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

namespace ryCommon
{
    /// <summary>
    /// 大文件与批量文件操作类,支持中途取消操作,本类需要实例化操作
    /// </summary>
    public class BigFileOp
    {
        /// <summary>
        /// 传输进度
        /// </summary>
        /// <param name="curValue">当前传输完成的值</param>
        /// <param name="totalValue">全部值,为-1表示无法获取</param>
        /// <param name="percent">当前传输的百分比,为-1表示无法获取</param>
        public delegate void TranProgressHandler(long curValue, long totalValue, double percent);
        /// <summary>
        /// 传输进度
        /// </summary>
        public static event TranProgressHandler OnProgress;
        /// <summary>
        /// 取消事件
        /// </summary>
        public static event CancelEventHandler OnCanel;
        /// <summary>
        /// 大文件按流复制文件,支持自动创建目标文件夹。  true：复制成功   false：复制失败
        /// </summary>
        /// <param name="soucrePath">原始文件路径</param>
        /// <param name="targetPath">复制目标文件路径</param>
        /// <returns></returns>
        public bool CopyBigFile(string soucrePath, string targetPath)
        {
            try
            {
                var TranSize = 1024 * 1024 * 2;//每次读取2M
                //读取复制文件流
                using (FileStream fsRead = new FileStream(soucrePath, FileMode.Open, FileAccess.Read))
                {
                    if (System.IO.File.Exists(targetPath))
                    {
                        if (RyFiles.DeleteFile(targetPath) != 0)
                        {
                            return false;
                        }
                    }
                    RyFiles.CreateDirectory(System.IO.Path.GetDirectoryName(targetPath));
                    OnProgress?.Invoke(0, fsRead.Length, 0);
                    var totalSize = fsRead.Length;
                    //写入文件复制流
                    using (FileStream fsWrite = new FileStream(targetPath, FileMode.OpenOrCreate, FileAccess.Write))
                    {
                        byte[] buffer = new byte[TranSize]; 
                        var curSize = 0L;
                        CancelEventArgs e1 = new CancelEventArgs();
                        //可能文件比较大，要循环读取，每次读取2M
                        while (true)
                        {
                            if (OnCanel != null)
                            {
                                OnCanel?.Invoke(this, e1);
                                if (e1.Cancel) {
                                    fsWrite.Close();
                                    RyFiles.DeleteFile(targetPath);
                                    break;
                                }
                            }
                            //每次读取的数据    n：是每次读取到的实际数据大小
                            int n = fsRead.Read(buffer, 0, buffer.Count());
                            //如果n=0说明读取的数据为空，已经读取到最后了，跳出循环
                            if (n == 0)
                            {
                                break;
                            }
                            curSize += n;
                            OnProgress?.Invoke(curSize, totalSize, totalSize == 0 ? 0 : curSize / (double)totalSize);
                            //写入每次读取的实际数据大小
                            fsWrite.Write(buffer, 0, n);
                        }
                    }
                    OnProgress?.Invoke(totalSize, totalSize, 100);
                    if (!System.IO.File.Exists(targetPath))
                    {
                        return false;
                    }
                }
                return true;
            }
            catch
            {
                return false;
            }
        }
        /// <summary>
        /// 复制文件夹到目标文件夹,不支持进度事件,支持中途取消
        /// </summary>
        /// <param name="fromDir">源文件夹</param>
        /// <param name="ToDir">目标文件夹</param>
        /// <returns>返回复制操作是否成功的标识，成功返回0，负数表示复制失败的文件数量。1表示源文件夹不存在</returns>
        public int CopyFolder(string fromDir, string ToDir)
        {
           return CopyFolder(fromDir,ToDir,0,-1,out _);
        }
        /// <summary>
        /// 复制文件或文件夹到目标路径,不支持进度事件,支持中途取消
        /// </summary>
        /// <param name="fromPath">源路径</param>
        /// <param name="ToPath">目标路径</param>
        /// <returns>返回复制操作是否成功的标识，成功返回0，负数表示复制失败的文件数量。1表示源文件夹不存在</returns>
        public int CopyFileOrFolder(string fromPath, string ToPath)
        {
            if(System.IO.File.Exists(fromPath))
            {
                return CopyBigFile(fromPath, ToPath)?0:-1;
            }
            else if (System.IO.Directory.Exists(fromPath))
            {
                return CopyFolder(fromPath, ToPath, 0, -1, out _);
            }
            else
            {
                return 1;
            }
        }
        /// <summary>
        /// 复制文件夹到目标文件夹,支持进度事件,支持中途取消
        /// </summary>
        /// <param name="fromDir">源文件夹</param>
        /// <param name="ToDir">目标文件夹</param>
        /// <returns>返回复制操作是否成功的标识，成功返回0，负数表示复制失败的文件数量。1表示源文件夹不存在</returns>
        public int CopyFolderByProgress(string fromDir, string ToDir)
        {
            var FileCount = GetFilesCount(fromDir);
            return CopyFolder(fromDir, ToDir, 0, FileCount, out _);
        }
        /// <summary>
        /// 复制文件夹到目标文件夹,支持中途取消
        /// </summary>
        /// <param name="fromDir">源文件夹</param>
        /// <param name="ToDir">目标文件夹</param>
        /// <param name="StartCount">初始的文件数量</param>
        /// <param name="TotalCount">总数量,如果不计算,则使用-1</param>
        /// <param name="Count">操作的数量,包含成功的和失败的</param>
        /// <returns>返回复制操作是否成功的标识，成功返回0，负数表示复制失败的文件数量。1表示源文件夹不存在</returns>
        private int CopyFolder(string fromDir, string ToDir,int StartCount,int TotalCount, out int Count)
        {
            Count = StartCount;
            var _fromDir = fromDir.TrimEnd('\\');
            var _ToDir = ToDir.TrimEnd('\\');
            if (!Directory.Exists(_fromDir)) { return 1; }
            var files = Directory.GetFiles(fromDir);
            var error = 0;
            CancelEventArgs e1 = new CancelEventArgs();
            foreach (var file in files)
            {
                if (OnCanel != null)
                {
                    OnCanel?.Invoke(this, e1);
                    if (e1.Cancel) { break; }
                }
                if (!CopyBigFile(file, _ToDir + "\\" + Path.GetFileName(file)))
                {
                    error++;
                }
                Count++;
                var percent = 0d;
                if (TotalCount>0) { percent = Count / (double)TotalCount; }
                else if (TotalCount == -1) { percent = -1; }
                OnProgress?.Invoke(Count, TotalCount, percent);
            }
            var dirs = Directory.GetDirectories(_fromDir);
            foreach (var dir in dirs)
            {
                int result = CopyFolder(dir, _ToDir + "\\" + Path.GetFileName(dir), Count, TotalCount, out var _Count);
                Count += _Count;
                if (OnCanel != null)
                {
                    OnCanel?.Invoke(this, e1);
                    if (e1.Cancel) { break; }
                }
                if (result > 0)
                {
                    error++;
                }
                else if (result < 0)
                {
                    error+=-result;
                }
            }
            return -error;
        }
        /// <summary>
        /// 获取文件夹中的文件数量
        /// </summary>
        /// <param name="Dir">文件夹路径</param>
        /// <returns>返回文件数量,中途取消则返回-1</returns>
        public int GetFilesCount(string Dir)
        {
            var _fromDir = Dir.TrimEnd('\\');
            if (!Directory.Exists(_fromDir)) { return 0; }
            var files = Directory.GetFiles(_fromDir);
            var count = 0;
            CancelEventArgs e1 = new CancelEventArgs();
            count += files.Length;
            var dirs = Directory.GetDirectories(_fromDir);
            foreach (var dir in dirs)
            {
                if (OnCanel != null)
                {
                    OnCanel?.Invoke(this, e1);
                    if (e1.Cancel) { count = -1; break; }
                }
                var result= GetFilesCount(dir);
                if (result == -1) { count = -1;break; }
                count+= result;
            }
            return count;
        }
        /// <summary>
        /// 获取文件夹的大小
        /// </summary>
        /// <param name="Dir">文件夹路径</param>
        /// <returns>返回文件数量,中途取消则返回-1</returns>
        public long GetFolderSize(string Dir)
        {
            var _fromDir = Dir.TrimEnd('\\');
            if (!Directory.Exists(_fromDir)) { return 0; }
            var files = Directory.GetFiles(_fromDir);
            var size = 0L;
            CancelEventArgs e1 = new CancelEventArgs();
            for (int i = 0; i < files.Length; i++)
            {
                if (OnCanel != null && i %5==0)
                {
                    OnCanel?.Invoke(this, e1);
                    if (e1.Cancel) { size = -1; break; }
                }
                size +=RyFiles.GetFileSize(files[i]);
            }
            var dirs = Directory.GetDirectories(_fromDir);
            foreach (var dir in dirs)
            {
                if (OnCanel != null)
                {
                    OnCanel?.Invoke(this, e1);
                    if (e1.Cancel) { size = -1; break; }
                }
                var result = GetFilesCount(dir);
                if (result == -1) { size = -1; break; }
                size += result;
            }
            return size;
        }
        /// <summary>
        /// 添加文件到指定文件夹,会进行自动重命名，并返回重命名后的文件名(含路径)
        /// </summary>
        /// <param name="filepath">要添加的文件路径</param>
        /// <param name="toFolder">要添加到的文件夹</param>
        /// <param name="RenameByTime">是否根据时间进行重命名</param>
        /// <param name="OK">返回是否成功执行</param>
        /// <returns>成功执行则返回路径，否则返回空</returns>
        public string AddFileToFolder(string filepath, string toFolder, bool RenameByTime, out bool OK)
        {
            OK = false;
            var _toFolder = toFolder.TrimEnd('\\');
            RyFiles.CreateDirectory(_toFolder);
            if (!System.IO.Directory.Exists(_toFolder)) { return ""; }
            if (!System.IO.File.Exists(filepath) && !System.IO.Directory.Exists(filepath)) { return ""; }
            var filename = System.IO.Path.GetFileName(filepath);
            if (RenameByTime) { filename = DateTime.Now.ToString("yyyyMMddHHmmss") + System.IO.Path.GetExtension(filepath); }
            if (!System.IO.File.Exists(_toFolder + "\\" + filename) && !System.IO.Directory.Exists(_toFolder + "\\" + filename))
            {
                if (CopyBigFile(filepath, _toFolder + "\\" + filename))
                {
                    OK = true;
                    return _toFolder + "\\" + filename;
                }
                return "";//如果复制失败,则返回空路径
            }
            else //如果目标路径已经存在同名文件
            {
                int index = 0;
                string filename_noext;
                if (RenameByTime) { filename_noext = DateTime.Now.ToString("yyyyMMddHHmmss"); }
                else { filename_noext = System.IO.Path.GetFileNameWithoutExtension(filepath); }
                var ext = System.IO.Path.GetExtension(filepath);
                CancelEventArgs e1 = new CancelEventArgs();
                while (index < 20) //最多重试20次
                {
                    if (OnCanel != null)
                    {
                        OnCanel?.Invoke(this, e1);
                        if (e1.Cancel)
                        {
                            break;
                        }
                    }
                    Random rd = new Random(Guid.NewGuid().GetHashCode());
                    if (RenameByTime) { filename_noext = DateTime.Now.ToString("yyyyMMddHHmmss"); }
                    var to_path = _toFolder + "\\" + filename_noext + "_" + rd.Next(1000, 9999) + ext;
                    if (!System.IO.File.Exists(to_path) && !System.IO.Directory.Exists(to_path))
                    {
                        if (CopyBigFile(filepath, to_path))
                        {
                            OK = true;
                            return to_path;
                        }
                        return "";
                    }
                    index++;
                }
                return "";
            }
        }
    }
}