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

Your use of this SDK or tool is subject to the Oculus SDK License Agreement, available at
https://developer.oculus.com/licenses/oculussdk/

Unless required by applicable law or agreed to in writing, the Utilities SDK distributed
under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
ANY KIND, either express or implied. See the License for the specific language governing
permissions and limitations under the License.
************************************************************************************/

using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.Events;

namespace Oculus.Interaction.Samples
{
    /// <summary>
    /// Performs a callback after a countdown timer has elapsed.
    /// The countdown can be enabled or disabled by an external party.
    /// </summary>
    public class CountdownTimer : MonoBehaviour
    {
        [SerializeField]
        private float _countdownTime = 1.0f;

        [SerializeField]
        private bool _countdownOn = false;

        [SerializeField]
        private UnityEvent _callback;

        [SerializeField]
        private UnityEvent<float> _progressCallback;

        private float _countdownTimer;


        public bool CountdownOn
        {
            get => _countdownOn;

            set
            {
                if (value)
                {
                    if (!_countdownOn)
                    {
                        _countdownTimer = _countdownTime;
                    }
                }

                _countdownOn = value;
            }
        }

        private void Awake()
        {
            Assert.IsTrue(_countdownTime >= 0, "Countdown Time must be positive.");
        }

        private void Update()
        {
            if (!_countdownOn || _countdownTimer < 0)
            {
                _progressCallback.Invoke(0);
                return;
            }

            _countdownTimer -= Time.deltaTime;
            if (_countdownTimer < 0f)
            {
                _countdownTimer = -1f;
                _callback.Invoke();
                _progressCallback.Invoke(1);
                return;
            }

            _progressCallback.Invoke(1 - _countdownTimer / _countdownTime);
        }
    }
}