From 8bd7314490e12d5501818e597144ffd5acc75564 Mon Sep 17 00:00:00 2001
From: u <u@billy>
Date: Mon, 1 May 2023 10:55:01 -0400
Subject: separate service, executable, and installer

---
 Makefile                               |  22 +++++++
 go.sh                                  | 104 ---------------------------------
 suspend-below-battery-capacity         |  51 ++++++++++++++++
 suspend-below-battery-capacity.service |   9 +++
 4 files changed, 82 insertions(+), 104 deletions(-)
 create mode 100644 Makefile
 delete mode 100755 go.sh
 create mode 100755 suspend-below-battery-capacity
 create mode 100644 suspend-below-battery-capacity.service

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..c876ade
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,22 @@
+UNIT = suspend-below-battery-capacity
+BINDIR = /usr/local/bin
+BINARIES = $(UNIT)
+.PHONY: all install-bin install
+
+all:
+	@echo "run 'make install' to install"
+
+ifeq ($(shell id -u),0)
+
+install: $(UNIT).service install-bin
+	systemctl enable --now $(shell realpath -e $<)
+
+install-bin:
+	install -t $(BINDIR) -- $(BINARIES)
+
+else
+
+install install-bin:
+	sudo $(MAKE) -$(MAKEFLAGS) $@
+
+endif
diff --git a/go.sh b/go.sh
deleted file mode 100755
index b9d6aea..0000000
--- a/go.sh
+++ /dev/null
@@ -1,104 +0,0 @@
-#!/bin/bash
-default_capacity_threshold=50
-capacity_threshold_file=$HOME/.config/powerloss-handler/capacity_threshold
-
-battery_dir=/sys/class/power_supply/BAT0
-status_file=$battery_dir/status
-capacity_file=$battery_dir/capacity
-
-UNIT=powerloss-handler
-CMD=$0
-
-FORCE_SUSPEND=
-
-self_install()
-{
-    if systemctl --user is-active "$UNIT" >/dev/null
-    then
-        systemctl --user stop "$UNIT"
-    fi
-    systemctl --user reset-failed "$UNIT" 2>/dev/null
-    systemd-run --user \
-                --unit "$UNIT" \
-                --property Restart="on-failure" \
-                -- "$CMD"
-}
-
-self_test()
-{
-    FORCE_SUSPEND=y
-    go
-    echo
-}
-
-do_suspend()
-{
-    systemctl suspend
-}
-
-go()
-{
-    read capacity < "$capacity_file" || return
-    case "$capacity" in
-        '' | *[^0-9]*)
-            echo "Error: unexpected value for battery capacity: $capacity" >&2
-            return 1 ;;
-    esac
-    read status < "$status_file" || return
-
-    if [ "$FORCE_SUSPEND" ]
-    then
-        status=Discharging
-        capacity=0
-        echo 'Warning: test: pretending battery is discharging at 0% capacity' >&2
-    fi
-
-    if [ -t 2 ]
-    then
-        printf '\r  %20s   %.2d%%\r' "$status" "$capacity" >&2
-    fi
-
-    if [ -f "$capacity_threshold_file" ]
-    then
-        read capacity_threshold < "$capacity_threshold_file"
-    else
-        capacity_threshold=$default_capacity_threshold
-    fi
-
-    [ "$status" = Discharging ] || return 0
-    if [ "$capacity" -lt "$capacity_threshold" ]
-    then
-        do_suspend
-    fi
-}
-
-main()
-{
-    if [ -e /usr/lib/bash/sleep ]
-    then
-        enable -f /usr/lib/bash/sleep sleep
-    else
-        echo 'Warning: not found: /usr/lib/bash/sleep (try: "sudo apt install bash-builtins")' >&2
-    fi
-
-    while true
-    do
-        go
-        sleep 1
-    done
-}
-
-if [ $# = 0 ]
-then
-    main
-else
-    case "$1" in
-        run) main ;;
-        install) self_install ;;
-        test) self_test ;;
-        *) echo "Error: unknown command: $*" >&2
-           echo "Valid commands: run install test" >&2
-           exit 1
-           ;;
-    esac
-fi
diff --git a/suspend-below-battery-capacity b/suspend-below-battery-capacity
new file mode 100755
index 0000000..114cf9b
--- /dev/null
+++ b/suspend-below-battery-capacity
@@ -0,0 +1,51 @@
+#!/bin/bash
+default_capacity_threshold=50
+
+if [ -e /usr/lib/bash/sleep ]
+then
+    enable -f /usr/lib/bash/sleep sleep
+else
+    echo 'Warning: not found: /usr/lib/bash/sleep (try: "sudo apt install bash-builtins")' >&2
+fi
+
+main()
+{
+    capacity_threshold=${1:-$default_capacity_threshold}
+    while true
+    do
+        check_batteries /sys/class/power_supply/BAT*
+        sleep 1
+    done
+}
+
+check_batteries()
+{
+    for dir in "$@"
+    do
+        [ -d "$dir" ] || continue
+        check_battery "$dir"
+    done
+}
+
+check_battery()
+{
+    battery_dir=$1
+
+    read status < "$battery_dir"/status || return
+    [ "$status" = Discharging ] || return 0
+
+    read capacity < "$battery_dir"/capacity || return
+    case "$capacity" in
+        '' | *[^0-9]*)
+            echo "Error: unexpected value for battery capacity: $capacity" >&2
+            return 1
+            ;;
+    esac
+
+    if [ "$capacity" -lt "$capacity_threshold" ]
+    then
+        systemctl suspend
+    fi
+}
+
+main "$@"
diff --git a/suspend-below-battery-capacity.service b/suspend-below-battery-capacity.service
new file mode 100644
index 0000000..bd42596
--- /dev/null
+++ b/suspend-below-battery-capacity.service
@@ -0,0 +1,9 @@
+[Unit]
+Description = Suspend machine when battery capacity drops below threshhold
+
+[Service]
+ExecStart = suspend-below-battery-capacity 50
+Restart = on-failure
+
+[Install]
+WantedBy = default.target
-- 
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