knot

#!/bin/bash

source $PLUG_PATH/cfgs

help_msg() {
    log "
    knot: the tas(k-not)ifier
    desc: notify next task initialization when previous task is finished
    help: knot [args]
    args:
        -c, --create <knots>        finish task and create knots
        -b, --break  <knots>        break the knots after knots creation
        -d, --delete                delete all knots
        -u, --usage                 show examples of usage
        -h, --help                  display this help
    "
}

examples() {
    log "
    example 1:
        Use knots to schedule task1 and task2,
        where task2 is dependent on task1.
        Start task1 and create a knot:
        $ task1 && knot -c <knot_name>
        Start task2 after knot is created:
        $ knot -b <knot_name> && task2
    example 2:
        Use knots to initiate multiple tasks:
        $ task1 && knot -c k1 k2
        $ knot -b k1 && task2
        $ knot -b k2 && task3
    example 2:
        Use knots to wait for multiple tasks:
        $ task1 && knot -c k1
        $ task2 && knot -c k2
        $ knot -b k1 k2 && task2
    "
}

prereqs() {
    check_dir $KNOT_DIR
    knot_name="$KNOT_DIR/.knot"
}

create() {
    shift;
    [ "$#" -eq 0 ] && err "no knot given"
    for knot in "$@"; do
        knot_name="$KNOT_DIR/$knot.knot"
        touch $knot_name
    done
}

till() {
    shift;
    [ "$#" -eq 0 ] && err "no knot given"
    while true; do
        created=true
        for knot in "$@"; do
            knot_name="$KNOT_DIR/$knot.knot"
            [ ! -e $knot_name ] && created=false && break
        done
        [ $created = true ] && break
        echo "still waiting"
        sleep $KNOT_TIME
    done
    delete $@
}

delete() {
    shift;
    [ "$#" -eq 0 ] && rm -rf $KNOT_DIR/*.knot
    for knot in "$@"; do
        knot_name="$KNOT_DIR/$knot.knot"
        rm -rf $knot_name
    done
}

options() {
    case $1 in
        -c | --create ) create $@;;
        -b | --break  ) till $@;;
        -d | --delete ) delete;;
        -u | --usage  ) examples;;
           *          ) help_msg;;
    esac
}

init $@