using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
namespace WMS.Untils
{
    /// <summary>
    /// 文件帮助
    /// </summary>
    public class FileHelper
    {
        private static char[] base64CodeArray = new char[]
        {
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
            '0', '1', '2', '3', '4',  '5', '6', '7', '8', '9', '+', '/', '='
        };




        /// <summary>
        /// 判断一个文件是否是图片
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        public static bool IsImage(string name)
        {
            var extension = Path.GetExtension(name).ToLower();

            var imageExtensions = new List<string> { ".jpg", ".png", ".ico", ".tif", ".bmp", ".gif" };
            return imageExtensions.Contains(extension);
        }

        /// <summary>
        /// 判断一个文件是否为pdf文件
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        public static bool IsPdf(string name)
        {
            var extension = Path.GetExtension(name).ToLower();
            var pdfExtensions = new List<string> { ".pdf" };
            return pdfExtensions.Contains(extension);
        }

        /// <summary>
        /// 将指定路径下的文件转为byte数组
        /// </summary>
        /// <param name="path">指定路径</param>
        /// <returns></returns>
        public static byte[] GetBytesByFile(string path)
        {
            try
            {
                if (!File.Exists(path))
                {
                    return new byte[0];
                }

                var fileInfo = new FileInfo(path);
                byte[] buff = new byte[fileInfo.Length];

                var fileStream = fileInfo.OpenRead();
                fileStream.Read(buff, 0, int.Parse(fileStream.Length.ToString()));
                fileStream.Close();
                return buff;
            }
            catch (Exception ex)
            {
                return new byte[0];
            }
        }

        /// <summary>
        /// 将指定路径下的图片转成base64字符串
        /// </summary>
        /// <param name="path"></param>
        /// <returns></returns>
        public static string GetBase64Str(string path)
        {

            try
            {

                using (MemoryStream ms1 = new MemoryStream())
                {
                    var bmp1 = new Bitmap(path);
                    bmp1.Save(ms1, System.Drawing.Imaging.ImageFormat.Jpeg);
                    byte[] arr1 = new byte[ms1.Length];
                    ms1.Position = 0;
                    ms1.Read(arr1, 0, (int)ms1.Length);
                    ms1.Close();
                    bmp1.Dispose();
                    return Convert.ToBase64String(arr1);
                }
            }
            catch (Exception ex)
            {
                return null;
            }
        }


        public static string GetBase64Str(Bitmap bitMap)
        {

            try
            {

                using (MemoryStream ms1 = new MemoryStream())
                {
                    bitMap.Save(ms1, System.Drawing.Imaging.ImageFormat.Jpeg);
                    byte[] arr1 = new byte[ms1.Length];
                    ms1.Position = 0;
                    ms1.Read(arr1, 0, (int)ms1.Length);
                    ms1.Close();
                    return Convert.ToBase64String(arr1);
                }
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        /// <summary>
        /// 是否base64字符串
        /// </summary>
        /// <param name="base64Str">要判断的字符串</param>
        /// <param name="bytes">字符串转换成的字节数组</param>
        /// <returns></returns>
        public static bool IsBase64(string base64Str, out byte[] bytes)
        {
            //string strRegex = "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$";
            bytes = null;
            if (string.IsNullOrEmpty(base64Str))
                return false;
            else
            {
                if (base64Str.Contains(","))
                    base64Str = base64Str.Split(',')[1];
                if (base64Str.Length % 4 != 0)
                    return false;
                if (base64Str.Any(c => !base64CodeArray.Contains(c)))
                    return false;
            }
            try
            {
                bytes = Convert.FromBase64String(base64Str);
                return true;
            }
            catch (FormatException)
            {
                return false;
            }
        }

        /// <summary>
        /// 把base64字符串转换成Bitmap
        /// </summary>
        /// <param name="base64Str">要转换的base64字符串</param>
        /// <returns></returns>
        public static Bitmap Base64ToBitmap(string base64Str)
        {
            Bitmap bitmap = null;
            byte[] bytes = null;
            try
            {
                if (IsBase64(base64Str, out bytes))
                {
                    using (MemoryStream stream = new MemoryStream(bytes))
                    {
                        stream.Seek(0, SeekOrigin.Begin);//为了避免有时候流指针定位错误，显式定义一下指针位置
                        bitmap = new Bitmap(stream);
                    }
                }
            }
            catch (Exception)
            {
                bitmap = null;
            }
            return bitmap;
        }


        /// <summary>
        /// 删除文件夹strDir中nDays天以前的文件
        /// </summary>
        /// <param name="dir"></param>
        /// <param name="days"></param>
        public static void DeleteOldFiles(string dir, int days)
        {
            try
            {
                if (!Directory.Exists(dir) || days < 1) return;

                var now = DateTime.Now;
                foreach (var f in Directory.GetFileSystemEntries(dir).Where(f => File.Exists(f)))
                {
                    var t = File.GetCreationTime(f);

                    var elapsedTicks = now.Ticks - t.Ticks;
                    var elapsedSpan = new TimeSpan(elapsedTicks);

                    if (elapsedSpan.TotalDays > days) File.Delete(f);
                }
            }
            catch (Exception)
            {
                // ignored
            }
        }



    }
}