#!/bin/sh
# git merge-pr [PRNUM][@REMOTE] [GIT-AM FLAGS...] - list or apply GitHub pull request from command-line
set -e

PR=$1
REMOTE=
case "$PR" in
*@*)
	REMOTE=${PR#*@}
	PR=${PR%%@*}
esac

URL=$(git ls-remote --get-url $REMOTE)

PROJECT=${URL%.git}
PROJECT=${PROJECT##*:}
PROJECT=${PROJECT#//github.com/}

if [ -z "$PR" ]; then
	wget -q -O- --header 'Accept: application/json' \
		"https://api.github.com/repos/${PROJECT}/pulls?direction=asc" |
		jq -r 'if length > 0
			then .[] | "\(.number) <\(.user.login)> \(.title)"
			else "No open pull requests." end'
	exit $?
else
	shift
fi

PATCH="$(mktemp)"
trap "rm -f $PATCH" INT TERM EXIT
wget -nv -O "$PATCH" https://github.com/$PROJECT/pull/"$PR".patch
WHITESPACE="$(git config --get merge-pr.whitespace || true)"
git am "--whitespace=${WHITESPACE:-warn}" "$@" "$PATCH"

if [ "$(git config --bool --get merge-pr.autoclose)" = false ]; then
	exit 0
fi

# Rewrite last commit message to close GitHub issue.
GIT_EDITOR="git -c trailer.closes.ifExists=replace interpret-trailers \
	--trailer 'Closes: #$PR [via git-merge-pr]' --in-place" \
git commit --quiet --amend