//========= Copyright 2015, Valve Corporation, All rights reserved. ===========
//
// Purpose: Wrapper for working with SteamVR controller input
//
// Example usage:
//
//	var deviceIndex = SteamVR_Controller.GetDeviceIndex(SteamVR_Controller.DeviceRelation.Leftmost);
//	if (deviceIndex != -1 && SteamVR_Controller.Input(deviceIndex).GetPressDown(SteamVR_Controller.ButtonMask.Trigger))
//		SteamVR_Controller.Input(deviceIndex).TriggerHapticPulse(1000);
//
//=============================================================================

using UnityEngine;
using Valve.VR;

public class SteamVR_Controller
{
	public class ButtonMask
	{
		public const ulong System			= (1ul << (int)EVRButtonId.k_EButton_System); // reserved
		public const ulong ApplicationMenu	= (1ul << (int)EVRButtonId.k_EButton_ApplicationMenu);
		public const ulong Grip				= (1ul << (int)EVRButtonId.k_EButton_Grip);
		public const ulong Axis0			= (1ul << (int)EVRButtonId.k_EButton_Axis0);
		public const ulong Axis1			= (1ul << (int)EVRButtonId.k_EButton_Axis1);
		public const ulong Axis2			= (1ul << (int)EVRButtonId.k_EButton_Axis2);
		public const ulong Axis3			= (1ul << (int)EVRButtonId.k_EButton_Axis3);
		public const ulong Axis4			= (1ul << (int)EVRButtonId.k_EButton_Axis4);
		public const ulong Touchpad			= (1ul << (int)EVRButtonId.k_EButton_SteamVR_Touchpad);
		public const ulong Trigger			= (1ul << (int)EVRButtonId.k_EButton_SteamVR_Trigger);
	}

	public class Device
	{
		public Device(uint i) { index = i; }
		public uint index { get; private set; }

		public bool valid { get; private set; }
		public bool connected { get { Update(); return pose.bDeviceIsConnected; } }
		public bool hasTracking { get { Update(); return pose.bPoseIsValid; } }

		public bool outOfRange { get { Update(); return pose.eTrackingResult == ETrackingResult.Running_OutOfRange || pose.eTrackingResult == ETrackingResult.Calibrating_OutOfRange; } }
		public bool calibrating { get { Update(); return pose.eTrackingResult == ETrackingResult.Calibrating_InProgress || pose.eTrackingResult == ETrackingResult.Calibrating_OutOfRange; } }
		public bool uninitialized { get { Update(); return pose.eTrackingResult == ETrackingResult.Uninitialized; } }

		// These values are only accurate for the last controller state change (e.g. trigger release), and by definition, will always lag behind
		// the predicted visual poses that drive SteamVR_TrackedObjects since they are sync'd to the input timestamp that caused them to update.
		public SteamVR_Utils.RigidTransform transform { get { Update(); return new SteamVR_Utils.RigidTransform(pose.mDeviceToAbsoluteTracking); } }
		public Vector3 velocity { get { Update(); return new Vector3(pose.vVelocity.v0, pose.vVelocity.v1, -pose.vVelocity.v2); } }
		public Vector3 angularVelocity { get { Update(); return new Vector3(-pose.vAngularVelocity.v0, -pose.vAngularVelocity.v1, pose.vAngularVelocity.v2); } }

		public VRControllerState_t GetState() { Update(); return state; }
		public VRControllerState_t GetPrevState() { Update(); return prevState; }
		public TrackedDevicePose_t GetPose() { Update(); return pose; }

		VRControllerState_t state, prevState;
		TrackedDevicePose_t pose;
		int prevFrameCount = -1;
		public void Update()
		{
			if (Time.frameCount != prevFrameCount)
			{
				prevFrameCount = Time.frameCount;
				prevState = state;

				var system = OpenVR.System;
				if (system != null)
				{
					valid = system.GetControllerStateWithPose(SteamVR_Render.instance.trackingSpace, index, ref state, ref pose);
					UpdateHairTrigger();
				}
			}
		}

		public bool GetPress(ulong buttonMask) { Update(); return (state.ulButtonPressed & buttonMask) != 0; }
		public bool GetPressDown(ulong buttonMask) { Update(); return (state.ulButtonPressed & buttonMask) != 0 && (prevState.ulButtonPressed & buttonMask) == 0; }
		public bool GetPressUp(ulong buttonMask) { Update(); return (state.ulButtonPressed & buttonMask) == 0 && (prevState.ulButtonPressed & buttonMask) != 0; }

		public bool GetPress(EVRButtonId buttonId) { return GetPress(1ul << (int)buttonId); }
		public bool GetPressDown(EVRButtonId buttonId) { return GetPressDown(1ul << (int)buttonId); }
		public bool GetPressUp(EVRButtonId buttonId) { return GetPressUp(1ul << (int)buttonId); }

		public bool GetTouch(ulong buttonMask) { Update(); return (state.ulButtonTouched & buttonMask) != 0; }
		public bool GetTouchDown(ulong buttonMask) { Update(); return (state.ulButtonTouched & buttonMask) != 0 && (prevState.ulButtonTouched & buttonMask) == 0; }
		public bool GetTouchUp(ulong buttonMask) { Update(); return (state.ulButtonTouched & buttonMask) == 0 && (prevState.ulButtonTouched & buttonMask) != 0; }

		public bool GetTouch(EVRButtonId buttonId) { return GetTouch(1ul << (int)buttonId); }
		public bool GetTouchDown(EVRButtonId buttonId) { return GetTouchDown(1ul << (int)buttonId); }
		public bool GetTouchUp(EVRButtonId buttonId) { return GetTouchUp(1ul << (int)buttonId); }

		public Vector2 GetAxis(EVRButtonId buttonId = EVRButtonId.k_EButton_SteamVR_Touchpad)
		{
			Update();
			var axisId = (uint)buttonId - (uint)EVRButtonId.k_EButton_Axis0;
			switch (axisId)
			{
				case 0: return new Vector2(state.rAxis0.x, state.rAxis0.y);
				case 1: return new Vector2(state.rAxis1.x, state.rAxis1.y);
				case 2: return new Vector2(state.rAxis2.x, state.rAxis2.y);
				case 3: return new Vector2(state.rAxis3.x, state.rAxis3.y);
				case 4: return new Vector2(state.rAxis4.x, state.rAxis4.y);
			}
			return Vector2.zero;
		}

		public void TriggerHapticPulse(ushort durationMicroSec = 500, EVRButtonId buttonId = EVRButtonId.k_EButton_SteamVR_Touchpad)
		{
			var system = OpenVR.System;
			if (system != null)
			{
				var axisId = (uint)buttonId - (uint)EVRButtonId.k_EButton_Axis0;
				system.TriggerHapticPulse(index, axisId, (char)durationMicroSec);
			}
		}

		public float hairTriggerDelta = 0.1f; // amount trigger must be pulled or released to change state
		float hairTriggerLimit;
		bool hairTriggerState, hairTriggerPrevState;
		void UpdateHairTrigger()
		{
			hairTriggerPrevState = hairTriggerState;
			var value = state.rAxis1.x; // trigger
			if (hairTriggerState)
			{
				if (value < hairTriggerLimit - hairTriggerDelta || value <= 0.0f)
					hairTriggerState = false;
			}
			else
			{
				if (value > hairTriggerLimit + hairTriggerDelta || value >= 1.0f)
					hairTriggerState = true;
			}
			hairTriggerLimit = hairTriggerState ? Mathf.Max(hairTriggerLimit, value) : Mathf.Min(hairTriggerLimit, value);
		}

		public bool GetHairTrigger() { Update(); return hairTriggerState; }
		public bool GetHairTriggerDown() { Update(); return hairTriggerState && !hairTriggerPrevState; }
		public bool GetHairTriggerUp() { Update(); return !hairTriggerState && hairTriggerPrevState; }
	}

	private static Device[] devices;

	public static Device Input(int deviceIndex)
	{
		if (devices == null)
		{
			devices = new Device[OpenVR.k_unMaxTrackedDeviceCount];
			for (uint i = 0; i < devices.Length; i++)
				devices[i] = new Device(i);
		}

		return devices[deviceIndex];
	}

	public static void Update()
	{
		for (int i = 0; i < OpenVR.k_unMaxTrackedDeviceCount; i++)
			Input(i).Update();
	}

	// This helper can be used in a variety of ways.  Beware that indices may change
	// as new devices are dynamically added or removed, controllers are physically
	// swapped between hands, arms crossed, etc.
	public enum DeviceRelation
	{
		First,
		// radially
		Leftmost,
		Rightmost,
		// distance - also see vr.hmd.GetSortedTrackedDeviceIndicesOfClass
		FarthestLeft,
		FarthestRight,
	}
	public static int GetDeviceIndex(DeviceRelation relation,
		ETrackedDeviceClass deviceClass = ETrackedDeviceClass.Controller,
		int relativeTo = (int)OpenVR.k_unTrackedDeviceIndex_Hmd) // use -1 for absolute tracking space
	{
		var result = -1;

		var invXform = ((uint)relativeTo < OpenVR.k_unMaxTrackedDeviceCount) ?
			Input(relativeTo).transform.GetInverse() : SteamVR_Utils.RigidTransform.identity;

		var system = OpenVR.System;
		if (system == null)
			return result;

		var best = -float.MaxValue;
		for (int i = 0; i < OpenVR.k_unMaxTrackedDeviceCount; i++)
		{
			if (i == relativeTo || system.GetTrackedDeviceClass((uint)i) != deviceClass)
				continue;

			var device = Input(i);
			if (!device.connected)
				continue;

			if (relation == DeviceRelation.First)
				return i;

			float score;

			var pos = invXform * device.transform.pos;
			if (relation == DeviceRelation.FarthestRight)
			{
				score = pos.x;
			}
			else if (relation == DeviceRelation.FarthestLeft)
			{
				score = -pos.x;
			}
			else
			{
				var dir = new Vector3(pos.x, 0.0f, pos.z).normalized;
				var dot = Vector3.Dot(dir, Vector3.forward);
				var cross = Vector3.Cross(dir, Vector3.forward);
				if (relation == DeviceRelation.Leftmost)
				{
					score = (cross.y > 0.0f) ? 2.0f - dot : dot;
				}
				else
				{
					score = (cross.y < 0.0f) ? 2.0f - dot : dot;
				}
			}
			
			if (score > best)
			{
				result = i;
				best = score;
			}
		}

		return result;
	}
}

