Add countdown

diff --git a/main.c b/main.c
index 0e1bb50..06d1713 100644 (file)
--- a/main.c
+++ b/main.c
@@ -1,21 +1,84 @@
 #include <stdio.h>
 #include <wiringPi.h>
+#include <time.h>
+#define COIN_BUTTON 7
+#define CREDIT_EXTENSION 10
 
-int main (void)
+int expires = -1;
+int one_second_ago = 0;
+
+void init_gpio()
 {
-  printf ("Short pin 7 and 9 to see something cool.\n") ;
+  wiringPiSetup();
+  pinMode(COIN_BUTTON, INPUT);
+  pullUpDnControl(COIN_BUTTON, PUD_UP);
+}
 
-  wiringPiSetup ();
+int now()
+{
+  return (unsigned)time(NULL);
+}
 
-  pinMode(7, INPUT) ;
-  pullUpDnControl(7, PUD_UP);
+int time_over()
+{
+  if(one_second_ago != now() && expires != -1)
+  {
+    printf("You have %d seconds remaining\n", expires - now());
+    one_second_ago = now();
+  }
 
-  while(1)
+  if(expires == now())
   {
-    if (digitalRead(7) == LOW) //Low is pressed
-      printf("Yay!\n");
+    printf("It's all ogre now\n");
+    expires = -1;
+    return 1;
+  }
 
-      while(digitalRead(7) == LOW) //This just  causes the loop to wait til the button is released
-          delay(10);
+  return expires == -1;
+}
+
+int read_button()
+{
+  if(digitalRead(COIN_BUTTON) == LOW)
+  {
+    printf("Nice! I just added %d to your time.\n", CREDIT_EXTENSION);
+
+    //Increment timer
+    if(expires == -1) //Initial credit, set the expiry to now plus time
+    {
+        expires = now() + CREDIT_EXTENSION;
+    } else { //expiry already set, simply extend by time
+        expires += CREDIT_EXTENSION;
+    }
+
+    //wait for button to be released
+    while(digitalRead(COIN_BUTTON) == LOW)
+    {
+       //I don't see this happening, but in principle if the button is held down
+       //It would be possible to stop the switch happening after time runs out
+       //So we must check for that here.
+       if(time_over())
+         break;
+
+       delay(10);
+    }
+
+    return 1;
+  }
+
+  return 0;
+}
+
+int main (void)
+{
+  init_gpio();
+  printf ("Short pin 7 and 9 to increment timer.\n") ;
+
+  while(1)
+  {
+    read_button();
+    //I don't really need to call this here but I'm doing it to see output.
+    time_over();
+    delay(10);
   }
 }