Extra2D/Extra2D/include/extra2d/render/camera/viewport_adapter.h

#pragma once

#include <extra2d/core/math_types.h>
#include <extra2d/core/types.h>
#include <string>

namespace extra2d {

/**
 * @brief 视口缩放模式
 */
enum class ViewportScaleMode {
    None,               // 无缩放
    Letterbox,          // 保持宽高比，黑边
    Crop,               // 保持宽高比，裁剪
    Stretch,            // 拉伸填充
    IntegerScale        // 整数缩放
};

/**
 * @brief 视口对齐方式
 */
enum class ViewportAlign {
    Center,
    TopLeft,
    TopCenter,
    TopRight,
    CenterLeft,
    CenterRight,
    BottomLeft,
    BottomCenter,
    BottomRight
};

/**
 * @brief 视口配置
 */
struct ViewportConfig {
    float designWidth = 1280.0f;
    float designHeight = 720.0f;
    ViewportScaleMode scaleMode = ViewportScaleMode::Letterbox;
    ViewportAlign align = ViewportAlign::Center;
    bool integerScaleOnly = false;
    float minScale = 0.5f;
    float maxScale = 4.0f;

    ViewportConfig() = default;

    ViewportConfig(float width, float height,
                   ViewportScaleMode mode = ViewportScaleMode::Letterbox)
        : designWidth(width), designHeight(height), scaleMode(mode) {}

    /**
     * @brief 创建 HD (1280x720) 配置
     */
    static ViewportConfig hd() {
        return ViewportConfig(1280.0f, 720.0f);
    }

    /**
     * @brief 创建 Full HD (1920x1080) 配置
     */
    static ViewportConfig fullHd() {
        return ViewportConfig(1920.0f, 1080.0f);
    }

    /**
     * @brief 创建 4K (3840x2160) 配置
     */
    static ViewportConfig uhd4k() {
        return ViewportConfig(3840.0f, 2160.0f);
    }
};

/**
 * @brief 视口计算结果
 */
struct ViewportResult {
    float x = 0.0f;
    float y = 0.0f;
    float width = 0.0f;
    float height = 0.0f;
    float scale = 1.0f;
    int offsetX = 0;
    int offsetY = 0;
    int screenWidth = 0;
    int screenHeight = 0;

    ViewportResult() = default;

    /**
     * @brief 获取视口矩形
     */
    Rect getRect() const { return Rect(x, y, width, height); }

    /**
     * @brief 获取缩放后的设计尺寸
     */
    Size getScaledDesignSize() const { return Size(width / scale, height / scale); }
};

/**
 * @brief 视口适配器
 *
 * 处理不同屏幕尺寸和宽高比的视口适配
 */
class ViewportAdapter {
public:
    ViewportAdapter();
    explicit ViewportAdapter(const ViewportConfig& config);
    ~ViewportAdapter() = default;

    // ========================================================================
    // 配置
    // ========================================================================

    /**
     * @brief 设置配置
     */
    void setConfig(const ViewportConfig& config);

    /**
     * @brief 获取配置
     */
    const ViewportConfig& getConfig() const { return config_; }

    /**
     * @brief 设置设计尺寸
     */
    void setDesignSize(float width, float height);

    /**
     * @brief 设置缩放模式
     */
    void setScaleMode(ViewportScaleMode mode);

    /**
     * @brief 设置对齐方式
     */
    void setAlign(ViewportAlign align);

    // ========================================================================
    // 更新
    // ========================================================================

    /**
     * @brief 更新视口
     */
    void update(int screenWidth, int screenHeight);

    /**
     * @brief 获取结果
     */
    const ViewportResult& getResult() const { return result_; }

    // ========================================================================
    // 查询
    // ========================================================================

    /**
     * @brief 获取设计宽度
     */
    float getDesignWidth() const { return config_.designWidth; }

    /**
     * @brief 获取设计高度
     */
    float getDesignHeight() const { return config_.designHeight; }

    /**
     * @brief 获取设计宽高比
     */
    float getDesignAspectRatio() const;

    /**
     * @brief 获取屏幕宽度
     */
    int getScreenWidth() const { return result_.screenWidth; }

    /**
     * @brief 获取屏幕高度
     */
    int getScreenHeight() const { return result_.screenHeight; }

    /**
     * @brief 获取屏幕宽高比
     */
    float getScreenAspectRatio() const;

    /**
     * @brief 获取当前缩放
     */
    float getScale() const { return result_.scale; }

    /**
     * @brief 获取视口偏移 X
     */
    int getOffsetX() const { return result_.offsetX; }

    /**
     * @brief 获取视口偏移 Y
     */
    int getOffsetY() const { return result_.offsetY; }

    // ========================================================================
    // 坐标转换
    // ========================================================================

    /**
     * @brief 屏幕坐标转设计坐标
     */
    Vec2 screenToDesign(const Vec2& screenPos) const;

    /**
     * @brief 设计坐标转屏幕坐标
     */
    Vec2 designToScreen(const Vec2& designPos) const;

    // ========================================================================
    // 调试
    // ========================================================================

    /**
     * @brief 获取调试名称
     */
    const std::string& getDebugName() const { return debugName_; }

    /**
     * @brief 设置调试名称
     */
    void setDebugName(const std::string& name) { debugName_ = name; }

private:
    /**
     * @brief 计算视口
     */
    void calculateViewport();

    /**
     * @brief 计算缩放
     */
    float calculateScale() const;

    /**
     * @brief 计算偏移
     */
    void calculateOffset();

    ViewportConfig config_;
    ViewportResult result_;
    std::string debugName_;
};

} // namespace extra2d