#!/usr/bin/env bash
set -o pipefail

export YEAR=$(printf '%(%Y)T' -1)
export MONTH=$(printf '%(%m)T' -1)
export DAY=$(printf '%(%d)T' -1)
export HOUR=$(printf '%(%H)T' -1)
export MINUTE=$(printf '%(%M)T' -1)
export DAYOFWEEK=$(printf '%(%w)T' -1)
export MAILTO=$USER
export SENDMAIL=/usr/sbin/sendmail

run_tasks() {
    local basename
    local default_subject
    local logfile
    local send_email
    local task

    send_email=0

    for task in "tasks/$HOSTNAME/"*; do
        if ! [[ -e "$task" ]]; then
            break
        else
            basename=$(basename "$task")
            basename=${basename%.sh}
        fi

        if source "$task" && condition; then
            echo "[!] $basename"
            (
                logfile="logs/$basename.$(printf '%(%Y-%m-%dT%H:%M%z)T' -1)"

                if ! run &> "$logfile"; then
                    send_email=${send_email:-1}
                    default_subject="$basename (failed)"
                else
                    default_subject="$basename"
                fi

                [[ "$send_email" -ne 0 ]] && {
                    echo "Date: $(date -R)"
                    echo "From: Cron Script <$USER@$HOSTNAME>"
                    echo "To: <$MAILTO>"
                    echo "Subject: ${SUBJECT:-$default_subject}"
                    echo
                    cat "$logfile"
                } | "$SENDMAIL" -oi -- "$MAILTO"

                if [[ -e "$logfile" ]] && ! [[ -s "$logfile" ]]; then
                    rm "$logfile"
                fi
            ) &
        else
            echo "[ ] $basename"
        fi
    done

    wait
}

main() {
    local line
    local log_format
    local _

    case "$1" in
      "")
        log_format='%(%Y-%m-%dT%H:%M:%S%z)T [%d]: %s\n'
        while read line; do
            printf "$log_format" -1 "$$" "$line" | tee -a master-log
        done < <(echo "Started:"; run_tasks 2>&1; echo "Finished.")
      ;;

      -e)
        shopt -s nullglob
        for _ in tasks/"$HOSTNAME"/*"$2"*; do
            $EDITOR -- tasks/"$HOSTNAME"/*"$2"*
            exit
        done

        $EDITOR -- "tasks/$HOSTNAME/$2"
      ;;

      -l)
        if which tree &> /dev/null; then
            tree tasks
        else
            ls -l -R tasks
        fi
    esac
}

cd "$(dirname "$(readlink -f "$0")")"
mkdir -p logs "tasks/$HOSTNAME"
main "$@"