using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace Update.Utils
{
    public static class FileExtensions
    {
        /// <summary>
        /// 生成文件的md5
        /// </summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        private static string FilenameMutexKey(string filename)
        {
            return Functions.GenMd5(filename);
        }

        /// <summary>
        /// 写入二进制值
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="bytes"></param>
        public static void WriteBytes(string filename, byte[] bytes)
        {
            if (bytes != null)
            {
                string key = FilenameMutexKey(filename);
                CheckDirectory(Path.GetDirectoryName(filename), true);
                void act()
                {
                    File.WriteAllBytes(filename, bytes);
                }
                MutexExtensions.Exec(key, act);
            }
        }


        /// <summary>
        /// 添加所有文本
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="txt"></param>
        /// <param name="encoding"></param>
        public static void AppendAllText(string filename, string txt, Encoding encoding = null)
        {
            encoding = encoding ?? Encoding.UTF8;
            string key = FilenameMutexKey(filename);
            CheckDirectory(Path.GetDirectoryName(filename), true);
            void act()
            {
                File.AppendAllText(filename, txt, encoding);
            }
            MutexExtensions.Exec(key, act);
        }

        /// <summary>
        /// 检查目录是否存在，如果不存在，将根据条件创建或不创建
        /// </summary>
        /// <param name="p"></param>
        /// <param name="create">如果目录不存在，是否创建</param>
        /// <returns></returns>
        public static bool CheckDirectory(string p, bool create)
        {

            bool res = false;
            if (!string.IsNullOrEmpty(p))
            {
                res = Directory.Exists(p);

                if (!res && create)
                {
                    Directory.CreateDirectory(p);
                    res = true;
                }
            }
            return res;
        }


        /// <summary>
        /// 获取制定路径文件的md5值
        /// </summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        public static string FileMd5(string filename)
        {
            string res = "";
            try
            {
                using (FileStream file = new FileStream(filename, FileMode.Open))
                using (MD5 md5 = new MD5CryptoServiceProvider())
                {
                    byte[] retVal = md5.ComputeHash(file);
                    StringBuilder sb = new StringBuilder();
                    for (int i = 0; i < retVal.Length; i++)
                    {
                        sb.Append(retVal[i].ToString("x2"));
                    }
                    res = sb.ToString();
                }
            }
            catch
            {

            }
            return res;
        }
    }
}