/******************************************************************************
 * Spine Runtimes Software License v2.5
 *
 * Copyright (c) 2013-2016, Esoteric Software
 * All rights reserved.
 *
 * You are granted a perpetual, non-exclusive, non-sublicensable, and
 * non-transferable license to use, install, execute, and perform the Spine
 * Runtimes software and derivative works solely for personal or internal
 * use. Without the written permission of Esoteric Software (see Section 2 of
 * the Spine Software License Agreement), you may not (a) modify, translate,
 * adapt, or develop new applications using the Spine Runtimes or otherwise
 * create derivative works or improvements of the Spine Runtimes or (b) remove,
 * delete, alter, or obscure any trademarks or any copyright, trademark, patent,
 * or other intellectual property or proprietary rights notices on or in the
 * Software, including any copy thereof. Redistributions in binary or source
 * form must include this license and terms.
 *
 * THIS SOFTWARE IS PROVIDED BY ESOTERIC SOFTWARE "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 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 THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/

using UnityEngine;
using System.Collections.Generic;

namespace Spine.Unity {
	[RequireComponent(typeof(Animator))]
	public class SkeletonAnimator : SkeletonRenderer, ISkeletonAnimation {

		[SerializeField] protected MecanimTranslator translator;
		public MecanimTranslator Translator { get { return translator; } }

		#region Bone Callbacks (ISkeletonAnimation)
		protected event UpdateBonesDelegate _UpdateLocal;
		protected event UpdateBonesDelegate _UpdateWorld;
		protected event UpdateBonesDelegate _UpdateComplete;

		/// <summary>
		/// Occurs after the animations are applied and before world space values are resolved.
		/// Use this callback when you want to set bone local values.</summary>
		public event UpdateBonesDelegate UpdateLocal { add { _UpdateLocal += value; } remove { _UpdateLocal -= value; } }

		/// <summary>
		/// Occurs after the Skeleton's bone world space values are resolved (including all constraints).
		/// Using this callback will cause the world space values to be solved an extra time.
		/// Use this callback if want to use bone world space values, and also set bone local values.</summary>
		public event UpdateBonesDelegate UpdateWorld { add { _UpdateWorld += value; } remove { _UpdateWorld -= value; } }

		/// <summary>
		/// Occurs after the Skeleton's bone world space values are resolved (including all constraints).
		/// Use this callback if you want to use bone world space values, but don't intend to modify bone local values.
		/// This callback can also be used when setting world position and the bone matrix.</summary>
		public event UpdateBonesDelegate UpdateComplete { add { _UpdateComplete += value; } remove { _UpdateComplete -= value; } }
		#endregion

		public override void Initialize (bool overwrite) {
			if (valid && !overwrite) return;
			base.Initialize(overwrite);
			if (!valid) return;

			if (translator == null) translator = new MecanimTranslator();
			translator.Initialize(GetComponent<Animator>(), this.skeletonDataAsset);
		}

		public void Update () {
			if (!valid) return;

			#if UNITY_EDITOR
			if (Application.isPlaying) {
				translator.Apply(skeleton);
			} else {
				var translatorAnimator = translator.Animator;
				if (translatorAnimator != null && translatorAnimator.isInitialized)
					translator.Apply(skeleton);
			}
			#else
			translator.Apply(skeleton);
			#endif

			// UpdateWorldTransform and Bone Callbacks
			{
				if (_UpdateLocal != null)
					_UpdateLocal(this);

				skeleton.UpdateWorldTransform();

				if (_UpdateWorld != null) {
					_UpdateWorld(this);
					skeleton.UpdateWorldTransform();
				}

				if (_UpdateComplete != null)
					_UpdateComplete(this);	
			}
		}

		[System.Serializable]
		public class MecanimTranslator {
			#region Inspector
			public bool autoReset = true;
			public MixMode[] layerMixModes = new MixMode[0];
			#endregion

			public enum MixMode { AlwaysMix, MixNext, SpineStyle }

			readonly Dictionary<int, Spine.Animation> animationTable = new Dictionary<int, Spine.Animation>(IntEqualityComparer.Instance);
			readonly Dictionary<AnimationClip, int> clipNameHashCodeTable = new Dictionary<AnimationClip, int>(AnimationClipEqualityComparer.Instance);
			readonly List<Animation> previousAnimations = new List<Animation>();
			readonly List<AnimatorClipInfo> clipInfoCache = new List<AnimatorClipInfo>();
			readonly List<AnimatorClipInfo> nextClipInfoCache = new List<AnimatorClipInfo>();

			Animator animator;
			public Animator Animator { get { return this.animator; } }

			public void Initialize (Animator animator, SkeletonDataAsset skeletonDataAsset) {
				this.animator = animator;

				previousAnimations.Clear();

				animationTable.Clear();
				var data = skeletonDataAsset.GetSkeletonData(true);
				foreach (var a in data.Animations)
					animationTable.Add(a.Name.GetHashCode(), a);

				clipNameHashCodeTable.Clear();
				clipInfoCache.Clear();
				nextClipInfoCache.Clear();
			}

			public void Apply (Skeleton skeleton) {
				if (layerMixModes.Length < animator.layerCount)
					System.Array.Resize<MixMode>(ref layerMixModes, animator.layerCount);

				//skeleton.Update(Time.deltaTime); // Doesn't actually do anything, currently. (Spine 3.6).

				// Clear Previous
				if (autoReset) {
					var previousAnimations = this.previousAnimations;
					for (int i = 0, n = previousAnimations.Count; i < n; i++)
						previousAnimations[i].SetKeyedItemsToSetupPose(skeleton);

					previousAnimations.Clear();
					for (int layer = 0, n = animator.layerCount; layer < n; layer++) {
						float layerWeight = (layer == 0) ? 1 : animator.GetLayerWeight(layer); // Animator.GetLayerWeight always returns 0 on the first layer. Should be interpreted as 1.
						if (layerWeight <= 0) continue;

						AnimatorStateInfo nextStateInfo = animator.GetNextAnimatorStateInfo(layer);

						bool hasNext = nextStateInfo.fullPathHash != 0;

						int clipInfoCount, nextClipInfoCount;
						IList<AnimatorClipInfo> clipInfo, nextClipInfo;
						GetAnimatorClipInfos(layer, out clipInfoCount, out nextClipInfoCount, out clipInfo, out nextClipInfo);

						for (int c = 0; c < clipInfoCount; c++) {
							var info = clipInfo[c];
							float weight = info.weight * layerWeight; if (weight == 0) continue;
							previousAnimations.Add(GetAnimation(info.clip));
						}

						if (hasNext) {
							for (int c = 0; c < nextClipInfoCount; c++) {
								var info = nextClipInfo[c];
								float weight = info.weight * layerWeight; if (weight == 0) continue;
								previousAnimations.Add(GetAnimation(info.clip));
							}
						}
					}
				}

				// Apply
				for (int layer = 0, n = animator.layerCount; layer < n; layer++) {
					float layerWeight = (layer == 0) ? 1 : animator.GetLayerWeight(layer); // Animator.GetLayerWeight always returns 0 on the first layer. Should be interpreted as 1.
					AnimatorStateInfo stateInfo = animator.GetCurrentAnimatorStateInfo(layer);
					AnimatorStateInfo nextStateInfo = animator.GetNextAnimatorStateInfo(layer);

					bool hasNext = nextStateInfo.fullPathHash != 0;

					int clipInfoCount, nextClipInfoCount;
					IList<AnimatorClipInfo> clipInfo, nextClipInfo;
					GetAnimatorClipInfos(layer, out clipInfoCount, out nextClipInfoCount, out clipInfo, out nextClipInfo);

					MixMode mode = layerMixModes[layer];
					if (mode == MixMode.AlwaysMix) {
						// Always use Mix instead of Applying the first non-zero weighted clip.
						for (int c = 0; c < clipInfoCount; c++) {
							var info = clipInfo[c];	float weight = info.weight * layerWeight; if (weight == 0) continue;
							GetAnimation(info.clip).Apply(skeleton, 0, AnimationTime(stateInfo.normalizedTime, info.clip.length, stateInfo.loop, stateInfo.speed < 0), stateInfo.loop, null, weight, MixPose.Current, MixDirection.In);
						}
						if (hasNext) {
							for (int c = 0; c < nextClipInfoCount; c++) {
								var info = nextClipInfo[c]; float weight = info.weight * layerWeight; if (weight == 0) continue;
								GetAnimation(info.clip).Apply(skeleton, 0, AnimationTime(nextStateInfo.normalizedTime , info.clip.length, nextStateInfo.speed < 0), nextStateInfo.loop, null, weight, MixPose.Current, MixDirection.In);
							}
						}
					} else { // case MixNext || SpineStyle
						// Apply first non-zero weighted clip
						int c = 0;
						for (; c < clipInfoCount; c++) {
							var info = clipInfo[c]; float weight = info.weight * layerWeight; if (weight == 0) continue;
							GetAnimation(info.clip).Apply(skeleton, 0, AnimationTime(stateInfo.normalizedTime, info.clip.length, stateInfo.loop, stateInfo.speed < 0), stateInfo.loop, null, 1f, MixPose.Current, MixDirection.In);
							break;
						}
						// Mix the rest
						for (; c < clipInfoCount; c++) {
							var info = clipInfo[c]; float weight = info.weight * layerWeight; if (weight == 0) continue;
							GetAnimation(info.clip).Apply(skeleton, 0, AnimationTime(stateInfo.normalizedTime, info.clip.length, stateInfo.loop, stateInfo.speed < 0), stateInfo.loop, null, weight, MixPose.Current, MixDirection.In);
						}

						c = 0;
						if (hasNext) {
							// Apply next clip directly instead of mixing (ie: no crossfade, ignores mecanim transition weights)
							if (mode == MixMode.SpineStyle) {
								for (; c < nextClipInfoCount; c++) {
									var info = nextClipInfo[c]; float weight = info.weight * layerWeight; if (weight == 0) continue;
									GetAnimation(info.clip).Apply(skeleton, 0, AnimationTime(nextStateInfo.normalizedTime , info.clip.length, nextStateInfo.speed < 0), nextStateInfo.loop, null, 1f, MixPose.Current, MixDirection.In);
									break;
								}
							}
							// Mix the rest
							for (; c < nextClipInfoCount; c++) {
								var info = nextClipInfo[c];	float weight = info.weight * layerWeight; if (weight == 0) continue;
								GetAnimation(info.clip).Apply(skeleton, 0, AnimationTime(nextStateInfo.normalizedTime , info.clip.length, nextStateInfo.speed < 0), nextStateInfo.loop, null, weight, MixPose.Current, MixDirection.In);
							}
						}
					}
				}
			}

			static float AnimationTime (float normalizedTime, float clipLength, bool loop, bool reversed) {
				if (reversed)
					normalizedTime = (1-normalizedTime + (int)normalizedTime) + (int)normalizedTime;
				float time = normalizedTime * clipLength;
				if (loop) return time;
				const float EndSnapEpsilon = 1f/30f; // Workaround for end-duration keys not being applied.
				return (clipLength - time < EndSnapEpsilon) ? clipLength : time; // return a time snapped to clipLength;
			}

			static float AnimationTime (float normalizedTime, float clipLength, bool reversed) {
				if (reversed)
					normalizedTime = (1-normalizedTime + (int)normalizedTime) + (int)normalizedTime;

				return normalizedTime * clipLength;
			}

			void GetAnimatorClipInfos (
				int layer,
				out int clipInfoCount,
				out int nextClipInfoCount,
				out IList<AnimatorClipInfo> clipInfo,
				out IList<AnimatorClipInfo> nextClipInfo) {
				clipInfoCount = animator.GetCurrentAnimatorClipInfoCount(layer);
				nextClipInfoCount = animator.GetNextAnimatorClipInfoCount(layer);
				if (clipInfoCache.Capacity < clipInfoCount) clipInfoCache.Capacity = clipInfoCount;
				if (nextClipInfoCache.Capacity < nextClipInfoCount) nextClipInfoCache.Capacity = nextClipInfoCount;
				animator.GetCurrentAnimatorClipInfo(layer, clipInfoCache);
				animator.GetNextAnimatorClipInfo(layer, nextClipInfoCache);

				clipInfo = clipInfoCache;
				nextClipInfo = nextClipInfoCache;
			}

			Spine.Animation GetAnimation (AnimationClip clip) {
				int clipNameHashCode;
				if (!clipNameHashCodeTable.TryGetValue(clip, out clipNameHashCode)) {
					clipNameHashCode = clip.name.GetHashCode();
					clipNameHashCodeTable.Add(clip, clipNameHashCode);
				}
				Spine.Animation animation;
				animationTable.TryGetValue(clipNameHashCode, out animation);
				return animation;
			}

			class AnimationClipEqualityComparer : IEqualityComparer<AnimationClip> {
				internal static readonly IEqualityComparer<AnimationClip> Instance = new AnimationClipEqualityComparer();
				public bool Equals (AnimationClip x, AnimationClip y) { return x.GetInstanceID() == y.GetInstanceID(); }
				public int GetHashCode (AnimationClip o) { return o.GetInstanceID(); }
			}

			class IntEqualityComparer : IEqualityComparer<int> {
				internal static readonly IEqualityComparer<int> Instance = new IntEqualityComparer();
				public bool Equals (int x, int y) { return x == y; }
				public int GetHashCode(int o) { return o; }
			}
		}

	}
}
