Add toggle support

This adds the -t,--toggle switch, which will toggle brightness between
the current set value, 0, and back. Note that this writes a state file
to /tmp/luminous.state to track the the original brightness when dimming
to nothing.

1 files changed, 38 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index 9ee733f..d78a40d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -22,6 +22,7 @@
 #include "config.h"
 
 #define CONF "/etc/luminous.conf"
+#define STATE "/tmp/luminous.state"
 
 // For string macros
 #define xstr(s) str(s)
@@ -85,6 +86,25 @@ int fgeti(char* path) {
 
 
 /**
+ * write_state:
+ * Writes the current brightness level to a text file.
+ *
+ * @path   Path to the file to contain the current brightness
+ */
+int write_state(char* path, int cur) {
+  FILE* fd;
+  fd = fopen(path, "w");
+
+  if(!fd)
+    return errno;
+
+  fprintf(fd, "%d", cur);
+  fclose(fd);
+  return 0;
+}
+
+
+/**
  * fade:
  * @props Props struct containing runtime parameters
  *
@@ -141,6 +161,9 @@ int fade(struct props* props) {
     props->cur += step * direction;
     steps--;
   }
+  // The step loop got us very close to the destination brightness, just finish
+  // things off since the math rarely works evenly.
+  fprintf(fd, "%d\n", props->lvl);
   fclose(fd);
   return 0;
 }
@@ -200,6 +223,21 @@ int parseargs(struct props* out, int argc, char* argv[]) {
       i++;
       out->duration = atoi(argv[i]);
 
+    } else if(strcmp(argv[i], "-t") == 0 || strcmp(argv[i], "--toggle") == 0) {
+      FILE* fd = fopen(STATE, "r");
+      // If somehow we are at zero and there is no statefile, set brightness to
+      // half max.
+      if(out->cur < out->max * .02) {
+        // If 0, we increase brightness which means reading from statefile
+        if(!fd)
+          write_state(STATE, out->lvl = out->max / 2);
+        else
+          out->lvl = fgeti(STATE);
+      } else {
+        write_state(STATE, out->cur);
+        out->lvl = 0;
+      }
+
     } else if(strcmp(argv[i], "-l") == 0 || strcmp(argv[i], "--level") == 0) {
       i++;
       // Account for relative and absolute increments and decrements