// Copyright (c) 2018-2019 Kiwano - Nomango
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#pragma once
#include <kiwano-physics/Body.h>
#include <kiwano-physics/Joint.h>

namespace kiwano
{
namespace physics
{
KGE_DECLARE_SMART_PTR(World);

/**
 * \~chinese
 * \defgroup Physics 物理模块
 */

/**
 * \addtogroup Physics
 * @{
 */

/**
 * \~chinese
 * @brief 物理世界
 */
class KGE_API World : public Stage
{
    friend class Body;
    friend class Joint;

public:
    World();

    virtual ~World();

    /// \~chinese
    /// @brief 获取重力 [N]
    Vec2 GetGravity() const;

    /// \~chinese
    /// @brief 设置重力 [N]
    void SetGravity(Vec2 gravity);

    /// \~chinese
    /// @brief 获取物理接触列表
    ContactList GetContactList();

    /// \~chinese
    /// @brief 获取全局缩放比例
    /// @details 缩放比例是指由物理世界的单位米转换到屏幕像素的比例，默认比例为1:100
    float GetGlobalScale() const;

    /// \~chinese
    /// @brief 设置全局缩放比例
    /// @details 缩放比例是指由物理世界的单位米转换到屏幕像素的比例，默认比例为1:100
    void SetGlobalScale(float scale);

    /// \~chinese
    /// @brief 游戏世界单位转换为物理世界单位
    /// @details 根据全局缩放比例将物理世界的单位米转换为像素单位
    float World2Stage(float value) const;

    /// \~chinese
    /// @brief 游戏世界单位转换为物理世界单位
    /// @details 根据全局缩放比例将物理世界的单位米转换为像素单位
    Vec2 World2Stage(const b2Vec2& pos) const;

    /// \~chinese
    /// @brief 物理世界单位转换为游戏世界单位
    /// @details 根据全局缩放比例将像素单位转换为物理世界的单位米
    float Stage2World(float value) const;

    /// \~chinese
    /// @brief 物理世界单位转换为游戏世界单位
    /// @details 根据全局缩放比例将像素单位转换为物理世界的单位米
    b2Vec2 Stage2World(const Vec2& pos) const;

    /// \~chinese
    /// @brief 设置速度迭代次数, 默认为 6
    void SetVelocityIterations(int vel_iter);

    /// \~chinese
    /// @brief 设置位置迭代次数, 默认为 2
    void SetPositionIterations(int pos_iter);

    b2World* GetB2World();

    const b2World* GetB2World() const;

private:
    /// \~chinese
    /// @brief 移除物体
    void RemoveBody(Body* body);

    /// \~chinese
    /// @brief 移除所有物体
    void RemoveAllBodies();

    /// \~chinese
    /// @brief 添加关节
    void AddJoint(Joint* joint);

    /// \~chinese
    /// @brief 移除关节
    void RemoveJoint(Joint* joint);

    /// \~chinese
    /// @brief 移除所有关节
    void RemoveAllJoints();

    /// \~chinese
    /// @brief 关节被移除
    void JointRemoved(b2Joint* joint);

protected:
    void Update(Duration dt) override;

private:
    b2World world_;
    int     vel_iter_;
    int     pos_iter_;
    float   global_scale_;

    class DestructionListener;
    friend DestructionListener;
    DestructionListener* destruction_listener_;

    class ContactListener;
    friend ContactListener;
    ContactListener* contact_listener_;

    bool           removing_joint_;
    Vector<Joint*> joints_;
};

/** @} */

inline float World::GetGlobalScale() const
{
    return global_scale_;
}

inline void World::SetGlobalScale(float scale)
{
    global_scale_ = scale;
}

inline float World::World2Stage(float value) const
{
    return value * GetGlobalScale();
}

inline Vec2 World::World2Stage(const b2Vec2& pos) const
{
    return Point(World2Stage(pos.x), World2Stage(pos.y));
}

inline float World::Stage2World(float value) const
{
    return value / GetGlobalScale();
}

inline b2Vec2 World::Stage2World(const Vec2& pos) const
{
    return b2Vec2(Stage2World(pos.x), Stage2World(pos.y));
}

inline void World::SetVelocityIterations(int vel_iter)
{
    vel_iter_ = vel_iter;
}

inline void World::SetPositionIterations(int pos_iter)
{
    pos_iter_ = pos_iter;
}
}  // namespace physics
}  // namespace kiwano