#!/usr/bin/env dash

# shellcheck source=/dev/null
SHELL_LIBRARY_VERSION="2.1.2" . %SHELL_LIBRARY_PATH

help() {
    cat <<EOF
Automatically remove merged branches (remote and local)

USAGE:
    git-cleanup [OPTIONS]

OPTIONS:
    --remote    | -r
                            Act on remote branches

    --help      | -h
                            Display this help and exit.

    --version   | -v
                            Display version and copyright information and exit.
EOF
}

# This should always be the correct answer.
get_default_branch() {
    # source: https://stackoverflow.com/a/50056710
    # We assume, that 'origin' is the remote in use
    git remote show origin | sed -n '/HEAD branch/s|.*: ||p'
}

cleanup() {
    default_branch="$(get_default_branch)"

    merged_branches="$(git branch --merged "$default_branch" --no-contains "$default_branch" --format='%(refname:short)')"

    # shellcheck disable=2086
    # We expect the branches to not contain spaces and want git to deal with them
    # separately
    [ "$merged_branches" ] && git branch --delete $merged_branches
}
cleanup_remote() {
    default_branch="$(get_default_branch)"

    merged_branches="$(git branch --remotes --merged "$default_branch" --no-contains "$default_branch" --format='%(refname:short)' | sed 's|origin/||')"

    # shellcheck disable=2086
    # We expect the branches to not contain spaces and want git to deal with them
    # separately
    [ "$merged_branches" ] && git push --delete origin $merged_branches
}

remote=false
for arg in "$@"; do
    case "$arg" in
    "--help" | "-h")
        help
        exit 0
        ;;
    "--version" | "-v")
        version
        exit 0
        ;;
    "--remote" | "-r")
        remote=true
        ;;
    esac
done

if [ "$remote" = "true" ]; then
    cleanup_remote
elif [ "$remote" = "false" ]; then
    cleanup
else
    die "BUG: 'remote' is not true or false but: '$remote'"
fi

# vim: ft=sh