using System.Diagnostics;
using System.IO;
using System.Text.Json;
using System.Text.Json.Serialization;
using TaskbarLauncher.Models;

namespace TaskbarLauncher.Services;

public static class ConfigService
{
    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        WriteIndented = true,
        PropertyNameCaseInsensitive = true
    };

    static ConfigService()
    {
        JsonOptions.Converters.Add(new JsonStringEnumConverter());
    }

    public static string AppFolder => AppContext.BaseDirectory;

    public static string ConfigPath => Path.Combine(AppFolder, "config.json");

    public static string BackupFolder => Path.Combine(AppFolder, "backups");

    public static LauncherConfig Load()
    {
        if (!File.Exists(ConfigPath))
        {
            LauncherConfig defaults = CreateDefaultConfig();
            Save(defaults);
            return defaults;
        }

        string json = File.ReadAllText(ConfigPath);
        LauncherConfig config = JsonSerializer.Deserialize<LauncherConfig>(json, JsonOptions) ?? CreateDefaultConfig();
        NormalizeDisplayModes(config);
        Save(config);
        return config;
    }

    public static void Save(LauncherConfig config)
    {
        string json = JsonSerializer.Serialize(config, JsonOptions);
        File.WriteAllText(ConfigPath, json);
    }

    public static string Backup()
    {
        Directory.CreateDirectory(BackupFolder);
        if (!File.Exists(ConfigPath))
        {
            Save(CreateDefaultConfig());
        }

        string timestamp = DateTime.Now.ToString("yyyyMMdd-HHmmss");
        string backupPath = Path.Combine(BackupFolder, $"config-{timestamp}.json");
        File.Copy(ConfigPath, backupPath, overwrite: false);
        return backupPath;
    }

    public static LauncherConfig Restore(string sourcePath)
    {
        if (!File.Exists(sourcePath))
        {
            throw new FileNotFoundException("The selected config file was not found.", sourcePath);
        }

        string json = File.ReadAllText(sourcePath);
        LauncherConfig config = JsonSerializer.Deserialize<LauncherConfig>(json, JsonOptions)
            ?? throw new InvalidDataException("The selected config file could not be read.");

        NormalizeDisplayModes(config);
        Save(config);
        return config;
    }

    public static void OpenConfigFolder()
    {
        Directory.CreateDirectory(AppFolder);
        Process.Start(new ProcessStartInfo
        {
            FileName = AppFolder,
            UseShellExecute = true
        });
    }

    private static LauncherConfig CreateDefaultConfig()
    {
        LauncherConfig config = new()
        {
            Items =
            [
                new LauncherItem
                {
                    Title = "Folders",
                    Type = LauncherItemType.Menu,
                    Children =
                    [
                        new LauncherItem
                        {
                            Title = "Documents",
                            Type = LauncherItemType.Folder,
                            Target = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
                        },
                        new LauncherItem
                        {
                            Title = "Downloads",
                            Type = LauncherItemType.Folder,
                            Target = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Downloads")
                        }
                    ]
                },
                new LauncherItem
                {
                    Title = "Apps",
                    Type = LauncherItemType.Menu,
                    Children =
                    [
                        new LauncherItem
                        {
                            Title = "Notepad",
                            Type = LauncherItemType.App,
                            Target = "notepad.exe",
                            IconPath = "notepad.exe"
                        }
                    ]
                }
            ]
        };

        NormalizeDisplayModes(config);
        return config;
    }

    private static void NormalizeDisplayModes(LauncherConfig config)
    {
        foreach (LauncherItem item in config.Items)
        {
            NormalizeDisplayModes(item);
        }
    }

    private static void NormalizeDisplayModes(LauncherItem item)
    {
        if (!Enum.IsDefined(item.DisplayMode))
        {
            item.DisplayMode = LauncherDisplayMode.CompactList;
        }

        foreach (LauncherItem child in item.Children)
        {
            NormalizeDisplayModes(child);
        }
    }
}