using Engine.Input;

namespace PresenterConsole;

public class ConsoleInputHandler : IInputHandler
{
    private readonly HashSet<ConsoleKey> _currentKeys = [];
    private readonly HashSet<ConsoleKey> _previousKeys = [];
    private ConsoleModifiers _currentModifiers;
    private ConsoleModifiers _previousModifiers;

    public void Update(double deltaTime)
    {
        // Save previous state
        _previousKeys.Clear();
        foreach (var key in _currentKeys)
        {
            _previousKeys.Add(key);
        }

        _previousModifiers = _currentModifiers;

        // Clear current state
        _currentKeys.Clear();
        _currentModifiers = 0;

        // Read keys
        while (Console.KeyAvailable)
        {
            var keyInfo = Console.ReadKey(intercept: true);
            _currentKeys.Add(keyInfo.Key);
            _currentModifiers |= keyInfo.Modifiers;
        }
    }

    public bool IsKeyPressed(KeyCode keyCode)
    {
        if (IsModifierKey(keyCode))
            return IsModifierActive(keyCode);

        return _currentKeys.Contains(ConvertToConsoleKey(keyCode));
    }

    public bool IsKeyJustPressed(KeyCode keyCode)
    {
        if (IsModifierKey(keyCode))
            return IsModifierActive(keyCode) && !WasModifierActive(keyCode);

        var consoleKey = ConvertToConsoleKey(keyCode);
        return _currentKeys.Contains(consoleKey) && !_previousKeys.Contains(consoleKey);
    }

    public bool IsKeyRepeat(KeyCode keyCode)
    {
        if (IsModifierKey(keyCode))
            return IsModifierActive(keyCode) && WasModifierActive(keyCode);

        var consoleKey = ConvertToConsoleKey(keyCode);
        return _currentKeys.Contains(consoleKey) && _previousKeys.Contains(consoleKey);
    }

    public bool IsMouseButtonPressed(MouseButton button)
    {
        return false;
    }

    public bool IsMouseButtonJustPressed(MouseButton button)
    {
        return false;
    }

    private static bool IsModifierKey(KeyCode keyCode) => keyCode is KeyCode.Ctrl or KeyCode.Backspace or KeyCode.Shift;

    private bool IsModifierActive(KeyCode keyCode) => keyCode switch
    {
        KeyCode.Ctrl => (_currentModifiers & ConsoleModifiers.Control) != 0,
        KeyCode.Alt => (_currentModifiers & ConsoleModifiers.Alt) != 0,
        KeyCode.Shift => (_currentModifiers & ConsoleModifiers.Shift) != 0,
        _ => false
    };

    private bool WasModifierActive(KeyCode keyCode) => keyCode switch
    {
        KeyCode.Ctrl => (_previousModifiers & ConsoleModifiers.Control) != 0,
        KeyCode.Alt => (_previousModifiers & ConsoleModifiers.Alt) != 0,
        KeyCode.Shift => (_previousModifiers & ConsoleModifiers.Shift) != 0,
        _ => false
    };

    private static ConsoleKey ConvertToConsoleKey(KeyCode keyCode) => keyCode switch
    {
        KeyCode.A => ConsoleKey.A,
        KeyCode.B => ConsoleKey.B,
        KeyCode.C => ConsoleKey.C,
        KeyCode.D => ConsoleKey.D,
        KeyCode.E => ConsoleKey.E,
        KeyCode.F => ConsoleKey.F,
        KeyCode.G => ConsoleKey.G,
        KeyCode.H => ConsoleKey.H,
        KeyCode.I => ConsoleKey.I,
        KeyCode.J => ConsoleKey.J,
        KeyCode.K => ConsoleKey.K,
        KeyCode.L => ConsoleKey.L,
        KeyCode.M => ConsoleKey.M,
        KeyCode.N => ConsoleKey.N,
        KeyCode.O => ConsoleKey.O,
        KeyCode.P => ConsoleKey.P,
        KeyCode.Q => ConsoleKey.Q,
        KeyCode.R => ConsoleKey.R,
        KeyCode.S => ConsoleKey.S,
        KeyCode.T => ConsoleKey.T,
        KeyCode.U => ConsoleKey.U,
        KeyCode.V => ConsoleKey.V,
        KeyCode.W => ConsoleKey.W,
        KeyCode.X => ConsoleKey.X,
        KeyCode.Y => ConsoleKey.Y,
        KeyCode.Z => ConsoleKey.Z,
        KeyCode.Enter => ConsoleKey.Enter,
        KeyCode.Escape => ConsoleKey.Escape,
        KeyCode.Space => ConsoleKey.Spacebar,
        KeyCode.Tab => ConsoleKey.Tab,
        KeyCode.Backspace => ConsoleKey.Backspace,
        KeyCode.Up => ConsoleKey.UpArrow,
        KeyCode.Down => ConsoleKey.DownArrow,
        KeyCode.Left => ConsoleKey.LeftArrow,
        KeyCode.Right => ConsoleKey.RightArrow,
        _ => throw new ArgumentOutOfRangeException(nameof(keyCode), $"No mapping defined for {keyCode}")
    };
}