/******************************************************************************
 * 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.
 *****************************************************************************/

#define SPINE_OPTIONAL_RENDEROVERRIDE
#define SPINE_OPTIONAL_MATERIALOVERRIDE

using System.Collections.Generic;
using UnityEngine;

namespace Spine.Unity {
	/// <summary>Renders a skeleton.</summary>
	[ExecuteInEditMode, RequireComponent(typeof(MeshFilter), typeof(MeshRenderer)), DisallowMultipleComponent]
	[HelpURL("http://esotericsoftware.com/spine-unity-documentation#Rendering")]
	public class SkeletonRenderer : MonoBehaviour, ISkeletonComponent, IHasSkeletonDataAsset {

		public delegate void SkeletonRendererDelegate (SkeletonRenderer skeletonRenderer);
		public event SkeletonRendererDelegate OnRebuild;

		/// <summary> Occurs after the vertex data is populated every frame, before the vertices are pushed into the mesh.</summary>
		public event Spine.Unity.MeshGeneratorDelegate OnPostProcessVertices;

		public SkeletonDataAsset skeletonDataAsset;
		public SkeletonDataAsset SkeletonDataAsset { get { return skeletonDataAsset; } } // ISkeletonComponent
		public string initialSkinName;
		public bool initialFlipX, initialFlipY;

		#region Advanced
		// Submesh Separation
		[UnityEngine.Serialization.FormerlySerializedAs("submeshSeparators")] [SpineSlot] public string[] separatorSlotNames = new string[0];
		[System.NonSerialized] public readonly List<Slot> separatorSlots = new List<Slot>();

		[Range(-0.1f, 0f)] public float zSpacing;
		//public bool renderMeshes = true;
		public bool useClipping = true;
		public bool immutableTriangles = false;
		public bool pmaVertexColors = true;
		/// <summary>Clears the state when this component or its GameObject is disabled. This prevents previous state from being retained when it is enabled again. When pooling your skeleton, setting this to true can be helpful.</summary>
		public bool clearStateOnDisable = false;
		public bool tintBlack = false;
		public bool singleSubmesh = false;

		[UnityEngine.Serialization.FormerlySerializedAs("calculateNormals")]
		public bool addNormals = false;
		public bool calculateTangents = false;

		public bool logErrors = false;

		#if SPINE_OPTIONAL_RENDEROVERRIDE
		public bool disableRenderingOnOverride = true;
		public delegate void InstructionDelegate (SkeletonRendererInstruction instruction);
		event InstructionDelegate generateMeshOverride;
		public event InstructionDelegate GenerateMeshOverride {
			add {
				generateMeshOverride += value;
				if (disableRenderingOnOverride && generateMeshOverride != null) {
					Initialize(false);
					meshRenderer.enabled = false;
				}
			}
			remove {
				generateMeshOverride -= value;
				if (disableRenderingOnOverride && generateMeshOverride == null) {
					Initialize(false);
					meshRenderer.enabled = true;
				}
			}
		}
		#endif

		#if SPINE_OPTIONAL_MATERIALOVERRIDE
		[System.NonSerialized] readonly Dictionary<Material, Material> customMaterialOverride = new Dictionary<Material, Material>();
		public Dictionary<Material, Material> CustomMaterialOverride { get { return customMaterialOverride; } }
		#endif

		// Custom Slot Material
		[System.NonSerialized] readonly Dictionary<Slot, Material> customSlotMaterials = new Dictionary<Slot, Material>();
		public Dictionary<Slot, Material> CustomSlotMaterials { get { return customSlotMaterials; } }
		#endregion

		MeshRenderer meshRenderer;
		MeshFilter meshFilter;

		[System.NonSerialized] public bool valid;
		[System.NonSerialized] public Skeleton skeleton;
		public Skeleton Skeleton {
			get {
				Initialize(false);
				return skeleton;
			}
		}
			
		[System.NonSerialized] readonly SkeletonRendererInstruction currentInstructions = new SkeletonRendererInstruction();
		readonly MeshGenerator meshGenerator = new MeshGenerator();
		[System.NonSerialized] readonly MeshRendererBuffers rendererBuffers = new MeshRendererBuffers();

		#region Runtime Instantiation
		public static T NewSpineGameObject<T> (SkeletonDataAsset skeletonDataAsset) where T : SkeletonRenderer {
			return SkeletonRenderer.AddSpineComponent<T>(new GameObject("New Spine GameObject"), skeletonDataAsset);
		}

		/// <summary>Add and prepare a Spine component that derives from SkeletonRenderer to a GameObject at runtime.</summary>
		/// <typeparam name="T">T should be SkeletonRenderer or any of its derived classes.</typeparam>
		public static T AddSpineComponent<T> (GameObject gameObject, SkeletonDataAsset skeletonDataAsset) where T : SkeletonRenderer {
			var c = gameObject.AddComponent<T>();
			if (skeletonDataAsset != null) {
				c.skeletonDataAsset = skeletonDataAsset;
				c.Initialize(false);
			}
			return c;
		}

		/// <summary>Applies MeshGenerator settings to the SkeletonRenderer and its internal MeshGenerator.</summary>
		public void SetMeshSettings (MeshGenerator.Settings settings) {
			this.calculateTangents = settings.calculateTangents;
			this.immutableTriangles = settings.immutableTriangles;
			this.pmaVertexColors = settings.pmaVertexColors;
			this.tintBlack = settings.tintBlack;
			this.useClipping = settings.useClipping;
			this.zSpacing = settings.zSpacing;

			this.meshGenerator.settings = settings;
		}
		#endregion

		public virtual void Awake () {
			Initialize(false);
		}

		void OnDisable () {
			if (clearStateOnDisable && valid)
				ClearState();
		}

		void OnDestroy () {
			rendererBuffers.Dispose();
			valid = false;
		}

		/// <summary>
		/// Clears the previously generated mesh and resets the skeleton's pose.</summary>
		public virtual void ClearState () {
			meshFilter.sharedMesh = null;
			currentInstructions.Clear();
			if (skeleton != null) skeleton.SetToSetupPose();
		}

		public void EnsureMeshGeneratorCapacity (int minimumVertexCount) {
			meshGenerator.EnsureVertexCapacity(minimumVertexCount);
		}

		/// <summary>
		/// Initialize this component. Attempts to load the SkeletonData and creates the internal Skeleton object and buffers.</summary>
		/// <param name="overwrite">If set to <c>true</c>, it will overwrite internal objects if they were already generated. Otherwise, the initialized component will ignore subsequent calls to initialize.</param>
		public virtual void Initialize (bool overwrite) {
			if (valid && !overwrite)
				return;

			// Clear
			{
				if (meshFilter != null)
					meshFilter.sharedMesh = null;

				meshRenderer = GetComponent<MeshRenderer>();
				if (meshRenderer != null) meshRenderer.sharedMaterial = null;

				currentInstructions.Clear();
				rendererBuffers.Clear();
				meshGenerator.Begin();
				skeleton = null;
				valid = false;
			}

			if (!skeletonDataAsset) {
				if (logErrors) Debug.LogError("Missing SkeletonData asset.", this);
				return;
			}

			SkeletonData skeletonData = skeletonDataAsset.GetSkeletonData(false);
			if (skeletonData == null) return;
			valid = true;

			meshFilter = GetComponent<MeshFilter>();
			meshRenderer = GetComponent<MeshRenderer>();
			rendererBuffers.Initialize();

			skeleton = new Skeleton(skeletonData) {
				flipX = initialFlipX,
				flipY = initialFlipY
			};

			if (!string.IsNullOrEmpty(initialSkinName) && !string.Equals(initialSkinName, "default", System.StringComparison.Ordinal))
				skeleton.SetSkin(initialSkinName);

			separatorSlots.Clear();
			for (int i = 0; i < separatorSlotNames.Length; i++)
				separatorSlots.Add(skeleton.FindSlot(separatorSlotNames[i]));

			LateUpdate(); // Generate mesh for the first frame it exists.

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

		/// <summary>
		/// Generates a new UnityEngine.Mesh from the internal Skeleton.</summary>
		public virtual void LateUpdate () {
			if (!valid) return;

			#if SPINE_OPTIONAL_RENDEROVERRIDE
			bool doMeshOverride = generateMeshOverride != null;
			if ((!meshRenderer.enabled)	&& !doMeshOverride) return;
			#else
			const bool doMeshOverride = false;
			if (!meshRenderer.enabled) return;
			#endif
			var currentInstructions = this.currentInstructions;
			var workingSubmeshInstructions = currentInstructions.submeshInstructions;
			var currentSmartMesh = rendererBuffers.GetNextMesh(); // Double-buffer for performance.

			bool updateTriangles;

			if (this.singleSubmesh) {
				// STEP 1. Determine a SmartMesh.Instruction. Split up instructions into submeshes. =============================================
				MeshGenerator.GenerateSingleSubmeshInstruction(currentInstructions, skeleton, skeletonDataAsset.atlasAssets[0].materials[0]);

				// STEP 1.9. Post-process workingInstructions. ==================================================================================
				#if SPINE_OPTIONAL_MATERIALOVERRIDE
				if (customMaterialOverride.Count > 0) // isCustomMaterialOverridePopulated 
					MeshGenerator.TryReplaceMaterials(workingSubmeshInstructions, customMaterialOverride);
				#endif

				// STEP 2. Update vertex buffer based on verts from the attachments.  ===========================================================
				meshGenerator.settings = new MeshGenerator.Settings {
					pmaVertexColors = this.pmaVertexColors,
					zSpacing = this.zSpacing,
					useClipping = this.useClipping,
					tintBlack = this.tintBlack,
					calculateTangents = this.calculateTangents,
					addNormals = this.addNormals
				};
				meshGenerator.Begin();
				updateTriangles = SkeletonRendererInstruction.GeometryNotEqual(currentInstructions, currentSmartMesh.instructionUsed);
				if (currentInstructions.hasActiveClipping) {
					meshGenerator.AddSubmesh(workingSubmeshInstructions.Items[0], updateTriangles);
				} else {
					meshGenerator.BuildMeshWithArrays(currentInstructions, updateTriangles);
				}

			} else {
				// STEP 1. Determine a SmartMesh.Instruction. Split up instructions into submeshes. =============================================
				MeshGenerator.GenerateSkeletonRendererInstruction(currentInstructions, skeleton, customSlotMaterials, separatorSlots, doMeshOverride, this.immutableTriangles);

				// STEP 1.9. Post-process workingInstructions. ==================================================================================
				#if SPINE_OPTIONAL_MATERIALOVERRIDE
				if (customMaterialOverride.Count > 0) // isCustomMaterialOverridePopulated 
					MeshGenerator.TryReplaceMaterials(workingSubmeshInstructions, customMaterialOverride);
				#endif

				#if SPINE_OPTIONAL_RENDEROVERRIDE
				if (doMeshOverride) {
					this.generateMeshOverride(currentInstructions);
					if (disableRenderingOnOverride) return;
				}
				#endif

				updateTriangles = SkeletonRendererInstruction.GeometryNotEqual(currentInstructions, currentSmartMesh.instructionUsed);

				// STEP 2. Update vertex buffer based on verts from the attachments.  ===========================================================
				meshGenerator.settings = new MeshGenerator.Settings {
					pmaVertexColors = this.pmaVertexColors,
					zSpacing = this.zSpacing,
					useClipping = this.useClipping,
					tintBlack = this.tintBlack,
					calculateTangents = this.calculateTangents,
					addNormals = this.addNormals
				};
				meshGenerator.Begin();
				if (currentInstructions.hasActiveClipping)
					meshGenerator.BuildMesh(currentInstructions, updateTriangles);
				else
					meshGenerator.BuildMeshWithArrays(currentInstructions, updateTriangles);
			}

			if (OnPostProcessVertices != null) OnPostProcessVertices.Invoke(this.meshGenerator.Buffers);

			// STEP 3. Move the mesh data into a UnityEngine.Mesh ===========================================================================
			var currentMesh = currentSmartMesh.mesh;
			meshGenerator.FillVertexData(currentMesh);
			rendererBuffers.UpdateSharedMaterials(workingSubmeshInstructions);
			if (updateTriangles) { // Check if the triangles should also be updated.
				meshGenerator.FillTriangles(currentMesh);
				meshRenderer.sharedMaterials = rendererBuffers.GetUpdatedSharedMaterialsArray();
			} else if (rendererBuffers.MaterialsChangedInLastUpdate()) {
				meshRenderer.sharedMaterials = rendererBuffers.GetUpdatedSharedMaterialsArray();
			}

			meshGenerator.FillLateVertexData(currentMesh);

			// STEP 4. The UnityEngine.Mesh is ready. Set it as the MeshFilter's mesh. Store the instructions used for that mesh. ===========
			meshFilter.sharedMesh = currentMesh;
			currentSmartMesh.instructionUsed.Set(currentInstructions);
		}
	}
}