dotfiles/home/.local/bin/scripts/gui/hyprland/hyprland-monitord

#!/usr/bin/env bash
set -euo pipefail

# Simple script that listens for changes in monitor configuration and performs
# certain configured actions.

# Copyright 2024 ItsDrike <me@itsdrike.com>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 59 Temple
# Place, Suite 330, Boston, MA  02111-1307  USA

SCRIPTS_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/hyprland-monitord"
ADD_SCRIPT="$SCRIPTS_DIR/added.sh"
REMOVE_SCRIPT="$SCRIPTS_DIR/removed.sh"

if [ "$#" -ne 0 ]; then
  >&2 echo "CLI arguments are not supported"
  exit 1
fi

if [ -z "$HYPRLAND_INSTANCE_SIGNATURE" ]; then
  >&2 echo "Hyprland is not running, IPC not available"
  exit 1
fi

SOCKET_PATH="${XDG_RUNTIME_DIR:-/run/user/$UID}/hypr/$HYPRLAND_INSTANCE_SIGNATURE/.socket2.sock"

# Older versions of hyprland used a different socket path
# (if someone still actually needs this condition, please for gods sake update)
if ! [ -S "$SOCKET_PATH" ]; then
  SOCKET_PATH="/tmp/hypr/$HYPRLAND_INSTANCE_SIGNATURE/.socket2.sock"
fi

if ! [ -S "$SOCKET_PATH" ]; then
  >&2 echo "Hyprland IPC socket2 file wasn't found!"
  exit 1
fi

# Will block and listen to the hyprland socket messages, outputting them.
# Generally used like: hyprland_ipc | while read line; do handle $line; done
# Read <https://wiki.hyprland.org/IPC/> for output format and available events
# Note: requires openbsd version of netcat.
# $1 - Optional event to listen for (no event filtering will be done if not provided)
hyprland_ipc() {
  if [ "$#" -eq 0 ]; then
    nc -U "$SOCKET_PATH" | while read -r line; do
      echo "$line"
    done
  else
    nc -U "$SOCKET_PATH" | while read -r line; do
      if echo "$line" | grep -E "$1>>" >/dev/null; then
        echo "$line" | awk -F '>>' '{print $2}'
      fi
    done
  fi
}

# Function ran whenever the monitoraddedv2 event is emitted
handle_add() {
  local monitor_id
  local monitor_name
  local monitor_description
  monitor_id="$(echo "$1" | cut -d',' -f1)"
  monitor_name="$(echo "$1" | cut -d',' -f2)"
  monitor_description="$(echo "$1" | cut -d',' -f3)"

  >&2 echo "Monitor added: $monitor_id;$monitor_name;$monitor_description"

  if [ -f "$ADD_SCRIPT" ]; then
    "$ADD_SCRIPT" "$monitor_id" "$monitor_name" "$monitor_description"
  else
    >&2 echo "Add script file not found ($ADD_SCRIPT)"
  fi
}

# Function ran whenever the monitorremoved event is emitted
handle_remove() {
  local monitor_name
  monitor_name="$1"

  >&2 echo "Monitor removed: $monitor_name"

  if [ -f "$REMOVE_SCRIPT" ]; then
    "$REMOVE_SCRIPT" "$monitor_name"
  else
    >&2 echo "Remove script file not found ($REMOVE_SCRIPT)"
  fi
}

>&2 echo "Listening for monitor IPC events"

hyprland_ipc "monitoraddedv2" | while read -r line; do
  handle_add "$line"
done &

hyprland_ipc "monitorremoved" | while read -r line; do
  handle_remove "$line"
done &

wait