using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class RandomLook : MonoBehaviour {

	public Transform[] eyeballJoints;
	public SkinnedMeshRenderer headMesh;
	public SkinnedMeshRenderer Lashes;
	public string blinkBlendShapeName;
	[Tooltip("Eyes look target. Leave blank for random")]
	public Transform lookTarget;
	public bool randomLook = true;
	public bool eyesTrackTarget = false;
	public bool randomBlink = true;
	[Header("\tLook Settings")]
	[Tooltip("Average time between changing random look direction (s)")]
	[Range(0.5f, 10.0f)]
	public float changeLookPeriod = 3f;
	[Tooltip("Maximum random look direction angle (degrees, < 90)")]
	[Range(0f, 70.0f)]
	public float randomLookMaxAngle = 20f;
	[Tooltip("Cutoff angle for eye tracking (degrees, < 90)")]
	[Range(0f, 70.0f)]
	public float eyeTrackMaxAngle = 10f;
	[Header("\tBlink Settings")]
	[Tooltip("Average blink time (s)")]
	[Range(0.5f, 10.0f)]
	public float blinkPeriod = 3f;
	[Tooltip("Blink speed")]
	[Range(0.0f, 1.0f)]
	public float blinkSpeed = 0.7f;
	[Tooltip("Blink hold closed time")]
	[Range(0.0f, 0.2f)]
	public float blinkHoldTime = 0.03f;
	[Tooltip("Blink closed amount")]
	[Range(0.0f, 1.0f)]
	public float blinkClosedLimit = 1f;
	[Tooltip("Blink open amount")]
	[Range(0.0f, 1.0f)]
	public float blinkOpenLimit = 0f;

	public Vector3 lookAngleOffset = Vector3.zero;
	public Vector3 eyesForwardVector = Vector3.forward;


	int blinkBSindex = -1;

	float lastBlinkTime = 0;
	float lastLookChangeTime = 0;

	float blinkPeriodRandom = 0;
	float lookChangePeriodRandom = 0;

	[Header("\tControlled by script. Leave false")]
	public bool blinking = false;

	Quaternion[] EyeballStartDirection = new Quaternion[2];

	GameObject RandomLookTarget;
	GameObject EyesCenterObject;

	Transform randomLookTarget;
	

	Coroutine blinkBlendRoutine;
	Mesh m;

	// Use this for initialization
	void Start () {
		if (eyeballJoints.Length == 0)
		{
			randomLook = false;
			eyesTrackTarget = false;
		}
		else if (eyeballJoints[0] == null | eyeballJoints[1] == null)
		{
			randomLook = false;
			eyesTrackTarget = false;
		}
		else
		{
			StartCoroutine(GetStartAngles());
			
			if (!randomLook & (lookTarget != null))
				eyesTrackTarget = true;
			else if (randomLook)
			{
				InitializeRandomLook();
			}
			else
			{
				eyesTrackTarget = false;
			}
		}

		if (!string.IsNullOrEmpty(blinkBlendShapeName)){
			m = headMesh.sharedMesh;
			for (int i = 0; i < m.blendShapeCount; i++)
			{
				string s = m.GetBlendShapeName(i);
				if (m.GetBlendShapeName(i) == blinkBlendShapeName)
				{
					blinkBSindex = i;
					break;
				}
			}
			if (blinkBSindex == -1)
			{
				print("Warning: blink blendshape " + blinkBlendShapeName + " not found");
				randomBlink = false;
			}
		}
		lastBlinkTime = 0;
		blinkPeriodRandom = (Random.Range(0f, 10f) - 5f) / 5f;
		if (blinkClosedLimit < blinkOpenLimit)
			blinkClosedLimit = blinkOpenLimit;

	}
	
	// Update is called once per frame
	void FixedUpdate () {
		if (randomBlink & ((Time.time - (lastBlinkTime+blinkPeriodRandom)) > blinkPeriod))
		{
			StartBlink();
			lastBlinkTime = Time.time;
			blinkPeriodRandom = (Random.Range(0f, 10f) - 5f) / 5f;
		}
		if ((randomLook) & ((Time.time - (lastLookChangeTime + lookChangePeriodRandom)) > changeLookPeriod))
		{
			StartRandomLook();
			lastLookChangeTime = Time.time;
			lookChangePeriodRandom = (Random.Range(0f, 10f) - 5f) / 5f;
		}
		else if (eyesTrackTarget)
		{
			eyeballJoints[0].LookAt(lookTarget);
			eyeballJoints[0].Rotate(lookAngleOffset);
			eyeballJoints[1].localRotation = eyeballJoints[0].localRotation;

			float difference = Quaternion.Angle(eyeballJoints[0].localRotation*Quaternion.Euler(lookAngleOffset), EyeballStartDirection[0]);

			if (difference > eyeTrackMaxAngle)
			{
				eyeballJoints[0].localRotation = Quaternion.Lerp(EyeballStartDirection[0], eyeballJoints[0].localRotation, eyeTrackMaxAngle / difference);
				eyeballJoints[1].localRotation = eyeballJoints[0].localRotation;
			}

		}


	}

	public void StartRandomLook()
	{
		// Set new random look target position
		if (randomLookTarget == null)
			InitializeRandomLook();
		float randomTargetDistance = 1f;
		float randomTheta = Random.Range(-randomLookMaxAngle, randomLookMaxAngle) * Mathf.PI / 180f;
		float randomPhi = Random.Range(-randomLookMaxAngle, randomLookMaxAngle) * Mathf.PI / 180f;

		randomLookTarget.localPosition = new Vector3(randomTargetDistance / Mathf.Tan( Mathf.PI / 2 - randomTheta ), randomTargetDistance / Mathf.Tan(Mathf.PI / 2 - randomPhi), randomTargetDistance);
		eyeballJoints[0].LookAt(randomLookTarget);
		eyeballJoints[0].Rotate(lookAngleOffset);
		eyeballJoints[1].localRotation = eyeballJoints[0].localRotation;
	}

	void InitializeRandomLook()
	{
		eyesTrackTarget = false;
		EyesCenterObject = new GameObject("EyesCenter");
		EyesCenterObject.transform.position = (eyeballJoints[0].position + eyeballJoints[1].position) / 2;
		EyesCenterObject.transform.forward = eyesForwardVector;
		EyesCenterObject.transform.parent = eyeballJoints[0].parent;
		RandomLookTarget = new GameObject("RandomLookTarget");
		randomLookTarget = RandomLookTarget.transform;
		randomLookTarget.SetParent(EyesCenterObject.transform, true);
	}

	public void StartBlink()
	{
		if (!blinking)
		{
			blinkBlendRoutine = StartCoroutine(BlinkBlend());
		}
	}

	IEnumerator BlinkBlend()
	{		
		// Start blink animation
		blinking = true;
		float dt = Time.deltaTime;
		int steps = Mathf.RoundToInt((0.1f / (blinkSpeed*3 + 0.01f)) / dt * (blinkClosedLimit - blinkOpenLimit));
		headMesh.SetBlendShapeWeight(blinkBSindex, 0);
		Lashes.SetBlendShapeWeight(blinkBSindex, 0);
		for (int i=0; i<steps; i++)
		{
			float amount = (float)i / (float)steps * 100f;
			headMesh.SetBlendShapeWeight(blinkBSindex, amount);
			Lashes.SetBlendShapeWeight(blinkBSindex, amount);
			if (i%2==0)
				yield return new WaitForSeconds(dt);
		}
		headMesh.SetBlendShapeWeight(blinkBSindex, blinkClosedLimit*100);
		Lashes.SetBlendShapeWeight(blinkBSindex, blinkClosedLimit*100);
		yield return new WaitForSeconds(blinkHoldTime);
		for (int i = 0; i < steps; i++)
		{
			float amount = (float)i / (float)steps * 100f;
			headMesh.SetBlendShapeWeight(blinkBSindex, blinkClosedLimit*100 - amount);
			Lashes.SetBlendShapeWeight(blinkBSindex, blinkClosedLimit*100 - amount);
			if (i%2==0)
				yield return new WaitForSeconds(dt);
		}
		headMesh.SetBlendShapeWeight(blinkBSindex, 0);
		Lashes.SetBlendShapeWeight(blinkBSindex, 0);
		blinking = false;
	}

	IEnumerator GetStartAngles()
	{
		yield return new WaitForSeconds(.3f);
		EyeballStartDirection[0] = eyeballJoints[0].localRotation;
		EyeballStartDirection[1] = eyeballJoints[1].localRotation;
	}

}