using System.IO;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace DeskCore;

public enum DesignMode { System, Light, Dark }
public enum ViewMode { Small, Medium, Large, List }

public class CategoryMeta
{
    public string? Glyph { get; set; }
    public string? Color { get; set; }
    public bool Fence { get; set; }
    public double? FenceX { get; set; }
    public double? FenceY { get; set; }
    public double FenceW { get; set; } = 340;
    public double FenceH { get; set; } = 260;
    public bool FenceCollapsed { get; set; }
}

public class SortRule
{
    public string Contains { get; set; } = "";
    public string Category { get; set; } = "";
}

/// <summary>Alle Einstellungen, gespeichert in %APPDATA%\DeskCore\settings.json.</summary>
public class AppSettings
{
    public DesignMode Design { get; set; } = DesignMode.System;
    public ViewMode View { get; set; } = ViewMode.Medium;

    public bool TrayEnabled { get; set; } = true;
    public bool CloseToTray { get; set; } = true;
    public bool TrayHintShown { get; set; }

    public bool HotkeyEnabled { get; set; } = true;
    public int HotkeyModifiers { get; set; } = Hotkey.ModWin | Hotkey.ModShift;
    public int HotkeyKey { get; set; } = 0x44; // D

    public bool AutoSort { get; set; }
    public bool AutoSortRemoveFromDesktop { get; set; }
    public List<SortRule> Rules { get; set; } = [];

    public bool FencesEnabled { get; set; } = true;

    // Fenster merken (WPF-Einheiten)
    public double? WindowLeft { get; set; }
    public double? WindowTop { get; set; }
    public double? WindowWidth { get; set; }
    public double? WindowHeight { get; set; }
    public bool WindowMaximized { get; set; }

    // Updates
    public bool AutoUpdateCheck { get; set; } = true;
    public DateTime? LastUpdateCheck { get; set; }
    public string? SkippedVersion { get; set; }

    public List<string> CategoryOrder { get; set; } = [];
    public Dictionary<string, CategoryMeta> Categories { get; set; } = new(StringComparer.OrdinalIgnoreCase);

    // ---------- Laden/Speichern ----------

    public static readonly string Folder = Migration.Pick(Environment.SpecialFolder.ApplicationData);
    private static readonly string FilePath = Path.Combine(Folder, "settings.json");

    public static readonly JsonSerializerOptions Json = new()
    {
        WriteIndented = true,
        Converters = { new JsonStringEnumConverter() },
    };

    public static AppSettings Current { get; private set; } = Load();

    public static event Action? Saved;

    private static AppSettings Load()
    {
        AppSettings s;
        try
        {
            s = File.Exists(FilePath)
                ? JsonSerializer.Deserialize<AppSettings>(File.ReadAllText(FilePath), Json) ?? new()
                : new();
        }
        catch { s = new(); }

        s.Categories = new(s.Categories ?? [], StringComparer.OrdinalIgnoreCase);
        s.Rules ??= [];
        s.CategoryOrder ??= [];

        // Übernahme der alten Einstellung aus Version 2
        var old = Path.Combine(Folder, "design.txt");
        if (File.Exists(old))
        {
            try
            {
                var v = File.ReadAllText(old).Trim();
                s.Design = v == "Light" ? DesignMode.Light : v == "Dark" ? DesignMode.Dark : DesignMode.System;
                File.Delete(old);
            }
            catch { }
        }
        return s;
    }

    public void Save()
    {
        try
        {
            Directory.CreateDirectory(Folder);
            File.WriteAllText(FilePath, JsonSerializer.Serialize(this, Json));
        }
        catch { }
        Saved?.Invoke();
    }

    public CategoryMeta Meta(string category)
    {
        if (!Categories.TryGetValue(category, out var m))
            Categories[category] = m = new CategoryMeta();
        return m;
    }

    public void RenameCategory(string oldName, string newName)
    {
        if (Categories.Remove(oldName, out var m)) Categories[newName] = m;
        for (int i = 0; i < CategoryOrder.Count; i++)
            if (string.Equals(CategoryOrder[i], oldName, StringComparison.OrdinalIgnoreCase)) CategoryOrder[i] = newName;
        foreach (var r in Rules)
            if (string.Equals(r.Category, oldName, StringComparison.OrdinalIgnoreCase)) r.Category = newName;
    }

    public void RemoveCategory(string name)
    {
        Categories.Remove(name);
        CategoryOrder.RemoveAll(n => string.Equals(n, name, StringComparison.OrdinalIgnoreCase));
        Rules.RemoveAll(r => string.Equals(r.Category, name, StringComparison.OrdinalIgnoreCase));
    }
}