#!/bin/bash

# /lib/systemd/system-sleep/rtcwake

# chmod a+rx

AWAKE_TIME="01:23:45" # hour:minute:second

GAP="10 seconds"      # precision of awake time in date(1) format

WAIT_TRIGGER='true'   # test to go back to sleep when action is finished 

                      # typically pgrep on user or for specific process

WAIT_TRIGGER_DELAY=60 # sleep duration in seconds between two tests with WAIT_TRIGGER

MAX_TRIGGER=60        # don't go back to sleep if WAIT_TRIGGER isn't true

                      # after WAIT_TRIGGER_DELAY * MAX_TRIGGER seconds

LOG=/dev/null

# same format than AWAKE_TIME but as an array of times in increase order

#AWAKE_TIMES=("01:23:45" "02:46:00" "13:57:00" "20:00:00")

#WAIT_TRIGGER_DELAYS=(60 60 60 60)

#WAIT_TRIGGERS=("true" "true" "true" "true")

#MAX_TRIGGERS=(60 60 60 60)

#ON_ERRORS=()

unset RTCWAKE_TIME AWAKE_TIME

test -r $0.conf && source $0.conf # all previous variables can be set here

echo -e "\n$(date) $1/$2" >> $LOG

function set_RTCWAKE_TIME () {

    NOW=$(date +%_H%M%S)

    if test -z "$AWAKE_TIME"; then

        for ((i=0; i<${#AWAKE_TIMES[@]}; i++)); do

            if test $NOW -lt ${AWAKE_TIMES[i]//:}; then

                RTCWAKE_TIME=$(date +%s -d ${AWAKE_TIMES[i]})

                break

            elif test $i -eq $((${#AWAKE_TIMES[@]} - 1)); then

                RTCWAKE_TIME=$(date +%s -d "tomorrow ${AWAKE_TIMES[0]}")

            fi

        done

    else

        RTCWAKE_TIME=$([ $NOW -lt ${AWAKE_TIME//:} ] && date +%s -d $AWAKE_TIME || date +%s -d "tomorrow $AWAKE_TIME")

    fi

    suspend_duration=$(( $RTCWAKE_TIME - $(date +%s) ))

    if test $suspend_duration -gt ${MIN_TIME_BEFORE_NEXT_AWAKE:-600}; then

        date_awake=$(date -d "$suspend_duration seconds")

        echo "$NOW: will be awaken in $suspend_duration seconds ($date_awake) (mode=$1)" >> $LOG

        rtcwake -m $1 -s $suspend_duration

    else

        echo "$NOW: no need to suspend because next awake is scheduled in less than $((${MIN_TIME_BEFORE_NEXT_AWAKE:-600} / 60)) minutes"

    fi

}

case "$1/$2" in

    pre/suspend)

        set_RTCWAKE_TIME no

        ;;

    post/suspend)

        at -M now <<< "$0 post wait-for-trigger" > /dev/null 2>&1

        ;;

    post/wait-for-trigger)

        NOW=$(date +%_H%M%S)

        if test -z "$AWAKE_TIME"; then

            for ((i=0; i<${#AWAKE_TIMES[@]}; i++)); do

                if test $NOW -ge ${AWAKE_TIMES[i]//:} -a $NOW -le $(date +%_H%M%S -d "${AWAKE_TIMES[i]} $GAP"); then

                    AWAKE_TIME=${AWAKE_TIMES[i]}

                    WAIT_TRIGGER_DELAY=${WAIT_TRIGGER_DELAYS[i]:-60}

                    MAX_TRIGGER=${MAX_TRIGGERS[i]:-60}

                    WAIT_TRIGGER=${WAIT_TRIGGERS[i]:-true}

                    test -n "${ON_ERRORS[i]}" && ON_ERROR=${ON_ERRORS[i]}

                    test -n "${AWAKE_ACTIONS[i]}" && AWAKE_ACTION=${AWAKE_ACTIONS[i]}

                    break

                fi

            done

        fi

        test -n "$AWAKE_ACTION" && at -M now <<< $AWAKE_ACTION >> $LOG 2>&1

        if test -n "$AWAKE_TIME" && test $NOW -ge ${AWAKE_TIME//:} -a $NOW -le $(date +%_H%M%S -d "$AWAKE_TIME $GAP"); then

            cat >> $LOG << EOL

NOW: $NOW

AWAKE_TIME: $AWAKE_TIME

WAIT_TRIGGER_DELAY: $WAIT_TRIGGER_DELAY

WAIT_TRIGGER: $WAIT_TRIGGER

MAX_TRIGGER: $MAX_TRIGGER

EOL

            COUNT=1

            while sleep $WAIT_TRIGGER_DELAY && eval "$WAIT_TRIGGER"; do

                let COUNT++

                if test $COUNT -eq $MAX_TRIGGER; then

                    if test -n "$ON_ERROR"; then

                        eval "$ON_ERROR"

                    fi

                    break

                fi

            done

            unset AWAKE_TIME

            test -r $0.conf && source $0.conf

            set_RTCWAKE_TIME mem

        else

            echo "rtcwake -m disable" >> $LOG

            rtcwake -m disable

        fi

        ;;

esac