#!/usr/bin/sh
# @author nate zhou
# @since 2025,2026
# @depends brightnessctl
# bright - changing monitor backlight brightness and track status
# also see:
#   - .local/bin/wobd for setting an indicator in a wayland environment
#   - .local/bin/damblocks for sending signals to update status bars

# This script has completions: `.config/{z,ba}sh/completions/_scripts.{z,ba}sh`

#set -x
DAMBLOCKS="${XDG_RUNTIME_DIR}/damblocks.pid"

[ "$XDG_SESSION_TYPE" = "wayland" ] \
    && MENU="${HOME}/.local/bin/wmenu-color" \
       FIFO="${XDG_RUNTIME_DIR}/wob.fifo" \
    || MENU="dmenu" \
       FIFO="${XDG_RUNTIME_DIR}/xob.fifo"

# save brightness to XDG_CACHE_DIR for reboot consistency
BRIGHTNESS="${XDG_CACHE_HOME}/brightness.level"

usage() {
    cat <<_EOF_
USAGE
        $(basename $0) [OPTION]
        Without an option, $(basename $0) reloads damblocks brightness module
        and FIFO
OPTIONS
        --minus     decrease brightness by 1%
        --minus10   decrease brightness by 10%
        --plus      increase brightness by 1%
        --plus10    increase brightness by 10%
        --max       set brightness to 100%
        --min       set brightness to 0%
        --no-fifo   reload damblocks brightness moduel without FIFO
_EOF_
    exit 0
}

parseBrightness() {
    grep 'Current brightness' \
            | tr '()' ' ' | cut -d' ' -f5 | sed 's/%//' \
            | tee "$FIFO" "$BRIGHTNESS" \
        && kill -38 "$(cat $DAMBLOCKS)";
}

# don't direct to FIFO if brightness change is triggered by an idle manager.
parseBrightnessIdle() {
    grep 'Current brightness' \
            | tr '()' ' ' | cut -d' ' -f5 | sed 's/%//' > "$BRIGHTNESS" \
        && kill -38 "$(cat $DAMBLOCKS)";
}

changeBrightness() {
    brightnessctl set "$1" | parseBrightness
}

while [ -n "$1" ]; do
    case "$1" in
        --minus)
            changeBrightness '1%-'
            ;;
        --minus10)
            changeBrightness '10%-'
            ;;
        --plus)
            changeBrightness '1%+'
            ;;
        --plus10)
            changeBrightness '10%+'
            ;;
        --max)
            changeBrightness '100%'
            ;;
        --min)
            changeBrightness '0%'
            ;;
        --no-fifo)
            brightnessctl | parseBrightnessIdle
            return
            ;;
        *)
            usage
            ;;
    esac
    shift
done

[ -z "$1" ] && brightnessctl | parseBrightness