#pragma once

#include <VTUserAll.hpp>
#include <vector>
#include <cstdint>
#include <cinttypes>
#include <type_traits>

namespace BMap {
	
	class BMMeshTransition {
	private:
		struct TransitionVertex {
			TransitionVertex(
				const LibCmo::VxMath::VxVector3& vec,
				const LibCmo::VxMath::VxVector3& norm,
				const LibCmo::VxMath::VxVector2& uv);
			LibCmo::VxMath::VxVector3 m_Vertex;
			LibCmo::VxMath::VxVector3 m_Norm;
			LibCmo::VxMath::VxVector2 m_UV;
		};
		struct TransitionFace {
			TransitionFace(LibCmo::CKDWORD _i1, LibCmo::CKDWORD _i2, LibCmo::CKDWORD _i3, LibCmo::CKDWORD mtl_id);
			LibCmo::CKDWORD m_Idx1, m_Idx2, m_Idx3;
			LibCmo::CKDWORD m_MtlSlotIdx;
		};
		struct TransitionVertexCompare {
			bool operator()(const TransitionVertex& lhs, const TransitionVertex& rhs) const;
		};

	public:
		BMMeshTransition();
		~BMMeshTransition();
		LIBCMO_DISABLE_COPY_MOVE(BMMeshTransition);

		bool PrepareVertexCount(LibCmo::CKDWORD count);
		LibCmo::VxMath::VxVector3* PrepareVertex();
		bool PrepareNormalCount(LibCmo::CKDWORD count);
		LibCmo::VxMath::VxVector3* PrepareNormal();
		bool PrepareUVCount(LibCmo::CKDWORD count);
		LibCmo::VxMath::VxVector2* PrepareUV();
		bool PrepareMtlSlotCount(LibCmo::CKDWORD count);
		LibCmo::CK2::CK_ID* PrepareMtlSlot();
		bool PrepareFaceCount(LibCmo::CKDWORD count);
		LibCmo::CKDWORD* PrepareFaceVertexIndices();
		LibCmo::CKDWORD* PrepareFaceNormalIndices();
		LibCmo::CKDWORD* PrepareFaceUVIndices();
		LibCmo::CKDWORD* PrepareFaceMtlSlot();

		bool Parse(LibCmo::CK2::ObjImpls::CKMesh* write_into_mesh);

	private:
		void DoRealParse();
		void ApplyToMesh(LibCmo::CK2::ObjImpls::CKMesh* write_into_mesh);

		bool m_IsVertexOK, m_IsNormalOK, m_IsUVOK, m_IsFaceOK, m_IsMtlSlotOK;
		bool m_IsParsed;

		std::vector<LibCmo::VxMath::VxVector3> m_Vertexs, m_Normals;
		std::vector<LibCmo::VxMath::VxVector2> m_UVs;
		std::vector<LibCmo::CKDWORD> m_FaceVertexs, m_FaceNormals, m_FaceUVs;
		std::vector<LibCmo::CKDWORD> m_FaceMtlSlotIdxs;
		std::vector<LibCmo::CK2::CK_ID> m_MtlSlots;

		std::vector<TransitionVertex> m_ProcVertexs;
		std::vector<TransitionFace> m_ProcFaces;
		/**
		@brief The core duplication vertex remover.
		@remark
		unordered_map have performance problem when dealing with massive data (in this case, big mesh).
		so we use map to get stable time cost.
		*/
		std::map<TransitionVertex, LibCmo::CKDWORD, TransitionVertexCompare> m_ProcDupRemover;
	};

	class BMFile {
	public:
		BMFile(LibCmo::CKSTRING temp_folder, LibCmo::CKSTRING texture_folder, LibCmo::CKDWORD encoding_count, LibCmo::CKSTRING* encodings, bool is_reader);
		~BMFile();
		LIBCMO_DISABLE_COPY_MOVE(BMFile);

		// ===== help functions ===== 

		/**
		 * @brief Check whether this instance is freezed.
		 * @return True if freezed. This instance should be free immediately.
		*/
		bool IsFreezed();
		bool Load(LibCmo::CKSTRING filename);
		bool Save(LibCmo::CKSTRING filename, LibCmo::CKINT compress_level);
		LibCmo::CK2::ObjImpls::CKObject* GetObjectPtr(LibCmo::CK2::CK_ID objid);

		// ===== visitors ===== 

	private:
		LibCmo::CKDWORD CommonGetObjectCount(std::vector<LibCmo::CK2::CK_ID>& container) {
			if (m_IsFreezed || !m_IsReader) return 0;
			return static_cast<LibCmo::CKDWORD>(container.size());
		}
		LibCmo::CK2::CK_ID CommonGetObject(std::vector<LibCmo::CK2::CK_ID>& container, LibCmo::CKDWORD idx) {
			if (m_IsFreezed || !m_IsReader || idx >= container.size()) return 0;
			return container[idx];
		}
		LibCmo::CK2::CK_ID CommonCreateObject(std::vector<LibCmo::CK2::CK_ID>& container, LibCmo::CK2::CK_CLASSID cid) {
			// only available in writer
			if (m_IsFreezed || m_IsReader) return 0;

			// try create object and get its pointer
			LibCmo::CK2::ObjImpls::CKObject* obj = m_Context->CreateObject(cid, nullptr);
			// check creation validation
			if (obj == nullptr) return 0;

			// if success, write its id and emplace its id into list
			LibCmo::CK2::CK_ID objid = obj->GetID();
			container.emplace_back(objid);
			return objid;
		}
	public:
		LibCmo::CKDWORD GetGroupCount();
		LibCmo::CK2::CK_ID GetGroup(LibCmo::CKDWORD idx);
		LibCmo::CK2::CK_ID CreateGroup();
		LibCmo::CKDWORD Get3dObjectCount();
		LibCmo::CK2::CK_ID Get3dObject(LibCmo::CKDWORD idx);
		LibCmo::CK2::CK_ID Create3dObject();
		LibCmo::CKDWORD GetMeshCount();
		LibCmo::CK2::CK_ID GetMesh(LibCmo::CKDWORD idx);
		LibCmo::CK2::CK_ID CreateMesh();
		LibCmo::CKDWORD GetMaterialCount();
		LibCmo::CK2::CK_ID GetMaterial(LibCmo::CKDWORD idx);
		LibCmo::CK2::CK_ID CreateMaterial();
		LibCmo::CKDWORD GetTextureCount();
		LibCmo::CK2::CK_ID GetTexture(LibCmo::CKDWORD idx);
		LibCmo::CK2::CK_ID CreateTexture();

	private:
		/**
		 * @brief True if all operation of this instance should be rejected.
		*/
		bool m_IsFreezed;
		bool m_IsReader;
		LibCmo::CK2::CKContext* m_Context;

		std::vector<LibCmo::CK2::CK_ID> m_ObjGroups;
		std::vector<LibCmo::CK2::CK_ID> m_Obj3dObjects;
		std::vector<LibCmo::CK2::CK_ID> m_ObjMeshs;
		std::vector<LibCmo::CK2::CK_ID> m_ObjMaterials;
		std::vector<LibCmo::CK2::CK_ID> m_ObjTextures;

	};

}