From f7599e9564b0101a1731987d95b32e081eea0a71 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Mon, 14 Nov 2022 22:22:43 -0500
Subject: [PATCH] Change the linux battery script to be triggered by changes in
 battery state via upower.

---
 .../sway/files/waybar_battery_linux.bash      | 103 ++++++++----------
 ansible/roles/sway/tasks/linux.yaml           |   1 +
 2 files changed, 48 insertions(+), 56 deletions(-)

diff --git a/ansible/roles/sway/files/waybar_battery_linux.bash b/ansible/roles/sway/files/waybar_battery_linux.bash
index 96274d3..9b4ffea 100644
--- a/ansible/roles/sway/files/waybar_battery_linux.bash
+++ b/ansible/roles/sway/files/waybar_battery_linux.bash
@@ -1,72 +1,63 @@
 #!/usr/bin/env bash
 #
-# Read battery status in FreeBSD
+# Read battery status in Linux
 set -euo pipefail
 IFS=$'\n\t'
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-SLEEP_INTERVAL=${SLEEP_INTERVAL:-30}
+batteries=$(upower --enumerate | grep BAT)
 
-batteries=$(find /sys/class/power_supply -name 'BAT*')
+function generate_battery_update {
+    local battery_path=$1
+    local battery_status=$(upower --show-info "$battery_path")
+    local battery_state=$(grep 'state:' <<<"$battery_status" | awk '{print $2}')
+    local battery_percentage=$(grep 'percentage:' <<<"$battery_status" | awk '{print $2}')
+    battery_percentage=${battery_percentage%\%}
+    local time_remaining=$(grep 'time to empty:' <<<"$battery_status" | sed 's/\W*time to empty:\W*//g')
+    local battery_icon=""
+    local class=""
 
-while true; do
-    text=""
-    tooltip=""
-    percentage=""
-    class=""
-
-    while read bat; do
-        battery_now=$(cat "$bat/charge_now")
-        battery_capacity=$(cat "$bat/charge_full")
-        battery_percentage=$(( battery_now * 100 / battery_capacity ))
-        battery_status=$(cat "$bat/status")
-        seconds_remaining="-1"
-
-        if [ $battery_status = "Charging" ]; then
-            if [ $battery_percentage -eq 100 ]; then
-                battery_icon=""
-            else
-                battery_icon=""
-            fi
-        elif [ $battery_percentage -le 20 ]; then
-            battery_icon=""
-        elif [ $battery_percentage -le 40 ]; then
-            battery_icon=""
-        elif [ $battery_percentage -le 60 ]; then
-            battery_icon=""
-        elif [ $battery_percentage -le 80 ]; then
-            battery_icon=""
-        elif [ $battery_percentage -lt 100 ]; then
-            battery_icon=""
+    if [ $battery_state = "charging" ]; then
+        if [ $battery_percentage -eq 100 ]; then
+            battery_icon=""
         else
-            battery_icon=""
+            battery_icon=""
         fi
+    elif [ $battery_percentage -le 20 ]; then
+        battery_icon=""
+    elif [ $battery_percentage -le 40 ]; then
+        battery_icon=""
+    elif [ $battery_percentage -le 60 ]; then
+        battery_icon=""
+    elif [ $battery_percentage -le 80 ]; then
+        battery_icon=""
+    elif [ $battery_percentage -lt 100 ]; then
+        battery_icon=""
+    else
+        battery_icon=""
+    fi
 
-        if [ $battery_percentage -le 15 ]; then
-            class="critical"
-        elif [ $battery_percentage -le 30 ]; then
-            class="warning"
-        fi
-
-        if [ $seconds_remaining -eq -1 ]; then
-            time_remaining="unknown time remaining."
-        else
-            time_remaining=$(printf '%dh:%dm:%ds\n' $((seconds_remaining/3600)) $((seconds_remaining%3600/60)) $((seconds_remaining%60)) )
-        fi
-
-        text="$text${battery_percentage}% ${battery_icon}"
-        tooltip="$tooltip${time_remaining}"
-        percentage="$percentage${battery_percentage}"
-    done<<<"$batteries"
-
-
-    jq --unbuffered --compact-output <<EOF
+    if [ $battery_percentage -le 15 ]; then
+        class="critical"
+    elif [ $battery_percentage -le 30 ]; then
+        class="warning"
+    fi
+        jq --unbuffered --compact-output <<EOF
 {
-"text":"$text",
-"tooltip":"$tooltip",
-"percentage":${percentage},
+"text":"${battery_percentage}% ${battery_icon}",
+"tooltip":"$time_remaining",
+"percentage":${battery_percentage},
 "class":"${class}"
 }
 EOF
-    sleep $SLEEP_INTERVAL
+}
+
+while read bat; do
+    generate_battery_update "$bat"
+done<<<"$batteries"
+
+upower --monitor | grep --line-buffered 'device changed:' | while read l; do
+    while read bat; do
+        generate_battery_update "$bat"
+    done<<<"$batteries"
 done
diff --git a/ansible/roles/sway/tasks/linux.yaml b/ansible/roles/sway/tasks/linux.yaml
index 7dbb665..b532ab0 100644
--- a/ansible/roles/sway/tasks/linux.yaml
+++ b/ansible/roles/sway/tasks/linux.yaml
@@ -2,6 +2,7 @@
   package:
     name:
       - bc # For waybar sound script
+      - upower # Needed for waybar battery script
     state: present
 
 - name: Install scripts