// Pure text helpers for the structured transcript, kept when
// structuredRender.ts's imperative DOM builders were deleted (#253):
// markdown rendering (sanitized) and the elapsed/context formatters.

import { marked, Renderer } from "marked";

import { escapeHtml } from "../../html.js";

/** Small inline renderer retained for compact labels and focused tests. */
export function renderInlineMarkdown(text: string): string {
  const escaped = escapeHtml(text);
  return escaped
    .replace(/`([^`]+)`/g, "<code>$1</code>")
    .replace(/\*\*([^*]+)\*\*/g, "<strong>$1</strong>")
    .replace(/(?<!\*)\*([^*]+)\*(?!\*)/g, "<em>$1</em>");
}

/** Render assistant output as GFM, then sanitize the complete result before it
 * enters the DOM. This gives transcripts proper tables, lists, code blocks and
 * links without trusting model-authored HTML or URL attributes. */
export function renderMarkdown(text: string): string {
  const renderer = new Renderer();
  renderer.html = ({ text: raw }) => escapeHtml(raw);
  renderer.image = ({ text: alt }) => escapeHtml(alt ? `[image: ${alt}]` : "[image]");
  renderer.link = ({ href, title, tokens }) => {
    const label = renderer.parser.parseInline(tokens);
    const scheme = /^([a-z][a-z\d+.-]*):/i.exec(href.trim())?.[1]?.toLowerCase();
    if (scheme && !["http", "https", "mailto"].includes(scheme)) return label;
    const safeTitle = title ? ` title="${escapeHtml(title)}"` : "";
    return `<a href="${escapeHtml(href)}"${safeTitle}>${label}</a>`;
  };

  return marked.parse(text, { async: false, gfm: true, renderer });
}

function compactNumber(value: number): string {
  if (Math.abs(value) < 1_000) return String(value);
  if (Math.abs(value) < 1_000_000) return `${(value / 1_000).toFixed(value % 1_000 === 0 ? 0 : 1)}k`;
  return `${(value / 1_000_000).toFixed(value % 1_000_000 === 0 ? 0 : 1)}m`;
}

export function formatElapsed(milliseconds: number): string {
  const seconds = Math.max(0, Math.floor(milliseconds / 1_000));
  if (seconds < 60) return `${seconds}s`;
  const minutes = Math.floor(seconds / 60);
  const remainder = seconds % 60;
  return remainder === 0 ? `${minutes}m` : `${minutes}m ${remainder}s`;
}

export function formatContextTokens(value: number): string {
  return `${compactNumber(value)} context`;
}