const fs = require('fs');
const changelog = fs.readFileSync('CHANGELOG.md', 'utf8');
const RELEASE_LINE_REGEX = /^- (\[#.*?\]\(.*?\))?.*?! - (.*)$/gm;
const VERSION_TITLE_REGEX = /^## (\d+\.\d+\.\d+(-rc\.\d+)?)$/gm;
const isPrerelease = process.env.PRERELEASE === 'true';
const formatted = changelog
.replace(/^### Major Changes\n\n/gm, '')
.replace(/^### Minor Changes\n\n/gm, '')
.replace(/^### Patch Changes\n\n/gm, '')
.replace(/^(- \[.*\n)\n(?=-)/gm, '$1')
.replace(RELEASE_LINE_REGEX, (_, pr, entry) => (pr ? `- ${entry} (${pr})` : `- ${entry}`))
.replace(VERSION_TITLE_REGEX, `\n## $1 (${new Date().toISOString().split('T')[0]})`)
.replace(/^## \d\.\d\.\d-rc\S+[^]+?(?=^#)/gm, section => (isPrerelease ? section : ''));
fs.writeFileSync('CHANGELOG.md', formatted);