/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated January 1, 2020. Replaces all prior versions.
 *
 * Copyright (c) 2013-2020, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
 * BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/

using UnityEngine;
using System.Collections;
using Spine;

namespace Spine.Unity {
	/// <summary>
	/// Use this as a condition-blocking yield instruction for Unity Coroutines.
	/// The routine will pause until the AnimationState.TrackEntry fires its End event.</summary>
	public class WaitForSpineTrackEntryEnd : IEnumerator {

		bool m_WasFired = false;

		public WaitForSpineTrackEntryEnd (Spine.TrackEntry trackEntry) {
			SafeSubscribe(trackEntry);
		}

		void HandleEnd (TrackEntry trackEntry) {
			m_WasFired = true;
		}

		void SafeSubscribe (Spine.TrackEntry trackEntry) {
			if (trackEntry == null) {
				// Break immediately if trackEntry is null.
				Debug.LogWarning("TrackEntry was null. Coroutine will continue immediately.");
				m_WasFired = true;
			} else {
				trackEntry.End += HandleEnd;
			}
		}

		#region Reuse
		/// <summary>
		/// One optimization high-frequency YieldInstruction returns is to cache instances to minimize GC pressure.
		/// Use NowWaitFor to reuse the same instance of WaitForSpineAnimationEnd.</summary>
		public WaitForSpineTrackEntryEnd NowWaitFor (Spine.TrackEntry trackEntry) {
			SafeSubscribe(trackEntry);
			return this;
		}
		#endregion

		#region IEnumerator
		bool IEnumerator.MoveNext () {
			if (m_WasFired) {
				((IEnumerator)this).Reset();	// auto-reset for YieldInstruction reuse
				return false;
			}

			return true;
		}
		void IEnumerator.Reset () { m_WasFired = false; }
		object IEnumerator.Current { get { return null; } }
		#endregion

	}

}