WEB-SCRAPING-ANGLE-SHARP-MAIN

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Windows;
using AngleSharp;
using System.Net;

namespace webBot9000
{
    class GUI
    {
        public Application application;
        public MainGui maingui;
        public GUI()
        {
            //RUN GUI IN NEW THREAD
            Thread GuiThread = new Thread(InitializeGUI);
            //SET THE THREAD TO BE SPECIALLY FOR GUI
            GuiThread.SetApartmentState(ApartmentState.STA);
            //START THE THREAD
            GuiThread.Start();
        }
        public void InitializeGUI()
        {
            //CREATE THE USER-CONTROL CLASS, THAT WILL BE OUR GUI
            maingui = new MainGui();

            //CREATE NEW APPLICATION CLASS, THAT WILL RUN THE GUI WINDOWS
            application = new System.Windows.Application();

            //CREATE A NEW GUI WINDOW
            application.MainWindow = new System.Windows.Window();

            //SET SOME GUI WINDOW SETTINGS
            application.MainWindow.Height = 450;
            application.MainWindow.Width = 800;
            //THIS WILL ABORT ALL OF THE THREADS
            application.MainWindow.Closing += (x, e) => { Environment.Exit(0); };

            //SET OUR GUI WINDOW CONTENT TO OUR USER-CONTROL GUI CONTENT
            application.MainWindow.Content = maingui;

            //SHOW THE WINDOW
            application.MainWindow.Show();

            //RUN THE APPLICATION WHICH HANDLES THE RESPONSIVE GUI
            application.Run();
        }
    }
    class AngleSharp
    {
        //WE WILL STORE HERE ALL THE LINKS THAT WE CHECK
        public List<string> AllLinks;

        //THIS IS FOR ANGLE-SHARP CONFIGURATION
        IConfiguration config;
        IBrowsingContext context;

        //THIS WILL BE USED FOR DOWNLOADING THE HTML FROM LINKS
        WebClient client = new WebClient();

        public AngleSharp()
        {
            //CONFIGURE OUR HTML PARSER WHICH IS ANGLE-SHARP
            config = Configuration.Default.WithDefaultLoader();
            context = BrowsingContext.New(config);

            //CREATE LIST WHERE WE WILL STORE ALL LINKS
            AllLinks = new List<string>();
        }

        public async Task<List<string>> GetTheLinks(string url, string LookFor)
        {
            //LIST THAT WE WILL RETURN IF WE FIND ANY LINKS THAT CONTAINS THE SPECIFIED WORD
            List<string> FoundLinks = new List<string>();

            //TRY DOWNLOADING HTML, PARSING IT, SEARCHING IT, IT CRASHES OFTEN BECAUSE OF BAD LINKS
            try
            {
                //DOWNLOAD THE SPECIFIED URL
                string source = client.DownloadString(url);

                //PARSE THE DOWNLOADED HTML
                var HTML = await context.OpenAsync(req => req.Content(source));

                //SEARCH FOR LINKS
                var LinkList = HTML.GetElementsByTagName("a");

                //CONVERT LINKS TO STRINGS
                List<string> LinkList_Strings = LinkList.Select(item => item.GetAttribute("href")).ToList();

                //CHECK EVERY STRING
                foreach (string item in LinkList_Strings)
                {
                    //IF THE STRING IS A VALID LINK
                    if (Uri.TryCreate(item, UriKind.Absolute, out Uri uriResult) && (uriResult.Scheme == Uri.UriSchemeHttp || uriResult.Scheme == Uri.UriSchemeHttps))
                    {
                        //IF WE ALREADY HAVE THE STRING
                        if (!AllLinks.Contains(item))
                        {
                            //IF IT IS, ADD IT TO THE LIST
                            AllLinks.Add(item);

                            //IF IT CONTAINS THE WORD, ADD IT TO FOUND-LINKS LIST TOO
                            if (item.Contains(LookFor))
                                FoundLinks.Add(item);
                        }
                    }
                }
            }
            catch (Exception)
            {
                //RETURN THE LIST IF IT CRASHES
                return FoundLinks;
            }

            //RETURN THE LIST IF IT DOESN'T CRASH
            return FoundLinks;
        }
    }
    class main
    {
        //CLASS FOR CREATING GUI
        static GUI gui;

        //CLASS FOR SEARCHING LINKS
        static AngleSharp anglesharp;

        //BOOL FOR STOPPING THE SEARCH FOR THE LINKS
        public static bool searching = false;

        static void Main()
        {
            //LOAD GUI
            gui = new GUI();

            //LOAD ENGINE
            anglesharp = new AngleSharp();
        }

        public static void ToggleLinkSearch(string looking_at, string looking_for)
        {
            //GET BUTTON STATUS
            string ButtonState = string.Empty;
            Application.Current.Dispatcher.Invoke(() =>
            {
                ButtonState = gui.maingui.SEARCH_BUTTON.Content.ToString();
            });

            //IF BUTTON STATUS IS SET TO SEARCH - BEGIN SEARCH
            if (ButtonState == "SEARCH")
            {
                //RESET EVERYTHING BACK TO ZERO
                Application.Current.Dispatcher.Invoke(() =>
                {
                    //RESET GUI COUNTER
                    gui.maingui.COUNT.Text = "0";
                    //RESET GUI LIST
                    gui.maingui.ViewList.Items.Clear();
                });
                //RESET INTERNAL LINK LIST
                anglesharp.AllLinks.Clear();

                //UPDATE SEARCH STATUS
                searching = true;

                //ADD FIRST PAGE FROM WHERE WE WILL START
                anglesharp.AllLinks.Add(looking_at);

                ////START NEW THREAD WITH INFINITE LOOP
                new Thread(async () => {

                    //GRABS A LINK FROM THE LIST AND SEARCHES IT
                    for (int i = 0; searching == true; i++)
                    {
                        //SEARCH LINK FROM LIST, FOR SPECIFIED WORD
                        var FoundLinks = await anglesharp.GetTheLinks(anglesharp.AllLinks[i], looking_for);

                        //UPDATE GUI
                        Application.Current.Dispatcher.Invoke(() =>
                        {
                            //UPDATE THE COUNTER
                            gui.maingui.COUNT.Text = anglesharp.AllLinks.Count.ToString();
                            //IF WE FOUND LINKS, ADD THEM
                            if (FoundLinks.Count > 0)
                            {
                                //ADD THE LINKS
                                foreach (var item in FoundLinks)
                                    gui.maingui.ViewList.Items.Add(item);
                                //FORCE SCROLL THE LIST TO THE BOTTOM
                                gui.maingui.ViewList.SelectedIndex = gui.maingui.ViewList.Items.Count - 1;
                                gui.maingui.ViewList.ScrollIntoView(gui.maingui.ViewList.SelectedItem);
                            }
                        });

                    }
                    //UPDATE THE GUI AFTER LOOP WAS STOPPED
                    Application.Current.Dispatcher.Invoke(() =>
                    {
                        //RESET BUTTON STATUS/TEXT
                        gui.maingui.SEARCH_BUTTON.Content = "SEARCH";
                        //ENABLE THE BUTTONN
                        gui.maingui.SEARCH_BUTTON.IsEnabled = true;
                    });
                }).Start();
                //UPDATE THE GUI AFTER THE LOOP WAS STARTED
                Application.Current.Dispatcher.Invoke(() =>
                {
                    //SET BUTTON STATUS/TEXT TO STOP
                    gui.maingui.SEARCH_BUTTON.Content = "STOP";
                });
            }
            //IF BUTTON STATUS IS STOP
            else
            {
                //UPDATE SEARCH STATUS
                searching = false;

                //DISABLE THE BUTTON - IT WILL BE ENABLED AFTER THREAD STOPS - (AFTER LOOP)
                Application.Current.Dispatcher.Invoke(() =>
                {
                    gui.maingui.SEARCH_BUTTON.IsEnabled = false;
                });
            }

        }
    }
}