From da6ca327f75c661f1a48b23e27e77c4df1081f0d Mon Sep 17 00:00:00 2001
From: elbachir-one <bachiralfa@gmail.com>
Date: Fri, 1 Aug 2025 12:19:30 +0100
Subject: [PATCH] Fix: change battery_notify to return const char * for
 compatibility

---
 components/battery.c | 47 ++++++++++++++++++++++++++++++++++++++++++++
 config.def.h         | 11 +++++++++++
 slstatus.h           |  1 +
 3 files changed, 59 insertions(+)

diff --git a/components/battery.c b/components/battery.c
index 1c753f9..432f714 100644
--- a/components/battery.c
+++ b/components/battery.c
@@ -1,6 +1,7 @@
 /* See LICENSE file for copyright and license details. */
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "../slstatus.h"
 #include "../util.h"
@@ -20,6 +21,13 @@
 	#define POWER_SUPPLY_CURRENT  "/sys/class/power_supply/%s/current_now"
 	#define POWER_SUPPLY_POWER    "/sys/class/power_supply/%s/power_now"
 
+	const char notify_cmd[] = "notify-send";
+	const char battery_str[] = "Battery";
+	int last_notified_level = 0;
+
+	extern const int notifiable_levels[];
+	extern const size_t notifiable_levels_count;
+
 	static const char *
 	pick(const char *bat, const char *f1, const char *f2, char *path,
 	     size_t length)
@@ -49,6 +57,45 @@
 		return bprintf("%d", cap_perc);
 	}
 
+const char *battery_notify(const char *bat)
+{
+	int cap_perc;
+	char state[12];
+	char path[PATH_MAX];
+
+	if (esnprintf(path, sizeof(path), POWER_SUPPLY_CAPACITY, bat) < 0 || pscanf(path, "%d", &cap_perc) != 1)
+		return NULL;
+
+	if (esnprintf(path, sizeof(path), POWER_SUPPLY_STATUS, bat) < 0 || pscanf(path, "%12[a-zA-Z ]", &state) != 1)
+		return NULL;
+
+	if (strcmp("Charging", state) == 0) {
+		last_notified_level = 0;
+		return NULL;
+	}
+
+	if (strcmp("Discharging", state) != 0)
+		return NULL;
+
+	char cmd[28];
+
+	for (size_t i = 0; i < notifiable_levels_count; i++) {
+		if (notifiable_levels[i] != cap_perc)
+			continue;
+
+		if (notifiable_levels[i] != last_notified_level) {
+			last_notified_level = notifiable_levels[i];
+
+			snprintf(cmd, sizeof(cmd), "%s %s %d%%", notify_cmd, battery_str, cap_perc);
+			system(cmd);
+
+			break;
+		}
+	}
+
+	return NULL;
+}
+
 	const char *
 	battery_state(const char *bat)
 	{
diff --git a/config.def.h b/config.def.h
index 100093e..d7e77d2 100644
--- a/config.def.h
+++ b/config.def.h
@@ -9,11 +9,21 @@ static const char unknown_str[] = "n/a";
 /* maximum output string length */
 #define MAXLEN 2048
 
+/* battery levels to notify - add any levels you want to receive notification for (in percent) */
+const int notifiable_levels[] = {
+    20,
+    10,
+    5,
+};
+const size_t notifiable_levels_count = sizeof(notifiable_levels) / sizeof(notifiable_levels[0]);
+
 /*
  * function            description                     argument (example)
  *
  * battery_perc        battery percentage              battery name (BAT0)
  *                                                     NULL on OpenBSD/FreeBSD
+ * battery_notify      linux battery notifications     battery name (BAT0)
+ *                                                     OpenBSD/FreeBSD not supported
  * battery_remaining   battery remaining HH:MM         battery name (BAT0)
  *                                                     NULL on OpenBSD/FreeBSD
  * battery_state       battery charging state          battery name (BAT0)
@@ -67,4 +77,5 @@ static const char unknown_str[] = "n/a";
 static const struct arg args[] = {
 	/* function format          argument */
 	{ datetime, "%s",           "%F %T" },
+	{ battery_notify, "",       "BAT0" }, /* There is nothing to print its just a notifications*/
 };
diff --git a/slstatus.h b/slstatus.h
index 394281c..061d80a 100644
--- a/slstatus.h
+++ b/slstatus.h
@@ -2,6 +2,7 @@
 
 /* battery */
 const char *battery_perc(const char *);
+const char *battery_notify(const char *);
 const char *battery_remaining(const char *);
 const char *battery_state(const char *);
 
-- 
2.50.1