/**
 * Deep Research V2.0 — Word 导出服务
 *
 * 将 synthesisReport + resultList 拼接为完整 Markdown，
 * 调用 Python 微服务（Pandoc）转换为 .docx。
 *
 * 文献清单中标题直接作为超链接，确保 Word 中可点击。
 */

import axios from 'axios';
import { prisma } from '../../../config/database.js';
import { logger } from '../../../common/logging/index.js';
import type { LiteratureItem } from '../utils/resultParser.js';

const EXTRACTION_SERVICE_URL = process.env.EXTRACTION_SERVICE_URL || 'http://localhost:8000';

class WordExportService {

  async exportTaskToWord(taskId: string): Promise<{
    buffer: Buffer;
    filename: string;
  }> {
    const task = await prisma.aslResearchTask.findUnique({
      where: { id: taskId },
    });

    if (!task) throw new Error('任务不存在');
    if (task.status !== 'completed') throw new Error('任务尚未完成');

    const markdown = this.buildMarkdown(
      task.query,
      task.synthesisReport,
      task.resultList as LiteratureItem[] | null,
      task.completedAt,
    );

    const docxBuffer = await this.convertToDocx(markdown, task.query);

    const safeQuery = task.query.replace(/[^\u4e00-\u9fa5a-zA-Z0-9]/g, '').slice(0, 30);
    const dateStr = new Date().toISOString().slice(0, 10).replace(/-/g, '');
    const filename = `DeepResearch_${safeQuery}_${dateStr}.docx`;

    return { buffer: docxBuffer, filename };
  }

  private buildMarkdown(
    query: string,
    report: string | null,
    resultList: LiteratureItem[] | null,
    completedAt: Date | null,
  ): string {
    const parts: string[] = [];

    parts.push(`# Deep Research 报告\n`);
    parts.push(`检索主题： ${query}\n`);
    parts.push(`生成时间： ${completedAt ? new Date(completedAt).toLocaleString('zh-CN') : new Date().toLocaleString('zh-CN')}\n`);
    parts.push('---\n');

    if (report) {
      parts.push('## 综合分析报告\n');
      let cleaned = report.replace(/\*\*([^*]+)\*\*/g, '$1');
      cleaned = this.expandReferenceLinks(cleaned);
      parts.push(cleaned);
      parts.push('\n');
    }

    if (resultList && resultList.length > 0) {
      parts.push('---\n');
      parts.push(`## 文献清单（共 ${resultList.length} 篇）\n`);

      resultList.forEach((item, idx) => {
        const title = item.title || '(无标题)';
        const url = item.url || (item.pmid ? `https://pubmed.ncbi.nlm.nih.gov/${item.pmid}/` : '');

        const titleLine = url ? `[${title}](${url})` : title;
        parts.push(`### ${idx + 1}. ${titleLine}\n`);

        const details: string[] = [];
        if (item.authors) details.push(`作者: ${item.authors}`);
        if (item.journal) details.push(`期刊: ${item.journal}`);
        if (item.year) details.push(`年份: ${item.year}`);
        if (item.studyType) details.push(`研究类型: ${item.studyType}`);
        if (item.pmid) details.push(`PMID: ${item.pmid}`);

        if (details.length > 0) {
          parts.push(details.join(' | '));
        }

        if (url) {
          parts.push(`\n链接: ${url}`);
        }

        parts.push('\n');
      });
    }

    parts.push('---\n');
    parts.push('*本报告由 AI Clinical Research 平台 Deep Research 引擎自动生成*\n');

    return parts.join('\n');
  }

  /**
   * 将 [[N]](url) 格式的引用链接展开为 [N] url 形式，
   * 使 Word 中引用旁边可见完整 URL。
   */
  private expandReferenceLinks(text: string): string {
    return text.replace(
      /\[\[(\d+)\]\]\((https?:\/\/[^\s)]+)\)/g,
      '[$1]($2) ($2)'
    );
  }

  private async convertToDocx(markdown: string, title: string): Promise<Buffer> {
    try {
      logger.info('[WordExport] Converting Markdown → Word');

      const response = await axios.post(
        `${EXTRACTION_SERVICE_URL}/api/convert/docx`,
        {
          content: markdown,
          use_template: true,
          title: `Deep Research: ${title.slice(0, 50)}`,
        },
        {
          responseType: 'arraybuffer',
          timeout: 30000,
        }
      );

      logger.info(`[WordExport] Conversion success, size: ${response.data.length} bytes`);
      return Buffer.from(response.data);
    } catch (error) {
      logger.error('[WordExport] Conversion failed:', error);
      throw new Error(`Word 转换失败: ${error instanceof Error ? error.message : 'Unknown error'}`);
    }
  }
}

export const wordExportService = new WordExportService();