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

namespace ClipForge
{
    /// <summary>Converts between hotkey modifier/vk and display strings.</summary>
    public static class HotkeyHelper
    {
        public const uint MOD_ALT = 0x0001;
        public const uint MOD_CONTROL = 0x0002;
        public const uint MOD_SHIFT = 0x0004;
        public const uint MOD_WIN = 0x0008;
        public const uint MOD_NOREPEAT = 0x4000;

        private static readonly Dictionary<VirtualKey, string> KeyNames = new()
        {
            { VirtualKey.LeftButton, "LMB" },
            { VirtualKey.RightButton, "RMB" },
            { VirtualKey.Cancel, "Cancel" },
            { VirtualKey.Back, "Backspace" },
            { VirtualKey.Tab, "Tab" },
            { VirtualKey.Clear, "Clear" },
            { VirtualKey.Enter, "Enter" },
            { VirtualKey.Shift, "Shift" },
            { VirtualKey.Control, "Ctrl" },
            { VirtualKey.Menu, "Alt" },
            { VirtualKey.Pause, "Pause" },
            { VirtualKey.CapitalLock, "Caps Lock" },
            { VirtualKey.Kana, "Kana" },
            { VirtualKey.Hangul, "Hangul" },
            { VirtualKey.Junja, "Junja" },
            { VirtualKey.Final, "Final" },
            { VirtualKey.Hanja, "Hanja" },
            { VirtualKey.Kanji, "Kanji" },
            { VirtualKey.Escape, "Escape" },
            { VirtualKey.Convert, "Convert" },
            { VirtualKey.NonConvert, "NonConvert" },
            { VirtualKey.Accept, "Accept" },
            { VirtualKey.ModeChange, "ModeChange" },
            { VirtualKey.Space, "Space" },
            { VirtualKey.PageUp, "PgUp" },
            { VirtualKey.PageDown, "PgDn" },
            { VirtualKey.End, "End" },
            { VirtualKey.Home, "Home" },
            { VirtualKey.Left, "Left" },
            { VirtualKey.Up, "Up" },
            { VirtualKey.Right, "Right" },
            { VirtualKey.Down, "Down" },
            { VirtualKey.Select, "Select" },
            { VirtualKey.Print, "Print" },
            { VirtualKey.Execute, "Execute" },
            { VirtualKey.Snapshot, "Print Screen" },
            { VirtualKey.Insert, "Insert" },
            { VirtualKey.Delete, "Delete" },
            { VirtualKey.Help, "Help" },
            { VirtualKey.Number0, "0" },
            { VirtualKey.Number1, "1" },
            { VirtualKey.Number2, "2" },
            { VirtualKey.Number3, "3" },
            { VirtualKey.Number4, "4" },
            { VirtualKey.Number5, "5" },
            { VirtualKey.Number6, "6" },
            { VirtualKey.Number7, "7" },
            { VirtualKey.Number8, "8" },
            { VirtualKey.Number9, "9" },
            { VirtualKey.A, "A" },
            { VirtualKey.B, "B" },
            { VirtualKey.C, "C" },
            { VirtualKey.D, "D" },
            { VirtualKey.E, "E" },
            { VirtualKey.F, "F" },
            { VirtualKey.G, "G" },
            { VirtualKey.H, "H" },
            { VirtualKey.I, "I" },
            { VirtualKey.J, "J" },
            { VirtualKey.K, "K" },
            { VirtualKey.L, "L" },
            { VirtualKey.M, "M" },
            { VirtualKey.N, "N" },
            { VirtualKey.O, "O" },
            { VirtualKey.P, "P" },
            { VirtualKey.Q, "Q" },
            { VirtualKey.R, "R" },
            { VirtualKey.S, "S" },
            { VirtualKey.T, "T" },
            { VirtualKey.U, "U" },
            { VirtualKey.V, "V" },
            { VirtualKey.W, "W" },
            { VirtualKey.X, "X" },
            { VirtualKey.Y, "Y" },
            { VirtualKey.Z, "Z" },
            { VirtualKey.LeftWindows, "Win" },
            { VirtualKey.RightWindows, "Win" },
            { VirtualKey.Application, "App" },
            { VirtualKey.Sleep, "Sleep" },
            { VirtualKey.NumberPad0, "Num 0" },
            { VirtualKey.NumberPad1, "Num 1" },
            { VirtualKey.NumberPad2, "Num 2" },
            { VirtualKey.NumberPad3, "Num 3" },
            { VirtualKey.NumberPad4, "Num 4" },
            { VirtualKey.NumberPad5, "Num 5" },
            { VirtualKey.NumberPad6, "Num 6" },
            { VirtualKey.NumberPad7, "Num 7" },
            { VirtualKey.NumberPad8, "Num 8" },
            { VirtualKey.NumberPad9, "Num 9" },
            { VirtualKey.Multiply, "Num *" },
            { VirtualKey.Add, "Num +" },
            { VirtualKey.Separator, "Num ," },
            { VirtualKey.Subtract, "Num -" },
            { VirtualKey.Decimal, "Num ." },
            { VirtualKey.Divide, "Num /" },
            { VirtualKey.F1, "F1" },
            { VirtualKey.F2, "F2" },
            { VirtualKey.F3, "F3" },
            { VirtualKey.F4, "F4" },
            { VirtualKey.F5, "F5" },
            { VirtualKey.F6, "F6" },
            { VirtualKey.F7, "F7" },
            { VirtualKey.F8, "F8" },
            { VirtualKey.F9, "F9" },
            { VirtualKey.F10, "F10" },
            { VirtualKey.F11, "F11" },
            { VirtualKey.F12, "F12" },
            { VirtualKey.F13, "F13" },
            { VirtualKey.F14, "F14" },
            { VirtualKey.F15, "F15" },
            { VirtualKey.F16, "F16" },
            { VirtualKey.F17, "F17" },
            { VirtualKey.F18, "F18" },
            { VirtualKey.F19, "F19" },
            { VirtualKey.F20, "F20" },
            { VirtualKey.F21, "F21" },
            { VirtualKey.F22, "F22" },
            { VirtualKey.F23, "F23" },
            { VirtualKey.F24, "F24" },
            { VirtualKey.NumberKeyLock, "NumLock" },
            { VirtualKey.Scroll, "Scroll Lock" },
            { VirtualKey.LeftShift, "Shift" },
            { VirtualKey.RightShift, "Shift" },
            { VirtualKey.LeftControl, "Ctrl" },
            { VirtualKey.RightControl, "Ctrl" },
            { VirtualKey.LeftMenu, "Alt" },
            { VirtualKey.RightMenu, "Alt" },
        };

        /// <summary>Format modifier flags + virtual key as display string (e.g. "Alt + PgUp").</summary>
        public static string ToDisplayString(uint modifiers, uint vk)
        {
            var parts = new List<string>();
            if ((modifiers & MOD_WIN) != 0) parts.Add("Win");
            if ((modifiers & MOD_CONTROL) != 0) parts.Add("Ctrl");
            if ((modifiers & MOD_ALT) != 0) parts.Add("Alt");
            if ((modifiers & MOD_SHIFT) != 0) parts.Add("Shift");
            var keyName = GetKeyName((VirtualKey)vk);
            if (!string.IsNullOrEmpty(keyName))
                parts.Add(keyName);
            return parts.Count > 0 ? string.Join(" + ", parts) : "None";
        }

        public static string GetKeyName(VirtualKey key)
        {
            return KeyNames.TryGetValue(key, out var name) ? name : key.ToString();
        }

        /// <summary>True if the key is typically used only as a modifier (don't use as sole key).</summary>
        public static bool IsModifierKey(VirtualKey key)
        {
            return key == VirtualKey.LeftWindows || key == VirtualKey.RightWindows
                || key == VirtualKey.Control || key == VirtualKey.LeftControl || key == VirtualKey.RightControl
                || key == VirtualKey.Menu || key == VirtualKey.LeftMenu || key == VirtualKey.RightMenu
                || key == VirtualKey.Shift || key == VirtualKey.LeftShift || key == VirtualKey.RightShift;
        }
    }
}