using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Linq;
using System.Runtime.ExceptionServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FlexenabledLic
{
    public delegate void LoginResultEventHandler(LoginResult loginResult);
    public struct LoginResult
    {
        public int Status;
        public string Message;
        public string AppName;
    }
    /// <summary>
    /// 登录管理的类.
    /// </summary>
    public class LicHelp
    {
        private LoginResult result;
        public LoginResult Result
        {
            get { return result; }
            private set { result = value; }
        }
        public LoginResultEventHandler LoginResultEvent;
        private BackgroundWorker backgroundWorker1;
        private string AppName;
        /// <summary>
        /// Prevents a default instance of the <see cref="LicHelp"/> class from being created.
        /// </summary>
        private LicHelp()
        {
            backgroundWorker1 = new BackgroundWorker();
            backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
            backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(loginWorkerCompleted);
        }
        /// <summary>
        /// 登录结果事件.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The e.</param>
        private void loginWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            result = (LoginResult)e.Result;
            //if (result.Status != 2)
            //{
                LoginResultEvent?.Invoke(result);
            //}
        }

        /// <summary>
        /// 执行登录.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The e.</param>
        [HandleProcessCorruptedStateExceptions]
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            LoginResult loginResult = new LoginResult();
            loginResult.Status = 1;
            loginResult.AppName = AppName;
            BackgroundWorker worker = sender as BackgroundWorker;            
            try
            {
                if (!File.Exists("FlexDll.dll"))
                {
                    loginResult.Status = 2; // 该状态表示不需要使用FlexDll.dll进行登录
                    loginResult.Message = "FlexDll.dll未找到";
                    e.Result = loginResult;
                    return;
                }
                else
                {
                    LicHelp.Initialize();
                }
            }
            catch (Exception ex)
            {
                string strMsg = ex.Message;
                loginResult.Status = 1;
                if (strMsg.Contains("FlexDll.dll"))
                {
                    loginResult.Status = 2;// 该状态表示不需要使用FlexDll.dll进行登录
                }
                loginResult.Message = ex.Message;
                e.Result = loginResult;
                return;
            }
            StringBuilder strLogResult = new StringBuilder(200);
            int nStat = 2;
            try
            {
                nStat = LicHelp.CheckOut(AppName, strLogResult);
                if (nStat != 0)
                {
                    loginResult.Message = "登录失败";
                }
                else
                {
                    loginResult.Message = "登录成功";
                }
            }
            catch { }
            loginResult.Status = nStat;
            // 将结果传递给 RunWorkerCompleted 事件
            e.Result = loginResult;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="LicHelp"/> class.
        /// </summary>
        /// <param name="appName">The app name.</param>
        public LicHelp(string appName):this()
        {
            AppName = appName;
        }
        /// <summary>
        /// 执行登录
        /// </summary>
        public void DoLogin()
        {
            if (!backgroundWorker1.IsBusy)
            {
                backgroundWorker1.RunWorkerAsync(AppName);
            }
        }
        /// <summary>
        /// 执行登出.
        /// </summary>
        /// <returns>An int.</returns>
        public int LogOut()
        {
            int nStat = -1;
            try
            {
                nStat = CheckIn(AppName);
                CleanUp();
            }
            catch { }
            return nStat;
        }

        /// prototypes from DLL
        [DllImport("FlexDll.dll", CharSet = CharSet.Ansi)]
        public static extern int Initialize();
        [DllImport("FlexDll.dll", CharSet = CharSet.Ansi)]
        public static extern int CheckOut(String FeatureName, StringBuilder OutMsg);
        [DllImport("FlexDll.dll", CharSet = CharSet.Ansi)]
        public static extern int CheckIn(String FeatureName);
        [DllImport("FlexDll.dll", CharSet = CharSet.Ansi)]
        public static extern int CleanUp();
    }
}