const { exec } = require('child_process')

const log = require('npmlog')

const SemanticReleaseError = require('@semantic-release/error')

module.exports = function ({lastRelease, options}, cb) {
  const branch = options.branch
  const from = lastRelease.gitHead
  const range = (from ? from + '..' : '') + 'HEAD'

  if (!from) return extract()

  exec(`git branch --contains ${from}`, (err, stdout) => {
    if (err) return cb(err)
    let inHistory = false

    const branches = stdout.split('\n')
    .map((result) => {
      if (branch === result.replace('*', '').trim()) {
        inHistory = true
        return null
      }
      return result.trim()
    })
    .filter(branch => !!branch)

    if (!inHistory) {
      log.error('commits',
`The commit the last release of this package was derived from is no longer
in the direct history of the "${branch}" branch.
This means semantic-release can not extract the commits between now and then.
This is usually caused by force pushing or releasing from an unrelated branch.
You can recover from this error by publishing manually or restoring
the commit "${from}".` + (branches.length ?
        `\nHere is a list of branches that still contain the commit in question: \n * ${branches.join('\n * ')}` :
        ''
      ))
      return cb(new SemanticReleaseError('Commit not in history', 'ENOTINHISTORY'))
    }

    extract()
  })

  function extract () {
    exec(
      `git log -E --format=%H==SPLIT==%B==END== ${range}`,
      (err, stdout) => {
        if (err) return cb(err)

        cb(null, String(stdout).split('==END==\n')

        .filter((raw) => !!raw.trim())

        .map((raw) => {
          const data = raw.split('==SPLIT==')
          return {
            hash: data[0],
            message: data[1]
          }
        }))
      }
    )
  }
}