#!/usr/bin/env bash

set -eu

if [  -z "${1-}" ] ; then
    echo "mr number or URL required. See --help for usage." 1>&2
    exit 1
fi

remote_ref_kind=merge-requests

if test "$1" = "clean"; then
  git for-each-ref refs/heads/mr/* --format='%(refname)' | while read -r ref; do
    git branch -D "${ref#refs/heads/}"
  done
  exit 0
elif [[ $1 =~ ^(https?://[^/]+/(.+))/merge_requests/([0-9]+).*$ ]]; then
  remote=${BASH_REMATCH[1]}.git
  id=${BASH_REMATCH[3]}
elif [[ $1 =~ ^(https?://[^/]+/(.+))/pulls/([0-9]+).*$ ]]; then
  # Forgejo/Codeberg pull request URL, e.g.
  # https://codeberg.org/owner/repository/pulls/453
  remote=${BASH_REMATCH[1]}.git
  id=${BASH_REMATCH[3]}
  remote_ref_kind=pull
else
  id=$1
  remote=${2:-origin}
fi

branch=mr/$id
remote_ref=refs/$remote_ref_kind/$id/head
git fetch -fu "$remote" "$remote_ref:$branch"
git checkout "$branch"
git config --local --replace "branch.$branch.merge" "$remote_ref"
git config --local --replace "branch.$branch.remote" "$remote"