using CookComputing.XmlRpc;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using System;
using System.Diagnostics;
using System.IO;
using System.IO.Compression;
using System.Net;
using System.Net.Http;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Threading;
using System.Threading.Tasks;
using System.Xml;

namespace IoTDameon
{
    public class UpdateIoTNodeService : BackgroundService
    {
        private readonly ILogger<UpdateIoTNodeService> _logger;
        private readonly IWebHostEnvironment _env;
        private readonly IConfiguration _cfg;
        private readonly IHttpClientFactory _httpClientFactory;

        public bool IsUpdating { get; set; }

        public UpdateIoTNodeService(ILogger<UpdateIoTNodeService> logger, IWebHostEnvironment env, IConfiguration cfg, IHttpClientFactory httpClientFactory)
        {
            this._logger = logger;
            this._env = env;
            this._cfg = cfg;
            this._httpClientFactory = httpClientFactory;
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            _logger.LogDebug($"update service start");
            stoppingToken.Register(() => _logger.LogDebug("update service stop"));
            while (!stoppingToken.IsCancellationRequested)
            {
                this.Update();
                await Task.Delay(1000 * 60, stoppingToken);
            }
            await Task.CompletedTask;
        }

        private void Update()
        {
            if (this.IsUpdating)
            {
                return;
            }
            else
            {
                this.IsUpdating = true;
            }
            try
            {
                UpdateInternal();
            }
            catch (Exception ex)
            {
                this._logger.LogError(ex, "update error");
            }
            this.IsUpdating = false;
        }

        private void UpdateInternal()
        {
            var processName = "iotnode";
            var appFolder = "IoTNode";
            var port = 8002;
            var proxyUrl = "http://localhost:9001/RPC2";
            var root = Directory.GetParent(_env.ContentRootPath).FullName;
            var appPath = Path.Combine(root, appFolder);
            var name = $"{appFolder}.zip";
            var backupPath = Path.Combine(root, $"{appFolder}_bk");
            var file = Path.Combine(root, name);
            var currentCheckSum = string.Empty;
            //检查是否有更新
            this._logger.LogInformation("check last version");
            var currentVersion = this._httpClientFactory.CreateClient().GetAsync($"http://localhost:{port}/Home/GetVersion").Result.Content.ReadAsStringAsync().Result;
            var server = this._httpClientFactory.CreateClient().GetAsync($"http://localhost:{port}/Home/GetServer").Result.Content.ReadAsStringAsync().Result;
            var serverUrl = $"{server}/{processName}.xml";
            this._logger.LogInformation($"request url:{serverUrl}");
            var info = this._httpClientFactory.CreateClient().GetAsync(serverUrl).Result.Content.ReadAsStringAsync().Result;
            var doc = new XmlDocument();
            doc.LoadXml(info);
            var lastVersion = doc.GetElementsByTagName("version")[0].InnerText.Trim();
            var lastCheckSum = doc.GetElementsByTagName("checksum")[0].InnerText.Trim();
            if (currentVersion != lastVersion)
            {
                this._logger.LogInformation($"current version {currentVersion} does not equals {lastVersion}");
                //查看是否已下载更新并删除旧的更新文件
                if (File.Exists(file))
                {
                    currentCheckSum = getCheckSum(file);
                    if (currentCheckSum != lastCheckSum)
                    {
                        this._logger.LogWarning($"current file hash {currentCheckSum} does not equals last file hash {lastCheckSum}");
                        File.Delete(file);
                        this._logger.LogWarning($"delete old file {file}");
                    }
                }
                //下载更新并校验
                if (!File.Exists(file))
                {
                    var bytes = this._httpClientFactory.CreateClient().GetAsync($"{server}/{name}").Result.Content.ReadAsByteArrayAsync().Result;
                    using var fs = File.Create(file);
                    fs.Write(bytes);
                    currentCheckSum = getCheckSum(file);
                    if (currentCheckSum != lastCheckSum)
                    {
                        this._logger.LogWarning($"download file hash {currentCheckSum} does not math hash in xml {lastCheckSum}");
                        File.Delete(file);
                        this._logger.LogWarning($"delete old file {file}");
                    }
                }
                if (File.Exists(file))
                {
                    this._logger.LogWarning($"begin update");
                    //关闭要更新的程序
                    var proxy = XmlRpcProxyGen.Create<ISupervisorService>();
                    proxy.Url = proxyUrl;
                    proxy.Credentials = new NetworkCredential("usr", "pwd");
                    try
                    {
                        proxy.stopProcess(processName);
                        this._logger.LogWarning($"close process {processName}");
                    }
                    catch (XmlRpcFaultException ex)
                    {
                        if (ex.FaultCode != 60)
                        {
                            throw ex;
                        }
                        else
                        {
                            this._logger.LogWarning($"close error，{processName} is alreday stoped");
                        }
                    }
                    //备份要更新的程序
                    try
                    {
                        Directory.Move(appPath, backupPath);
                        this._logger.LogInformation($"back up {appPath}");
                    }
                    catch (Exception ex)
                    {
                        this._logger.LogError(ex, ex.Message);
                        throw new Exception("backup error", ex);
                    }
                    Directory.CreateDirectory(appPath);
                    this._logger.LogInformation($"mkdir {appPath}");
                    foreach (var item in Directory.GetFiles(backupPath,"*.db"))
                    {
                        File.Copy(item, Path.Combine(appPath, Path.GetFileName(item)));
                    }
                    this._logger.LogInformation($"copy db files to {appPath}");
                    //更新程序
                    try
                    {
                        ZipFile.ExtractToDirectory(file, root, true);
                        this._logger.LogInformation($"unzip {file} to {appPath}");
                    }
                    catch (Exception ex)
                    {
                        this._logger.LogError(ex, ex.Message);
                        Directory.Delete(appPath, true);
                        Directory.Move(backupPath, appPath);
                        throw new Exception("upzip error，restore old files", ex);
                    }
                    //设置权限
                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
                    {
                        var updateScript = Path.Combine(appPath, "update.sh");
                        var command = $"-c \"chmod 755 {updateScript}\"";
                        Console.WriteLine(command);
                        Console.WriteLine(command.Bash());
                        Console.WriteLine(updateScript.Bash());
                        this._logger.LogInformation($"chmod and run {updateScript}");
                    }
                    //启动更新程序
                    proxy.startProcess(processName);
                    this._logger.LogInformation($"{appPath} start");
                }
            }
        }

        private string getCheckSum(string file)
        {
            using var sha = SHA512.Create();
            using var fs = File.OpenRead(file);
            var checksum = BitConverter.ToString(sha.ComputeHash(fs)).Replace("-", "").ToLower();
            return checksum;
        }
    }
}