import { marked, Renderer } from 'marked';
import type { Tokens } from 'marked';
import katex from 'katex';
import DOMPurify from 'dompurify';

const mdRenderer = new Renderer();
const defaultLinkRenderer = mdRenderer.link.bind(mdRenderer);
mdRenderer.link = (token: Tokens.Link): string => {
  const html = defaultLinkRenderer(token);
  return html.replace(/^<a\s/, '<a target="_blank" rel="noopener" ');
};

const renderLatexInHtml = (html: string): string => {
  // 匹配块级公式（$$...$$）
  html = html.replace(/\$\$(.*?)\$\$/gs, (_match, formula) => {
    return katex.renderToString(formula.trim(), {
      displayMode: true,
      throwOnError: false,
      strict: false,
      trust: true,
    });
  });
  // 匹配行内公式（$...$）
  html = html.replace(/\$(.*?)\$/g, (_match, formula) => {
    return katex.renderToString(formula.trim(), {
      displayMode: false,
      throwOnError: false,
      strict: false,
    });
  });
  return html;
};

const processFootnotes = (html: string, maxId?: number): string => {
  if (maxId === undefined) {
    // 无 citations 上下文，剥离所有 [^n] 标记
    return html.replace(/\[\^\d+\]/g, '');
  }
  // 有效编号范围 [1, maxId]，范围外的剥离
  return html.replace(/\[\^(\d+)\]/g, (_match, n) => {
    const id = parseInt(n, 10);
    if (id >= 1 && id <= maxId) {
      return `<sup class="footnote-ref" data-n="${id}">[${n}]</sup>`;
    }
    return '';
  });
};

export const renderMarkdown = (
  text: string,
  icons?: { copy: string; download: string; preview: string; copySuccess: string },
  maxCitationId?: number
): string => {
  if (!text) return '';
  const processed = text.replace(/<br\s*\/?>/gi, '  \n');
  let html = marked.parse(processed, { renderer: mdRenderer }) as string;
  html = processFootnotes(html, maxCitationId);
  html = renderLatexInHtml(html);
  // Sanitize HTML to prevent XSS attacks
  html = DOMPurify.sanitize(html, {
    ADD_TAGS: ['img'],
    ADD_ATTR: ['target', 'data-action', 'data-table', 'data-icon', 'data-icon-success', 'data-n'],
  });
  // 原始 HTML 锚点不经过 marked link renderer，统一补 target/rel
  html = html.replace(/<a\b[^>]*>/gi, (tag) => {
    let attrs = '';
    if (!/\btarget\s*=/i.test(tag)) attrs += ' target="_blank"';
    if (!/\brel\s*=/i.test(tag)) attrs += ' rel="noopener"';
    return attrs ? tag.replace(/^<a\b/i, '<a' + attrs) : tag;
  });
  return icons ? wrapTables(html, icons) : html;
};

export const wrapTables = (html: string, icons: { copy: string; download: string; preview: string; copySuccess: string }): string => {
  return html.replace(/<table>([\s\S]*?)<\/table>/g, (match) => {
    const encodedTable = encodeURIComponent(match);
    return `<div class="markdown-table-wrapper">
      <div class="table-actions">
        <span class="table-action-btn" data-action="copy" data-table="${encodedTable}" data-icon="${icons.copy}" data-icon-success="${icons.copySuccess}" title="复制Markdown">
          <img src="${icons.copy}" width="14" height="14" />
        </span>
        <span class="table-action-btn" data-action="csv" data-table="${encodedTable}" title="下载CSV">
          <img src="${icons.download}" width="14" height="14" />
        </span>
        <span class="table-action-btn" data-action="preview" data-table="${encodedTable}" title="预览表格">
          <img src="${icons.preview}" width="14" height="14" />
        </span>
      </div>
      ${match}
    </div>`;
  });
};

export const tableHtmlToMarkdown = (tableHtml: string): string => {
  const parser = new DOMParser();
  const doc = parser.parseFromString(tableHtml, 'text/html');
  const table = doc.querySelector('table');
  if (!table) return tableHtml;

  const rows: string[][] = [];
  table.querySelectorAll('tr').forEach((tr) => {
    const cells: string[] = [];
    tr.querySelectorAll('th, td').forEach((cell) => {
      cells.push(cell.textContent?.trim() || '');
    });
    rows.push(cells);
  });

  if (rows.length === 0) return tableHtml;

  const colCount = Math.max(...rows.map((r) => r.length));
  const normalized = rows.map((r) => {
    while (r.length < colCount) r.push('');
    return r;
  });

  const lines: string[] = [];
  lines.push('| ' + normalized[0].join(' | ') + ' |');
  lines.push('| ' + normalized[0].map(() => '---').join(' | ') + ' |');
  for (let i = 1; i < normalized.length; i++) {
    lines.push('| ' + normalized[i].join(' | ') + ' |');
  }
  return lines.join('\n');
};

export const tableHtmlToCsv = (tableHtml: string): string => {
  const parser = new DOMParser();
  const doc = parser.parseFromString(tableHtml, 'text/html');
  const table = doc.querySelector('table');
  if (!table) return '';

  const rows: string[] = [];
  table.querySelectorAll('tr').forEach((tr) => {
    const cells: string[] = [];
    tr.querySelectorAll('th, td').forEach((cell) => {
      const text = (cell.textContent?.trim() || '').replace(/"/g, '""');
      cells.push(`"${text}"`);
    });
    rows.push(cells.join(','));
  });

  return '' + rows.join('\n');
};

export const formatFileSize = (bytes: number): string => {
  if (bytes < 1024) return bytes + ' B';
  if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(2) + ' KB';
  return (bytes / (1024 * 1024)).toFixed(2) + ' MB';
};

export const isImageFile = (filename: string): boolean => /\.(jpg|jpeg|png|gif|bmp|webp|svg|ico|tiff|tif)$/i.test(filename);

export const isPdfFile = (filename: string): boolean => /\.pdf$/i.test(filename);

export const isVideoFile = (filename: string): boolean => /\.(mp4|webm|ogg|mov|avi|mkv|flv|wmv|m4v)$/i.test(filename);

export const isAudioFile = (filename: string): boolean => /\.(mp3|wav|ogg|aac|flac|wma|m4a|opus)$/i.test(filename);

export const isMdFile = (filename: string): boolean => /\.md$/i.test(filename);

export const isWordFile = (filename: string): boolean => /\.(doc|docx)$/i.test(filename);

export const isOldDocFile = (filename: string): boolean => /\.doc$/i.test(filename) && !/\.docx$/i.test(filename);

export const isExcelFile = (filename: string): boolean => /\.(xls|xlsx)$/i.test(filename);

export const isCsvFile = (filename: string): boolean => /\.csv$/i.test(filename);

export const isTextFile = (filename: string): boolean =>
  /\.(txt|md|json|csv|xml|yaml|yml|log|ini|toml|cfg|conf|env|gitignore|dockerignore|editorconfig|prettierrc|eslintrc|babelrc|properties|sh|bat|ps1|cmd|bash|zsh|fish|sql|graphql|proto|js|ts|jsx|tsx|vue|css|scss|sass|less|html|htm|svelte|py|java|kt|kts|c|cpp|h|hpp|cc|cxx|cs|go|rs|rb|php|swift|m|mm|r|R|lua|pl|pm|hs|ex|exs|erl|clj|scala|dart|zig|nim|v|sol|tf|hcl|gradle|cmake|makefile|mk)$/i.test(
    filename
  );

export const getFileExtension = (filename: string): string => {
  const match = filename.match(/\.([^.]+)$/);
  return match ? `.${match[1]}`.toUpperCase() : '';
};