--[[
@title PictUAV2
@param s Secs/frame
@default s 2
@param h Sequence hours
@default h 1
@param m Sequence minutes
@default m 5
@param e Endless? 0=No 1=Yes
@default e 1
@param f Focus: 0=Every 1=Start
@default f 1
@param d Display off frame 0=never
@default d 0
--]]
print( "PictUAV2 Started " )
-- convert parameters into readable variable names
secs_frame, hours, minutes, endless, focus_at_start, display_off_frame = s, h, m, (e > 0), (f > 0), d

props = require "propcase"

-- derive actual running parameters from the more human-friendly input
-- parameters
function calculate_parameters (seconds_per_frame, hours, minutes, start_ticks)
   local ticks_per_frame = 1000 * secs_frame -- ticks per frame
   local total_frames = (hours * 3600 + minutes * 60) / secs_frame -- total frames
   local end_ticks = start_ticks + total_frames * ticks_per_frame -- ticks at end of sequence
   return ticks_per_frame, total_frames, end_ticks
end

function print_status (frame, total_frames, ticks_per_frame, end_ticks, endless)
   local free = get_jpg_count()
   if endless then
      local h, m, s = ticks_to_hms(frame * ticks_per_frame)
      print("#" .. frame .. ", " .. h .. "h " .. m .. "m " .. s .. "s")
   else
      local h, m, s = ticks_to_hms(end_ticks - get_tick_count())
      print(frame .. "/" .. total_frames .. ", " .. h .. "h" .. m .. "m" .. s .. "s/" .. free .. " left")
   end
end

function ticks_to_hms (ticks)
   local secs = (ticks + 500) / 1000 -- round to nearest seconds
   local s = secs % 60
   secs = secs / 60
   local m = secs % 60
   local h = secs / 60
   return h, m, s
end

-- sleep, but using wait_click(); return true if a key was pressed, else false
function next_frame_sleep (frame, start_ticks, ticks_per_frame)
   -- this calculates the number of ticks between now and the time of
   -- the next frame
   local sleep_time = (start_ticks + frame * ticks_per_frame) - get_tick_count()
   if sleep_time < 1 then
      sleep_time = 1
   end
   wait_click(sleep_time)
   return not is_key("no_key")
end

-- delay for the appropriate amount of time, but respond to
-- the display key (allows turning off display to save power)
-- return true if we should exit, else false
function frame_delay (frame, start_ticks, ticks_per_frame)
   -- this returns true while a key has been pressed, and false if
   -- none
   while next_frame_sleep (frame, start_ticks, ticks_per_frame) do
      -- honour the display button
      if is_key("print") then
	 click("print")
      end
      -- if set key is pressed, indicate that we should stop
      if is_key("set") then
	 return true
      end
   end
   return false
end

-- click "print" to turn on/off display
function seek_display_mode()
   click "print"
end

-- switch to autofocus mode, pre-focus, then go to manual focus mode
function pre_focus()
   local focused = false
   local try = 1
   while not focused and try <= 5 do
      print("Pre-focus attempt " .. try)
      press("shoot_half")
      sleep(2000)
      if get_prop(18) > 0 then
	 focused = true
	 set_aflock(1)
      end
      release("shoot_half")
      sleep(500)
      try = try + 1
   end
   return focused
end


-- This is the program core, a loop:
Started = 0
print( "PictUAV2 loop " )
a = -1;
repeat
	aold = a
	a = get_usb_power()
	if (a ~= aold) then
		print("a = " .. a)
	end
	
	-- If pulses are 90 msec or greater, shutdown directly and end.
	if (a>8) then
	        print( "shutting down " )
			shut_down()
			sleep(1500)
	end

	-- If pulses are greater than 30 msec start recording
	if (a>3) or (Started == 1) then
		if Started == 0 then
			print( "recording Started " )

			sleep(1500)
			Started = 1
			if focus_at_start then
			   if not pre_focus() then
				  print "Unable to reach pre-focus"
			   end
			end
			
			start_ticks = get_tick_count()
			
			ticks_per_frame, total_frames, end_ticks = calculate_parameters(secs_frame, hours, minutes, start_ticks)
			
			frame = 1
			
			print "Press SET to exit"
		end	
		print_status(frame, total_frames, ticks_per_frame, end_ticks, endless)
	   shoot()
	
	   if frame_delay(frame, start_ticks, ticks_per_frame) then
		  print "User quit"
		  break
	   end
	   frame = frame + 1
		
	end
until ( false )
print( "PictUAV2 ended " )