import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer, SafeHtml } from '@angular/platform-browser';
import { marked } from 'marked';
import Prism from 'prismjs';

// 导入需要的语言支持
import 'prismjs/components/prism-clike';
import 'prismjs/components/prism-markup';
import 'prismjs/components/prism-javascript';
import 'prismjs/components/prism-typescript';
import 'prismjs/components/prism-python';
import 'prismjs/components/prism-go';
import 'prismjs/components/prism-java';
import 'prismjs/components/prism-csharp';
import 'prismjs/components/prism-php';
import 'prismjs/components/prism-ruby';
import 'prismjs/components/prism-bash';
import 'prismjs/components/prism-sql';
import 'prismjs/components/prism-json';
import 'prismjs/components/prism-yaml';
import 'prismjs/components/prism-markdown';

@Pipe({
  name: 'markdown',
  standalone: true
})
export class MarkdownPipe implements PipeTransform {
  constructor(private sanitizer: DomSanitizer) {}

  transform(value: string): SafeHtml {
    if (!value) {
      return '';
    }

    // 预处理：将标签替换为美化版本
    const processedContent = this.preprocessTags(value);
    
    // 配置marked（使用基本配置）
    marked.setOptions({
      gfm: true,
      breaks: true
    });

    // 解析markdown
    let html = marked.parse(processedContent) as string;
    
    // 后处理：添加代码高亮和样式
    html = this.postprocessCodeBlocks(html);
    
    // 安全注入HTML
    return this.sanitizer.bypassSecurityTrustHtml(html);
  }

  /**
   * 预处理：将文本标签替换为美化版本和可折叠区域
   */
  private preprocessTags(content: string): string {
    // 处理 [思考] 标签及其内容
    content = this.processTagWithContent(content, '思考', '💭', 'thinking');
    
    // 处理 [工具] 标签及其内容
    content = this.processTagWithContent(content, '工具', '🛠️', 'tool');
    
    // 处理 [错误] 标签
    content = content.replace(/\[错误\]/g, '<span class="error-tag">❌ 错误</span>');
    
    return content;
  }

  /**
   * 处理标签及其后的内容，转换为可折叠区域
   */
  private processTagWithContent(content: string, tagName: string, emoji: string, cssClass: string): string {
    // 正则表达式匹配 [标签] 及其后的内容（直到下一个标签或字符串结束）
    const pattern = new RegExp(`\\[${tagName}\\]\\s*([\\s\\S]*?)(?=\\n\\s*\\[|$)`, 'g');
    
    return content.replace(pattern, (match, tagContent) => {
      // 清理内容前后的空白
      const trimmedContent = tagContent.trim();
      if (!trimmedContent) {
        return `<details class="${cssClass}-details"><summary class="${cssClass}-summary">${emoji} ${tagName}</summary></details>`;
      }
      
      return `<details class="${cssClass}-details" ${cssClass === 'thinking' || cssClass === 'tool' ? '' : 'open'}><summary class="${cssClass}-summary">${emoji} ${tagName}</summary>${trimmedContent}</details>`;
    });
  }

  /**
   * 后处理：添加代码高亮和样式
   */
  private postprocessCodeBlocks(html: string): string {
    // 使用正则表达式匹配代码块
    const codeBlockRegex = /<pre><code\s*(?:class="language-([^"]+)")?>([\s\S]*?)<\/code><\/pre>/gi;
    
    html = html.replace(codeBlockRegex, (match, lang, code) => {
      const language = lang || 'plaintext';
      
      try {
        // 使用Prism高亮代码
        const highlighted = Prism.highlight(code, Prism.languages[language] || Prism.languages['plaintext'], language);
        return `<pre class="prism-code language-${language}"><code class="language-${language}">${highlighted}</code></pre>`;
      } catch (e) {
        // 如果高亮失败，返回原始代码块
        return `<pre class="prism-code language-${language}"><code class="language-${language}">${code}</code></pre>`;
      }
    });
    
    return html;
  }
}