ui: drop vditor

packages/ui-default/backendlib/markdown-it-katex.ts

@@ -0,0 +1,140 @@
+// https://github.com/waylonflinn/markdown-it-katex/blob/master/index.js
+import { Logger } from 'hydrooj';
+import katex from 'katex';
+
+const logger = new Logger('katex');
+
+function isValidDelim(state, pos) {
+  const max = state.posMax;
+  const prevChar = pos > 0 ? state.src.charCodeAt(pos - 1) : -1;
+  const nextChar = pos + 1 <= max ? state.src.charCodeAt(pos + 1) : -1;
+  let canOpen = true;
+  let canClose = true;
+  if (prevChar === 0x09
+    ||/* \t */ (nextChar >= 0x30/* "0" */ && nextChar <= 0x39/* "9" */)) canClose = false;
+  if (nextChar === 0x09/* \t */) canOpen = false;
+  return {
+    canOpen,
+    canClose,
+  };
+}
+
+function inline(state, silent) {
+  let pos;
+  if (state.src[state.pos] !== '$') return false;
+  let res = isValidDelim(state, state.pos);
+  if (!res.canOpen) {
+    if (!silent) state.pending += '$';
+    state.pos += 1;
+    return true;
+  }
+  const start = state.pos + 1;
+  let match = start;
+  // eslint-disable-next-line no-cond-assign
+  while ((match = state.src.indexOf('$', match)) !== -1) {
+    pos = match - 1;
+    while (state.src[pos] === '\\') pos -= 1;
+    if ((match - pos) % 2) break;
+    match += 1;
+  }
+  if (match === -1) {
+    if (!silent) state.pending += '$';
+    state.pos = start;
+    return true;
+  }
+  if (match - start === 0) {
+    if (!silent) state.pending += '$$';
+    state.pos = start + 1;
+    return true;
+  }
+  res = isValidDelim(state, match);
+  if (!res.canClose) {
+    if (!silent) state.pending += '$';
+    state.pos = start;
+    return true;
+  }
+  if (!silent) {
+    const token = state.push('math_inline', 'math', 0);
+    token.markup = '$';
+    token.content = state.src.slice(start, match);
+  }
+  state.pos = match + 1;
+  return true;
+}
+
+function escapeHtml(unsafe) {
+  return unsafe
+    .replace(/&/g, '&amp;')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#039;');
+}
+
+function block(state, start, end, silent) {
+  let lastLine;
+  let lastPos;
+  let found = false;
+  let pos = state.bMarks[start] + state.tShift[start];
+  let max = state.eMarks[start];
+  if (pos + 2 > max) return false;
+  if (state.src.slice(pos, pos + 2) !== '$$') return false;
+  pos += 2;
+  let firstLine = state.src.slice(pos, max);
+  if (silent) return true;
+  if (firstLine.trim().slice(-2) === '$$') {
+    firstLine = firstLine.trim().slice(0, -2);
+    found = true;
+  }
+  let next = start;
+  while (!found) {
+    next++;
+    if (next >= end) break;
+    pos = state.bMarks[next] + state.tShift[next];
+    max = state.eMarks[next];
+    if (pos < max && state.tShift[next] < state.blkIndent) break;
+    if (state.src.slice(pos, max).trim().slice(-2) === '$$') {
+      lastPos = state.src.slice(0, max).lastIndexOf('$$');
+      lastLine = state.src.slice(pos, lastPos);
+      found = true;
+    }
+  }
+  state.line = next + 1;
+  const token = state.push('math_block', 'math', 0);
+  token.block = true;
+  token.content = (firstLine && firstLine.trim() ? `${firstLine}\n` : '')
+    + state.getLines(start + 1, next, state.tShift[start], true)
+    + (lastLine && lastLine.trim() ? lastLine : '');
+  token.map = [start, state.line];
+  token.markup = '$$';
+  return true;
+}
+
+export default function plugin(md) {
+  const options = { throwOnError: false, strict: 'ignore', displayMode: false };
+  const render = (latex: string, displayMode = false) => {
+    options.displayMode = displayMode;
+    try {
+      latex = latex.replace(/\\def{\\([a-zA-Z0-9]+)}/g, '\\def\\$1');
+      return katex.renderToString(latex, options);
+    } catch (error) {
+      if (options.throwOnError) logger.error(error);
+      return `<p class='${displayMode ? 'katex-block ' : ''}katex-error' title='${escapeHtml(error.toString())}'>${escapeHtml(latex)}</p>`;
+    }
+  };
+  const inlineRenderer = function (tokens, idx) {
+    if (tokens[idx].content.length > 50) return `$${tokens[idx].content}$`;
+    return render(tokens[idx].content);
+  };
+
+  const blockRenderer = function (tokens, idx) {
+    if (tokens[idx].content.length > 50) return `$$${tokens[idx].content}$$`;
+    return `${render(tokens[idx].content, true)}\n`;
+  };
+  md.inline.ruler.after('escape', 'math_inline', inline);
+  md.block.ruler.after('blockquote', 'math_block', block, {
+    alt: ['paragraph', 'reference', 'blockquote', 'list'],
+  });
+  md.renderer.rules.math_inline = inlineRenderer;
+  md.renderer.rules.math_block = blockRenderer;
+}