import { createInterface } from 'node:readline'
import { createWriteStream } from 'node:fs'
import { spawn } from 'node:child_process'

import prompts from 'prompts'

const subsystem = /((?<=^packages\/)@uppy\/[a-z0-9-]+|(?<=^)(?:docs|e2e|examples))\//
async function inferPackageForCommit (sha, spawnOptions) {
  const cp = spawn('git', ['--no-pager', 'log', '-1', '--name-only', sha], spawnOptions)
  const candidates = {}
  for await (const path of createInterface({ input: cp.stdout })) {
    const match = subsystem.exec(path)
    if (match != null) {
      candidates[match[1]] ??= 0
      candidates[match[1]]++
    }
  }
  const maxVal = Math.max(...Object.values(candidates))
  return {
    inferredPackages: Number.isFinite(maxVal)
      ? Object.entries(candidates).flatMap(
        ([pkg, nbOfFiles]) => (nbOfFiles === maxVal || nbOfFiles === maxVal - 1 ? [pkg] : []),
      ).join(',')
      : 'meta',
    candidates,
  }
}

export default async function formatChangeLog (
  spawnOptions,
  LAST_RELEASE_COMMIT,
  changeLogUrl,
) {
  const changeLogCommits = createWriteStream(changeLogUrl)

  const gitLog = spawn('git', [
    '--no-pager',
    'log',
    '--format="%H::%s::%an"',
    `${LAST_RELEASE_COMMIT}..HEAD`,
  ], spawnOptions)
  const expectedFormat = /^"([a-f0-9]+)::(?:((?:@uppy\/[a-z0-9-]+(?:,@uppy\/[a-z0-9-]+)*)|meta|docs|e2e|examples):\s?)?(.+?)(\s\(#\d+\))?::(.+)"$/ // eslint-disable-line max-len
  for await (const log of createInterface({ input: gitLog.stdout })) {
    const [, sha, packageName, title, PR, authorName] = expectedFormat.exec(log)

    const formattedCommitTitle = {
      packageName,
      title,
      authorInfo: PR ? `${authorName} / #${PR.slice(3, -1)}` : authorName,
    }

    if (!packageName) {
      console.log(
        `No package info found in commit title: ${sha} (https://github.com/transloadit/uppy/commit/${sha})`,
      )
      console.log(log)
      const { inferredPackages, candidates } = await inferPackageForCommit(sha, spawnOptions)
      const { useInferred } = await prompts({
        type: 'confirm',
        name: 'useInferred',
        message: `Assign commit to ${inferredPackages} (inferred from the files it touches)?`,
        initial: true,
      })

      if (useInferred) {
        formattedCommitTitle.packageName = inferredPackages
      } else {
        const response = await prompts({
          type: 'autocompleteMultiselect',
          name: 'value',
          message: 'Which package(s) does this commit belong to?',
          min: 1,
          choices: [
            { title: 'Docs', value: 'docs' },
            { title: 'Meta', value: 'meta' },
            ...Object.entries(candidates)
              .sort((a, b) => a[1] > b[1])
              .map(([value]) => ({ title: value, value })),
          ],
        })
        if (!Array.isArray(response.value)) throw new Error('Aborting release')
        formattedCommitTitle.packageName = response.value.join(',')
      }
    }

    changeLogCommits.write(
      `- ${formattedCommitTitle.packageName}: ${formattedCommitTitle.title} (${formattedCommitTitle.authorInfo})\n`,
    )
  }

  changeLogCommits.close()
}