using System;
using System.ComponentModel.DataAnnotations;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Windows;
using Alphaleonis.Win32.Filesystem;
using IniParser;
using IniParser.Model;
using IniParser.Model.Configuration;
using IniParser.Parser;
using Wabbajack.Common;
using Wabbajack.Lib.CompilationSteps.CompilationErrors;
using Wabbajack.Lib.Downloaders;
using Wabbajack.Lib.NexusApi;
using Wabbajack.Lib.Validation;
using Directory = Alphaleonis.Win32.Filesystem.Directory;
using File = Alphaleonis.Win32.Filesystem.File;
using Path = Alphaleonis.Win32.Filesystem.Path;
using SectionData = Wabbajack.Common.SectionData;

namespace Wabbajack.Lib
{
    public class MO2Installer : AInstaller
    {
        public bool WarnOnOverwrite { get; set; } = true;

        public override ModManager ModManager => ModManager.MO2;

        public string GameFolder { get; set; }

        public MO2Installer(string archive, ModList modList, string outputFolder, string downloadFolder, SystemParameters parameters)
            : base(
                  archive: archive,
                  modList: modList,
                  outputFolder: outputFolder, 
                  downloadFolder: downloadFolder,
                  parameters: parameters)
        {
        }

        protected override async Task<bool> _Begin(CancellationToken cancel)
        {
            if (cancel.IsCancellationRequested) return false;
            var metric = Metrics.Send(Metrics.BeginInstall, ModList.Name);

            ConfigureProcessor(20, ConstructDynamicNumThreads(await RecommendQueueSize()));
            var game = ModList.GameType.MetaData();

            if (GameFolder == null)
                GameFolder = game.GameLocation();

            if (GameFolder == null)
            {
                var otherGame = game.CommonlyConfusedWith.Where(g => g.MetaData().IsInstalled).Select(g => g.MetaData()).FirstOrDefault();
                if (otherGame != null)
                {
                    await Utils.Log(new CriticalFailureIntervention(
                            $"In order to do a proper install Wabbajack needs to know where your {game.HumanFriendlyGameName} folder resides. However this game doesn't seem to be installed, we did however find a installed " +
                            $"copy of {otherGame.HumanFriendlyGameName}, did you install the wrong game?",
                            $"Could not locate {game.HumanFriendlyGameName}"))
                        .Task;
                }
                else
                {
                    await Utils.Log(new CriticalFailureIntervention(
                            $"In order to do a proper install Wabbajack needs to know where your {game.HumanFriendlyGameName} folder resides. However this game doesn't seem to be installed",
                            $"Could not locate {game.HumanFriendlyGameName}"))
                        .Task;
                }

                Utils.Log("Exiting because we couldn't find the game folder.");
                return false;
            }

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Validating Game ESMs");
            ValidateGameESMs();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Validating Modlist");
            await ValidateModlist.RunValidation(Queue, ModList);

            Directory.CreateDirectory(OutputFolder);
            Directory.CreateDirectory(DownloadFolder);

            if (Directory.Exists(Path.Combine(OutputFolder, Consts.MO2ModFolderName)) && WarnOnOverwrite)
            {
                if ((await Utils.Log(new ConfirmUpdateOfExistingInstall { ModListName = ModList.Name, OutputFolder = OutputFolder }).Task) == ConfirmUpdateOfExistingInstall.Choice.Abort)
                {
                    Utils.Log("Exiting installation at the request of the user, existing mods folder found.");
                    return false;
                }
            }

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Optimizing ModList");
            await OptimizeModlist();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Hashing Archives");
            await HashArchives();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Downloading Missing Archives");
            await DownloadArchives();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Hashing Remaining Archives");
            await HashArchives();

            var missing = ModList.Archives.Where(a => !HashedArchives.ContainsKey(a.Hash)).ToList();
            if (missing.Count > 0)
            {
                foreach (var a in missing)
                    Info($"Unable to download {a.Name}");
                if (IgnoreMissingFiles)
                    Info("Missing some archives, but continuing anyways at the request of the user");
                else
                    Error("Cannot continue, was unable to download one or more archives");
            }

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Priming VFS");
            await PrimeVFS();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Building Folder Structure");
            BuildFolderStructure();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Installing Archives");
            await InstallArchives();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Installing Included files");
            await InstallIncludedFiles();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Installing Archive Metas");
            await InstallIncludedDownloadMetas();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Building BSAs");
            await BuildBSAs();

            if (cancel.IsCancellationRequested) return false;
            UpdateTracker.NextStep("Generating Merges");
            await zEditIntegration.GenerateMerges(this);

            UpdateTracker.NextStep("Set MO2 into portable");
            ForcePortable();

            UpdateTracker.NextStep("Create Empty Output Mods");
            CreateOutputMods();

            UpdateTracker.NextStep("Updating System-specific ini settings");
            SetScreenSizeInPrefs();

            UpdateTracker.NextStep("Installation complete! You may exit the program.");
            var metric2 = Metrics.Send(Metrics.FinishInstall, ModList.Name);

            return true;
        }

        private void CreateOutputMods()
        {
            Directory.EnumerateFiles(Path.Combine(OutputFolder, "profiles"), "settings.ini", DirectoryEnumerationOptions.Recursive).Do(f =>
            {
                var ini = f.LoadIniFile();
                if (ini == null)
                {
                    Utils.Log($"settings.ini is null for {f}, skipping");
                    return;
                }

                var overwrites = ini.custom_overwrites;
                if (overwrites == null)
                {
                    Utils.Log("No custom overwrites found, skipping");
                    return;
                }

                if (overwrites is SectionData data)
                {
                    data.Coll.Do(keyData =>
                    {
                        var v = keyData.Value;
                        var mod = Path.Combine(OutputFolder, Consts.MO2ModFolderName, v);

                        if (!Directory.Exists(mod))
                            Directory.CreateDirectory(mod);
                    });
                }
            });
        }

        private void ForcePortable()
        {
            var path = Path.Combine(OutputFolder, "portable.txt");
            if (File.Exists(path)) return;

            try
            {
                File.WriteAllText(path, "Created by Wabbajack");
            }
            catch (Exception e)
            {
                Utils.Error(e, $"Could not create portable.txt in {OutputFolder}");
            }
        }

        private async Task InstallIncludedDownloadMetas()
        {
            await ModList.Directives
                   .OfType<ArchiveMeta>()
                   .PMap(Queue, directive =>
                   {
                       Status($"Writing included .meta file {directive.To}");
                       var outPath = Path.Combine(DownloadFolder, directive.To);
                       if (File.Exists(outPath)) File.Delete(outPath);
                       File.WriteAllBytes(outPath, LoadBytesFromPath(directive.SourceDataID));
                   });
        }

        private void ValidateGameESMs()
        {
            foreach (var esm in ModList.Directives.OfType<CleanedESM>().ToList())
            {
                var filename = Path.GetFileName(esm.To);
                var gameFile = Path.Combine(GameFolder, "Data", filename);
                Utils.Log($"Validating {filename}");
                var hash = gameFile.FileHash();
                if (hash != esm.SourceESMHash)
                {
                    Utils.ErrorThrow(new InvalidGameESMError(esm, hash, gameFile));
                }
            }
        }

        private async Task BuildBSAs()
        {
            var bsas = ModList.Directives.OfType<CreateBSA>().ToList();
            Info($"Building {bsas.Count} bsa files");

            foreach (var bsa in bsas)
            {
                Status($"Building {bsa.To}");
                var sourceDir = Path.Combine(OutputFolder, Consts.BSACreationDir, bsa.TempID);

                var bsaSize = bsa.FileStates.Select(state => File.GetSize(Path.Combine(sourceDir, state.Path))).Sum();

                using (var a = bsa.State.MakeBuilder(bsaSize))
                {
                    var streams = await bsa.FileStates.PMap(Queue, state =>
                    {
                        Status($"Adding {state.Path} to BSA");
                        var fs = File.OpenRead(Path.Combine(sourceDir, state.Path));
                        a.AddFile(state, fs);
                        return fs;
                    });

                    Info($"Writing {bsa.To}");
                    a.Build(Path.Combine(OutputFolder, bsa.To));
                    streams.Do(s => s.Dispose());
                }
            }

            var bsaDir = Path.Combine(OutputFolder, Consts.BSACreationDir);
            if (Directory.Exists(bsaDir))
            {
                Info($"Removing temp folder {Consts.BSACreationDir}");
                Utils.DeleteDirectory(bsaDir);
            }
        }

        private async Task InstallIncludedFiles()
        {
            Info("Writing inline files");
            await ModList.Directives
                .OfType<InlineFile>()
                .PMap(Queue, directive =>
                {
                    Status($"Writing included file {directive.To}");
                    var outPath = Path.Combine(OutputFolder, directive.To);
                    if (File.Exists(outPath)) File.Delete(outPath);
                    if (directive is RemappedInlineFile)
                        WriteRemappedFile((RemappedInlineFile)directive);
                    else if (directive is CleanedESM)
                        GenerateCleanedESM((CleanedESM)directive);
                    else
                        File.WriteAllBytes(outPath, LoadBytesFromPath(directive.SourceDataID));
                });
        }

        private void GenerateCleanedESM(CleanedESM directive)
        {
            var filename = Path.GetFileName(directive.To);
            var gameFile = Path.Combine(GameFolder, "Data", filename);
            Info($"Generating cleaned ESM for {filename}");
            if (!File.Exists(gameFile)) throw new InvalidDataException($"Missing {filename} at {gameFile}");
            Status($"Hashing game version of {filename}");
            var sha = gameFile.FileHash();
            if (sha != directive.SourceESMHash)
                throw new InvalidDataException(
                    $"Cannot patch {filename} from the game folder because the hashes do not match. Have you already cleaned the file?");

            var patchData = LoadBytesFromPath(directive.SourceDataID);
            var toFile = Path.Combine(OutputFolder, directive.To);
            Status($"Patching {filename}");
            using (var output = File.Open(toFile, FileMode.Create))
            using (var input = File.OpenRead(gameFile))
            {
                Utils.ApplyPatch(input, () => new MemoryStream(patchData), output);
            }
        }

        private void SetScreenSizeInPrefs()
        {
            var config = new IniParserConfiguration {AllowDuplicateKeys = true, AllowDuplicateSections = true};
            foreach (var file in Directory.EnumerateFiles(Path.Combine(OutputFolder, "profiles"), "*refs.ini",
                DirectoryEnumerationOptions.Recursive))
            {
                try
                {
                    var parser = new FileIniDataParser(new IniDataParser(config));
                    var data = parser.ReadFile(file);
                    bool modified = false;
                    if (data.Sections["Display"] != null)
                    {

                        if (data.Sections["Display"]["iSize W"] != null && data.Sections["Display"]["iSize H"] != null)
                        {
                            data.Sections["Display"]["iSize W"] =
                                SystemParameters.ScreenWidth.ToString(CultureInfo.CurrentCulture);
                            data.Sections["Display"]["iSize H"] =
                                SystemParameters.ScreenHeight.ToString(CultureInfo.CurrentCulture);
                            modified = true;
                        }

                    }
                    if (data.Sections["MEMORY"] != null)
                    {
                        if (data.Sections["MEMORY"]["VideoMemorySizeMb"] != null)
                        {
                            data.Sections["MEMORY"]["VideoMemorySizeMb"] =
                                SystemParameters.EnbLEVRAMSize.ToString(CultureInfo.CurrentCulture);
                            modified = true;
                        }
                    }

                    if (modified) 
                        parser.WriteFile(file, data);
                }
                catch (Exception ex)
                {
                    Utils.Log($"Skipping screen size remap for {file} due to parse error.");
                    continue;
                }
            }
        }

        private void WriteRemappedFile(RemappedInlineFile directive)
        {
            var data = Encoding.UTF8.GetString(LoadBytesFromPath(directive.SourceDataID));

            data = data.Replace(Consts.GAME_PATH_MAGIC_BACK, GameFolder);
            data = data.Replace(Consts.GAME_PATH_MAGIC_DOUBLE_BACK, GameFolder.Replace("\\", "\\\\"));
            data = data.Replace(Consts.GAME_PATH_MAGIC_FORWARD, GameFolder.Replace("\\", "/"));

            data = data.Replace(Consts.MO2_PATH_MAGIC_BACK, OutputFolder);
            data = data.Replace(Consts.MO2_PATH_MAGIC_DOUBLE_BACK, OutputFolder.Replace("\\", "\\\\"));
            data = data.Replace(Consts.MO2_PATH_MAGIC_FORWARD, OutputFolder.Replace("\\", "/"));

            data = data.Replace(Consts.DOWNLOAD_PATH_MAGIC_BACK, DownloadFolder);
            data = data.Replace(Consts.DOWNLOAD_PATH_MAGIC_DOUBLE_BACK, DownloadFolder.Replace("\\", "\\\\"));
            data = data.Replace(Consts.DOWNLOAD_PATH_MAGIC_FORWARD, DownloadFolder.Replace("\\", "/"));

            File.WriteAllText(Path.Combine(OutputFolder, directive.To), data);
        }

        public static IErrorResponse CheckValidInstallPath(string path, string downloadFolder)
        {
            var ret = Utils.IsDirectoryPathValid(path);
            if (!ret.Succeeded) return ret;

            if (!Directory.Exists(path)) return ErrorResponse.Success;

            // Check folder does not have a Wabbajack ModList
            foreach (var file in Directory.EnumerateFiles(path))
            {
                if (!File.Exists(file)) continue;
                if (System.IO.Path.GetExtension(file).Equals(Consts.ModListExtension))
                {
                    return ErrorResponse.Fail($"Cannot install into a folder with a Wabbajack ModList inside of it");
                }
            }

            // Check folder is either empty, or a likely valid previous install
            if (!Directory.IsEmpty(path))
            {
                // If we have a MO2 install, assume good to go
                if (Directory.EnumerateFiles(path).Any(file =>
                {
                    var fileName = Path.GetFileName(file);
                    if (fileName.Equals("ModOrganizer.exe", StringComparison.OrdinalIgnoreCase)) return true;
                    if (fileName.Equals("ModOrganizer.ini", StringComparison.OrdinalIgnoreCase)) return true;
                    return false;
                }))
                {
                    return ErrorResponse.Success;
                }

                // If we don't have a MO2 install, and there's any file that's not in the downloads folder, mark failure
                if (Directory.EnumerateFiles(path).Any(file =>
                {
                    var fileName = Path.GetFileName(file);
                    if (string.IsNullOrWhiteSpace(downloadFolder)) return true;
                    return !Utils.IsUnderneathDirectory(file, downloadFolder);
                }))
                {
                    return ErrorResponse.Fail($"Cannot install into a non-empty folder that does not look like a previous WJ installation.\n" +
                        $"To override, delete all installed files from your target installation folder.  Any files in your download folder are okay to keep.");
                }
            }

            return ErrorResponse.Success;
        }
    }
}