import { DocumentAST, DocumentBlock } from '../types/block';
import { recomputeNumbering, cleanHeadingContent } from './autoNumber';

const REG_PATTERN = /(?:GB(?:\/T)?\s*\d+(?:\.\d+)?(?:-\d{4})?|YY(?:\/T)?\s*\d+(?:\.\d+)?(?:-\d{4})?|ISO\s*\d+|IEC\s*\d+|MDR|FDA|NMPA)/g;

function generateId(): string {
  return 'blk_' + Math.random().toString(36).substring(2, 10);
}

/**
 * markdownToBlockAST: 将 Markdown 文本解析为 Block AST 树
 */
export function markdownToBlockAST(
  md: string,
  meta?: Partial<DocumentAST>
): DocumentAST {
  const safeMd = typeof md === 'string' ? md : '';
  const lines = safeMd.split(/\r?\n/);
  const blocks: DocumentBlock[] = [];

  let i = 0;
  while (i < lines.length) {
    const rawLine = lines[i];
    const trimmed = rawLine.trim();

    // 空行跳过
    if (trimmed === '') {
      i++;
      continue;
    }

    // 1. 分隔线 (Divider)
    if (/^(\*{3,}|-{3,}|_{3,})$/.test(trimmed)) {
      blocks.push({
        id: generateId(),
        type: 'divider',
        content: '',
      });
      i++;
      continue;
    }

    // 2. 标题 (Heading # ~ ######)
    const headingMatch = rawLine.match(/^(#{1,6})\s+(.*)$/);
    if (headingMatch) {
      const level = headingMatch[1].length;
      const rawTitle = headingMatch[2].trim();
      const cleanedTitle = cleanHeadingContent(rawTitle);

      blocks.push({
        id: generateId(),
        type: 'heading',
        level,
        content: cleanedTitle || rawTitle,
      });
      i++;
      continue;
    }

    // 3. 代码围栏 (Code Block: ```mermaid / ```math / ```)
    if (trimmed.startsWith('```')) {
      const lang = trimmed.slice(3).trim().toLowerCase();
      const codeLines: string[] = [];
      i++;
      while (i < lines.length && !lines[i].trim().startsWith('```')) {
        codeLines.push(lines[i]);
        i++;
      }
      if (i < lines.length && lines[i].trim().startsWith('```')) {
        i++; // 跳过结束 fence
      }

      const codeContent = codeLines.join('\n');
      if (lang === 'mermaid') {
        blocks.push({
          id: generateId(),
          type: 'mermaid',
          content: codeContent,
          properties: {
            caption: '系统拓扑与流转时序图',
          },
        });
      } else if (lang === 'math' || lang === 'latex') {
        blocks.push({
          id: generateId(),
          type: 'math',
          content: codeContent,
        });
      } else {
        // 普通段落代码块
        blocks.push({
          id: generateId(),
          type: 'paragraph',
          content: '```' + lang + '\n' + codeContent + '\n```',
        });
      }
      continue;
    }

    // 4. 数学公式 ($$ ... $$)
    if (trimmed.startsWith('$$')) {
      const mathLines: string[] = [];
      if (trimmed.length > 2 && trimmed.endsWith('$$')) {
        // 单行 $$公式$$
        mathLines.push(trimmed.slice(2, -2).trim());
        i++;
      } else {
        i++;
        while (i < lines.length && !lines[i].trim().endsWith('$$')) {
          mathLines.push(lines[i]);
          i++;
        }
        if (i < lines.length && lines[i].trim().endsWith('$$')) {
          const last = lines[i].trim();
          if (last !== '$$') {
            mathLines.push(last.replace(/\$\$$/, '').trim());
          }
          i++;
        }
      }
      blocks.push({
        id: generateId(),
        type: 'math',
        content: mathLines.join('\n'),
      });
      continue;
    }

    // 5. 引用/合规警示块 (> ...)
    if (trimmed.startsWith('>')) {
      const calloutLines: string[] = [];
      while (i < lines.length && lines[i].trim().startsWith('>')) {
        calloutLines.push(lines[i].trim().replace(/^>\s?/, ''));
        i++;
      }
      const calloutText = calloutLines.join(' ');
      const regs = Array.from(calloutText.matchAll(REG_PATTERN), (m) => m[0]);
      blocks.push({
        id: generateId(),
        type: 'callout',
        content: calloutText,
        properties: {
          calloutType: regs.length > 0 ? 'regulatory' : 'info',
          regulations: regs,
        },
      });
      continue;
    }

    // 6. GFM 表格 (| col1 | col2 |)
    if (trimmed.startsWith('|') && trimmed.endsWith('|')) {
      const tableRows: string[][] = [];
      while (i < lines.length && lines[i].trim().startsWith('|') && lines[i].trim().endsWith('|')) {
        const curRow = lines[i].trim();
        // 忽略表头分割线行 |---|---|
        if (!/^\|(?:\s*:?-+:?\s*\|)+$/.test(curRow)) {
          const cells = curRow
            .slice(1, -1)
            .split('|')
            .map((c) => c.trim());
          tableRows.push(cells);
        }
        i++;
      }

      blocks.push({
        id: generateId(),
        type: 'table',
        content: '',
        properties: {
          tableData: tableRows,
          caption: '技术参数与法规符合性对照表',
        },
      });
      continue;
    }

    // 7. 纯独立列表块 (List Block: 全部非空行均为列表语法)
    if (/^\s*(\d+\.|[-*+])\s+/.test(trimmed)) {
      const listLines: string[] = [];
      const isOrdered = /^\s*\d+\.\s+/.test(trimmed);
      let startNumber = 1;
      if (isOrdered) {
        const m = trimmed.match(/^\s*(\d+)\./);
        if (m) startNumber = parseInt(m[1], 10) || 1;
      }

      while (
        i < lines.length &&
        lines[i].trim() !== '' &&
        /^\s*(\d+\.|[-*+])\s+/.test(lines[i].trim())
      ) {
        listLines.push(lines[i]);
        i++;
      }

      const listItems = listLines
        .map((l) => l.replace(/^\s*(\d+\.|[-*+])\s+/, '').trim())
        .filter(Boolean);

      blocks.push({
        id: generateId(),
        type: 'list',
        content: listLines.join('\n'),
        properties: {
          isOrdered,
          startNumber,
          listItems,
        },
      });
      continue;
    }

    // 8. 常规段落 (Paragraph)
    const paraLines: string[] = [];
    while (
      i < lines.length &&
      lines[i].trim() !== '' &&
      !lines[i].trim().startsWith('#') &&
      !lines[i].trim().startsWith('```') &&
      !lines[i].trim().startsWith('$$') &&
      !lines[i].trim().startsWith('>') &&
      !(lines[i].trim().startsWith('|') && lines[i].trim().endsWith('|')) &&
      !/^\s*(\d+\.|[-*+])\s+/.test(lines[i].trim()) &&
      !/^(\*{3,}|-{3,}|_{3,})$/.test(lines[i].trim())
    ) {
      paraLines.push(lines[i]);
      i++;
    }

    const paraContent = paraLines.join('\n');
    const regs = Array.from(paraContent.matchAll(REG_PATTERN), (m) => m[0]);

    blocks.push({
      id: generateId(),
      type: 'paragraph',
      content: paraContent,
      properties: {
        regulations: regs.length > 0 ? regs : undefined,
      },
    });
  }

  const rootBlock: DocumentBlock = {
    id: 'root-doc',
    type: 'document',
    content: '',
    children: blocks,
  };

  // 执行自动重编号
  recomputeNumbering(rootBlock);

  return {
    docId: meta?.docId || 'doc_' + Math.random().toString(36).substring(2, 8),
    title: meta?.title || (blocks[0]?.type === 'heading' ? blocks[0].content : '未命名受控文档'),
    taskKey: meta?.taskKey || 'feasibility_reg',
    version: meta?.version || 'V1.0',
    category: meta?.category || 'workflow',
    creatorId: meta?.creatorId,
    creatorName: meta?.creatorName,
    sharedAt: meta?.sharedAt,
    lifecycleState: meta?.lifecycleState || 'drafting',
    isClaimed: meta?.isClaimed ?? false,
    author: meta?.author || '',
    authorId: meta?.authorId,
    reviewer: meta?.reviewer || '',
    reviewerId: meta?.reviewerId,
    approver: meta?.approver || '',
    approverId: meta?.approverId,
    dutiesAuthoritative: meta?.dutiesAuthoritative,
    dutyPolicy: meta?.dutyPolicy,
    revisionEtag: meta?.revisionEtag,
    summary: meta?.summary || '由项目助手自动生成的受控交付物',
    updatedAt: meta?.updatedAt || new Date().toISOString().replace('T', ' ').substring(0, 16),
    rootBlock,
  };
}