        /// 读取全部文本
        /// </summary>
        public static string ReadAllText(string fileName)
        {
            if (string.IsNullOrEmpty(fileName))
                return default;
            if (!File.Exists(fileName))
                return default;
            var encoding = GetEncoding(fileName);
            return File.ReadAllText(fileName, encoding);
        }

        /// <summary>
        /// 读取全部行
        /// </summary>
        public static List<string> ReadAllLines(string fileName)
        {
            if (string.IsNullOrEmpty(fileName))
                return default;
            if (!File.Exists(fileName))
                return default;
            var encoding = GetEncoding(fileName);
            return File.ReadAllLines(fileName, encoding)?.ToList();
        }

    }
}