'use client';

import { useEffect, useRef, useState, useCallback, useMemo } from 'react';
import Reveal from 'reveal.js';
import 'reveal.js/dist/reveal.css';
import { marked } from 'marked';

const parseThemeFromContent = (content) => {
  if (!content || !content.startsWith('---')) return null;
  
  const frontmatterEnd = content.indexOf('---', 3);
  if (frontmatterEnd === -1) return null;
  
  const frontmatter = content.substring(3, frontmatterEnd);
  const themeMatch = frontmatter.match(/theme:\s*(\w+)/);
  return themeMatch ? themeMatch[1] : null;
};

const loadTheme = async (themeName) => {
  if (!themeName) return;
  
  try {
    await import(`./themes/${themeName}.css`);
  } catch (error) {
    try {
      await import(`reveal.js/dist/theme/${themeName}.css`);
    } catch (error2) {
      await import('reveal.js/dist/theme/black.css');
    }
  }
};

const REVEAL_CONFIG = {
  hash: true,
  transition: 'slide',
  transitionSpeed: 'default',
  backgroundTransition: 'fade',
  controls: true,
  progress: true,
  center: true,
  touch: true,
  loop: false,
  rtl: false,
  navigationMode: 'default',
  shuffle: false,
  fragments: true,
  fragmentInURL: false,
  embedded: false,
  help: true,
  showNotes: true,
  autoPlayMedia: null,
  preloadIframes: null,
  autoSlide: 0,
  autoSlideStoppable: true,
  autoSlideMethod: Reveal.navigateNext,
  defaultTiming: null,
  mouseWheel: false,
  hideInactiveCursor: true,
  hideCursorTime: 5000,
  previewLinks: false,
  postMessage: true,
  postMessageEvents: false,
  focusBodyOnPageVisibilityChange: true,
  viewDistance: 3,
  mobileViewDistance: 2,
  display: 'block',
  hideAnchorsOnUrl: false,
  plugins: []
};

marked.setOptions({
  breaks: true,
  gfm: true,
  headerIds: false,
  mangle: false,
});

export default function Presentation({ data }) {
  const deckRef = useRef(null);
  const revealRef = useRef(null);
  const [mounted, setMounted] = useState(false);
  const [error, setError] = useState(null);

  useEffect(() => {
    setMounted(true);
  }, []);

  const parseMarkdownToSlides = useCallback((data) => {
    if (!data) {
      return `<section><h1>演示文稿</h1><p>暂无内容</p></section>`;
    }

    try {
      if (data.content) {
        return parseContentSlides(data);
      }

      return `<section><h1>${data.title || '演示文稿'}</h1><p>暂无内容</p></section>`;
    } catch (err) {
      return `<section><h1>解析错误</h1><p>内容解析失败，请检查数据格式</p></section>`;
    }
  }, []);

  const parseContentSlides = (data) => {
    // 移除frontmatter部分，只处理内容部分
    let content = data.content;
    
    // 如果内容以---开头，说明有frontmatter，需要移除
    if (content.startsWith('---')) {
      const frontmatterEnd = content.indexOf('---', 3);
      if (frontmatterEnd !== -1) {
        content = content.substring(frontmatterEnd + 3).trim();
      }
    }
    
    const slideSeparators = /^---$/gm;
    const sections = content.split(slideSeparators);
    
    return sections.map((section, index) => {
      const trimmedSection = section.trim();
      if (!trimmedSection) return '';
      
      // 匹配背景和类属性
      const slideCommentMatch = trimmedSection.match(/<!-- \.slide: ([^>]+) -->/);
      let backgroundAttr = '';
      let classAttr = '';
      let contentWithoutComment = trimmedSection;
      
      if (slideCommentMatch) {
        const slideAttrs = slideCommentMatch[1];
        
        // 提取data-background属性
        const backgroundMatch = slideAttrs.match(/data-background="([^"]+)"/);
        if (backgroundMatch) {
          backgroundAttr = ` data-background="${backgroundMatch[1]}"`;
        }
        
        // 提取class属性
        const classMatch = slideAttrs.match(/class="([^"]+)"/);
        if (classMatch) {
          classAttr = ` class="${classMatch[1]}"`;
        }
        
        // 移除整个slide注释
        contentWithoutComment = trimmedSection.replace(/<!-- \.slide: [^>]+ -->/g, '');
      }
      
      const htmlContent = marked(contentWithoutComment);
      
      if (index === 0 && !htmlContent.includes('<h1>') && data.title) {
        return `<section${backgroundAttr}${classAttr}><h1>${data.title}</h1>${htmlContent}</section>`;
      }
      
      return `<section${backgroundAttr}${classAttr}>${htmlContent}</section>`;
    }).join('');
  };

  const initializeReveal = useCallback(async () => {
    if (!deckRef.current || !data) return;

    try {
      if (revealRef.current) {
        revealRef.current.destroy();
      }

      const themeName = data.theme || parseThemeFromContent(data.content) || 'default';
      await loadTheme(themeName);

      revealRef.current = new Reveal(deckRef.current, REVEAL_CONFIG);
      revealRef.current.initialize();

      const slides = parseMarkdownToSlides(data);
      const slidesContainer = deckRef.current.querySelector('.slides');
      if (slidesContainer) {
        slidesContainer.innerHTML = slides;
      }

      setError(null);
    } catch (err) {
      setError('PPT初始化失败，请刷新页面重试');
    }
  }, [data, parseMarkdownToSlides]);

  useEffect(() => {
    if (mounted && data) {
      initializeReveal();
    }

    return () => {
      if (revealRef.current) {
        revealRef.current.destroy();
      }
    };
  }, [mounted, data, initializeReveal]);

  if (error) {
    return (
      <div className="min-h-screen bg-black flex items-center justify-center">
        <div className="text-white text-xl text-center">
          <p className="mb-4">PPT加载失败</p>
          <p className="text-sm text-gray-400">{error}</p>
          <button 
            onClick={() => window.location.reload()} 
            className="mt-4 px-4 py-2 bg-blue-600 text-white rounded hover:bg-blue-700"
          >
            刷新页面
          </button>
        </div>
      </div>
    );
  }



  return (
    <>
      <div className="reveal-container">
        <div 
          ref={deckRef} 
          className="reveal"
        >
          <div className="slides">
          </div>
        </div>
      </div>

      <style jsx global>{`
        .reveal-container {
          height: 100%;
          width: 100%;
          position: fixed;
          top: 0;
          left: 0;
          z-index: 1000;
        }

        .reveal-container .reveal .slides section {
          height: 100% !important;
          display: flex !important;
          flex-direction: column !important;
          justify-content: center !important;
          align-items: center !important;
          text-align: center !important;
          padding: 2rem !important;
          box-sizing: border-box !important;
        }

        .reveal-container .reveal .slides section > * {
          margin: 0.5rem 0 !important;
        }

        .reveal-container .reveal .slides section h1,
        .reveal-container .reveal .slides section h2,
        .reveal-container .reveal .slides section h3 {
          margin-bottom: 1rem !important;
        }

        .reveal-container .reveal .slides section p {
          margin: 0.5rem 0 !important;
          line-height: 1.6 !important;
        }

        .reveal-container .reveal .slides section img,
        .reveal-container .reveal .slides section video {
          max-width: 100% !important;
          height: auto !important;
          margin: 1rem 0 !important;
        }
      `}</style>
    </>
  );
}