itools-gui 0.0.1

//! 渲染系统模块
//!
//! 提供 GUI 渲染功能，包括组件渲染、布局计算和绘制。

use crate::{components::Component, style::Style};

/// 渲染器结构体
pub struct Renderer {
    /// 渲染后端
    backend: Box<dyn RenderBackend>,
}

/// 渲染后端 trait
pub trait RenderBackend {
    /// 初始化渲染后端
    fn initialize(&mut self) -> Result<(), Box<dyn std::error::Error>>;

    /// 清理渲染后端
    fn cleanup(&mut self);

    /// 开始渲染帧
    fn begin_frame(&mut self);

    /// 结束渲染帧
    fn end_frame(&mut self);

    /// 渲染组件
    fn render_component(&mut self, component: &Component, x: f32, y: f32, width: f32, height: f32);

    /// 绘制矩形
    fn draw_rect(&mut self, x: f32, y: f32, width: f32, height: f32, style: &Style);

    /// 绘制文本
    fn draw_text(&mut self, text: &str, x: f32, y: f32, style: &Style);

    /// 测量文本尺寸
    fn measure_text(&mut self, text: &str, style: &Style) -> (f32, f32);
}

impl Renderer {
    /// 创建新的渲染器
    ///
    /// # 参数
    /// - `backend`: 渲染后端
    ///
    /// # 返回值
    /// 渲染器实例
    pub fn new(backend: Box<dyn RenderBackend>) -> Self {
        Self { backend }
    }

    /// 初始化渲染器
    ///
    /// # 返回值
    /// 初始化结果
    pub fn initialize(&mut self) -> Result<(), Box<dyn std::error::Error>> {
        self.backend.initialize()
    }

    /// 清理渲染器
    pub fn cleanup(&mut self) {
        self.backend.cleanup();
    }

    /// 开始渲染帧
    pub fn begin_frame(&mut self) {
        self.backend.begin_frame();
    }

    /// 结束渲染帧
    pub fn end_frame(&mut self) {
        self.backend.end_frame();
    }

    /// 渲染组件树
    ///
    /// # 参数
    /// - `root`: 根组件
    /// - `width`: 渲染宽度
    /// - `height`: 渲染高度
    pub fn render(&mut self, root: &Component, width: f32, height: f32) {
        self.begin_frame();
        self.render_component_recursive(root, 0.0, 0.0, width, height);
        self.end_frame();
    }

    /// 递归渲染组件
    ///
    /// # 参数
    /// - `component`: 当前组件
    /// - `x`: 组件 x 坐标
    /// - `y`: 组件 y 坐标
    /// - `width`: 组件宽度
    /// - `height`: 组件高度
    fn render_component_recursive(&mut self, component: &Component, x: f32, y: f32, width: f32, height: f32) {
        if !component.properties().visible {
            return;
        }

        // 渲染当前组件
        self.backend.render_component(component, x, y, width, height);

        // 递归渲染子组件
        for child in component.children() {
            // 这里将实现子组件的布局计算
            // 暂时使用简单的垂直布局
            let child_y = y + 50.0; // 简单示例，实际需要更复杂的布局计算
            self.render_component_recursive(child, x + 20.0, child_y, width - 40.0, 40.0);
        }
    }
}

/// 示例渲染后端
#[derive(Debug)]
pub struct ExampleRenderBackend {
    /// 初始化状态
    initialized: bool,
}

impl ExampleRenderBackend {
    /// 创建新的示例渲染后端
    ///
    /// # 返回值
    /// 示例渲染后端实例
    pub fn new() -> Self {
        Self { initialized: false }
    }
}

impl RenderBackend for ExampleRenderBackend {
    fn initialize(&mut self) -> Result<(), Box<dyn std::error::Error>> {
        println!("Initializing example render backend");
        self.initialized = true;
        Ok(())
    }

    fn cleanup(&mut self) {
        println!("Cleaning up example render backend");
        self.initialized = false;
    }

    fn begin_frame(&mut self) {
        println!("Beginning render frame");
    }

    fn end_frame(&mut self) {
        println!("Ending render frame");
    }

    fn render_component(&mut self, component: &Component, x: f32, y: f32, width: f32, height: f32) {
        println!("Rendering component {} at ({}, {}, {}, {})", component.id(), x, y, width, height);
        // 这里将实现实际的组件渲染逻辑
    }

    fn draw_rect(&mut self, x: f32, y: f32, width: f32, height: f32, _style: &Style) {
        println!("Drawing rect at ({}, {}, {}, {})", x, y, width, height);
        // 这里将实现实际的矩形绘制逻辑
    }

    fn draw_text(&mut self, text: &str, x: f32, y: f32, _style: &Style) {
        println!("Drawing text '{}' at ({}, {})", text, x, y);
        // 这里将实现实际的文本绘制逻辑
    }

    fn measure_text(&mut self, text: &str, _style: &Style) -> (f32, f32) {
        // 简单示例，返回固定尺寸
        (text.len() as f32 * 8.0, 16.0)
    }
}