-- The theme is what decides what's actually shown on screen, what kind of
-- transitions are available (if any), and what kind of inputs there are,
-- if any. In general, it drives the entire display logic by creating Movit
-- chains, setting their parameters and then deciding which to show when.
--
-- Themes are written in Lua, which reflects a simplified form of the Movit API
-- where all the low-level details (such as texture formats) are handled by the
-- C++ side and you generally just build chains.
io.write("hello from lua\n");

local live_signal_num = 0;
local preview_signal_num = 1;

-- The main live chain. Currently just about input 0 with some color correction.
local main_chain = EffectChain.new(16, 9);
local input0 = main_chain:add_live_input();
input0:connect_signal(0);
local resample_effect = main_chain:add_effect(ResampleEffect.new(), input0);
resample_effect:set_int("width", 320);
resample_effect:set_int("height", 180);
local padding_effect = main_chain:add_effect(IntegralPaddingEffect.new(), resample_effect);
padding_effect:set_int("width", 1280);
padding_effect:set_int("height", 720);
padding_effect:set_int("left", 30);
padding_effect:set_int("top", 60);
local wb_effect = main_chain:add_effect(WhiteBalanceEffect.new(), padding_effect);
main_chain:finalize(true);
-- local input1 = main_chain.add_input(Inputs.create(1));
-- local resample_effect = main_chain.add_effect(ResampleEffect.new(), input0);
-- local padding_effect = main_chain.add_effect(IntegralPaddingEffect.new());

-- A chain to show a single input on screen.
local simple_chain = EffectChain.new(16, 9);
local simple_chain_input = simple_chain:add_live_input();
simple_chain_input:connect_signal(0);  -- First input card. Can be changed whenever you want.
simple_chain:finalize(false);

-- Returns the number of outputs in addition to the live (0) and preview (1).
-- Called only once, at the start of the program.
function num_channels()
	return 2;
end

-- Called every frame.
function get_transitions()
	return {"Cut", "Fade", "Zoom!"};
end

function transition_clicked(num, t)
	-- Only a cut for now.
	local temp = live_signal_num;
	live_signal_num = preview_signal_num;
	preview_signal_num = temp;
end

function channel_clicked(num, t)
	-- Presumably change the preview here.
	io.write("STUB: channel_clicked\n");
end

-- Called every frame. Get the chain for displaying at input <num>,
-- where 0 is live, 1 is preview, 2 is the first channel to display
-- in the bottom bar, and so on up to num_channels()+1. t is the 
-- current time in seconds. width and height are the dimensions of
-- the output, although you can ignore them if you don't need them
-- (they're useful if you want to e.g. know what to resample by).
--
-- You should return two objects; the chain itself, and then a
-- function (taking no parameters) that is run just before rendering.
-- The function needs to call connect_signal on any inputs, so that
-- it gets updated video data for the given frame. (You are allowed
-- to switch which input your input is getting from between frames,
-- but not calling connect_signal results in undefined behavior.)
-- If you want to change any parameters in the chain, this is also
-- the right place.
--
-- NOTE: The chain returned must be finalized with the Y'CbCr flag
-- if and only if num==0.
function get_chain(num, t, width, height)
	if num == 0 then  -- Live.
		prepare = function()
			input0:connect_signal(live_signal_num);
			wb_effect:set_float("output_color_temperature", 3500.0 + t * 100.0);
		end
		return main_chain, prepare;
	end
	if num == 1 then  -- Preview.
		prepare = function()
			simple_chain_input:connect_signal(preview_signal_num);
		end
		return simple_chain, prepare;
	end
	if num == 2 then
		prepare = function()
			simple_chain_input:connect_signal(0);
		end
		return simple_chain, prepare;
	end
	if num == 3 then
		prepare = function()
			simple_chain_input:connect_signal(1);
		end
		return simple_chain, prepare;
	end
end