using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace IStation.Untity
{
    /// <summary>
    /// 流转换
    /// </summary>
    public class StreamTransfer
    {
        /// <summary>
        /// 转换为字节数组
        /// </summary>
        public static byte[] ToBytes(Stream stream)
        {
            if (stream == null)
                return default;
            try
            {
                var positon = stream.Position;
                var bts = new byte[stream.Length];
                stream.Seek(0, SeekOrigin.Begin);
                stream.Read(bts, 0, bts.Length);
                stream.Position = positon;
                return bts;
            }
            catch
            {
                return default;
            }
        }

        /// <summary>
        /// 从字节数组中转换为流
        /// </summary>
        public static Stream FromBytes(byte[] bts)
        {
            if (bts == null)
                return null;
            var stream = new MemoryStream(bts);
            stream.Position = 0;
            return stream;
        }

        /// <summary>
        /// 从图片转换为流
        /// </summary>
        public static Stream FromImage(Image img)
        {
            if (img == null)
                return default;
            try
            {
                var ms = new MemoryStream();
                img.Save(ms, img.RawFormat);
                ms.Position = 0;
                return ms;
            }
            catch
            {
                return default;
            }
        }

        /// <summary>
        /// 从文件转换为流
        /// </summary>
        public static Stream FromFile(string fileName)
        {
            if (string.IsNullOrEmpty(fileName))
                return default;
            if (!File.Exists(fileName))
                return default;
            try
            {
                using (var stream = new FileStream(fileName, FileMode.Open))
                {
                    var ms = new MemoryStream();
                    stream.CopyTo(ms);
                    ms.Position = 0;
                    return ms;
                }
            }
            catch
            {
                return default;
            }
        }

        /// <summary>
        /// 转换为文件
        /// </summary>
        public static void ToFile(Stream stream, string fileName)
        {
            if (stream == null)
                return;
            if (string.IsNullOrEmpty(fileName))
                return;
            try
            {
                using (var fileStream = new FileStream(fileName, FileMode.Create, FileAccess.Write, FileShare.None))
                {
                    var position = stream.Position;
                    stream.Position = 0;
                    stream.CopyTo(fileStream);
                    fileStream.Flush();
                    stream.Position = position;
                }
            }
            catch (SystemException ex)
            {
                throw ex;
            }
        }






    }
}