djcev.com

#!/bin/sh
#
#  Copyright (c) 2021, Cameron Vanderzanden. Available under the
#  terms of the 2-clause BSD license. Please see the file "LICENSE" in
#  the root dir of this repository for more information.
#
#- config/redshift/hooks/background.sh 2020/05/12 cev, last updated 2021/12/12
## Usage: background.sh [-hvV] command argument1 argument2
## 
##     Redshift hook script for automated background setting based on
##     day/night period. Requires a directory of background files and
##     a directory of character files.
## 
##       -h     Show help.
##       -v     Verbose output (for debugging? purposes).
##       -V     Print version info.
## 
##     Valid commands are currently:
##       clear               Clear temporary files.
##       period-changed      Set background to one corresponding with argument2.
## 
##     This script expects wallpaper filenames to have three fields separated
##     by an underscore: name, scene name, and period (day, interval, and
##     night). For example:
##         game1_scene1_day.jpg
##         game1_scene1_interval.jpg
##         game1_scene1_night.jpg
##         game1_scene2_day.jpg
##             ... and so on.
## 
##     Character filenames are similarly separated by underscore and have four
##     fields: name, character name, period, and s1 through s3 (where s1 is
##     displayed on low system load average and s3 on high). An example:
##         game1_character1_day_s1.jpg
##         game1_character1_day_s2.jpg
##         game1_character1_day_s3.jpg
##         game1_character1_interval_s1.jpg
##             ... and so on, filling out the necessary combinations.
## 
##     For more information read the script, it's not too complicated.
## 
#

[ -x $HOME/bin/cev_print.sh ] && . $HOME/bin/cev_print.sh

self="${0##*'/'}"
verbose=""

# default directories
tmpdir="/tmp/back_$(id -u -n)"
walldir="/z/gfx/wallpapers"
chardir="/z/gfx/rootchar"

# default tempfiles
gamef="$tmpdir/game"
charf="$tmpdir/character"
scenef="$tmpdir/scene"

# placeholders; used & defined below
game=""
char=""
scene=""

randlist() {
    # max for rng; exit if zero.
    max="$(wc -l $1)"
    max=${max%' '*}
    [ $max -lt 1 ] && exit 1
    # random number within 1-$max
    if [ -x "$(which jot)" ]; then
        n=$(jot -r 1 1 $max)            # BSD
    elif [ -x "$(which shuf)" ]; then
        n=$(shuf -i 1-$max -n 1)        # GNU; may or may not work
    else
        # this really doesn't work. awk rand() seems to be the problem.
        etime=$(date -j -f "%a %b %d %T %Z %Y" "`date`" "+%s")
        r=$(awk "BEGIN {srand($etime); print rand()}")
        n=$(expr ${r##*.} % $max)
        unset etime && unset r
    fi
    sed -n "${n}p" $1
}

select_game() {
    find "$walldir" -type f -iname "*jpg" -print | while read r; do
        basename "$r" | cut -d '_' -f 1 >> ${gamef}s
    done
    # don't do a uniq pass here
    randlist ${gamef}s > ${gamef}
    rm ${gamef}s
}

select_character() {
    find "$chardir" -type f -iname "${game}*" -print | while read r; do
        basename "$r" | cut -d '_' -f 2 >> ${charf}1
    done
    cat ${charf}1 | uniq >> ${charf}s
    randlist ${charf}s > ${charf}
    rm ${charf}1 ${charf}s
}

select_scene() {
    find "$walldir" -type f -iname "${game}*" -print | while read r; do
        basename "$r" | cut -d '_' -f 2 >> ${scenef}1
    done
    cat ${scenef}1 | uniq >> /${scenef}s
    randlist ${scenef}s | cut -d '.' -f 1 > ${scenef}
    rm ${scenef}1 ${scenef}s
}

select_set() {
    select_game
    game="$(cat ${gamef})"
    [ "$verbose" ] && print_self && printf "select_set: game %s\n" "$game"
    select_character
    char="$(cat ${charf})"
    [ "$verbose" ] && print_self && printf "select_set: character %s\n" "$char"
    select_scene
    scene="$(cat ${scenef})"
    [ "$verbose" ] && print_self && printf "select_set: scene %s\n" "$scene"
}

check_set() {
    if [ ! -f ${gamef} -o ! -f ${charf} -o ! -f ${scenef} ]; then
        select_set
    else
        last=$(stat -f %m ${charf})
        curr=$(date +%s)
        elapsed=$(($curr - $last))
        elapsed=$(($elapsed / 3600))
        if [ $elapsed -gt 22 ]; then
            [ "$verbose" ] && print_self && \
                printf "selection is over 22 hours old.\n"
            select_set
        else
            game="$(cat ${gamef})"
            char="$(cat ${charf})"
            scene="$(cat ${scenef})"
        fi
    fi
}

clear_character_images() {
    if [ -d "$tmpdir" ]; then
        if [ "$verbose" ]; then
            print_self
            printf "clearing character images %s\n" "$tmpdir"
        fi
        for i in 1 2 3; do
            if [ -f "${tmpdir}/s$i.png" ]; then
                rm ${verbose} ${tmpdir}/s$i.png
            fi
        done
    fi
}

while getopts "hvV?" option; do
    case $option in
        h) print_help && exit ;;
        v) verbose="-v" ;;
        V) print_version && exit ;;
        "?") print_help && exit ;;
    esac
    shift $((OPTIND - 1))
done

[ ! -d "$tmpdir" ] && mkdir -p "$tmpdir"

case $1 in
    clear)
        clear_character_images
        [ "$verbose" ] && print_self && printf "clearing temp files\n"
        rm ${verbose} ${gamef} ${charf} ${scenef}
        rmdir ${verbose} ${tmpdir}
        exit 0
        ;;
    period-changed)
        check_set
        case $3 in
            [Dd]aytime)                period="day" ;;
            [Nn]ight)                  period="night" ;;
            [Tt]ransition)             period="interval" ;;
        esac
        clear_character_images
        $HOME/bin/back.sh ${verbose} $walldir/${game}_${scene}_$period.???
        [ "$verbose" ] && print_self && printf "copying character files\n"
        for i in 1 2 3; do
            cp ${verbose} "$chardir"/${game}_${char}_${period}_s$i.png \
                "$tmpdir"/s$i.png
        done
        exit 0
        ;;
    *)
        print_help && print_self && printf 'invalid argument(s): %s\n' "$*"
        exit 1
        ;;
esac