using System;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;
using System.Linq;
using System.Runtime.InteropServices;
namespace Humep.FileWatcher
{
    ///
    /// 日志文件操作
    /// Date:2011-06-01
    ///
    public static class FileHelper
    {
        ///
        /// 获取文件路径中最后的目录名
        ///
        ///
        ///
        public static string GetDirectoryName(string fullName)
        {
            if (string.IsNullOrWhiteSpace(fullName))
            {
                return null;
            }
            return fullName.Substring(0,fullName.LastIndexOf('\')+1);
        }
        ///
        /// 获取路径中的文件名称
        ///
        ///
        ///
        public static string GetFileName(string filePath)
        {
            if (string.IsNullOrWhiteSpace(filePath))
            {
                return string.Empty;
            }
            if (filePath.Length > 260)
            {
                return filePath.Substring(filePath.LastIndexOf('\') + 1, int.MaxValue);
            }
            return Path.GetFileName(filePath);
        }

        ///
        /// 文件名是否满足filePattern格式。
        ///
        ///
        public static bool IsMatched(string fileName, string filePattern)
        {
            if (string.IsNullOrWhiteSpace(fileName))
            {
                return false;
            }
            if (string.IsNullOrWhiteSpace(filePattern))
            {
                return false;
            }
            Regex regex = new Regex(filePattern, RegexOptions.IgnoreCase);
            return regex.IsMatch(fileName);
        }

        ///
        /// 读取文件内容
        ///
        ///
        ///
        public static string ReadAllText(string filePath)
        {
            if (string.IsNullOrWhiteSpace(filePath) || File.Exists(filePath) == false)
            {
                return string.Empty;
            }
            return File.ReadAllText(filePath);
        }
        ///
        /// 删除文件
        ///
        ///
        public static bool Delete(string filePath)
        {
            if (string.IsNullOrWhiteSpace(filePath))
            {
                return false;
            }
            if (!File.Exists(filePath))
            {
                return false;
            }
            File.Delete(filePath);
            return !File.Exists(filePath);
        }
        ///
        /// 删除目录下所有过期文件
        ///
        ///
        ///
        public static int ClearExpiredFiles(string directory, int expiredDays)
        {
            if (!Directory.Exists(directory))
            {
                return 0;
            }
            if (expiredDays 260)
            {
                return MoveLongPathFile(@"\?"+sourcePath,@"\?"+ targetPath);
            }
            File.Move(sourcePath, targetPath);
            return true;
        }

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true, EntryPoint = "MoveFile")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool MoveLongPathFile(string lpExistingFileName, string lpNewFileName);
        ///
        /// 单个文件移动
        ///
        ///
        ///
        ///
        ///
        public static bool MoveFile(string fileName, string sourceDirectory, string targetDirectory)
        {
            if (!File.Exists(fileName))
            {
                return false;
            }
            if (!Directory.Exists(sourceDirectory))
            {
                return false;
            }
            if (!Directory.Exists(targetDirectory))
            {
                return false;
            }
            string filePath = fileName.Replace(sourceDirectory, targetDirectory);
            string fileDir=Path.GetDirectoryName(filePath);
            if(!DirectoryHelper.CreateDirectory(fileDir))
            {
                return false;
            }
            return MoveFile(fileName, fileDir);
        }
        ///
        /// 重新生成新的文件路径
        ///
        ///
        ///
        public static string Rename(string filePath)
        {
            if (string.IsNullOrWhiteSpace(filePath))
            {
                return string.Empty;
            }
            string lastFileName = Path.GetFileNameWithoutExtension(filePath);
            string lastFileExtension = Path.GetExtension(filePath);
            //重命名，则随机在原来文件名后面加几个随机数字进行组装成新的名字
            Random random = new Random(System.DateTime.Now.Millisecond);
            string randomData = random.Next().ToString();
            //把原文件名的名字加上随机数，组装成新的文件名（避免重名）
            string newFileName = lastFileName + randomData;
            return Path.GetDirectoryName(filePath) + "\" + newFileName + lastFileExtension;
        }

    }
}