prfixbranch

#!/bin/bash

readonly program="$(basename "${0}")"
readonly commit_hash_file="/tmp/prfix_hash_save"
readonly issue_number_file="/tmp/prfix_issue_number_save"
remote='upstream' # use 'upstream' as default remote

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

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

    Options:
      -r <remote>, --remote <remote>   Use to specify a remote to push to (defaults to 'upstream').
      -c, --continue                   Use after making your fixes, to push your changes. If you use it with uncommitted changes, they'll all be squashed (fixup) into the original patch; else your commits will be preserved.
      -h, --help                       Show this help.
  " | sed -E 's/^ {4}//'
}

# read remote from git config
configured_remote="$(git config --get tiny-scripts.remote)"
if [[ -n "${configured_remote}" ]]; then
  remote="${configured_remote}"
fi

# available flags
args=()
while [[ "${1}" ]]; do
  case "${1}" in
    -h | --help)
      usage
      exit 0
      ;;
    -r | --remote)
      remote="${2}"
      shift
      ;;
    -c | --continue)
      push_changes="yes"
      ;;
    --)
      shift
      args+=("${@}")
      break
      ;;
    -*)
      syntax_error "unrecognized option: ${1}"
      ;;
    *)
      args+=("${1}")
      ;;
  esac
  shift
done
set -- "${args[@]}"

check_repo() {
  local_repo=$(git remote show origin -n | grep 'Fetch URL:' | sed 's|.*/||;s|\.git$||')
  remote_repo=$(sed -E 's|.*/(.*)/pull.*|\1|' <<< "${url}")

  if [[ "${local_repo}" != "${remote_repo}" ]]; then
    echo -e "\n$(tput setaf 1)You're trying to pull from '${remote_repo}' but you're on '${local_repo}'.$(tput sgr0)\n"
    exit 1
  fi
}

apply_patch() {
  url=$(perl -pe 's|(.*/pull/\d+).*|\1|' <<< "${1}") # clean url of extraneous information
  issue_number=$(sed 's|.*/||' <<< "${url}")
  patch_url="${url}.patch" # github pull request url, ending in '.patch'
  check_repo

  branch_name="fix-${issue_number}"
  git checkout -b "${branch_name}"
  curl --location --silent "${patch_url}" | git am --3way # get and apply patch

  git rev-parse HEAD > "${commit_hash_file}" # save hash from current commit
  echo "${issue_number}" > "${issue_number_file}" # save issue number

  echo "
    Make your necessary changes, and run
      ${program} -c

    If you have uncommitted changes, they'll be squashed into the original patch.
    If you have new commits, they’ll be included separately
  " | sed -E 's/^ {2}//'
}

push_changes() {
  original_commit="$(cat ${commit_hash_file})"
  original_issue="#$(cat ${issue_number_file})"
  branch_name="$(git rev-parse --abbrev-ref HEAD)"
  uncommitted_changes="$(git status --porcelain --untracked-files=no)"

  # squash your fixes into the original patch, if there are uncommitted changes
  if [[ "${uncommitted_changes}" ]]; then
    git commit --all --allow-empty-message --message ''
    git reset --soft "${original_commit}"
    # add message to close the original pull request
    original_commit_message="$(git log --oneline -1 | cat - | sed -E 's/^[^ ]* //')"
    git commit --amend --message "${original_commit_message}" --message "Closes ${original_issue}."
  fi

  # push and delete branch
  git push "${remote}" "${branch_name}"
  git checkout master
  git branch -D "${branch_name}"
}

if [[ "${1}" =~ https://github.com/* ]]; then
  apply_patch "${1}"
elif [[ "${push_changes}" == 'yes' ]]; then
  push_changes
else
  usage
  exit 1
fi