import { escapeHtml } from "../inline/render.js";
import type { BlockHandler } from "./handler.type.js";

export const codeBlockHandler = {
  render(raw: string, attrs?: Record<string, string>): string {
    const lang = attrs?.language;
    const filepath = attrs?.filepath;
    const codeAttrs: string[] = [];
    if (lang) codeAttrs.push(`class="language-${escapeHtml(lang)}"`);
    if (filepath) {
      codeAttrs.push(`data-filepath="${escapeHtml(filepath)}"`);
    }
    const attrStr = codeAttrs.length > 0 ? ` ${codeAttrs.join(" ")}` : "";
    const preAttrs: string[] = [];
    if (filepath) preAttrs.push(`data-filepath="${escapeHtml(filepath)}"`);
    const preAttrStr = preAttrs.length > 0 ? ` ${preAttrs.join(" ")}` : "";
    const escaped = escapeHtml(raw);
    const body = raw === "" || raw.endsWith("\n") ? escaped : `${escaped}\n`;
    return `<pre${preAttrStr}><code${attrStr}>${body}</code></pre>`;
  },

  serialize(raw: string, attrs?: Record<string, string>): string {
    const parts: string[] = [];
    if (attrs?.language) parts.push(attrs.language);
    for (const [k, v] of Object.entries(attrs ?? {})) {
      if (k === "language") continue;
      const needsQuote = v.includes(" ");
      parts.push(needsQuote ? `${k}="${v}"` : `${k}=${v}`);
    }
    // Widen the fence past any backtick run in the content, otherwise a code
    // sample containing ``` closes its own block and the document splits
    // into three on the next parse.
    let longest = 0;
    for (const run of raw.match(/`+/g) ?? []) {
      longest = Math.max(longest, run.length);
    }
    const fence = "`".repeat(Math.max(3, longest + 1));
    return `${fence}${parts.join(" ")}\n${raw}\n${fence}`;
  },
} satisfies BlockHandler;