battery: add format_below_threshold feature

i3status.c

@@ -316,6 +316,7 @@ int main(int argc, char *argv[]) {
 
     cfg_opt_t battery_opts[] = {
         CFG_STR("format", "%status %percentage %remaining", CFGF_NONE),
+        CFG_STR("format_below_threshold", NULL, CFGF_NONE),
         CFG_STR("format_down", "No battery", CFGF_NONE),
         CFG_STR("format_percentage", "%.02f%s", CFGF_NONE),
         CFG_STR("status_chr", "CHR", CFGF_NONE),
@@ -737,6 +738,7 @@ int main(int argc, char *argv[]) {
                     .number = (strcasecmp(title, "all") == 0 ? -1 : atoi(title)),
                     .path = cfg_getstr(sec, "path"),
                     .format = cfg_getstr(sec, "format"),
+                    .format_below_threshold = cfg_getstr(sec, "format_below_threshold"),
                     .format_down = cfg_getstr(sec, "format_down"),
                     .status_chr = cfg_getstr(sec, "status_chr"),
                     .status_bat = cfg_getstr(sec, "status_bat"),

include/i3status.h

@@ -266,6 +266,7 @@ typedef struct {
     int number;
     const char *path;
     const char *format;
+    const char *format_below_threshold;
     const char *format_down;
     const char *status_chr;
     const char *status_bat;

man/i3status.man

@@ -376,7 +376,8 @@ It is possible to define a low_threshold that causes the battery text to be
 colored +color_bad+. The +low_threshold+ type can be of +threshold_type+ "time"
 or "percentage". So, if you configure +low_threshold+ to 10 and +threshold_type+
 to "time", and your battery lasts another 9 minutes, it will be colored
-+color_bad+.
++color_bad+. You can customize the output format when below
++low_threshold+ with +format_below_threshold.+
 
 To show an aggregate of all batteries in the system, use "all" as the number. In
 this case (for Linux), the /sys path must contain the "%d" sequence. Otherwise,
@@ -395,6 +396,8 @@ FULL) is used.
 
 *Example format*: +%status %remaining (%emptytime %consumption)+
 
+*Example format_below_threshold*: +Warning: %remaining (%emptytime)+
+
 *Example format_down*: +No battery+
 
 *Example format_percentage*: +"%.02f%s"+

src/print_battery_info.c

@@ -575,6 +575,7 @@ static bool slurp_all_batteries(battery_info_ctx_t *ctx, struct battery_info *ba
 }
 
 void print_battery_info(battery_info_ctx_t *ctx) {
+    const char *selected_format = ctx->format;
     char *outwalk = ctx->buf;
     struct battery_info batt_info = {
         .full_design = -1,
@@ -650,9 +651,13 @@ void print_battery_info(battery_info_ctx_t *ctx) {
         if (batt_info.percentage_remaining >= 0 && strcasecmp(ctx->threshold_type, "percentage") == 0 && batt_info.percentage_remaining < ctx->low_threshold) {
             START_COLOR("color_bad");
             colorful_output = true;
+            if (ctx->format_below_threshold != NULL)
+                selected_format = ctx->format_below_threshold;
         } else if (batt_info.seconds_remaining >= 0 && strcasecmp(ctx->threshold_type, "time") == 0 && batt_info.seconds_remaining < 60 * ctx->low_threshold) {
             START_COLOR("color_bad");
             colorful_output = true;
+            if (ctx->format_below_threshold != NULL)
+                selected_format = ctx->format_below_threshold;
         }
     }
 
@@ -713,7 +718,7 @@ void print_battery_info(battery_info_ctx_t *ctx) {
         {.name = "%consumption", .value = string_consumption}};
 
     const size_t num = sizeof(placeholders) / sizeof(placeholder_t);
-    char *untrimmed = format_placeholders(ctx->format, &placeholders[0], num);
+    char *untrimmed = format_placeholders(selected_format, &placeholders[0], num);
     char *formatted = trim(untrimmed);
     OUTPUT_FORMATTED;
     free(formatted);

testcases/027-battery-low-threshold-format/BAT0_uevent

@@ -0,0 +1,4 @@
+POWER_SUPPLY_STATUS=Discharging
+POWER_SUPPLY_TIME_TO_EMPTY_NOW=42
+POWER_SUPPLY_CHARGE_FULL_DESIGN=7800000
+POWER_SUPPLY_CHARGE_NOW=1090000

testcases/027-battery-low-threshold-format/expected_output.txt

@@ -0,0 +1 @@
+BELOW_THRESHOLD

testcases/027-battery-low-threshold-format/i3status.conf

@@ -0,0 +1,13 @@
+general {
+        output_format = "none"
+}
+
+order += "battery 0"
+
+battery 0 {
+        format = "%status %percentage %remaining"
+        format_below_threshold = "BELOW_THRESHOLD"
+        low_threshold = 15
+        threshold_type = percentage
+        path = "testcases/027-battery-low-threshold-format/BAT0_uevent"
+}