#!/usr/bin/env bash

set -e

# Constants
SECONDS_UNTIL_FADE=$(( 1 * 60))
SECONDS_UNTIL_OFF=$(( 5 * 60))

COLOR_ON=ff0000
COLOR_FADE=880000
COLOR_OFF=000000

# Logging

if [[ "$1" = "debug" ]]; then
    echo "Running with debugging" >&2
    DEBUG="true"

    SECONDS_UNTIL_FADE=$(( 3 ))
    SECONDS_UNTIL_OFF=$(( 5 ))
fi

log() {
    if [[ "$DEBUG" = "true" ]]; then
        echo "$@" >&2
    fi
}

# Implementation

main() {
    CURRENT_STATE="UNKNOWN"
    LAST_POINTER_MOTION="$(date +%s)"

    if [ "$(ratbagctl list | wc -l)" -ne 1 ]; then
        echo "Not exactly one device found, exiting..."
        exit 1
    fi

    DEVICE="$(ratbagctl list | cut -d: -f1)"

    while true; do
        while read line; do
            LAST_POINTER_MOTION="$(date +%s)"
            break
        done < <(
            timeout 5s \
                libinput debug-events \
                | grep POINTER_MOTION
        )
        TIME_SINCE_LAST=$(( "$(date +%s)" - "$LAST_POINTER_MOTION" ))
        log "Last pointer motion was $TIME_SINCE_LAST seconds ago"
        if [ "$TIME_SINCE_LAST" -gt "$SECONDS_UNTIL_OFF" ]; then
            setState OFF "$COLOR_OFF"
        elif [ "$TIME_SINCE_LAST" -gt "$SECONDS_UNTIL_FADE" ]; then
            setState FADE "$COLOR_FADE"
        else
            setState ON "$COLOR_ON"
        fi
    done
}

setState() {
    STATE="$1"
    COLOR="$2"
    MODE="$3"

    if [[ "$STATE" = "$CURRENT_STATE" ]]; then
        log "Already in $STATE state"
        return
    fi
    log "Changing state to $STATE"
    CURRENT_STATE="$STATE"

    ratbagctl "$DEVICE" led 0 set mode on
    ratbagctl "$DEVICE" led 0 set color "$COLOR"
}

main