Extra2D/include/renderer/viewport_adapter.h

#pragma once

#include <types/base/types.h>
#include <types/math/vec2.h>
#include <types/math/rect.h>
#include <types/math/color.h>
#include <glm/mat4x4.hpp>

namespace extra2d {

/**
 * @brief 视口适配模式枚举
 */
enum class ViewportMode {
    AspectRatio,  // 保持宽高比，可能有黑边
    Stretch,      // 拉伸以填满屏幕
    Center,       // 居中显示
    Custom        // 自定义
};

/**
 * @brief 黑边位置枚举
 */
enum class LetterboxPosition {
    Center,
    LeftTop,
    RightTop,
    LeftBottom,
    RightBottom
};

/**
 * @brief 视口配置结构体
 */
struct ViewportConfig {
    float logicWidth = 1280.0f;           // 逻辑宽度
    float logicHeight = 720.0f;           // 逻辑高度
    ViewportMode mode = ViewportMode::AspectRatio;
    LetterboxPosition letterboxPosition = LetterboxPosition::Center;
    Color letterboxColor = Color::Black;
    bool autoScaleInCenterMode = true;
    float customScale = 1.0f;
    Vec2 customOffset = Vec2::Zero;
    Rect customViewport = Rect::Zero;
};

/**
 * @brief 视口计算结果结构体
 */
struct ViewportResult {
    Rect viewport;                        // 视口矩形
    float scaleX = 1.0f;                  // X方向缩放
    float scaleY = 1.0f;                  // Y方向缩放
    float uniformScale = 1.0f;            // 统一缩放
    Vec2 offset;                          // 视口偏移
    bool hasLetterbox = false;            // 是否有黑边

    struct Letterbox {
        Rect top;
        Rect bottom;
        Rect left;
        Rect right;
    } letterbox;
};

/**
 * @brief 视口适配器类
 * 
 * 处理不同屏幕尺寸的适配，保持逻辑分辨率与屏幕分辨率的映射关系
 */
class ViewportAdapter {
public:
    ViewportAdapter();
    ViewportAdapter(float logicWidth, float logicHeight);
    ~ViewportAdapter() = default;

    // 配置设置
    void setConfig(const ViewportConfig& config);
    const ViewportConfig& getConfig() const { return config_; }

    void setLogicSize(float width, float height);
    void setMode(ViewportMode mode);
    void setLetterboxPosition(LetterboxPosition position);
    void setLetterboxColor(const Color& color);

    // 更新和计算
    void update(int screenWidth, int screenHeight);
    const ViewportResult& getResult() const { return result_; }

    // 坐标转换
    Vec2 screenToLogic(const Vec2& screenPos) const;
    Vec2 logicToScreen(const Vec2& logicPos) const;
    Vec2 screenToLogic(float x, float y) const;
    Vec2 logicToScreen(float x, float y) const;

    // 矩阵获取
    glm::mat4 getMatrix() const;
    glm::mat4 getInvMatrix() const;

    // 区域检测
    bool isInViewport(const Vec2& screenPos) const;
    bool isInLetterbox(const Vec2& screenPos) const;

    // Getter 方法
    float getLogicWidth() const { return config_.logicWidth; }
    float getLogicHeight() const { return config_.logicHeight; }
    Size getLogicSize() const { return Size(config_.logicWidth, config_.logicHeight); }
    
    int getScreenWidth() const { return screenWidth_; }
    int getScreenHeight() const { return screenHeight_; }
    Size getScreenSize() const { return Size(static_cast<float>(screenWidth_), static_cast<float>(screenHeight_)); }
    
    float getScaleX() const { return result_.scaleX; }
    float getScaleY() const { return result_.scaleY; }
    float getUniformScale() const { return result_.uniformScale; }
    Vec2 getOffset() const { return result_.offset; }
    Rect getViewport() const { return result_.viewport; }
    bool hasLetterbox() const { return result_.hasLetterbox; }
    const ViewportResult::Letterbox& getLetterbox() const { return result_.letterbox; }

private:
    void calculateAspectRatio();
    void calculateStretch();
    void calculateCenter();
    void calculateCustom();
    void calculateLetterbox();
    void applyLetterboxPosition(float extraWidth, float extraHeight);

    ViewportConfig config_;
    ViewportResult result_;
    int screenWidth_ = 0;
    int screenHeight_ = 0;

    mutable glm::mat4 viewportMatrix_;
    mutable glm::mat4 inverseViewportMatrix_;
    mutable bool matrixDirty_ = true;
};

} // namespace extra2d