using WindowsInput;

namespace SteamController.Devices
{
    public class KeyboardController : IDisposable
    {
        public static readonly TimeSpan FirstRepeat = TimeSpan.FromMilliseconds(400);
        public static readonly TimeSpan NextRepeats = TimeSpan.FromMilliseconds(45);

        InputSimulator simulator = new InputSimulator();

        Dictionary<VirtualKeyCode, DateTime> keyCodes = new Dictionary<VirtualKeyCode, DateTime>();
        Dictionary<VirtualKeyCode, DateTime> lastKeyCodes = new Dictionary<VirtualKeyCode, DateTime>();

        public KeyboardController()
        {
        }

        public void Dispose()
        {
        }

        public bool this[System.Windows.Forms.Keys key]
        {
            get
            {
                if (key.HasFlag(System.Windows.Forms.Keys.Shift) && !this[VirtualKeyCode.SHIFT])
                    return false;
                if (key.HasFlag(System.Windows.Forms.Keys.Alt) && !this[VirtualKeyCode.MENU])
                    return false;
                if (key.HasFlag(System.Windows.Forms.Keys.Control) && !this[VirtualKeyCode.CONTROL])
                    return false;
                return this[(VirtualKeyCode)(key & System.Windows.Forms.Keys.KeyCode)];
            }
            set
            {
                if (value)
                {
                    this[VirtualKeyCode.SHIFT] = key.HasFlag(System.Windows.Forms.Keys.Shift);
                    this[VirtualKeyCode.MENU] = key.HasFlag(System.Windows.Forms.Keys.Alt);
                    this[VirtualKeyCode.CONTROL] = key.HasFlag(System.Windows.Forms.Keys.Control);
                    this[(VirtualKeyCode)(key & System.Windows.Forms.Keys.KeyCode)] = true;
                }
            }
        }

        public bool this[VirtualKeyCode key]
        {
            get { return keyCodes.ContainsKey(key); }
            set
            {
                if (key == VirtualKeyCode.None)
                    return;

                if (value)
                {
                    if (keyCodes.ContainsKey(key))
                        return;
                    if (!lastKeyCodes.TryGetValue(key, out var keyRepeat))
                        keyRepeat = DateTime.Now.Add(FirstRepeat);
                    keyCodes.Add(key, keyRepeat);
                }
            }
        }

        public VirtualKeyCode[] DownKeys
        {
            get { return keyCodes.Keys.ToArray(); }
        }

        internal void BeforeUpdate()
        {
            lastKeyCodes = keyCodes;
            keyCodes = new Dictionary<VirtualKeyCode, DateTime>();
        }

        private void Safe(Action action)
        {
            try
            {
                action();

                Managers.SASManager.Valid = true;
            }
            catch (InvalidOperationException)
            {
                Managers.SASManager.Valid = false;
            }
        }

        internal void Update()
        {
            // Key Up: it is missing now
            foreach (var keyUp in lastKeyCodes.Except(keyCodes))
            {
                Safe(() => simulator.Keyboard.KeyUp(keyUp.Key));
            }

            // Key Down: new keys being down
            foreach (var keyDown in keyCodes.Except(lastKeyCodes))
            {
                Safe(() => simulator.Keyboard.KeyDown(keyDown.Key));
            }

            // Key Repeats
            var now = DateTime.Now;
            foreach (var keyPress in keyCodes)
            {
                if (keyPress.Value > now)
                    continue;

                Safe(() => simulator.Keyboard.KeyPress(keyPress.Key));
                keyCodes[keyPress.Key] = DateTime.Now.Add(NextRepeats);
            }
        }

        public void Overwrite(VirtualKeyCode key, bool value)
        {
            if (value)
                this[key] = true;
            else
                keyCodes.Remove(key);
        }

        public void KeyPress(params VirtualKeyCode[] keyCodes)
        {
            Safe(() => simulator.Keyboard.KeyPress(keyCodes));
        }

        public void KeyPress(VirtualKeyCode modifierKey, params VirtualKeyCode[] keyCodes)
        {
            Safe(() => simulator.Keyboard.ModifiedKeyStroke(modifierKey, keyCodes));
        }

        public void KeyPress(IEnumerable<VirtualKeyCode> modifierKeys, params VirtualKeyCode[] keyCodes)
        {
            Safe(() => simulator.Keyboard.ModifiedKeyStroke(modifierKeys, keyCodes));
        }
    }
}