using System;
using System.Collections.Generic;
using System.Windows.Input;

namespace ytLive.Services;

/// <summary>
/// A modifier+key chord (e.g. Ctrl+F10, Alt+F1, F5).
/// Stored in the Settings table as "modifiers+vk" (both uint, decimal).
/// </summary>
public sealed record HotkeyChord(uint Modifiers, uint VirtualKey)
{
    public const uint MOD_ALT     = 0x0001;
    public const uint MOD_CONTROL = 0x0002;
    public const uint MOD_SHIFT   = 0x0004;
    public const uint MOD_WIN     = 0x0008;

    private static readonly Dictionary<uint, string> ModifierDisplay = new()
    {
        [MOD_CONTROL] = "Ctrl",
        [MOD_ALT]     = "Alt",
        [MOD_SHIFT]   = "Shift",
        [MOD_WIN]     = "Win",
    };

    /// <summary>Storage format: "modifiers+vk" (both decimal uint).</summary>
    public override string ToString() => $"{Modifiers}+{VirtualKey}";

    /// <summary>Parse from storage format ("modifiers+vk").</summary>
    public static HotkeyChord ParseStorage(string s)
    {
        var parts = s.Split('+');
        if (parts.Length != 2 ||
            !uint.TryParse(parts[0], out var mod) ||
            !uint.TryParse(parts[1], out var vk))
            throw new FormatException($"Invalid hotkey storage format: {s}");
        return new HotkeyChord(mod, vk);
    }

    /// <summary>Build from WPF Key + ModifierKeys (used during key capture).</summary>
    public static HotkeyChord FromWpf(Key key, ModifierKeys modifiers)
    {
        uint vk = (uint)KeyInterop.VirtualKeyFromKey(key);
        uint mod = 0;
        if (modifiers.HasFlag(ModifierKeys.Control)) mod |= MOD_CONTROL;
        if (modifiers.HasFlag(ModifierKeys.Alt))     mod |= MOD_ALT;
        if (modifiers.HasFlag(ModifierKeys.Shift))   mod |= MOD_SHIFT;
        if (modifiers.HasFlag(ModifierKeys.Windows))  mod |= MOD_WIN;
        return new HotkeyChord(mod, vk);
    }

    /// <summary>Human-readable display string: "Ctrl+F10", "Alt+F1", "F5".</summary>
    public string ToDisplayString()
    {
        var name = GetKeyName(VirtualKey);
        if (Modifiers == 0) return name;

        var sb = new System.Text.StringBuilder();
        if ((Modifiers & MOD_CONTROL) != 0) { sb.Append("Ctrl"); sb.Append('+'); }
        if ((Modifiers & MOD_ALT)     != 0) { sb.Append("Alt");  sb.Append('+'); }
        if ((Modifiers & MOD_SHIFT)   != 0) { sb.Append("Shift"); sb.Append('+'); }
        if ((Modifiers & MOD_WIN)     != 0) { sb.Append("Win");  sb.Append('+'); }
        sb.Append(name);
        return sb.ToString();
    }

    /// <summary>Human-readable display string for a binding that may be null (unbound).</summary>
    public static string DisplayString(HotkeyChord? chord) =>
        chord?.ToDisplayString() ?? "None";

    private static string GetKeyName(uint vk) =>
        KeyNames.TryGetValue(vk, out var name) ? name : $"VK 0x{vk:X2}";

    private static readonly Dictionary<uint, string> KeyNames = new()
    {
        // Letters A-Z (0x41-0x5A)
        [0x41]="A",[0x42]="B",[0x43]="C",[0x44]="D",[0x45]="E",
        [0x46]="F",[0x47]="G",[0x48]="H",[0x49]="I",[0x4A]="J",
        [0x4B]="K",[0x4C]="L",[0x4D]="M",[0x4E]="N",[0x4F]="O",
        [0x50]="P",[0x51]="Q",[0x52]="R",[0x53]="S",[0x54]="T",
        [0x55]="U",[0x56]="V",[0x57]="W",[0x58]="X",[0x59]="Y",
        [0x5A]="Z",
        // Digits 0-9 (0x30-0x39)
        [0x30]="0",[0x31]="1",[0x32]="2",[0x33]="3",[0x34]="4",
        [0x35]="5",[0x36]="6",[0x37]="7",[0x38]="8",[0x39]="9",
        // Function keys F1-F24 (0x70-0x87)
        [0x70]="F1",[0x71]="F2",[0x72]="F3",[0x73]="F4",[0x74]="F5",
        [0x75]="F6",[0x76]="F7",[0x77]="F8",[0x78]="F9",[0x79]="F10",
        [0x7A]="F11",[0x7B]="F12",[0x7C]="F13",[0x7D]="F14",
        [0x7E]="F15",[0x7F]="F16",[0x80]="F17",[0x81]="F18",
        [0x82]="F19",[0x83]="F20",[0x84]="F21",[0x85]="F22",
        [0x86]="F23",[0x87]="F24",
        // Navigation
        [0x08]="Bksp",[0x09]="Tab",[0x0D]="Enter",[0x13]="Pause",
        [0x14]="CapsLock",[0x1B]="Esc",[0x20]="Space",[0x21]="PgUp",
        [0x22]="PgDn",[0x23]="End",[0x24]="Home",[0x25]="←",
        [0x26]="↑",[0x27]="→",[0x28]="↓",[0x2C]="PrintScreen",
        [0x2D]="Insert",[0x2E]="Delete",
        // Numpad
        [0x60]="Num0",[0x61]="Num1",[0x62]="Num2",[0x63]="Num3",
        [0x64]="Num4",[0x65]="Num5",[0x66]="Num6",[0x67]="Num7",
        [0x68]="Num8",[0x69]="Num9",[0x6A]="*",[0x6B]="+",
        [0x6C]=".",[0x6D]="-",[0x6E]=".",[0x6F]="/",
        [0x90]="NumLock",[0x91]="ScrollLock",
        // Punctuation / symbols
        [0xBA]=";",[0xBB]="=",[0xBC]=",",[0xBD]="-",[0xBE]=".",
        [0xBF]="/",[0xC0]="`",[0xDB]="[",[0xDC]="\\",
        [0xDD]="]",[0xDE]="'",
        // Media / browser / apps
        [0xA0]="LShift",[0xA1]="RShift",
        [0xA2]="LCtrl",[0xA3]="RCtrl",
        [0xA4]="LAlt",[0xA5]="RAlt",
        [0xAD]="Mute",[0xAE]="VolDown",[0xAF]="VolUp",
        [0xB0]="Next",[0xB1]="Prev",[0xB3]="Stop",[0xB5]="Play",
        [0xE2]="OEM_102",
    };
}