#!/usr/bin/env bash
# reset environment variables that could interfere with normal usage
export GREP_OPTIONS=
# put all utility functions here

# make a temporary file
git_extra_mktemp() {
    mktemp -t "$(basename "$0")".XXXXXXX
}

git_extra_default_branch() {
    local default_branch
    default_branch=$(git config --get git-extras.default-branch)
    if [ -z "$default_branch" ]; then
        echo "master"
    else
        echo "$default_branch"
    fi
}
#
# check whether current directory is inside a git repository
#

is_git_repo() {
  git rev-parse --show-toplevel > /dev/null 2>&1
  result=$?
  if test $result != 0; then
    >&2 echo 'Not a git repo!'
    exit $result
  fi
}

is_git_repo

current_branch() {
    git rev-parse --abbrev-ref HEAD
}

usage() {
    echo "Usage: git merge-into [src] dest [--ff-only]"
}

cur_branch=$(current_branch)
if [ "${!#}" == '--ff-only' ]; then
    case $# in
        2 ) # dest --ff
            git push "$(git rev-parse --show-toplevel)" "$cur_branch":"$1";;
        3 )
            git push "$(git rev-parse --show-toplevel)" "$1":"$2";;
        * )
            usage
    esac
else
    case $# in
        1 )
            git checkout "$1"
            git merge "$cur_branch" "$1" && git checkout "$cur_branch"
            ;;
        2 )
            git checkout "$2"
            git merge "$1" "$2" && git checkout "$cur_branch"
            ;;
        * )
            usage
    esac
fi
