#!/bin/sh

set -eu

usage() {
    printf "Usage: %s [-l DEBUG_LEVEL] [-h]\n" "$0"
}

help() {
    cat << EOH
 SYNOPSIS
    $0 [-l DEBUG_LEVEL] [-h]

 DESCRIPTION

    $0 does things!

 OPTIONS

    -h    Show this help

    -l debug|info|notice|warning|error
          Debug level
EOH
}

on_interrupt() {
    log -l notice ""
    log -l notice "Process aborted!"

    exit 130
}

main() {
    while getopts "l:h" option; do
        case "${option}" in
            h) help; exit 0;;
            l) LOG_VERBOSE="$OPTARG";;
            ?) log -l error "$(usage)"; exit 1;;
        esac
    done

    # log [-t] [-l debug|info|notice|warning|error] message

    exit 0
}

log() {
    LOG_VERBOSE="${LOG_VERBOSE:-info}"
    LEVEL=info
    TIME=

    while getopts "tl:" option; do
        case "${option}" in
            l) LEVEL="$OPTARG"; shift $((OPTIND-1));;
            t) TIME="$(printf "[%s] " "$(date +'%Y-%m-%dT%H:%M:%S.%s')")"; shift $((OPTIND-1));;
            *) exit 1;;
        esac
    done

    if [ -t 2 ] && [ -z "${NO_COLOR-}" ]; then
        case "${LEVEL}" in
            debug) COLOR="$(tput setaf 3)";;
            notice) COLOR="$(tput setaf 4)";;
            warning) COLOR="$(tput setaf 5)";;
            error) COLOR="$(tput setaf 1)";;
            *) COLOR="$(tput sgr0)";;
        esac
    fi

    case "${LEVEL}" in
        debug) LEVEL=100;;
        notice) LEVEL=250;;
        warning) LEVEL=300;;
        error) LEVEL=400;;
        *) LEVEL=200;;
    esac

    case "${LOG_VERBOSE}" in
        debug) LOG_VERBOSE_VALUE=100;;
        notice) LOG_VERBOSE_VALUE=250;;
        warning) LOG_VERBOSE_VALUE=300;;
        error) LOG_VERBOSE_VALUE=400;;
        *) LOG_VERBOSE_VALUE=200;;
    esac

    if [ $LEVEL -ge $LOG_VERBOSE_VALUE ]; then
        printf "%s\n" "$*" | while IFS='' read -r LINE; do
            printf "%s%s%s\n" "${COLOR:-}" "${TIME:-}" "$LINE" >&2
        done
    fi
}

trap on_interrupt INT

main "$@"