#!/usr/bin/env node
import fs from 'node:fs';
import path from 'node:path';
import { loadConfig, DIRS } from './lib/config.js';
import { compareWeeks } from './lib/week.js';

/**
 * Emits the weekly Markdown summary posted as a GitHub issue comment,
 * matching the open-scans pattern: one comment per week, table per
 * domain, deltas against the previous week, links to the Pages report.
 *
 * Reads the same data/ summaries the HTML reports use. One truth.
 *
 * Usage: node src/issue-comment.js [--pages-base https://USER.github.io/REPO]
 * Output: docs/comment.md (also printed to stdout)
 */

const args = Object.fromEntries(
  process.argv.slice(2).join(' ').split('--').filter(Boolean).map((s) => {
    const [k, ...v] = s.trim().split(' ');
    return [k, v.join(' ') || true];
  })
);
const pagesBase = (args['pages-base'] ?? process.env.PAGES_BASE_URL ?? '').replace(/\/$/, '');

const config = loadConfig();
let out = `## Weekly scan summary\n\n`;
let latestWeek = null;

for (const target of config.targets) {
  const domainDir = path.join(DIRS.data, target.key);
  if (!fs.existsSync(domainDir)) continue;
  const weeks = fs
    .readdirSync(domainDir)
    .filter((w) => /^\d{4}-W\d{2}$/.test(w) && fs.existsSync(path.join(domainDir, w, 'summary.json')))
    .sort(compareWeeks);
  if (weeks.length === 0) continue;

  const week = weeks[weeks.length - 1];
  latestWeek = latestWeek && compareWeeks(latestWeek, week) > 0 ? latestWeek : week;
  const curr = JSON.parse(fs.readFileSync(path.join(domainDir, week, 'summary.json'), 'utf8'));
  const prev =
    weeks.length > 1
      ? JSON.parse(fs.readFileSync(path.join(domainDir, weeks[weeks.length - 2], 'summary.json'), 'utf8'))
      : null;

  const d = (a, b) => (prev ? ` (${a - b >= 0 ? '+' : ''}${a - b})` : '');
  const reportLink = pagesBase ? `${pagesBase}/reports/${target.key}/${week}/` : `docs/reports/${target.key}/${week}/`;

  out += `### ${target.domain}: ${week}\n\n`;
  out += `| Metric | This week | Notes |\n|---|---:|---|\n`;
  out += `| Pages audited (unique) | ${curr.pagesAudited ?? curr.pagesScanned}${prev ? d(curr.pagesAudited ?? curr.pagesScanned, prev.pagesAudited ?? prev.pagesScanned) : ''} | scanned by axe and/or Alfa |\n`;
  out += `| Median axe violations / page | ${curr.axe.medianViolations ?? 'n/a'}${prev && curr.axe.medianViolations != null && prev.axe.medianViolations != null ? d(curr.axe.medianViolations, prev.axe.medianViolations) : ''} | ${curr.axe.pagesWithViolations} pages affected |\n`;
  out += `| Median Alfa failures / page | ${curr.alfa.medianFailures ?? 'n/a'}${prev && curr.alfa.medianFailures != null && prev.alfa.medianFailures != null ? d(curr.alfa.medianFailures, prev.alfa.medianFailures) : ''} | ${curr.alfa.pagesWithFailures} pages affected |\n`;
  if (curr.sustainability) {
    out += `| Median page weight | ${Math.round(curr.sustainability.medianBytes / 1024)} KB${prev?.sustainability ? d(Math.round(curr.sustainability.medianBytes / 1024), Math.round(prev.sustainability.medianBytes / 1024)) : ''} | est. ${curr.sustainability.meanCo2g} g CO₂/page (SWD v4) |\n`;
  }

  const topAxe = Object.entries(curr.axe.rules)
    .sort(([, a], [, b]) => b.pages - a.pages)
    .slice(0, 5);
  if (topAxe.length) {
    out += `\nTop axe rules by pages affected: ${topAxe.map(([id, r]) => `\`${id}\` (${r.pages})`).join(', ')}.\n`;
  }
  out += `\n[Full report](${reportLink})\n\n`;
}

if (!latestWeek) out += `No scan data found yet.\n`;
out += `\n---\n*Generated by [vital-scans](https://github.com/${process.env.GITHUB_REPOSITORY ?? 'mgifford/vital-core'}). Automated checks cover roughly a third of accessibility barriers; manual testing with assistive technology remains essential.*\n`;

fs.mkdirSync(DIRS.docs, { recursive: true });
fs.writeFileSync(path.join(DIRS.docs, 'comment.md'), out);
console.log(out);