climergebutton

#!/bin/bash

readonly program="$(basename "${0}")"
readonly default_merge_strategy='squash'

function syntax_error {
  echo -e "${program}: ${1}\nTry \`${program} --help\` for more information." >&2
  exit 1
}

function usage {
  echo "
    Usage:
      ${program} [options] <github_pull_request_url>

    Multiple <github_pull_request_url> can be given, and will be processed in sequence.

    Options:
      -m, --merge-method   'merge', 'squash', or 'rebase'. Defaults to '${default_merge_strategy}'.
      -t, --ensure-token   Ask to save GitHub token if there is none, and exit.
      -h, --help           Show this help.
  " | sed -E 's/^ {4}//'
}

function get_github_token {
  readonly local operating_system="$(uname -s)"

  # Check if we already have a token set
  local github_token

  if [[ "${operating_system}" == 'Darwin' ]]; then
    github_token="$(security find-generic-password -s "${program} github token" -w 2>/dev/null)"
  else
    local token_file
    [[ -n "${XDG_CONFIG_HOME}" ]] && token_file="${XDG_CONFIG_HOME}/${program}/token" || token_file="${HOME}/.config/${program}/token"
    [[ -f "${token_file}" ]] && github_token="$(< "${token_file}")" || github_token=''
  fi

  if [[ -n "${github_token}" ]]; then
    echo "${github_token}"
    return 0
  fi

  # If we get here, there was no token set and we need to request one
  echo 'We need to create a new GitHub token to continue the script.' >&2

  readonly local machine_name="$(hostname -s)"

  local github_username github_password
  read -rp "Github username: " github_username
  read -rsp "Github password (never stored): " github_password
  echo >&2

  readonly local request=(curl --silent 'https://api.github.com/authorizations' --user "${github_username}:${github_password}" --data "{\"scopes\":[\"repo\"],\"note\":\"${program} for ${USER} on ${machine_name}\"}")

  local response="$("${request[@]}")"

  while grep --quiet 'Must specify two-factor authentication OTP code.' <<< "${response}"; do
    read -rp '2FA code: ' otp
    response="$("${request[@]}" --header "X-GitHub-OTP: ${otp}")"
  done

  if ! grep --quiet '"token"' <<< "${response}"; then
    echo -e "\n${response}" >&2
    exit 1
  fi

  github_token="$(grep 'token' <<< "${response}" | head -1 | cut -d'"' -f4)"

  if [[ "${operating_system}" == 'Darwin' ]]; then
    security add-generic-password -s "${program} github token" -a "${github_username}" -w "${github_token}"
  else
    mkdir -p "$(basename "${token_file}")"
    echo "${github_password}" > "${token_file}"
  fi

  echo "${github_token}"
}

function merge_pr {
  local url owner repo pr_number response

  url="$(perl -pe 's|(.*/pull/\d+).*|\1|' <<< "${1}")"
  owner="$(cut -d'/' -f4 <<< "${url}")"
  repo="$(cut -d'/' -f5 <<< "${url}")"
  pr_number="$(cut -d'/' -f7 <<< "${url}")"

  echo -n "Merging ${owner}/${repo}/${pr_number}… "

  response="$(curl --silent --request PUT --data "{ \"merge_method\": \"${merge_strategy:-${default_merge_strategy}}\" }" --header "Authorization: token ${github_token}" "https://api.github.com/repos/${owner}/${repo}/pulls/${pr_number}/merge")"

  if grep --quiet '"merged": true' <<< "${response}"; then
    echo 'Merged.'
  else
    response_message="$(grep 'message' <<< "${response}" | sed -E 's/.*"message": "(.*)".*/\1/')"
    echo "Failed (${response_message})."
    exit 1
  fi
}

# available flags
args=()
while [[ "${1}" ]]; do
  case "${1}" in
    -h | --help)
      usage
      exit 0
      ;;
    -m | --merge-method)
      merge_strategy="${2}"
      shift
      ;;
    -t | --ensure-token)
      ask_for_token='true'
      ;;
    --)
      shift
      args+=("${@}")
      break
      ;;
    -*)
      syntax_error "unrecognized option: ${1}"
      ;;
    *)
      args+=("${1}")
      ;;
  esac
  shift
done
set -- "${args[@]}"

readonly github_token="$(get_github_token)"

[[ -n "${ask_for_token}" ]] && exit 0

# Abort if no argument was given
if [[ "${#}" -eq 0 ]]; then
  usage
  exit 1
fi

while [[ "${1}" ]]; do # Allow for multiple github PR urls to be passed at once
  if [[ "${1}" =~ https://github.com/* ]]; then
    merge_pr "${1}"
    shift
  else
    usage
    exit 1
  fi
done