#!/bin/sh

# Triggered by <Control><Alt>n
# as defined in [org/gnome/settings-daemon/plugins/media-keys]
# in ~/.config/gnome-settings/key-bindings.ini
#
# Night Light control:
#
# - <Control><Alt>n => "when" toggle
#   + "Force" the screen to be warm right now!
#     (Turns Night Light on if it was off, and keeps it on all day)
#   + "Un-force" the Night Light into the local evening schedule
# - <Alt><Shift>n => "if" toggle
#   Plain on/off switch for the Night Light feature
#
# Neither key binding changes what the other controls, so they don't fight.
#
# Making the screen cooler or warmer with <Alt><Shift>Left/Right
# also forces "Night Light" on because adjusting this implies
# that the user wants to use it.
#
# State machine:
#                                                  TARGET STATE
#                             +--------------------------+--------------------------+
#      CURRENT STATE          | nl-toggle-schedule       | nl-toggle-enabled        |
#  +--------------------------+--------------------------+--------------------------+
#  | disabled, automatic      | enabled, force           | enabled, automatic (*)   |
#  | disabled, force          | enabled, force           | enabled, force           |
#  | enabled,  automatic      | enabled, force (*)       | disabled, automatic (*)  |
#  | enabled,  force          | enabled, automatic (*)   | disabled, force          |
#  +--------------------------+--------------------------+--------------------------+
#  (*) There are four cases where a user does not perceive a change on the screen.
#      Then, a notification is shown instead.
#
# See ~/.local/bin/night-light-toggle-enabled for the other half of the toggling logic


set -eu


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_before=$(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)

automatic=$(gsettings get $Schema night-light-schedule-automatic)
enabled=$(gsettings get $Schema night-light-enabled)


if [ "$automatic" = "true" ] || [ "$enabled" = "false" ]; then

    # Force "Night Light" enabled, enabling it if needed
    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

    if [ "$active_before" = "(<true>,)" ] && [ "$automatic" = "true" ]; then
        notify "is now forced to stay on and no longer on an automatic schedule"
    fi

else

    # Back to the live location's schedule
    gsettings set $Schema night-light-schedule-automatic true
    gsettings set $Schema night-light-schedule-from 18.0
    gsettings set $Schema night-light-schedule-to 6.0

    if [ "$active_before" = "(<true>,)" ]; then

        # Give the settings daemon a moment to recompute "NightLightActive"
        sleep 0.1

        active_after=$(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)

        if [ "$active_after" = "(<true>,)" ]; then
            notify "is still on because of an automatic schedule"
        fi

    fi

fi