#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (C) 2021-present Fewtarius
#               2021-present pkegg

. /etc/profile

set -e
set -o pipefail

LOG="/var/log/$(basename "$0").log"

### Summary
#   This script listens to volume keys on the RG351MP and adjusts volume
#   Fn + Volume up/down will adjust brightness
###


# Event examples for reference
# type 1 (EV_KEY), code 114 (KEY_VOLUMEDOWN), value 1
# type 1 (EV_KEY), code 115 (KEY_VOLUMEUP), value 1

VOL_EVENT='*(KEY_VOLUME*, value *' # This matches all volume events

VOL_UP='*UP), value *'  # Differentiate 'up' volume event
VOL_DOWN='*DOWN), value *' #Differentiate 'down' volume event

V_FUNC_KEY_EVENT='*('${DEVICE_VOL_MODIFIER}'), value *'

# Matches if a button was pressed (1), released (0) or held down (2)
PRESS='value [1-9]'
RELEASE='value 0'

# Volume repeat
VOLUME_REPEAT_MOD=4

# Brightness repeat
BRIGHTNESS_REPEAT_MOD=4

# Variable to keep track of Fn being currently pressed
FUNC_PRESSED=no

CONTROLLER_DISCONNECTED="*error reading: No such device"
DEVICE_DISCONNECTED="*error reading: No such device"

# Detect input devices automatically
for DEV in /dev/input/ev*
do
  unset SUPPORTS
  SUPPORTS=$(udevadm info ${DEV} | awk '/ID_INPUT_KEY=|ID_INPUT_JOYSTICK=/ {print $2}')
  if [ -n "${SUPPORTS}" ]
  then
    DEVICE=$(udevadm info ${DEV} | awk 'BEGIN {FS="="} /DEVNAME=/ {print $2}')
    INPUT_DEVICES+=("${DEVICE}")
  fi
done

# Logic:
#  - Listen to both:
#    - 'rg351' events to get volume keys (not part of the joystick api)
#    - 'joystick' events - as the V's 'fn' key is mapped to the joystick
#  - Switch statement keeps high level cases to only 'volume' and 'V function key'
#      this is to avoid processing for other events or creating a lot of cases as this will be called
#      for all button pushes
#  - Using 'read' means the loop is idle when no button is pressed

(

   for INPUT_DEVICE in ${INPUT_DEVICES[@]}
   do
     evtest "${INPUT_DEVICE}" 2>&1 &
   done
   wait
) | while read line; do
    case $line in
        (${CONTROLLER_DISCONNECTED})
        echo "Reloading due to ${CONTROLLER_DEVICE} reattach..." >${LOG} 2>&1
        exit 0
        ;;
        (${DEVICE_DISCONNECTED})
        echo "Reloading due to ${DEVICE} reattach..." >${LOG} 2>&1
        exit 0
        ;;
        (${VOL_EVENT})

          # We don't care when you 'let go' ('release') the volume button
          if [[ "$line" =~ ${RELEASE} ]]; then
             REPEAT_NUM=0
             continue
          fi

          # Setup for 'brightness' if Fn pressed
          if [[ "${FUNC_PRESSED}" == "yes" ]]; then
            COMMAND=/usr/bin/brightness
            UP="up"
            DOWN="down"
            REPEAT_MOD=${BRIGHTNESS_REPEAT_MOD}
          # Default to 'volume' if Fn is not pressed
          else
            COMMAND="/usr/bin/system_utils vol"
            UP="+"
            DOWN="-"
            REPEAT_MOD=${VOLUME_REPEAT_MOD}
          fi

          REPEAT_NUM=$(( ${REPEAT_NUM} + 1 ))

          # This isn't time to evaluate repeat so just skip
          if [[ "$line" == ${REPEAT_PRESS} && $(( ${REPEAT_NUM} % ${REPEAT_MOD} )) != "0" ]]; then
             continue
          fi

          INCREMENT_AMOUNT=5
          if [[ "${REPEAT_NUM}" -gt "20" ]]; then
             INCREMENT_AMOUNT=10
          fi

          # Run the commands to adjust volume/brightness
          if [[ "${line}" == ${VOL_UP} ]]; then
            ${COMMAND} ${UP} ${INCREMENT_AMOUNT} > /dev/null
          elif [[ "${line}" == ${VOL_DOWN} ]]; then
            ${COMMAND} ${DOWN} ${INCREMENT_AMOUNT} > /dev/null
          fi
        ;;

        (${V_FUNC_KEY_EVENT})

          ## We don't care about 'Fn' key repeats - continue
          #if [[ "$line" == ${REPEAT_PRESS} ]]; then
          #   continue
          #fi

          #Reset the number of repeats when Fn is pressed/release
          #  as repeat speed is different between volume/brightness
          REPEAT_NUM=0

          if [[ "${line}" =~ ${PRESS} ]]; then
            FUNC_PRESSED=yes
          elif [[ "${line}" == ${RELEASE} ]]; then
            FUNC_PRESSED=no
          fi
        ;;
    esac
done