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

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

git_extra_default_branch() {
    local extras_default_branch init_default_branch
    extras_default_branch=$(git config --get git-extras.default-branch)
    init_default_branch=$(git config --get init.defaultBranch)
    if [ -n "$extras_default_branch" ]; then
        echo "$extras_default_branch"
    elif [ -n "$init_default_branch" ]; then
        echo "$init_default_branch"
    else
        echo "main"
    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)

stashed=0
if [ -n "$(git status --porcelain)" ];
then
    echo "Local modifications detected, stashing"
    stashed=1
    git stash
fi

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

if [ $stashed -eq 1 ];
then
    git stash pop;
fi
