#!/usr/bin/env node
// Assembles sites/<site>/public/header.html from shared/header.template.html
// + sites/<site>/nav.html. Run automatically via each site's predev/prebuild.
import { readFileSync, writeFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import path from 'node:path';

const site = process.argv[2];
if (!site) {
  console.error('usage: render-header.mjs <site>');
  process.exit(1);
}

const root = path.resolve(fileURLToPath(import.meta.url), '../..');
const templatePath = path.join(root, 'shared/header.template.html');
const navPath = path.join(root, 'sites', site, 'nav.html');
const outPath = path.join(root, 'sites', site, 'public/header.html');

const template = readFileSync(templatePath, 'utf8');
const nav = readFileSync(navPath, 'utf8').trimEnd();

const placeholder = '<!--NAV_ITEMS-->';
const parts = template.split(placeholder);
if (parts.length !== 3) {
  console.error(`expected exactly 2 occurrences of ${placeholder} in ${templatePath}, found ${parts.length - 1}`);
  process.exit(1);
}

const indent = (block, spaces) =>
  block.split('\n').map(line => ' '.repeat(spaces) + line).join('\n');

const rendered = parts[0] + indent(nav, 8) + parts[1] + indent(nav, 10) + parts[2];
writeFileSync(outPath, rendered);