Major rewrite: switching back to Arch from NixOS

root/usr/local/bin/power-profiles-monitor

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [ "$EUID" -ne 0 ]; then
+  echo "You must run this script as root"
+  exit 1
+fi
+
+BAT=$(echo /sys/class/power_supply/BAT*) # only supports single-battery systems
+BAT_STATUS="$BAT/status"
+BAT_CAP="$BAT/capacity"
+OVERRIDE_FLAG="/tmp/power-monitor-override"
+
+POWER_SAVE_PERCENT=50 # Enter power-save mode if on bat and below this capacity
+
+HAS_PERFORMANCE="$(powerprofilesctl list | grep "performance" || true)" # the || true ignores grep failing with non-zero code
+
+# monitor loop
+prev=0
+while true; do
+  # check if override is set
+  if [ -f "$OVERRIDE_FLAG" ]; then
+    echo "Override flag set, waiting for release"
+    inotifywait -qq "$OVERRIDE_FLAG"
+    continue
+  fi
+
+  # read the current state
+  status="$(cat "$BAT_STATUS")"
+  capacity="$(cat "$BAT_CAP")"
+
+  if [[ $status == "Discharging" ]]; then
+    if [[ $capacity -le $POWER_SAVE_PERCENT ]]; then
+      profile="power-saver"
+    else
+      profile="balanced"
+    fi
+  else
+    if [[ -n $HAS_PERFORMANCE ]]; then
+      profile="performance"
+    else
+      profile="balanced"
+    fi
+  fi
+
+  # Set the new profile
+  if [[ "$profile" != "$prev" ]]; then
+    echo -en "Setting power profile to ${profile}\n"
+    powerprofilesctl set $profile
+    prev=$profile
+  fi
+
+  # wait for changes in status or capacity files
+  # i.e. for the next power change event
+  inotifywait -qq "$BAT_STATUS" "$BAT_CAP"
+done