#pragma once

#include "ecsmemorypool_global.h"
#include <QJsonObject>
#include <QList>
#include <QHash>
#include <memory_pages.h>

template<typename T>
concept CompenentType = requires(T t, T other, const QJsonObject & in, QJsonObject & out) {
	{ T::typeCode() } -> std::same_as<uint64_t>;
	{ T::typeSize() } -> std::same_as<uint16_t>;
	{ t.loadFrom(in) } -> std::same_as<void>;
	{ t.saveTo(out) } -> std::same_as<void>;
};

/// <summary>
/// 组件引用符号
/// </summary>
/// <typeparam name="T"></typeparam>
template<typename T> class ComponentRefer : protected MemoryElement {
public:
	ComponentRefer(ElementControlBlock* data) : MemoryElement(data) { referAdd(); }
	ComponentRefer(const ComponentRefer<T> &other) :MemoryElement(other.data_ptr) { referAdd(); }
	virtual ~ComponentRefer() { referSub(); }

	T* dataLock() {
		return (T*)(MemoryElement::dataLock());
	}
	void unlock() {
		MemoryElement::release();
	}

};


class ECSMEMORYPOOL_EXPORT ECSMemoryPool {
private:
	std::mutex _pool_protected_;

	/// <summary>
	/// 携带默认参数数据元素组件内存实例
	/// </summary>
	QHash<uint64_t, std::pair<uint16_t, void*>> _basic_component_memory_example;
	/// <summary>
	/// map<type_code，page_ptr> 内存页存储
	/// </summary>
	QMultiHash<uint64_t, MemoryPage*> _storage_pages;

public:
	ECSMemoryPool();

	/// <summary>
	/// 注册携带默认参数的数据组件
	/// </summary>
	/// <typeparam name="T"></typeparam>
	/// <param name="one"></param>
	template<CompenentType T> void registerComponent(const T &one) {
		std::lock_guard<std::mutex> lockx(_pool_protected_);

		auto ptr = new char[T::typeSize()];
		memcpy(ptr, &one, T::typeSize());

		// 注册组件数据类型
		auto type_code = T::typeCode();
		auto type_size = T::typeSize();
		_basic_component_memory_example[type_code] = std::make_pair(type_size, (void*)ptr);
	}

	/// <summary>
	/// 创建一个新的数据组件
	/// </summary>
	/// <typeparam name="T"></typeparam>
	/// <returns></returns>
	template<CompenentType T> ComponentRefer<T> generate() {
		std::lock_guard<std::mutex> lockx(_pool_protected_);

		auto type_code = T::typeCode();
		ElementControlBlock* refer_ptr = nullptr;
		// 获取指定类型关联的内存页
		QList<MemoryPage*> page_list = _storage_pages.values(type_code);

		// 迭代内存页集合
		for (auto page_ptr : page_list) {
			auto max_element_cnt = page_ptr->maxSliceCount();
			auto active_cnt = page_ptr->getActiveCount();
			// 初级校核可用数量
			if (active_cnt < max_element_cnt) {
				// 逐个查找数据元素
				for (auto eidx = 0; eidx < max_element_cnt; eidx++) {
					auto slice_ptr = page_ptr->getSlicePtr(eidx);
					// 访问排他
					slice_ptr->page_refer->lock();
					// 裁决元素可用性
					if (!slice_ptr->refer_count) {
						// 元素可用，引用占用
						slice_ptr->refer_count++;
						refer_ptr = slice_ptr;
						slice_ptr->page_refer->release();
						refer_ptr->page_refer->getActiveCount(1);
						// 跳转到元素重用
						goto exists_reuse;
					}
					else {
						slice_ptr->page_refer->release();
					}
				}
			}
		}
		{
			// 生成新的内存页
			auto new_page = new MemoryPage(MemoryElement::rawSize(T::typeSize()), type_code);
			_storage_pages.insert(type_code, new_page);
			refer_ptr = new_page->getSlicePtr(0);
			refer_ptr->page_refer->getActiveCount(1);
			refer_ptr->refer_count++;
		}

	exists_reuse:
		ComponentRefer<T> temp_inst(refer_ptr);
		auto data_pointer = temp_inst.dataLock();
		refer_ptr->refer_count--;
		auto dpair = _basic_component_memory_example[T::typeCode()];
		memcpy(data_pointer, dpair.second, dpair.first);
		temp_inst.unlock();
		return temp_inst;
	}
};