Enable button press detection with debouncing.

Added behavior that setup mode now toggles on and off with long press, and attempts to send a Yo when toggled off.

rebuild/main.lua

@@ -1,4 +1,7 @@
 DEBUG = true
+TIMERS = {
+  interrupt = 1
+}
 function debug_message(message)
   if DEBUG then
     print(message)
@@ -9,6 +12,7 @@ end
 local yo = require('yo')
 local server = require('server')
 local read = require('read')
+local button_pin = 6
 
 function wifi_setup(func, ...)
   wifi.setmode(wifi.STATIONAP)
@@ -43,3 +47,51 @@ end
 function long_press()
   wifi_setup(server.start)
 end
+
+function short_or_long_press()
+  local long_press_time = 3000 -- 3 seconds
+  local level = gpio.read(button_pin)
+  debug_message('short_or_long_press: ' .. level)
+
+  if level == 1 then -- button depressed
+    debug_message('short_or_long_press: pressed: start long press timer')
+    tmr.alarm(TIMERS.interrupt, long_press_time, 0, function()
+      debug_message('short_or_long_press: long press!')
+      if server.is_serving() then
+        debug_message('short_or_long_press: toggle setup OFF')
+        short_press()
+      else
+        debug_message('short_or_long_press: toggle setup ON')
+        long_press()
+      end
+    end)
+  else -- button released
+    debug_message('short_or_long_press: released: end long press timer')
+    tmr.stop(TIMERS.interrupt)
+    if not server.is_serving() then
+      debug_message('short_or_long_press: short press!')
+      short_press()
+    end
+  end
+end
+
+function debounce(func)
+  local last = 0 --units: microseconds
+  local delay = 50000 --units: microseconds
+
+  return function(...)
+    local now = tmr.now()
+    if now - last < delay then
+      tmr.stop(TIMERS.interrupt)
+      debug_message("debounce: prevented extra push")
+      return
+    end
+
+    last = now
+    debug_message("debounce: succeed")
+    return func(...)
+  end
+end
+
+gpio.mode(button_pin, gpio.INT, gpio.FLOAT)
+gpio.trig(button_pin, "both", debounce(short_or_long_press))