using Midi;
using System;
using System.Collections.Generic;
using System.Linq;

namespace IntelOrca.Launchpad
{
    public enum ToolbarButton { Up, Down, Left, Right, Session, User1, User2, Mixer }
    public enum SideButton { Volume, Pan, SoundA, SoundB, Stop, TrackOn, Solo, Arm }

    public class LaunchpadDevice
    {
        private InputDevice mInputDevice;
        private OutputDevice mOutputDevice;

        private bool mDoubleBuffered;
        private bool mDoubleBufferedState;

        private readonly LaunchpadButton[] mToolbar = new LaunchpadButton[8];
        private readonly LaunchpadButton[] mSide = new LaunchpadButton[8];
        private readonly LaunchpadButton[,] mGrid = new LaunchpadButton[8, 8];

        public event EventHandler<ButtonPressEventArgs> ButtonPressed;

        public LaunchpadDevice() : this(0) { }

        public LaunchpadDevice(int index)
        {
            InitialiseButtons();

            int i = 0;
            mInputDevice = InputDevice.InstalledDevices.Where(x => x.Name.Contains("Launchpad")).
                FirstOrDefault(x => i++ == index);
            i = 0;
            mOutputDevice = OutputDevice.InstalledDevices.Where(x => x.Name.Contains("Launchpad")).
                FirstOrDefault(x => i++ == index);

            if (mInputDevice == null)
                throw new LaunchpadException("Unable to find input device.");
            if (mOutputDevice == null)
                throw new LaunchpadException("Unable to find output device.");

            mInputDevice.Open();
            mOutputDevice.Open();

            mInputDevice.StartReceiving(new Clock(120));
            mInputDevice.NoteOn += mInputDevice_NoteOn;
            mInputDevice.ControlChange += mInputDevice_ControlChange;

            Reset();
        }
                

        private void InitialiseButtons()
        {
            for (int i = 0; i < 8; i++)
            {
                mToolbar[i] = new LaunchpadButton(this, ButtonType.Toolbar, 104 + i);
                mSide[i] = new LaunchpadButton(this, ButtonType.Side, i * 16 + 8);
            }

            for (int y = 0; y < 8; y++)
                for (int x = 0; x < 8; x++)
                    mGrid[x, y] = new LaunchpadButton(this, ButtonType.Grid, y * 16 + x);
        }

        private void StartDoubleBuffering()
        {
            mDoubleBuffered = true;
            mDoubleBufferedState = false;
            mOutputDevice.SendControlChange(Channel.Channel1, (Control)0, 32 | 16 | 1);
        }

        public void Refresh()
        {
            if (!mDoubleBufferedState)
                mOutputDevice.SendControlChange(Channel.Channel1, (Control)0, 32 | 16 | 4);
            else
                mOutputDevice.SendControlChange(Channel.Channel1, (Control)0, 32 | 16 | 1);
            mDoubleBufferedState = !mDoubleBufferedState;
        }

        private void EndDoubleBuffering()
        {
            mOutputDevice.SendControlChange(Channel.Channel1, (Control)0, 32 | 16);
            mDoubleBuffered = false;
        }

        public void Reset()
        {
            mOutputDevice.SendControlChange(Channel.Channel1, (Control)0, 0);
            Buttons.ToList().ForEach(x => x.RedBrightness = x.GreenBrightness = ButtonBrightness.Off);
        }

        private void mInputDevice_NoteOn(NoteOnMessage msg)
        {
            LaunchpadButton button = GetButton(msg.Pitch);
            if (button == null)
                return;

            button.State = (ButtonPressState)msg.Velocity;

            if (ButtonPressed != null && button.State == ButtonPressState.Down)
            {
                if ((int)msg.Pitch % 16 == 8)
                    ButtonPressed.Invoke(this, new ButtonPressEventArgs((SideButton)((int)msg.Pitch / 16)));
                else
                    ButtonPressed.Invoke(this, new ButtonPressEventArgs((int)msg.Pitch % 16, (int)msg.Pitch / 16));
            }
        }

        private void mInputDevice_ControlChange(ControlChangeMessage msg)
        {
            ToolbarButton toolbarButton = (ToolbarButton)((int)msg.Control - 104);

            LaunchpadButton button = GetButton(toolbarButton);
            if (button == null)
                return;

            button.State = (ButtonPressState)msg.Value;
            if (ButtonPressed != null && button.State == ButtonPressState.Down)
            {
                ButtonPressed.Invoke(this, new ButtonPressEventArgs(toolbarButton));
            }
        }

        public LaunchpadButton GetButton(ToolbarButton toolbarButton)
        {
            return mToolbar[(int)toolbarButton];
        }

        public LaunchpadButton GetButton(SideButton sideButton)
        {
            return mSide[(int)sideButton];
        }

        private LaunchpadButton GetButton(Pitch pitch)
        {
            int x = (int)pitch % 16;
            int y = (int)pitch / 16;
            if (x < 8 && y < 8)
                return mGrid[x, y];
            else if (x == 8 && y < 8)
                return mSide[y];

            return null;
        }

        public bool DoubleBuffered
        {
            get { return mDoubleBuffered; }
            set
            {
                if (mDoubleBuffered)
                    EndDoubleBuffering();
                else
                    StartDoubleBuffering();
            }
        }

        public LaunchpadButton this[int x, int y]
        {
            get { return mGrid[x, y]; }
        }

        public IEnumerable<LaunchpadButton> Buttons
        {
            get
            {
                for (int y = 0; y < 8; y++)
                    for (int x = 0; x < 8; x++)
                        yield return mGrid[x, y];
            }
        }

        internal OutputDevice OutputDevice
        {
            get { return mOutputDevice; }
        }
    }
}