#!/bin/bash

# INIT
echo "$$" > "$HOME/.cache/pidofbar"

# MODULES
update_crypto() {
    crypto="$(crypto)"
}

update_cpu() {
    cpu=" $(grep -o "^[^ ]*" /proc/loadavg)"
}

update_memory() {
    memory=" $(free -h | sed -n '2s/\([^ ]* *\)\{2\}\([^ ]*\).*/\2/p')"
}

update_bat() {
    local dir="$(echo /sys/class/power_supply/BAT* | sort -n | tail -n1)"
    bat="$(grep -q Charging "$dir/status" && printf '' || printf '')"
    bat="$bat $(cat "$dir/capacity")%"
}

update_vol() {
    local v; v="$(wpctl get-volume '@DEFAULT_AUDIO_SINK@')"

    if grep -q 'MUTED' <<< "$v"; then
        vol='🔇'
    else
        vol=" $((10#$(tr -dc '0-9' <<< "$v")))"
    fi
}

update_backlight() {
    local actual_brightness
    local max_brightness

    read -r actual_brightness </sys/class/backlight/*/actual_brightness
    read -r max_brightness </sys/class/backlight/*/max_brightness
    backlight=" $((actual_brightness * 100 / max_brightness))%"
}

update_time() {
    time="$(date "+%a %m/%d %R")"
}

# For calcurse users, refer https://github.com/pystardust/automeet
#update_event () {
#   event="$(calcurse -n | sed 1d | \
#       sed -E "s_^ *\[(.*):(.*)\] ([^\t]*)\t?.*_[\1h \2m->\3]_")"
#   [ "[]" = "$event" ] && event=""
#}

# modules that don't update on their own need to be run at the start for getting their initial value
update_vol
update_backlight

display() {
    xsetroot -name "$crypto | $cpu | $memory | $vol | $backlight | $bat | $time"
}

# SIGNALING
# trap  "<function>;display"        "RTMIN+n"
trap    "update_vol;display"        "RTMIN"
trap    "update_backlight;display"  "RTMIN+1"
trap    "update_bat;display"        "RTMIN+2"
# to update it from external commands
## kill -m "$(cat ~/.cache/pidofbar)"
# where m = 34 + n

sec=0
while true; do
    sleep 1 & wait && {
        [ $((sec % 3600)) -eq 0 ] && update_crypto
        [ $((sec % 5   )) -eq 0 ] && update_time
        [ $((sec % 5   )) -eq 0 ] && update_cpu
        [ $((sec % 5   )) -eq 0 ] && update_memory
        [ $((sec % 5   )) -eq 0 ] && update_bat
        [ $((sec % 5   )) -eq 0 ] && display

        sec="$((sec + 1))"
    }
done