//! PDF 渲染器模块 - Phase 3 (简化版)
//! 
//! 基于 pdfium-render 实现 PDF 文档渲染
//! 注意：实际使用需要配置 PDFium 二进制路径

use anyhow::Result;
use serde::{Deserialize, Serialize};

/// PDF 页面
#[derive(Debug, Clone)]
pub struct PdfPage {
    /// 页面索引 (从 0 开始)
    pub index: usize,
    /// 页面宽度 (points)
    pub width: f32,
    /// 页面高度 (points)
    pub height: f32,
}

/// PDF 文档
#[derive(Debug, Clone)]
pub struct PdfDocument {
    /// 文档标题
    pub title: String,
    /// 文件路径
    pub path: String,
    /// 总页数
    pub total_pages: usize,
    /// 页面列表
    pub pages: Vec<PdfPage>,
    /// 当前页
    pub current_page: usize,
}

/// PDF 渲染配置
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PdfRenderConfig {
    /// 缩放比例 (1.0 = 100%)
    pub scale: f32,
    /// 渲染宽度 (像素)
    pub render_width: u32,
    /// 是否启用抗锯齿
    pub antialias: bool,
}

impl Default for PdfRenderConfig {
    fn default() -> Self {
        Self {
            scale: 1.0,
            render_width: 1200,
            antialias: true,
        }
    }
}

/// PDF 渲染器
pub struct PdfRenderer {
    config: PdfRenderConfig,
    initialized: bool,
}

impl PdfRenderer {
    /// 创建 PDF 渲染器
    pub fn new(config: PdfRenderConfig) -> Result<Self> {
        Ok(Self {
            config,
            initialized: false,
        })
    }
    
    /// 初始化 PDFium (需要指定路径)
    pub fn init_pdfium(&mut self, pdfium_path: &str) -> Result<()> {
        // 实际实现需要绑定 PDFium 库
        // 这里仅做标记
        self.initialized = true;
        tracing::info!("PDFium initialized from: {}", pdfium_path);
        Ok(())
    }
    
    /// 检查是否已初始化
    pub fn is_initialized(&self) -> bool {
        self.initialized
    }
    
    /// 获取 PDF 文档信息
    pub fn get_pdf_info(&self, path: &str) -> Result<PdfDocument> {
        // TODO: 实际实现需要 pdfium-render
        // 这里返回模拟数据用于测试
        
        let title = std::path::Path::new(path)
            .file_stem()
            .and_then(|s| s.to_str())
            .unwrap_or("Untitled")
            .to_string();
        
        // 模拟 10 页文档
        let mut pages = Vec::new();
        for i in 0..10 {
            pages.push(PdfPage {
                index: i,
                width: 612.0, // Letter 尺寸
                height: 792.0,
            });
        }
        
        Ok(PdfDocument {
            title,
            path: path.to_string(),
            total_pages: pages.len(),
            pages,
            current_page: 0,
        })
    }
    
    /// 更新缩放比例
    pub fn set_scale(&mut self, scale: f32) {
        self.config.scale = scale.clamp(0.5, 3.0);
    }
    
    /// 获取当前配置
    pub fn get_config(&self) -> &PdfRenderConfig {
        &self.config
    }
    
    /// 生成 PDF 页面 HTML (占位符)
    pub fn page_to_html(&self, page: &PdfPage) -> String {
        format!(
            r#"<div class="pdf-page" data-page="{}" style="width: {}px; height: {}px;">
  <div class="pdf-page-placeholder">Page {}</div>
</div>"#,
            page.index + 1,
            page.width,
            page.height,
            page.index + 1
        )
    }
    
    /// 生成完整 PDF HTML
    pub fn document_to_html(&self, doc: &PdfDocument) -> String {
        let mut html = String::new();
        html.push_str("<div class=\"pdf-document\">\n");
        
        for page in &doc.pages {
            html.push_str(&self.page_to_html(page));
        }
        
        html.push_str("</div>");
        html
    }
}

/// PDF 导航状态
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PdfNavigation {
    /// 当前页
    pub current_page: usize,
    /// 总页数
    pub total_pages: usize,
    /// 缩放比例
    pub zoom: f32,
}

impl PdfNavigation {
    pub fn new(total_pages: usize) -> Self {
        Self {
            current_page: 0,
            total_pages,
            zoom: 1.0,
        }
    }
    
    pub fn next_page(&mut self) {
        if self.current_page < self.total_pages - 1 {
            self.current_page += 1;
        }
    }
    
    pub fn prev_page(&mut self) {
        if self.current_page > 0 {
            self.current_page -= 1;
        }
    }
    
    pub fn goto_page(&mut self, page: usize) {
        self.current_page = page.min(self.total_pages - 1);
    }
    
    pub fn zoom_in(&mut self) {
        self.zoom = (self.zoom + 0.25).min(3.0);
    }
    
    pub fn zoom_out(&mut self) {
        self.zoom = (self.zoom - 0.25).max(0.5);
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    
    #[test]
    fn test_pdf_renderer_creation() {
        let renderer = PdfRenderer::new(PdfRenderConfig::default());
        assert!(renderer.is_ok());
        
        let renderer = renderer.unwrap();
        assert!(!renderer.is_initialized());
    }
    
    #[test]
    fn test_pdf_navigation() {
        let mut nav = PdfNavigation::new(10);
        
        assert_eq!(nav.current_page, 0);
        assert_eq!(nav.total_pages, 10);
        
        nav.next_page();
        assert_eq!(nav.current_page, 1);
        
        nav.prev_page();
        assert_eq!(nav.current_page, 0);
        
        nav.goto_page(5);
        assert_eq!(nav.current_page, 5);
        
        nav.zoom_in();
        assert_eq!(nav.zoom, 1.25);
        
        nav.zoom_out();
        assert_eq!(nav.zoom, 1.0);
    }
    
    #[test]
    fn test_scale_clamping() {
        let mut renderer = PdfRenderer::new(PdfRenderConfig::default()).unwrap();
        
        renderer.set_scale(0.1);
        assert_eq!(renderer.config.scale, 0.5);
        
        renderer.set_scale(5.0);
        assert_eq!(renderer.config.scale, 3.0);
        
        renderer.set_scale(1.5);
        assert_eq!(renderer.config.scale, 1.5);
    }
    
    #[test]
    fn test_pdf_info() {
        let renderer = PdfRenderer::new(PdfRenderConfig::default()).unwrap();
        let doc = renderer.get_pdf_info("test.pdf");
        
        assert!(doc.is_ok());
        let doc = doc.unwrap();
        assert_eq!(doc.title, "test");
        assert_eq!(doc.total_pages, 10);
    }
}
