#!/usr/bin/env node
/**
 * Site Generator
 *
 * Reads markdown summaries from summaries/{id}.md and embeds them into
 * data/books.json so the site works offline without a server.
 *
 * Usage: node build.js
 *
 * Run this after editing any summary markdown files.
 */

const fs = require('fs');
const path = require('path');

const SUMMARIES_DIR = path.join(__dirname, 'summaries');
const BOOKS_JSON = path.join(__dirname, 'data', 'books.json');

function readSummary(id) {
  const filePath = path.join(SUMMARIES_DIR, `${id}.md`);

  if (!fs.existsSync(filePath)) {
    return null;
  }

  const content = fs.readFileSync(filePath, 'utf8').trim();
  const lines = content.split('\n');

  // Skip the title line (# Title) and return the rest
  const summaryLines = lines.slice(1).join('\n').trim();
  return summaryLines || null;
}

function build() {
  console.log('Building site...\n');

  // Read books.json
  const booksData = JSON.parse(fs.readFileSync(BOOKS_JSON, 'utf8'));

  let updated = 0;
  let missing = [];

  for (const book of booksData.books) {
    const summary = readSummary(book.id);

    if (summary) {
      book.summary = summary;
      updated++;
      console.log(`✓ ${book.title}`);
    } else {
      delete book.summary;
      missing.push(book.title);
      console.log(`✗ ${book.title} (no summary file)`);
    }
  }

  // Write updated books.json
  fs.writeFileSync(BOOKS_JSON, JSON.stringify(booksData, null, 2));

  console.log('\n=== Build Complete ===');
  console.log(`Summaries embedded: ${updated}`);
  console.log(`Missing summaries: ${missing.length}`);

  if (missing.length > 0) {
    console.log('\nCreate these files to add summaries:');
    missing.forEach(title => {
      const book = booksData.books.find(b => b.title === title);
      console.log(`  summaries/${book.id}.md`);
    });
  }

  console.log('\nSite is ready. Open index.html in a browser.');
}

build();