/************************************************************************************

Copyright (c) Facebook Technologies, LLC and its affiliates. All rights reserved.  

See SampleFramework license.txt for license terms.  Unless required by applicable law 
or agreed to in writing, the sample code is provided “AS IS” WITHOUT WARRANTIES OR 
CONDITIONS OF ANY KIND, either express or implied.  See the license for specific 
language governing permissions and limitations under the license.

************************************************************************************/

using System.Collections;
using UnityEngine;
using UnityEngine.Assertions;

namespace OculusSampleFramework
{
	public class WindmillBladesController : MonoBehaviour
	{
		private const float MAX_TIME = 1f;

		[SerializeField] private AudioSource _audioSource = null;
		[SerializeField] private AudioClip _windMillRotationSound = null;
		[SerializeField] private AudioClip _windMillStartSound = null;
		[SerializeField] private AudioClip _windMillStopSound = null;

		public bool IsMoving { get; private set; }

		private float _currentSpeed = 0f;
		private Coroutine _lerpSpeedCoroutine;
		private Coroutine _audioChangeCr;
		private Quaternion _originalRotation;
		private float _rotAngle = 0.0f;

		private void Start()
		{
			Assert.IsNotNull(_audioSource);
			Assert.IsNotNull(_windMillRotationSound);
			Assert.IsNotNull(_windMillStartSound);
			Assert.IsNotNull(_windMillStopSound);

			_originalRotation = transform.localRotation;
		}

		private void Update()
		{
			_rotAngle += _currentSpeed * Time.deltaTime;
			if (_rotAngle > 360.0f)
			{
				_rotAngle = 0.0f;
			}

			transform.localRotation = _originalRotation * Quaternion.AngleAxis(_rotAngle, Vector3.forward);
		}

		public void SetMoveState(bool newMoveState, float goalSpeed)
		{
			IsMoving = newMoveState;
			if (_lerpSpeedCoroutine != null)
			{
				StopCoroutine(_lerpSpeedCoroutine);
			}
			_lerpSpeedCoroutine = StartCoroutine(LerpToSpeed(goalSpeed));
		}

		private IEnumerator LerpToSpeed(float goalSpeed)
		{
			var totalTime = 0f;
			var startSpeed = _currentSpeed;

			if (_audioChangeCr != null)
			{
				StopCoroutine(_audioChangeCr);
			}

			// start up
			if (IsMoving)
			{
				_audioChangeCr = StartCoroutine(PlaySoundDelayed(_windMillStartSound,
				  _windMillRotationSound, _windMillStartSound.length * 0.95f));
			} // stop
			else
			{
				PlaySound(_windMillStopSound);
			}

			var diffSpeeds = Mathf.Abs(_currentSpeed - goalSpeed);
			while (diffSpeeds > Mathf.Epsilon)
			{
				_currentSpeed = Mathf.Lerp(startSpeed, goalSpeed, totalTime / MAX_TIME);
				totalTime += Time.deltaTime;
				yield return null;
				diffSpeeds = Mathf.Abs(_currentSpeed - goalSpeed);
			}

			_lerpSpeedCoroutine = null;
		}

		private IEnumerator PlaySoundDelayed(AudioClip initial, AudioClip clip, float timeDelayAfterInitial)
		{
			PlaySound(initial, false);
			yield return new WaitForSeconds(timeDelayAfterInitial);
			PlaySound(clip, true);
		}

		private void PlaySound(AudioClip clip, bool loop = false)
		{
			_audioSource.loop = loop;
			_audioSource.timeSamples = 0;
			_audioSource.clip = clip;
			_audioSource.Play();
		}
	}
}