using RyzStudio.IO;
using RyzStudio.Windows.Forms;
using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Diagnostics.Metrics;
using System.Net.Http;
using System.Net.Security;
using System.Reflection.Emit;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WebsiteSSLCertificateChecker
{
    public partial class MainForm : Form
    {
        protected const string DEFAULLT_LABEL_RESULTS = "SSL Certificate Results";

        protected CancellationTokenSource cancellationToken = new CancellationTokenSource();

        protected bool isBusy = false;
        protected bool requestCancel = false;



        public MainForm()
        {
            InitializeComponent();

            //memoBox1.TextBox.BackColor = memoBox1.BackColor;
            memoBox2.ReadOnly = false;

            Clear();
        }

        protected override void OnClosing(CancelEventArgs e)
        {
            base.OnClosing(e);

            if (this.IsBusy)
            {
                e.Cancel = true;
                return;
            }
        }


        public bool IsBusy
        {
            get => isBusy;
            set
            {
                isBusy = value;

                UIControl.SetEnable(memoBox2, !isBusy);
                UIControl.SetEnable(memoBox1, !isBusy);
                UIControl.SetValue(pictureBox1, (isBusy ? UIcon.GetIcon(typeof(UIResource), "loading_block") : null));
                UIControl.SetEnable(button5, !isBusy);
                UIControl.SetEnable(button1, !isBusy);
            }
        }


        /// <summary>
        /// New
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void newToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (this.IsBusy)
            {
                return;
            }

            Clear();
        }

        /// <summary>
        /// Close
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void exitToolStripMenuItem2_Click(object sender, EventArgs e)
        {
            if (this.IsBusy)
            {
                return;
            }

            this.Close();
        }

        /// <summary>
        /// Options
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void optionsToolStripMenuItem_Click(object sender, EventArgs e)
        {
            // do nothing
        }

        /// <summary>
        /// Help
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void viewHelpToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            try
            {
                System.Diagnostics.Process.Start(new ProcessStartInfo()
                {
                    FileName = AppResource.AppHelpURL,
                    UseShellExecute = true
                });
            }
            catch
            {
                // do nothing
            }
        }

        /// <summary>
        /// About
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            MessageBox.Show(Application.ProductName + " v" + Application.ProductVersion, "About", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }

        /// <summary>
        /// Clear URL address list
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void memoBox2_OnButtonClick(object sender, EventArgs e)
        {
            if (this.IsBusy)
            {
                return;
            }

            UIControl.SetText(memoBox2, string.Empty);
        }

        /// <summary>
        /// Clear SSL certificate results
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void memoBox1_OnButtonClick(object sender, EventArgs e)
        {
            if (this.IsBusy)
            {
                return;
            }
 
            UIControl.SetText(label1, DEFAULLT_LABEL_RESULTS);
            UIControl.SetText(memoBox1, string.Empty);
        }

        /// <summary>
        /// Run
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private async void button5_MouseClick(object sender, MouseEventArgs e)
        {
            if (this.IsBusy)
            {
                return;
            }

            this.IsBusy = true;

            int counter = 0;
            foreach (string line in memoBox2.Lines)
            {
                if (string.IsNullOrWhiteSpace(line))
                {
                    continue;
                }

                counter++;

                UIControl.SetText(label1, string.Format("{0} ({1})", DEFAULLT_LABEL_RESULTS, counter.ToString()));

                await RetrieveSSLInfo(line);
            }

            this.IsBusy = false;
        }

        /// <summary>
        /// Close
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_MouseClick(object sender, MouseEventArgs e)
        {
            if (this.IsBusy)
            {
                return;
            }

            this.Close();
        }

        protected void AddText(string text)
        {
            UIControl.AddLine(memoBox1, text);
        }

        private void Clear()
        {
            label1.Text = DEFAULLT_LABEL_RESULTS;
            memoBox1.Text = memoBox2.Text = string.Empty;
            memoBox1.WordWrap = memoBox2.WordWrap = false;
        }

        protected string ReFormatDateTime(string datetime)
        {
            if (string.IsNullOrWhiteSpace(datetime))
            {
                return string.Empty;
            }

            if (!DateTime.TryParse(datetime, out DateTime result))
            {
                return string.Empty;
            }

            return result.ToString("yyyy-MM-dd HH:mm:ss");
        }

        private async Task RetrieveSSLInfo(string url)
        {
            AddText("> " + url);

            HttpClientHandler clientHandler = new HttpClientHandler();

            clientHandler.ServerCertificateCustomValidationCallback = (requestMessage, certificate, chain, sslErrors) => {
                AddText("Requested URL = " + requestMessage.RequestUri);
                AddText("Subject = " + certificate?.Subject ?? string.Empty);
                AddText("Issuer = " + certificate?.Issuer ?? string.Empty);
                AddText("Effective Date = " + ReFormatDateTime(certificate!.GetEffectiveDateString()));
                AddText("Expiration Date = " + ReFormatDateTime(certificate.GetExpirationDateString()));
                AddText("Thumbprint = " + certificate.Thumbprint);

                AddText("Error = " + sslErrors);
                AddText(String.Empty);

                return sslErrors == SslPolicyErrors.None;
            };

            HttpClient webClient = new HttpClient(clientHandler);

            try
            {
                HttpResponseMessage response = await webClient.SendAsync(new HttpRequestMessage(HttpMethod.Head, url));
                response.EnsureSuccessStatusCode();
            }
            catch (HttpRequestException exc)
            {
                AddText("Error = " + exc.Message);
            }
            catch (Exception exc)
            {
                AddText("Error = " + exc.Message);
            }

            AddText(String.Empty.PadLeft(84, '-'));

            clientHandler.Dispose();
            webClient.Dispose();
        }

    }
}