/******************************************************************************
 * 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 System;
using System.Collections.Generic;

namespace Spine {
	public class Skeleton {
		internal SkeletonData data;
		internal ExposedList<Bone> bones;
		internal ExposedList<Slot> slots;
		internal ExposedList<Slot> drawOrder;
		internal ExposedList<IkConstraint> ikConstraints;
		internal ExposedList<TransformConstraint> transformConstraints;
		internal ExposedList<PathConstraint> pathConstraints;
		internal ExposedList<IUpdatable> updateCache = new ExposedList<IUpdatable>();
		internal ExposedList<Bone> updateCacheReset = new ExposedList<Bone>();
		internal Skin skin;
		internal float r = 1, g = 1, b = 1, a = 1;
		internal float time;
		internal bool flipX, flipY;
		internal float x, y;

		public SkeletonData Data { get { return data; } }
		public ExposedList<Bone> Bones { get { return bones; } }
		public ExposedList<IUpdatable> UpdateCacheList { get { return updateCache; } }
		public ExposedList<Slot> Slots { get { return slots; } }
		public ExposedList<Slot> DrawOrder { get { return drawOrder; } }
		public ExposedList<IkConstraint> IkConstraints { get { return ikConstraints; } }
		public ExposedList<PathConstraint> PathConstraints { get { return pathConstraints; } }
		public ExposedList<TransformConstraint> TransformConstraints { get { return transformConstraints; } }
		public Skin Skin { get { return skin; } set { skin = value; } }
		public float R { get { return r; } set { r = value; } }
		public float G { get { return g; } set { g = value; } }
		public float B { get { return b; } set { b = value; } }
		public float A { get { return a; } set { a = value; } }
		public float Time { get { return time; } set { time = value; } }
		public float X { get { return x; } set { x = value; } }
		public float Y { get { return y; } set { y = value; } }
		public bool FlipX { get { return flipX; } set { flipX = value; } }
		public bool FlipY { get { return flipY; } set { flipY = value; } }

		public Bone RootBone {
			get { return bones.Count == 0 ? null : bones.Items[0]; }
		}

		public Skeleton (SkeletonData data) {
			if (data == null) throw new ArgumentNullException("data", "data cannot be null.");
			this.data = data;

			bones = new ExposedList<Bone>(data.bones.Count);
			foreach (BoneData boneData in data.bones) {
				Bone bone;
				if (boneData.parent == null) {
					bone = new Bone(boneData, this, null);				
				} else {
					Bone parent = bones.Items[boneData.parent.index];
					bone = new Bone(boneData, this, parent);
					parent.children.Add(bone);
				}
				bones.Add(bone);
			}

			slots = new ExposedList<Slot>(data.slots.Count);
			drawOrder = new ExposedList<Slot>(data.slots.Count);
			foreach (SlotData slotData in data.slots) {
				Bone bone = bones.Items[slotData.boneData.index];
				Slot slot = new Slot(slotData, bone);
				slots.Add(slot);
				drawOrder.Add(slot);
			}

			ikConstraints = new ExposedList<IkConstraint>(data.ikConstraints.Count);
			foreach (IkConstraintData ikConstraintData in data.ikConstraints)
				ikConstraints.Add(new IkConstraint(ikConstraintData, this));

			transformConstraints = new ExposedList<TransformConstraint>(data.transformConstraints.Count);
			foreach (TransformConstraintData transformConstraintData in data.transformConstraints)
				transformConstraints.Add(new TransformConstraint(transformConstraintData, this));

			pathConstraints = new ExposedList<PathConstraint> (data.pathConstraints.Count);
			foreach (PathConstraintData pathConstraintData in data.pathConstraints)
				pathConstraints.Add(new PathConstraint(pathConstraintData, this));

			UpdateCache();
			UpdateWorldTransform();
		}

		/// <summary>Caches information about bones and constraints. Must be called if bones, constraints or weighted path attachments are added
		/// or removed.</summary>
		public void UpdateCache () {
			ExposedList<IUpdatable> updateCache = this.updateCache;
			updateCache.Clear();
			this.updateCacheReset.Clear();

			ExposedList<Bone> bones = this.bones;
			for (int i = 0, n = bones.Count; i < n; i++)
				bones.Items[i].sorted = false;

			ExposedList<IkConstraint> ikConstraints = this.ikConstraints;
			var transformConstraints = this.transformConstraints;
			var pathConstraints = this.pathConstraints;
			int ikCount = IkConstraints.Count, transformCount = transformConstraints.Count, pathCount = pathConstraints.Count;
			int constraintCount = ikCount + transformCount + pathCount;
			//outer:
			for (int i = 0; i < constraintCount; i++) {
				for (int ii = 0; ii < ikCount; ii++) {
					IkConstraint constraint = ikConstraints.Items[ii];
					if (constraint.data.order == i) {
						SortIkConstraint(constraint);
						goto continue_outer; //continue outer;
					}
				}
				for (int ii = 0; ii < transformCount; ii++) {
					TransformConstraint constraint = transformConstraints.Items[ii];
					if (constraint.data.order == i) {
						SortTransformConstraint(constraint);
						goto continue_outer; //continue outer;
					}
				}
				for (int ii = 0; ii < pathCount; ii++) {
					PathConstraint constraint = pathConstraints.Items[ii];
					if (constraint.data.order == i) {
						SortPathConstraint(constraint);
						goto continue_outer; //continue outer;
					}
				}
				continue_outer: {}
			}

			for (int i = 0, n = bones.Count; i < n; i++)
				SortBone(bones.Items[i]);
		}

		private void SortIkConstraint (IkConstraint constraint) {
			Bone target = constraint.target;
			SortBone(target);

			var constrained = constraint.bones;
			Bone parent = constrained.Items[0];
			SortBone(parent);

			if (constrained.Count > 1) {
				Bone child = constrained.Items[constrained.Count - 1];
				if (!updateCache.Contains(child))
					updateCacheReset.Add(child);
			}

			updateCache.Add(constraint);

			SortReset(parent.children);
			constrained.Items[constrained.Count - 1].sorted = true;
		}

		private void SortPathConstraint (PathConstraint constraint) {
			Slot slot = constraint.target;
			int slotIndex = slot.data.index;
			Bone slotBone = slot.bone;
			if (skin != null) SortPathConstraintAttachment(skin, slotIndex, slotBone);
			if (data.defaultSkin != null && data.defaultSkin != skin)
				SortPathConstraintAttachment(data.defaultSkin, slotIndex, slotBone);
			for (int ii = 0, nn = data.skins.Count; ii < nn; ii++)
				SortPathConstraintAttachment(data.skins.Items[ii], slotIndex, slotBone);

			Attachment attachment = slot.attachment;
			if (attachment is PathAttachment) SortPathConstraintAttachment(attachment, slotBone);

			var constrained = constraint.bones;
			int boneCount = constrained.Count;
			for (int i = 0; i < boneCount; i++)
				SortBone(constrained.Items[i]);

			updateCache.Add(constraint);

			for (int i = 0; i < boneCount; i++)
				SortReset(constrained.Items[i].children);
			for (int i = 0; i < boneCount; i++)
				constrained.Items[i].sorted = true;
		}

		private void SortTransformConstraint (TransformConstraint constraint) {
			SortBone(constraint.target);

			var constrained = constraint.bones;
			int boneCount = constrained.Count;
			if (constraint.data.local) {
				for (int i = 0; i < boneCount; i++) {
					Bone child = constrained.Items[i];
					SortBone(child.parent);
					if (!updateCache.Contains(child)) updateCacheReset.Add(child);
				}
			} else {
				for (int i = 0; i < boneCount; i++)
					SortBone(constrained.Items[i]);
			}

			updateCache.Add(constraint);

			for (int i = 0; i < boneCount; i++)
				SortReset(constrained.Items[i].children);
			for (int i = 0; i < boneCount; i++)
				constrained.Items[i].sorted = true;
		}

		private void SortPathConstraintAttachment (Skin skin, int slotIndex, Bone slotBone) {
			foreach (var entry in skin.Attachments)
				if (entry.Key.slotIndex == slotIndex) SortPathConstraintAttachment(entry.Value, slotBone);
		}

		private void SortPathConstraintAttachment (Attachment attachment, Bone slotBone) {
			if (!(attachment is PathAttachment)) return;
			int[] pathBones = ((PathAttachment)attachment).bones;
			if (pathBones == null)
				SortBone(slotBone);
			else {
				var bones = this.bones;
				for (int i = 0, n = pathBones.Length; i < n;) {
					int nn = pathBones[i++];
					nn += i;
					while (i < nn)
						SortBone(bones.Items[pathBones[i++]]);
				}
			}
		}

		private void SortBone (Bone bone) {
			if (bone.sorted) return;
			Bone parent = bone.parent;
			if (parent != null) SortBone(parent);
			bone.sorted = true;
			updateCache.Add(bone);
		}

		private static void SortReset (ExposedList<Bone> bones) {
			var bonesItems = bones.Items;
			for (int i = 0, n = bones.Count; i < n; i++) {
				Bone bone = bonesItems[i];
				if (bone.sorted) SortReset(bone.children);
				bone.sorted = false;
			}
		}

		/// <summary>Updates the world transform for each bone and applies constraints.</summary>
		public void UpdateWorldTransform () {
			var updateCacheReset = this.updateCacheReset;
			var updateCacheResetItems = updateCacheReset.Items;
			for (int i = 0, n = updateCacheReset.Count; i < n; i++) {
				Bone bone = updateCacheResetItems[i];
				bone.ax = bone.x;
				bone.ay = bone.y;
				bone.arotation = bone.rotation;
				bone.ascaleX = bone.scaleX;
				bone.ascaleY = bone.scaleY;
				bone.ashearX = bone.shearX;
				bone.ashearY = bone.shearY;
				bone.appliedValid = true;
			}
			var updateItems = this.updateCache.Items;
			for (int i = 0, n = updateCache.Count; i < n; i++)
				updateItems[i].Update();
		}

		/// <summary>Sets the bones, constraints, and slots to their setup pose values.</summary>
		public void SetToSetupPose () {
			SetBonesToSetupPose();
			SetSlotsToSetupPose();
		}

		/// <summary>Sets the bones and constraints to their setup pose values.</summary>
		public void SetBonesToSetupPose () {
			var bonesItems = this.bones.Items;
			for (int i = 0, n = bones.Count; i < n; i++)
				bonesItems[i].SetToSetupPose();

			var ikConstraintsItems = this.ikConstraints.Items;
			for (int i = 0, n = ikConstraints.Count; i < n; i++) {
				IkConstraint constraint = ikConstraintsItems[i];
				constraint.bendDirection = constraint.data.bendDirection;
				constraint.mix = constraint.data.mix;
			}

			var transformConstraintsItems = this.transformConstraints.Items;
			for (int i = 0, n = transformConstraints.Count; i < n; i++) {
				TransformConstraint constraint = transformConstraintsItems[i];
				TransformConstraintData constraintData = constraint.data;
				constraint.rotateMix = constraintData.rotateMix;
				constraint.translateMix = constraintData.translateMix;
				constraint.scaleMix = constraintData.scaleMix;
				constraint.shearMix = constraintData.shearMix;
			}

			var pathConstraintItems = this.pathConstraints.Items;
			for (int i = 0, n = pathConstraints.Count; i < n; i++) {
				PathConstraint constraint = pathConstraintItems[i];
				PathConstraintData constraintData = constraint.data;
				constraint.position = constraintData.position;
				constraint.spacing = constraintData.spacing;
				constraint.rotateMix = constraintData.rotateMix;
				constraint.translateMix = constraintData.translateMix;
			}
		}

		public void SetSlotsToSetupPose () {
			var slots = this.slots;
			var slotsItems = slots.Items;
			drawOrder.Clear();
			for (int i = 0, n = slots.Count; i < n; i++)
				drawOrder.Add(slotsItems[i]);

			for (int i = 0, n = slots.Count; i < n; i++)
				slotsItems[i].SetToSetupPose();
		}

		/// <returns>May be null.</returns>
		public Bone FindBone (string boneName) {
			if (boneName == null) throw new ArgumentNullException("boneName", "boneName cannot be null.");
			var bones = this.bones;
			var bonesItems = bones.Items;
			for (int i = 0, n = bones.Count; i < n; i++) {
				Bone bone = bonesItems[i];
				if (bone.data.name == boneName) return bone;
			}
			return null;
		}

		/// <returns>-1 if the bone was not found.</returns>
		public int FindBoneIndex (string boneName) {
			if (boneName == null) throw new ArgumentNullException("boneName", "boneName cannot be null.");
			var bones = this.bones;
			var bonesItems = bones.Items;
			for (int i = 0, n = bones.Count; i < n; i++)
				if (bonesItems[i].data.name == boneName) return i;
			return -1;
		}

		/// <returns>May be null.</returns>
		public Slot FindSlot (string slotName) {
			if (slotName == null) throw new ArgumentNullException("slotName", "slotName cannot be null.");
			var slots = this.slots;
			var slotsItems = slots.Items;
			for (int i = 0, n = slots.Count; i < n; i++) {
				Slot slot = slotsItems[i];
				if (slot.data.name == slotName) return slot;
			}
			return null;
		}

		/// <returns>-1 if the bone was not found.</returns>
		public int FindSlotIndex (string slotName) {
			if (slotName == null) throw new ArgumentNullException("slotName", "slotName cannot be null.");
			var slots = this.slots;
			var slotsItems = slots.Items;
			for (int i = 0, n = slots.Count; i < n; i++)
				if (slotsItems[i].data.name.Equals(slotName)) return i;
			return -1;
		}

		/// <summary>Sets a skin by name (see SetSkin).</summary>
		public void SetSkin (string skinName) {
			Skin foundSkin = data.FindSkin(skinName);
			if (foundSkin == null) throw new ArgumentException("Skin not found: " + skinName, "skinName");
			SetSkin(foundSkin);
		}

		/// <summary>
		/// <para>Attachments from the new skin are attached if the corresponding attachment from the old skin was attached. 
		/// If there was no old skin, each slot's setup mode attachment is attached from the new skin.</para>
		/// <para>After changing the skin, the visible attachments can be reset to those attached in the setup pose by calling 
		/// <see cref="Skeleton.SetSlotsToSetupPose()"/>. 
		/// Also, often <see cref="AnimationState.Apply(Skeleton)"/> is called before the next time the 
		/// skeleton is rendered to allow any attachment keys in the current animation(s) to hide or show attachments from the new skin.</para>
		/// </summary>
		/// <param name="newSkin">May be null.</param>
		public void SetSkin (Skin newSkin) {
			if (newSkin != null) {
				if (skin != null)
					newSkin.AttachAll(this, skin);
				else {
					ExposedList<Slot> slots = this.slots;
					for (int i = 0, n = slots.Count; i < n; i++) {
						Slot slot = slots.Items[i];
						string name = slot.data.attachmentName;
						if (name != null) {
							Attachment attachment = newSkin.GetAttachment(i, name);
							if (attachment != null) slot.Attachment = attachment;
						}
					}
				}
			}
			skin = newSkin;
		}

		/// <returns>May be null.</returns>
		public Attachment GetAttachment (string slotName, string attachmentName) {
			return GetAttachment(data.FindSlotIndex(slotName), attachmentName);
		}

		/// <returns>May be null.</returns>
		public Attachment GetAttachment (int slotIndex, string attachmentName) {
			if (attachmentName == null) throw new ArgumentNullException("attachmentName", "attachmentName cannot be null.");
			if (skin != null) {
				Attachment attachment = skin.GetAttachment(slotIndex, attachmentName);
				if (attachment != null) return attachment;
			}
			return data.defaultSkin != null ? data.defaultSkin.GetAttachment(slotIndex, attachmentName) : null;
		}

		/// <param name="attachmentName">May be null.</param>
		public void SetAttachment (string slotName, string attachmentName) {
			if (slotName == null) throw new ArgumentNullException("slotName", "slotName cannot be null.");
			ExposedList<Slot> slots = this.slots;
			for (int i = 0, n = slots.Count; i < n; i++) {
				Slot slot = slots.Items[i];
				if (slot.data.name == slotName) {
					Attachment attachment = null;
					if (attachmentName != null) {
						attachment = GetAttachment(i, attachmentName);
						if (attachment == null) throw new Exception("Attachment not found: " + attachmentName + ", for slot: " + slotName);
					}
					slot.Attachment = attachment;
					return;
				}
			}
			throw new Exception("Slot not found: " + slotName);
		}
			
		/// <returns>May be null.</returns>
		public IkConstraint FindIkConstraint (string constraintName) {
			if (constraintName == null) throw new ArgumentNullException("constraintName", "constraintName cannot be null.");
			ExposedList<IkConstraint> ikConstraints = this.ikConstraints;
			for (int i = 0, n = ikConstraints.Count; i < n; i++) {
				IkConstraint ikConstraint = ikConstraints.Items[i];
				if (ikConstraint.data.name == constraintName) return ikConstraint;
			}
			return null;
		}

		/// <returns>May be null.</returns>
		public TransformConstraint FindTransformConstraint (string constraintName) {
			if (constraintName == null) throw new ArgumentNullException("constraintName", "constraintName cannot be null.");
			ExposedList<TransformConstraint> transformConstraints = this.transformConstraints;
			for (int i = 0, n = transformConstraints.Count; i < n; i++) {
				TransformConstraint transformConstraint = transformConstraints.Items[i];
				if (transformConstraint.data.name == constraintName) return transformConstraint;
			}
			return null;
		}

		/// <returns>May be null.</returns>
		public PathConstraint FindPathConstraint (string constraintName) {
			if (constraintName == null) throw new ArgumentNullException("constraintName", "constraintName cannot be null.");
			ExposedList<PathConstraint> pathConstraints = this.pathConstraints;
			for (int i = 0, n = pathConstraints.Count; i < n; i++) {
				PathConstraint constraint = pathConstraints.Items[i];
				if (constraint.data.name.Equals(constraintName)) return constraint;
			}
			return null;
		}

		public void Update (float delta) {
			time += delta;
		}

		/// <summary>Returns the axis aligned bounding box (AABB) of the region and mesh attachments for the current pose.</summary>
		/// <param name="x">The horizontal distance between the skeleton origin and the left side of the AABB.</param>
		/// <param name="y">The vertical distance between the skeleton origin and the bottom side of the AABB.</param>
		/// <param name="width">The width of the AABB</param>
		/// <param name="height">The height of the AABB.</param>
		/// <param name="vertexBuffer">Reference to hold a float[]. May be a null reference. This method will assign it a new float[] with the appropriate size as needed.</param>
		public void GetBounds (out float x, out float y, out float width, out float height, ref float[] vertexBuffer) {
			float[] temp = vertexBuffer;
			temp = temp ?? new float[8];
			var drawOrderItems = this.drawOrder.Items;
			float minX = int.MaxValue, minY = int.MaxValue, maxX = int.MinValue, maxY = int.MinValue;
			for (int i = 0, n = this.drawOrder.Count; i < n; i++) {
				Slot slot = drawOrderItems[i];
				int verticesLength = 0;
				float[] vertices = null;
				Attachment attachment = slot.attachment;
				var regionAttachment = attachment as RegionAttachment;
				if (regionAttachment != null) {
					verticesLength = 8;
					vertices = temp;
					if (vertices.Length < 8) vertices = temp = new float[8];
					regionAttachment.ComputeWorldVertices(slot.bone, temp, 0);
				} else {
					var meshAttachment = attachment as MeshAttachment;
					if (meshAttachment != null) {
						MeshAttachment mesh = meshAttachment;
						verticesLength = mesh.WorldVerticesLength;
						vertices = temp;
						if (vertices.Length < verticesLength) vertices = temp = new float[verticesLength];
						mesh.ComputeWorldVertices(slot, 0, verticesLength, temp, 0);
					}
				}

				if (vertices != null) {
					for (int ii = 0; ii < verticesLength; ii += 2) {
						float vx = vertices[ii], vy = vertices[ii + 1];
						minX = Math.Min(minX, vx);
						minY = Math.Min(minY, vy);
						maxX = Math.Max(maxX, vx);
						maxY = Math.Max(maxY, vy);
					}
				}
			}
			x = minX;
			y = minY;
			width = maxX - minX;
			height = maxY - minY;
			vertexBuffer = temp;
		}
	}
}