dotfiles/.local/bin/night-light-make-warmer

#!/bin/sh

# Triggered by <Alt><Shift>Right
# as defined in [org/gnome/settings-daemon/plugins/media-keys]
# in ~/.config/gnome-settings/key-bindings.ini
#
# This script ensures "Night Light" is forced on
# or makes the screen a bit warmer than it currently is
#
# The default warmth is restored at login by ~/.local/bin/restore-gnome

set -eu


# GNOME's GUI lets one choose between 1700 and 4700 only,
# and 6500 is the point where no color correction is applied at all
# while 1000 is the absolute minimum supported by the OS
_MIN_TEMPERATURE=1200
_MAX_TEMPERATURE=4700

_DEFAULT_TEMPERATURE=2200


notify() {
    ID_FILE="${XDG_RUNTIME_DIR}/night-light-notification-id"
    _id=$(cat "$ID_FILE" 2>/dev/null || true)

    if [ -n "$_id" ]; then
        notify-send -p -t 5000 --replace-id="$_id" "Night Light" "$1" > "$ID_FILE" || rm -f "$ID_FILE"
    else
        notify-send -p -t 5000 "Night Light" "$1" > "$ID_FILE" || rm -f "$ID_FILE"
    fi
}


Schema=org.gnome.settings-daemon.plugins.color


active=$(gdbus call --session \
    --dest org.gnome.SettingsDaemon.Color \
    --object-path /org/gnome/SettingsDaemon/Color \
    --method org.freedesktop.DBus.Properties.Get \
    org.gnome.SettingsDaemon.Color NightLightActive)

applied=$(gdbus call --session \
    --dest org.gnome.SettingsDaemon.Color \
    --object-path /org/gnome/SettingsDaemon/Color \
    --method org.freedesktop.DBus.Properties.Get \
    org.gnome.SettingsDaemon.Color Temperature \
    | sed -E 's/.*uint32 ([0-9]+).*/\1/')

automatic=$(gsettings get $Schema night-light-schedule-automatic)
current=$(gsettings get $Schema night-light-temperature | awk '{print $2}')


if [ "$active" = "(<true>,)" ] \
        && { [ "$automatic" = "false" ] || [ $((applied - current)) -le 300 ]; }; then
    at_target=true
else
    at_target=false
fi


# Step only if the screen already shows the target tint
# while off or ramping in, forcing on below provides the warming already
if [ "$at_target" = "true" ]; then

    # 500 = (4700 - 1700 + 500) / 7
    # => Seven steps spanning more than the range in the GUI,
    #    mainly because we want to allow a bit more warmth (i.e., +500)
    new=$((current - 500))

    if [ "$new" -lt $_MIN_TEMPERATURE ]; then
        new=$_MIN_TEMPERATURE
    fi

    gsettings set $Schema night-light-temperature "uint32 $new"

# Untinted and parked at a cool target
# => Forcing on would barely show otherwise
elif [ "$active" = "(<false>,)" ] && [ "$current" -gt $_DEFAULT_TEMPERATURE ]; then

    gsettings set $Schema night-light-temperature "uint32 $_DEFAULT_TEMPERATURE"

fi


# Always force "Night Light" on, saving a <Control><Alt>n call,
# with the same settings as in ~/.local/bin/night-light-toggle-schedule
if [ "$active" = "(<false>,)" ] || [ "$automatic" = "true" ]; then
    gsettings set $Schema night-light-enabled true
    gsettings set $Schema night-light-schedule-automatic false
    gsettings set $Schema night-light-schedule-from 0.0
    gsettings set $Schema night-light-schedule-to 24.0
fi


# Notify only if the press produced no visible change
# (i.e., already at the minimum and not just snapped to full warmth by the force)
if [ "$at_target" = "true" ] && [ "$current" -le $_MIN_TEMPERATURE ]; then
    notify "is already as warm as it gets (${_MIN_TEMPERATURE}K)"
fi