using System;
using System.Diagnostics;
using System.IO;
using System.Security.Cryptography;
using System.Threading;


namespace SMAgentUpdater
{
    class Program
    {
        private static string updateFilePath = "../data/agentRecv/";

        static void Log(string strLog)
        {
            try
            {
                using (StreamWriter w = File.AppendText("updatelog.txt"))
                {
                    var msg = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + "|" + strLog + "\n";
                    w.WriteLine("{0}", msg);
                }
            }
            catch (Exception )
            {
            }
        }

        static void Log(string strFormat, params object[] argvList)
        {
            try
            {
                string strLog = string.Format(strFormat, argvList);
                using (StreamWriter w = File.AppendText("updatelog.txt"))
                {
                    var msg = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + "|" + strLog + "\n";
                    w.Write("{0}", msg);
                }
            }
            catch (Exception )
            {
            }
        }

        static void LogException(Exception ex)
        {
            try
            {
                Log("catch one exception");
                Log(ex.Message);
                Log(ex.Source);
                Log(ex.StackTrace);
            } 
            catch (Exception)
            {
            }
        }

        static bool IsWindows()
        {
            var os = Environment.OSVersion.ToString().ToLowerInvariant();
            return os.Contains("windows");
        }

        static string GetExeFileName()
        {
            string exename = "SMAgent";
            if (IsWindows())
            {
                exename += ".exe";
            }
            return exename;
        }

        static bool IsFileExist(string path)
        {
            if (File.Exists(path) == false)
            {
                Log("file {0} not exist", path);
                return false;
            }
            return true;
        }

        // recvFile目录下SMAgent和bin目录下MD5是否一致，如果recvFile新则更新
        static bool NeedUpdateAgent()
        {
            // 当前运行文件和更新程序在同一层级
            var dllFile = "SMAgent.dll";
            var pdbFile = "SMAgent.pdb";

            // 更新文件位置
            var updateDllFile = updateFilePath + "SMAgent.dll";
            var updatePdbFile = updateFilePath + "SMAgent.pdb";


            if (IsFileExist(dllFile) == false || IsFileExist(pdbFile) == false
                || IsFileExist(updateDllFile) == false || IsFileExist(updatePdbFile) == false)
            {
                Log("file not exist");
                return false;
            }


            try
            {
                string dllMd5, pdbMd5, updateExeMd5, updatePdbMd5;
                using (var md5 = MD5.Create())
                {
                    using (var stream = File.OpenRead(dllFile))
                    {
                        dllMd5 = BitConverter.ToString(md5.ComputeHash(stream)).Replace("-", "").ToLowerInvariant();
                    }

                    using (var stream = File.OpenRead(pdbFile))
                    {
                        pdbMd5 = BitConverter.ToString(md5.ComputeHash(stream)).Replace("-", "").ToLowerInvariant();
                    }

                    using (var stream = File.OpenRead(updateDllFile))
                    {
                        updateExeMd5 = BitConverter.ToString(md5.ComputeHash(stream)).Replace("-", "").ToLowerInvariant();
                    }

                    using (var stream = File.OpenRead(updatePdbFile))
                    {
                        updatePdbMd5 = BitConverter.ToString(md5.ComputeHash(stream)).Replace("-", "").ToLowerInvariant();
                    }
                }

                if (dllMd5 != updateExeMd5 || pdbMd5 != updatePdbMd5)
                {
                    // 暂时用文件生成时间来比较哪个更新一些，用版本号比较的话每次都要修改有点麻烦
                    if (File.GetCreationTime(dllFile) < File.GetCreationTime(updateDllFile)
                        && File.GetCreationTime(pdbFile) < File.GetCreationTime(updatePdbFile))
                    {
                        return true;
                    }
                    else
                    {
                        Log("update file is older than current file...");
                    }
                }
            }
            catch (Exception e)
            {
                LogException(e);
            }

            return false;
        }

        static bool IsProcessRunning(string name)
        {
            var proc = Process.GetProcessesByName(name);
            return proc.Length > 0;
        }

        static void StartProcess(string path, string name)
        {
            if (IsProcessRunning(name))
            {
                return;
            }

            int count = 0;
            var exeFile = path + "/" + name;
            Log("start process {0}", exeFile);

            while (count < 5)
            {
                ProcessStartInfo startInfo = new ProcessStartInfo(exeFile, "--id=0.3.1 start &");
                startInfo.CreateNoWindow = true;
                startInfo.WorkingDirectory = path;

                using (Process proc = new Process())
                {
                    proc.StartInfo = startInfo;
                    proc.EnableRaisingEvents = true;
                    proc.Start();
                }

                Thread.Sleep(2000);

                if (IsProcessRunning(name))
                {
                    Log("start succ...");
                    return;
                }

                count++;
            }
        }


        static void Main(string[] args)
        {
            try
            {
                Log("curr dir {0}, prepare update ...", Directory.GetCurrentDirectory());

                if (NeedUpdateAgent() == false)
                {
                    Log("no need to update ...");
                    return;
                }

                var proc = Process.GetProcessesByName("SMAgent");
                foreach (Process p in proc)
                {
                    p.Kill();
                    //p.WaitForExit();
                }

                int count = 0;
                while (IsProcessRunning("SMAgent") && count < 20)
                {
                    Thread.Sleep(500);
                    count++;
                }

                if (! IsProcessRunning("SMAgent"))
                {
                    File.Copy(updateFilePath + "SMAgent.dll", "SMAgent.dll", true);
                    File.Copy(updateFilePath + "SMAgent.pdb", "SMAgent.pdb", true);

                    StartProcess(Directory.GetCurrentDirectory(), "SMAgent");
                }
                else
                {
                    Log("stop agent fail");
                }
            }
            catch (Exception e)
            {
                LogException(e);
            }
        }
    }
}