MVP

lib/courses/lessonMarkdown.ts

@@ -0,0 +1,126 @@
+function escapeHtml(value: string): string {
+  return value
+    .replaceAll("&", "&")
+    .replaceAll("<", "&lt;")
+    .replaceAll(">", "&gt;")
+    .replaceAll('"', "&quot;")
+    .replaceAll("'", "&#39;");
+}
+
+function escapeAttribute(value: string): string {
+  return value.replaceAll("&", "&amp;").replaceAll('"', "&quot;");
+}
+
+function normalizeHttpUrl(rawUrl: string): string | null {
+  try {
+    const parsed = new URL(rawUrl);
+    if (parsed.protocol !== "http:" && parsed.protocol !== "https:") return null;
+    return parsed.toString();
+  } catch {
+    return null;
+  }
+}
+
+function renderInline(markdown: string): string {
+  let rendered = escapeHtml(markdown);
+
+  rendered = rendered.replace(/`([^`]+)`/g, (_match, value: string) => `<code>${value}</code>`);
+  rendered = rendered.replace(/\*\*([^*]+)\*\*/g, (_match, value: string) => `<strong>${value}</strong>`);
+  rendered = rendered.replace(/\*([^*]+)\*/g, (_match, value: string) => `<em>${value}</em>`);
+  rendered = rendered.replace(/\[([^\]]+)\]\(([^)\s]+)\)/g, (_match, label: string, url: string) => {
+    const safeUrl = normalizeHttpUrl(url);
+    if (!safeUrl) return label;
+    return `<a href="${escapeAttribute(safeUrl)}" target="_blank" rel="noopener noreferrer">${label}</a>`;
+  });
+
+  return rendered;
+}
+
+export function markdownToSafeHtml(markdown: string): string {
+  const source = markdown.replace(/\r\n/g, "\n").trim();
+  if (!source) return "<p>Sin contenido.</p>";
+
+  const lines = source.split("\n");
+  const output: string[] = [];
+  let listMode: "ol" | "ul" | null = null;
+
+  const closeList = () => {
+    if (!listMode) return;
+    output.push(listMode === "ol" ? "</ol>" : "</ul>");
+    listMode = null;
+  };
+
+  for (const rawLine of lines) {
+    const line = rawLine.trim();
+
+    if (!line) {
+      closeList();
+      continue;
+    }
+
+    const h3 = line.match(/^###\s+(.+)$/);
+    if (h3) {
+      closeList();
+      output.push(`<h3>${renderInline(h3[1])}</h3>`);
+      continue;
+    }
+
+    const h2 = line.match(/^##\s+(.+)$/);
+    if (h2) {
+      closeList();
+      output.push(`<h2>${renderInline(h2[1])}</h2>`);
+      continue;
+    }
+
+    const h1 = line.match(/^#\s+(.+)$/);
+    if (h1) {
+      closeList();
+      output.push(`<h1>${renderInline(h1[1])}</h1>`);
+      continue;
+    }
+
+    const ordered = line.match(/^\d+\.\s+(.+)$/);
+    if (ordered) {
+      if (listMode !== "ol") {
+        closeList();
+        output.push("<ol>");
+        listMode = "ol";
+      }
+      output.push(`<li>${renderInline(ordered[1])}</li>`);
+      continue;
+    }
+
+    const unordered = line.match(/^[-*]\s+(.+)$/);
+    if (unordered) {
+      if (listMode !== "ul") {
+        closeList();
+        output.push("<ul>");
+        listMode = "ul";
+      }
+      output.push(`<li>${renderInline(unordered[1])}</li>`);
+      continue;
+    }
+
+    const quote = line.match(/^>\s+(.+)$/);
+    if (quote) {
+      closeList();
+      output.push(`<blockquote>${renderInline(quote[1])}</blockquote>`);
+      continue;
+    }
+
+    closeList();
+    output.push(`<p>${renderInline(line)}</p>`);
+  }
+
+  closeList();
+  return output.join("\n");
+}
+
+export function markdownToPlainText(markdown: string): string {
+  return markdown
+    .replace(/\r\n/g, "\n")
+    .replace(/\[([^\]]+)\]\(([^)]+)\)/g, "$1")
+    .replace(/[`*_>#-]/g, "")
+    .replace(/\n{2,}/g, "\n")
+    .trim();
+}