using System.Diagnostics;
using System.IO;
using System.IO.Compression;

using Bloxstrap.Models;

using IniParser;
using IniParser.Model;
using System.Threading.Tasks;
using System.Linq;
using System.Collections.Generic;
using System;

namespace Bloxstrap.Helpers.Integrations
{
    internal class ReShade
    {
        // i havent even started this and i know for a fact this is gonna be a mess of an integration lol
        // there's a lot of nuances involved in how reshade functionality is supposed to work (shader management, config management, etc)
        // it's gonna be a bit of a pain in the ass, and i'm expecting a lot of bugs to arise from this...
        // well, looks like v1.7.0 is gonna be held back for quite a while lol

        // also, this is going to be fairly restrictive without a lot of heavy work
        // reshade's official installer gives you a list of shader packs and lets you choose which ones you want to install
        // and here we're effectively choosing for the user... hm...
        // i mean, it should be fine? importing shaders is still gonna be a thing, though maybe not as simple, but most people would be looking to use extravi's presets anyway

        private static string ShadersFolder { get => Path.Combine(Directories.ReShade, "Shaders"); }
        private static string TexturesFolder { get => Path.Combine(Directories.ReShade, "Textures"); }
        private static string ConfigLocation { get => Path.Combine(Directories.Modifications, "ReShade.ini"); }

        // the base url that we're fetching all our remote configs and resources and stuff from
        private const string BaseUrl = "https://raw.githubusercontent.com/Extravi/extravi.github.io/main/update";

        // this is a list of selectable shaders to download:
        // this should be formatted as { FolderName, GithubRepositoryUrl }
        private static readonly IReadOnlyDictionary<string, string> Shaders = new Dictionary<string, string>()
        {
            { "Stock",     "https://github.com/crosire/reshade-shaders/archive/refs/heads/master.zip" },

            // shaders required for extravi's presets:
            { "AlucardDH", "https://github.com/AlucardDH/dh-reshade-shaders/archive/refs/heads/master.zip" },
            { "AstrayFX",  "https://github.com/BlueSkyDefender/AstrayFX/archive/refs/heads/master.zip" },
            { "Depth3D",   "https://github.com/BlueSkyDefender/Depth3D/archive/refs/heads/master.zip" },
            { "Glamarye",  "https://github.com/rj200/Glamarye_Fast_Effects_for_ReShade/archive/refs/heads/main.zip" },
            { "NiceGuy",   "https://github.com/mj-ehsan/NiceGuy-Shaders/archive/refs/heads/main.zip" },
            { "prod80",    "https://github.com/prod80/prod80-ReShade-Repository/archive/refs/heads/master.zip" },
            { "qUINT",     "https://github.com/martymcmodding/qUINT/archive/refs/heads/master.zip" },
        };

        private static readonly string[] ExtraviPresetsShaders = new string[]
        {
            "AlucardDH",
            "AstrayFX",
            "Depth3D",
            "Glamarye",
            "NiceGuy",
            "prod80",
            "qUINT",
        };

        private static string GetSearchPath(string type, string name)
        {
            return $",..\\..\\ReShade\\{type}\\{name}";
        }

        public static async Task DownloadConfig()
        {
            Debug.WriteLine("[ReShade] Downloading/Upgrading config file...");

            {
                byte[] bytes = await App.HttpClient.GetByteArrayAsync($"{BaseUrl}/config.zip");

                using MemoryStream zipStream = new(bytes);
                using ZipArchive archive = new(zipStream);

                
                archive.Entries.Where(x => x.FullName == "ReShade.ini").First().ExtractToFile(ConfigLocation, true);

                // when we extract the file we have to make sure the last modified date is overwritten
                // or else it will synchronize with the config in the version folder
                // really the config adjustments below should do this for us, but this is just to be safe
                File.SetLastWriteTime(ConfigLocation, DateTime.Now);

                // we also gotta download the editor fonts
                foreach (ZipArchiveEntry entry in archive.Entries.Where(x => x.FullName.EndsWith(".ttf")))
                    entry.ExtractToFile(Path.Combine(Directories.ReShade, "Fonts", entry.FullName), true);
            }

            // now we have to adjust the config file to use the paths that we need
            // some of these can be removed later when the config file is better adjusted for bloxstrap by default

            FileIniDataParser parser = new();
            IniData data = parser.ReadFile(ConfigLocation);

            data["GENERAL"]["EffectSearchPaths"] = "..\\..\\ReShade\\Shaders";
            data["GENERAL"]["TextureSearchPaths"] = "..\\..\\ReShade\\Textures";
            data["GENERAL"]["PresetPath"] = data["GENERAL"]["PresetPath"].Replace(".\\reshade-presets\\", "..\\..\\ReShade\\Presets\\");
            data["SCREENSHOT"]["SavePath"] = "..\\..\\ReShade\\Screenshots";
            data["STYLE"]["EditorFont"] = data["STYLE"]["EditorFont"].Replace(".\\", "..\\..\\ReShade\\Fonts\\");
            data["STYLE"]["Font"] = data["STYLE"]["Font"].Replace(".\\", "..\\..\\ReShade\\Fonts\\");

            // add search paths for shaders and textures

            foreach (string name in Directory.GetDirectories(ShadersFolder).Select(x => Path.GetRelativePath(ShadersFolder, x)).ToArray())
                data["GENERAL"]["EffectSearchPaths"] += GetSearchPath("Shaders", name);

            foreach (string name in Directory.GetDirectories(TexturesFolder).Select(x => Path.GetRelativePath(TexturesFolder, x)).ToArray())
                data["GENERAL"]["TextureSearchPaths"] += GetSearchPath("Textures", name);

            parser.WriteFile(ConfigLocation, data);
        }

        public static void SynchronizeConfigFile()
        {
            Debug.WriteLine($"[ReShade] Synchronizing configuration file...");

            // yeah, this is going to be a bit of a pain
            // keep in mind the config file is going to be in two places: the mod folder and the version folder
            // so we have to make sure the two below scenaros work flawlessly:
            //  - if the user manually updates their reshade config in the mod folder or it gets updated, it must be copied to the version folder
            //  - if the user updates their reshade settings ingame, the updated config must be copied to the mod folder
            // the easiest way to manage this is to just compare the modification dates of the two
            // anyway, this is where i'm expecting most of the bugs to arise from
            // config synchronization will be done whenever roblox updates or whenever we launch roblox

            string modFolderConfigPath = ConfigLocation;
            string versionFolderConfigPath = Path.Combine(Directories.Versions, App.Settings.VersionGuid, "ReShade.ini");

            // we shouldn't be here if the mod config doesn't already exist
            if (!File.Exists(modFolderConfigPath))
            {
                Debug.WriteLine($"[ReShade] ReShade.ini in modifications folder does not exist, aborting sync");
                return;
            }

            // copy to the version folder if it doesn't already exist there
            if (!File.Exists(versionFolderConfigPath))
            {
                Debug.WriteLine($"[ReShade] ReShade.ini in version folder does not exist, synchronized with modifications folder");
                File.Copy(modFolderConfigPath, versionFolderConfigPath);
            }

            // if both the mod and version configs match, then we don't need to do anything
            if (Utilities.MD5File(modFolderConfigPath) == Utilities.MD5File(versionFolderConfigPath))
            {
                Debug.WriteLine($"[ReShade] ReShade.ini in version and modifications folder match");
                return;
            }

            FileInfo modFolderConfigFile = new(modFolderConfigPath);
            FileInfo versionFolderConfigFile = new(versionFolderConfigPath);

            if (modFolderConfigFile.LastWriteTime > versionFolderConfigFile.LastWriteTime)
            {
                // overwrite version config if mod config was modified most recently
                Debug.WriteLine($"[ReShade] ReShade.ini in version folder is older, synchronized with modifications folder");
                File.Copy(modFolderConfigPath, versionFolderConfigPath, true);
            }
            else if (versionFolderConfigFile.LastWriteTime > modFolderConfigFile.LastWriteTime)
            {
                // overwrite mod config if version config was modified most recently
                Debug.WriteLine($"[ReShade] ReShade.ini in modifications folder is older, synchronized with version folder");
                File.Copy(versionFolderConfigPath, modFolderConfigPath, true);
            }
        }

        public static async Task DownloadShaders(string name)
        {
            string downloadUrl = Shaders.First(x => x.Key == name).Value;

            // not all shader packs have a textures folder, so here we're determining if they exist purely based on if they have a Shaders folder
            if (Directory.Exists(Path.Combine(Directories.ReShade, "Shaders", name)))
                return;

            Debug.WriteLine($"[ReShade] Downloading shaders for {name}");

            {
                byte[] bytes = await App.HttpClient.GetByteArrayAsync(downloadUrl);

                using MemoryStream zipStream = new(bytes);
                using ZipArchive archive = new(zipStream);

                foreach (ZipArchiveEntry entry in archive.Entries)
                {
                    if (entry.FullName.EndsWith('/'))
                        continue;

                    // github branch zips have a root folder of the name of the branch, so let's just remove that
                    string fullPath = entry.FullName.Substring(entry.FullName.IndexOf('/') + 1);

                    // skip file if it's not in the Shaders or Textures folder
                    if (!fullPath.StartsWith("Shaders") && !fullPath.StartsWith("Textures"))
                        continue;

                    // ingore shaders with compiler errors
                    if (fullPath.EndsWith("dh_Lain.fx") || fullPath.EndsWith("dh_rtgi.fx"))
                        continue;

                    // and now we do it again because of how we're handling folder management
                    // e.g. reshade-shaders-master/Shaders/Vignette.fx should go to ReShade/Shaders/Stock/Vignette.fx
                    // so in this case, relativePath should just be "Vignette.fx"
                    string relativePath = fullPath.Substring(fullPath.IndexOf('/') + 1);

                    // now we stitch it all together
                    string extractionPath = Path.Combine(
                        Directories.ReShade,
                        fullPath.StartsWith("Shaders") ? "Shaders" : "Textures",
                        name,
                        relativePath
                    );

                    // make sure the folder that we're extracting it to exists
                    Directory.CreateDirectory(Path.GetDirectoryName(extractionPath)!);

                    // and now extract
                    await Task.Run(() => entry.ExtractToFile(extractionPath));
                }
            }

            // now we have to update ReShade.ini and add the installed shaders to the search paths
            FileIniDataParser parser = new();
            IniData data = parser.ReadFile(ConfigLocation);

            if (!data["GENERAL"]["EffectSearchPaths"].Contains(name))
                data["GENERAL"]["EffectSearchPaths"] += GetSearchPath("Shaders", name);

            // not every shader pack has a textures folder
            if (Directory.Exists(Path.Combine(Directories.ReShade, "Textures", name)) && !data["GENERAL"]["TextureSearchPaths"].Contains(name))
                data["GENERAL"]["TextureSearchPaths"] += GetSearchPath("Textures", name);

            parser.WriteFile(ConfigLocation, data);
        }

        public static void DeleteShaders(string name)
        {
            Debug.WriteLine($"[ReShade] Deleting shaders for {name}");

            string shadersPath = Path.Combine(Directories.ReShade, "Shaders", name);
            string texturesPath = Path.Combine(Directories.ReShade, "Textures", name);

            if (Directory.Exists(shadersPath))
                Directory.Delete(shadersPath, true);

            if (Directory.Exists(texturesPath))
                Directory.Delete(texturesPath, true);

            if (!File.Exists(ConfigLocation))
                return;

            // now we have to update ReShade.ini and remove the installed shaders from the search paths
            FileIniDataParser parser = new();
            IniData data = parser.ReadFile(ConfigLocation);

            string shaderSearchPaths = data["GENERAL"]["EffectSearchPaths"];
            string textureSearchPaths = data["GENERAL"]["TextureSearchPaths"];

            if (shaderSearchPaths.Contains(name))
            {
                string searchPath = GetSearchPath("Shaders", name);
                data["GENERAL"]["EffectSearchPaths"] = shaderSearchPaths.Remove(shaderSearchPaths.IndexOf(searchPath), searchPath.Length);
            }

            if (textureSearchPaths.Contains(name))
            {
                string searchPath = GetSearchPath("Textures", name);
                data["GENERAL"]["TextureSearchPaths"] = textureSearchPaths.Remove(textureSearchPaths.IndexOf(searchPath), searchPath.Length);
            }

            parser.WriteFile(ConfigLocation, data);
        }

        public static async Task InstallExtraviPresets()
        {
            Debug.WriteLine("[ReShade] Installing Extravi's presets...");

            foreach (string name in ExtraviPresetsShaders)
                await DownloadShaders(name);

            byte[] bytes = await App.HttpClient.GetByteArrayAsync($"{BaseUrl}/reshade-presets.zip");

            using MemoryStream zipStream = new(bytes);
            using ZipArchive archive = new(zipStream);

            foreach (ZipArchiveEntry entry in archive.Entries)
            {
                if (entry.FullName.EndsWith('/'))
                    continue;

                // remove containing folder
                string filename = entry.FullName.Substring(entry.FullName.IndexOf('/') + 1);

                await Task.Run(() => entry.ExtractToFile(Path.Combine(Directories.ReShade, "Presets", filename), true));
            }
        }

        public static void UninstallExtraviPresets()
        {
            Debug.WriteLine("[ReShade] Uninstalling Extravi's presets...");

            FileInfo[] presets = new DirectoryInfo(Path.Combine(Directories.ReShade, "Presets")).GetFiles();

            foreach (FileInfo preset in presets)
            {
                if (preset.Name.StartsWith("Extravi"))
                    preset.Delete();
            }

            foreach (string name in ExtraviPresetsShaders)
                DeleteShaders(name);
        }

        public static async Task CheckModifications()
        {
            Debug.WriteLine("[ReShade] Checking ReShade modifications... ");
            
            string injectorLocation = Path.Combine(Directories.Modifications, "dxgi.dll");

            // initialize directories
            Directory.CreateDirectory(Directories.ReShade);
            Directory.CreateDirectory(Path.Combine(Directories.ReShade, "Fonts"));
            Directory.CreateDirectory(Path.Combine(Directories.ReShade, "Screenshots"));
            Directory.CreateDirectory(Path.Combine(Directories.ReShade, "Shaders"));
            Directory.CreateDirectory(Path.Combine(Directories.ReShade, "Textures"));
            Directory.CreateDirectory(Path.Combine(Directories.ReShade, "Presets"));

            if (!App.Settings.UseReShadeExtraviPresets)
            {
                UninstallExtraviPresets();
                App.Settings.ExtraviPresetsVersion = "";
            }

            if (!App.Settings.UseReShade)
            {
                Debug.WriteLine("[ReShade] Uninstalling ReShade...");

                // delete any stock config files
                File.Delete(injectorLocation);
                File.Delete(ConfigLocation);

                App.Settings.ReShadeConfigVersion = "";

                DeleteShaders("Stock");

                return;
            }

            // the version manfiest contains the version of reshade available for download and the last date the presets were updated
            var versionManifest = await Utilities.GetJson<ReShadeVersionManifest>("https://raw.githubusercontent.com/Extravi/extravi.github.io/main/update/version.json");
            bool shouldFetchReShade = false;
            bool shouldFetchConfig = false;

            if (!File.Exists(injectorLocation))
            {
                shouldFetchReShade = true;
            }
            else if (versionManifest is not null)
            {
                // check if an update for reshade is available
                FileVersionInfo injectorVersionInfo = FileVersionInfo.GetVersionInfo(injectorLocation);

                if (injectorVersionInfo.ProductVersion != versionManifest.ReShade)
                    shouldFetchReShade = true;
            }

            // check if we should download a fresh copy of the config
            // extravi may need to update the config ota, in which case we'll redownload it
            if (!File.Exists(ConfigLocation) || versionManifest is not null && App.Settings.ReShadeConfigVersion != versionManifest.ConfigFile)
                shouldFetchConfig = true;

            if (shouldFetchReShade)
            {
                Debug.WriteLine("[ReShade] Installing/Upgrading ReShade...");

                {
                    byte[] bytes = await App.HttpClient.GetByteArrayAsync($"{BaseUrl}/dxgi.zip");
                    using MemoryStream zipStream = new(bytes);
                    using ZipArchive archive = new(zipStream);
                    archive.ExtractToDirectory(Directories.Modifications, true);
                }
            }

            if (shouldFetchConfig)
            {
                await DownloadConfig();

                if (versionManifest is not null)
                    App.Settings.ReShadeConfigVersion = versionManifest.ConfigFile;
            }

            await DownloadShaders("Stock");

            if (App.Settings.UseReShadeExtraviPresets && App.Settings.ExtraviPresetsVersion != versionManifest!.Presets)
            {
                await InstallExtraviPresets();
                App.Settings.ExtraviPresetsVersion = versionManifest.Presets;
            }

            SynchronizeConfigFile();
        }
    }
}