using System;
using System.Diagnostics;
using System.IO.Compression;
using System.IO;
using System.Linq;
using System.Net;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace TBMM
{
    partial class MainForm
    {
        public GameState CheckIfPatched()
        {
            if (GetExe() == null)
            {
                status.Text = "Status: Game not found";
                return GameState.NotFound;
            }
            string pnp = "Patch && Play";
            if (!File.Exists(GamePath(@"\IPA.exe")))
            {
                status.Text = "Status: Patcher missing\nClicking Play will install it";
                playbtn.Text = pnp;
                return GameState.NoPatcher;
            }
            if (gcipa.Updatable && !(gcipa.Version == new Version(1, 0, 0, 0) && gcipa.LatestVersion == new Version(4, 0, 0, 0)))
            {
                status.Text = "Status: Patcher outdated\nClicking play will update it";
                playbtn.Text = pnp;
                return GameState.OldPatcher;
            }
            string nopatch = "Status: Unpatched\nClicking Play patches it";
            string gc = GetExe().Replace(".exe", "");
            string backups = GamePath(@"\IPA\Backups\" + gc);
            if (!Directory.Exists(backups))
            {
                status.Text = nopatch;
                playbtn.Text = pnp;
                return GameState.Unpatched;
            }
            string backup = Directory.EnumerateDirectories(backups).OrderByDescending(name => Directory.GetLastWriteTimeUtc(name)).FirstOrDefault();
            if (backup == null)
            {
                status.Text = nopatch;
                playbtn.Text = pnp;
                return GameState.Unpatched;
            }
            if (File.GetLastWriteTime(GamePath($@"\{gc}_Data\Managed\Assembly-CSharp.dll"))
                > //If the file was updated at least 2 minutes after patching
                Directory.GetLastWriteTime(backup).AddMinutes(2)
                || !File.Exists(GamePath($@"\{gc}_Data\Managed\IllusionInjector.dll")))
            {
                status.Text = nopatch;
                playbtn.Text = pnp;
                return GameState.Unpatched;
            }
            status.Text = "Status: " + (unpatched.Checked ? "Mods disabled" : "Patched");
            playbtn.Text = "Play" + (unpatched.Checked ? " unmodded" : "");
            return GameState.Patched;
        }

        public async Task<bool?> PatchStartGame(string command = null)
        {
            if (!BeginWork()) return false;
            foreach (ListViewItem item in modlist.SelectedItems)
                item.Selected = false;
            bool? retOpenedWindowShouldStay = null;
            void EnsureShown(bool stay)
            {
                if (!Visible)
                {
                    Show();
                    retOpenedWindowShouldStay = stay;
                    TopMost = true; //It opens in the background otherwise - should be fine since it only shows for a couple seconds
                }
            }
            var status = CheckIfPatched();
            //bool justDownloadedPatcherSoDontWarnAboutIncompatibility = false;
            switch (status)
            {
                case GameState.NotFound:
                    MessageBox.Show("Techblox not found! Set the correct path in Settings.");
                    EndWork(false);
                    return retOpenedWindowShouldStay;
                case GameState.NoPatcher:
                case GameState.OldPatcher:
                    {
                        EnsureShown(false);
                        if (MessageBox.Show((status == GameState.NoPatcher
                            ? "The patcher (GCIPA) is not found. It's necessary to load the mods."
                            : "There is a patcher update available!"
                            ) + "\n\nIt will be downloaded from https://git.exmods.org/modtainers/GCIPA/releases and ran to patch the game. You can validate the game to restore the original game files or simply disable mods at any time.",
                            "Patcher download needed", MessageBoxButtons.OKCancel) == DialogResult.Cancel)
                        {
                            EndWork();
                            return retOpenedWindowShouldStay;
                        }
                        this.status.Text = "Status: Patching...";
                        int C = 0;
                        while (gcipa.DownloadURL == null && C < 20)
                            await Task.Delay(500); //The EnsureShown() call should download info about GCIPA
                        if (gcipa.DownloadURL == null)
                        {
                            MessageBox.Show("Could not get information about GCIPA in time. Please run TBMM manually.");
                            return retOpenedWindowShouldStay;
                        }
                        using (WebClient client = GetClient())
                        {
                            string url = gcipa.DownloadURL;
                            await client.DownloadFileTaskAsync(url, "IPA.zip");
                            using (var fs = new FileStream("IPA.zip", FileMode.Open))
                            using (var za = new ZipArchive(fs))
                                za.ExtractToDirectory(Configuration.GamePath, true); //Overwrite files that were left from a previous install of the patcher
                            File.Delete("IPA.zip");
                        }
                    }
                    GetInstalledMods(); //Update patcher state, should be fine for this rare event
                    status = CheckIfPatched();
                    break;
            }
            switch (status)
            {
                case GameState.NoPatcher: //Make sure it actually worked
                case GameState.OldPatcher:
                    EndWork(false);
                    return retOpenedWindowShouldStay;
                case GameState.Unpatched:
                    { //TODO: Wine
                        EnsureShown(false);
                        var psi = new ProcessStartInfo(GamePath(@"\IPA.exe"), GetExe() + " --nowait")
                        {
                            UseShellExecute = false,
                            RedirectStandardError = true,
                            RedirectStandardOutput = true,
                            WorkingDirectory = Configuration.GamePath,
                            CreateNoWindow = true
                        };
                        var process = Process.Start(psi);
                        process.BeginErrorReadLine();
                        process.BeginOutputReadLine();
                        process.EnableRaisingEvents = true;
                        modinfobox.Text = "";
                        DataReceivedEventHandler onoutput = (sender, e) =>
                        {
                            Invoke((Action)(() => modinfobox.Text += e.Data + Environment.NewLine));
                        };
                        process.OutputDataReceived += onoutput;
                        process.ErrorDataReceived += onoutput;
                        var (handler, task) = CheckStartGame(command);
                        process.Exited += handler;
                        await task;
                    }
                    break;
                case GameState.Patched:
                    {
                        //CheckStartGame(command)(null, null);
                        var (handler, task) = CheckStartGame(command);
                        handler(null, null);
                        await task;
                    }
                    break;
            }
            return retOpenedWindowShouldStay;
        }

        public enum GameState
        {
            NotFound,
            NoPatcher,
            OldPatcher,
            Unpatched,
            Patched
        }
    }
}