#!/usr/bin/env bash

REF=""
SINCE=""

while [[ $# -gt 0 ]]; do
    case "$1" in
        -r|--ref)
            if [[ -z "$2" ]]; then
                echo "error: option $1 requires an argument" >&2
                exit 1
            fi
            REF="$2"
            shift
            shift
            ;;
        *)
            # non-flag args accumulation, e.g. "last " + "week" -> "last week"
            SINCE="${SINCE:+$SINCE }$1"
            shift
            ;;
    esac
done

if [[ -n "$REF" && -n "$SINCE" ]]; then
    echo "error: '--ref <ref>' and '<date>' are mutually exclusive" >&2
    exit 1
fi

SINCE="${SINCE:-last week}"

if [[ -n "$REF" ]]; then
    git log --pretty='%h %an - %s' "$REF..HEAD"
else
    git log --pretty='%h %an - %s' --after="@{$SINCE}"
fi