import { readFile, writeFile } from 'node:fs/promises'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'

const root = join(dirname(fileURLToPath(import.meta.url)), '..', '..')
const args = process.argv.slice(2)
const version = option('--version')
const output = option('--output')

if (!/^\d+\.\d+\.\d+$/.test(version)) fail(`Invalid stable version: ${version}`)

const changelog = await readFile(join(root, 'CHANGELOG.md'), 'utf8')
const escaped = version.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
const lines = changelog.split(/\r?\n/)
const start = lines.findIndex((line) => new RegExp(`^## \\[${escaped}\\] - \\d{4}-\\d{2}-\\d{2}$`).test(line))
if (start === -1) fail(`CHANGELOG.md is missing the ${version} release section.`)

let end = lines.length
for (let index = start + 1; index < lines.length; index += 1) {
  if (/^##\s+/.test(lines[index])) {
    end = index
    break
  }
}

const notes = `${lines.slice(start, end).join('\n').trim()}\n`
await writeFile(join(root, output), notes, 'utf8')
process.stdout.write(`[release-notes] wrote ${output} for ${version}\n`)

function option(name) {
  const index = args.indexOf(name)
  const value = index === -1 ? undefined : args[index + 1]
  if (!value || value.startsWith('--')) fail(`${name} is required.`)
  return value
}

function fail(message) {
  process.stderr.write(`[release-notes] ${message}\n`)
  process.exit(1)
}