-- Nageru theme for TFK mini-tournament 2017, based on the default theme.

local futatabi_server = "http://10.42.0.1:9096"

local state = {
	transition_start = -2.0,
	transition_end = -1.0,
	transition_type = 0,
	transition_src_signal = 0,
	transition_dst_signal = 0,

	overlay_transition_start = -2.0,
	overlay_transition_end = -1.0,
	overlay_alpha_src = 0.0,
	overlay_alpha_dst = 1.0,
	overlay_enabled = false,

	stinger_in_progress = false,
	stinger_frame = 0,
	stinger_src_signal = 0,
	stinger_dst_signal = 0,
	stinger_save_overlay = false,

	live_signal_num = 0,
	preview_signal_num = 1
}
local NUM_CAMERAS = 7

-- Valid values for live_signal_num and preview_signal_num.
local INPUT0_SIGNAL_NUM = 0
local INPUT1_SIGNAL_NUM = 1
local INPUT2_SIGNAL_NUM = 2
local INPUT3_SIGNAL_NUM = 3
local INPUT4_SIGNAL_NUM = 4
local INPUT5_SIGNAL_NUM = 5
local INPUT6_SIGNAL_NUM = 6
local COMMENTATOR_SIGNAL_NUM = 4
local VIDEO_SIGNAL_NUM = NUM_CAMERAS
local SBS_SIGNAL_NUM = NUM_CAMERAS + 1
local STATIC_SIGNAL_NUM = NUM_CAMERAS + 2

-- Preview-only signal showing the current signal with the overlay.
-- Not valid for live_signal_num!
local OVERLAY_SIGNAL_NUM = NUM_CAMERAS + 3

-- Valid values for transition_type. (Cuts are done directly, so they need no entry.)
local NO_TRANSITION = 0
local ZOOM_TRANSITION = 1
local FADE_TRANSITION = 2

-- Last width/height/frame rate for each channel, if we have it.
-- Note that unlike the values we get from Nageru, the resolution is per
-- frame and not per field, since we deinterlace.
local last_resolution = {}

local cef_path = Nageru.THEME_PATH:match("(.*)/nageru/")
local cef_input = HTMLInput.new("file://" .. cef_path .. "/score.html")
cef_input:execute_javascript_async("play()")

local bg_video = VideoInput.new(cef_path .. "/flow-720.mp4", Nageru.VIDEO_FORMAT_YCBCR)
-- local iptv_video = VideoInput.new("http://10.34.129.69:9060/1/v.flv", Nageru.VIDEO_FORMAT_YCBCR)
local iptv_video = VideoInput.new(futatabi_server, Nageru.VIDEO_FORMAT_YCBCR)
iptv_video:change_rate(10.0)

local static_image = ImageInput.new(cef_path .. "/nageru/tfk_pause.png")
local first_frame = true
local multiviewer_enabled = false

function reload_cef()
	cef_input:reload()
	cef_input:execute_javascript_async("play()")
end

function disconnect_iptv()
	iptv_video:disconnect()
end

function toggle_multiviewer()
	multiviewer_enabled = not multiviewer_enabled
end

-- An overlay with variable alpha.
function make_overlay(scene, base)
	local image = scene:add_input(cef_input)
	local multiply_effect = scene:add_effect(MultiplyEffect.new())
	local overlay_effect = scene:add_optional_effect(OverlayEffect.new(), base, multiply_effect)
	return {
		image = image,
		multiply_effect = multiply_effect,
		overlay_effect = overlay_effect
	}
end

function make_fade_input(scene)
	local ret = {
		input = scene:add_input(),
		resample_effect = scene:add_optional_effect(ResampleEffect.new()),  -- Activated if scaling.
		wb_effect = scene:add_white_balance()
	}
	ret.overlay = make_overlay(scene, ret.wb_effect)
	return ret
end

-- A scene to fade between two inputs, of which either can be a picture
-- or a live input.
function make_fade_scene()
	local scene = Scene.new(16, 9)

	-- If fading between two live inputs, the overlay is put on top.
	-- If fading between the static picture and a live input,
	-- the overlay is put on the live input.
	local input0 = make_fade_input(scene)
	local input1 = make_fade_input(scene)
	local mix_effect = scene:add_effect(MixEffect.new(), input0.overlay.overlay_effect, input1.overlay.overlay_effect)
	local overlay = make_overlay(scene, mix_effect)

	-- At most one overlay can be active at any given time.
	input0.overlay.overlay_effect:promise_to_disable_if_enabled(input1.overlay.overlay_effect)
	input0.overlay.overlay_effect:promise_to_disable_if_enabled(overlay.overlay_effect)
	input1.overlay.overlay_effect:promise_to_disable_if_enabled(input0.overlay.overlay_effect)
	input1.overlay.overlay_effect:promise_to_disable_if_enabled(overlay.overlay_effect)
	overlay.overlay_effect:promise_to_disable_if_enabled(input0.overlay.overlay_effect)
	overlay.overlay_effect:promise_to_disable_if_enabled(input1.overlay.overlay_effect)

	scene:finalize(true)  -- Only used live, don't bother creating LQ versions.

	return {
		scene = scene,
		input0 = input0,
		input1 = input1,
		mix_effect = mix_effect,
		overlay = overlay
	}
end
fade_scene = make_fade_scene()

function make_sbs_input(scene, has_overlay)
	local input = scene:add_input()
	local wb_effect = scene:add_white_balance()
	local overlay = has_overlay and make_overlay(scene, wb_effect) or nil
	local resample_effect = scene:add_effect({ResampleEffect.new(), ResizeEffect.new()})
	local padding_effect = scene:add_effect(IntegralPaddingEffect.new())
	return {
		input = input,
		overlay = overlay,
		resample_effect = resample_effect,
		wb_effect = wb_effect,
		padding_effect = padding_effect
	}
end

-- Side-by-side scene.
function make_sbs_scene()
	local scene = Scene.new(16, 9)

	local bg = scene:add_input(bg_video)
	local input0 = make_sbs_input(scene, true)
	local input1 = make_sbs_input(scene, false)

	input0.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 0.0)
	input1.padding_effect:set_vec4("border_color", 0.0, 0.0, 0.0, 0.0)

	input0.input:display(0)
	input1.input:display(1)

	local i0 = scene:add_effect(OverlayEffect.new(), bg, input0.padding_effect)
	scene:add_effect(OverlayEffect.new(), i0, input1.padding_effect)
	scene:finalize()

	return {
		scene = scene,
		input0 = input0,
		input1 = input1,
		overlay = input0.overlay  -- May be nil.
	}
end
local sbs_scene = make_sbs_scene()

function make_simple_scene_no_finalize()
	local scene = Scene.new(16, 9)

	local input = scene:add_input()
	local resample_effect = scene:add_effect({ResampleEffect.new(), ResizeEffect.new(), IdentityEffect.new()})
	local wb_effect = scene:add_white_balance()
	local overlay = make_overlay(scene, wb_effect)

	return {
		scene = scene,
		input = input,
		wb_effect = wb_effect,
		resample_effect = resample_effect,
		overlay = overlay
	}
end

-- A scene to show a single input on screen.
function make_simple_scene()
	local scene = make_simple_scene_no_finalize()
	scene.scene:finalize()
	return scene
end
local simple_scene = make_simple_scene()

-- Load all the stinger frames.
local stinger_images = {}
for idx=0,24 do
	local filename = cef_path .. "/stinger/blur" .. string.rep("0", 3 - string.len(tostring(idx))) .. idx .. ".png"
	stinger_images[idx] = ImageInput.new(filename)
end

-- A scene to show a single input on screen, with a stinger on top.
function make_stinger_scene()
	local scene = make_simple_scene_no_finalize()
	scene.stinger_input = scene.scene:add_input()
	scene.scene:add_effect(OverlayEffect.new(), scene.overlay.overlay_effect, scene.stinger_input)
	scene.scene:finalize()
	return scene
end
local stinger_scene = make_stinger_scene()

-- A scene to show a single static picture on screen. Never with HTML overlay.
local static_scene = Scene.new(16, 9)
static_scene:add_input(static_image)
static_scene:finalize()

-- A scene to show the overlay and nothing more. LQ only,
-- since it is not a valid live signal.
local overlay_scene_lq = Scene.new(16, 9)
local overlay_scene_lq_input = overlay_scene_lq:add_input(cef_input)
overlay_scene_lq:finalize(false)

-- A debugging scene to show a simple multiviewer. HQ only, since there is no preview.
function make_multiview_scene()
	local scene = Scene.new(16, 9)
	local bg = scene:add_input(ImageInput.new(cef_path .. "/nageru/white.png"))
	local mv_width = 1280 / 3
	local mv_height = 720 / 3
	local mv_offset = (720 - mv_height * 2) / 2

	for input_idx=0,5 do
		local input = scene:add_input(input_idx)

		local resize = scene:add_effect(ResizeEffect.new())
		resize:set_int("width", mv_width)
		resize:set_int("height", mv_height)

		local padding = scene:add_effect(IntegralPaddingEffect.new())
		padding:set_int("width", 1280)
		padding:set_int("height", 720)
		padding:set_int("left", (input_idx % 3) * mv_width)
		padding:set_int("top", math.floor(input_idx / 3) * mv_height + mv_offset)

		local overlay = scene:add_effect(OverlayEffect.new(), bg, padding)
		bg = overlay
	end

	scene:finalize(true)
	return scene
end
local multiview_scene_hq = make_multiview_scene()

function needs_scale(signals, signal_num, width, height)
	if signal_num == STATIC_SIGNAL_NUM then
		-- We assume this is already correctly scaled at load time.
		return false
	end
	assert(is_plain_signal(signal_num))
	return (signals:get_width(signal_num) ~= width or signals:get_height(signal_num) ~= height)
end

function set_scale_parameters_if_needed(scene, signals, signal_num, width, height, hq)
	-- Futatabi rescaling will be linear, but original frames come back unscaled;
	-- make them linear, too, so that we don't get more sharpness on every other
	-- frame. This won't be right for fading, but it's probably hard to notice.
	if signal_num == VIDEO_SIGNAL_NUM then
		hq = false
	end

	if needs_scale(signals, signal_num, width, height) then
		if hq then
			scene.resample_effect:choose(ResampleEffect)  -- High-quality resampling.
		else
			scene.resample_effect:choose(ResizeEffect)  -- Low-quality resampling.
		end
		scene.resample_effect:set_int("width", width)
		scene.resample_effect:set_int("height", height)
	else
		scene.resample_effect:disable()
	end

end

-- API ENTRY POINT
-- 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 NUM_CAMERAS + 4  -- sbs, static picture, video and overlay
end

function is_plain_signal(num)
	return (num >= INPUT0_SIGNAL_NUM and num <= INPUT6_SIGNAL_NUM) or (num == VIDEO_SIGNAL_NUM)
end

-- Helper function to write e.g. “720p60”. The difference between this
-- and get_channel_resolution_raw() is that this one also can say that
-- there's no signal.
function get_channel_resolution(signal_num)
	local res = last_resolution[signal_num]
	if (not res) or not res.is_connected then
		return "disconnected"
	end
	if res.height <= 0 then
		return "no signal"
	end
	if not res.has_signal then
		if res.height == 525 then
			-- Special mode for the USB3 cards.
			return "no signal"
		end
		return get_channel_resolution_raw(res) .. ", no signal"
	else
		return get_channel_resolution_raw(res)
	end
end

-- Helper function to write e.g. “60” or “59.94”.
function get_frame_rate(res)
	local nom = res.frame_rate_nom
	local den = res.frame_rate_den
	if nom % den == 0 then
		return nom / den
	else
		return string.format("%.2f", nom / den)
	end
end

-- Helper function to write e.g. “720p60”.
function get_channel_resolution_raw(res)
	if res.interlaced then
		return res.height .. "i" .. get_frame_rate(res)
	else
		return res.height .. "p" .. get_frame_rate(res)
	end
end

function get_futatabi_status(str)
	local num_fields = 0
	local fields = {}
	for word in string.gmatch(str, '([^;]+)') do
		table.insert(fields, word)
		num_fields = num_fields + 1
	end
	if num_fields >= 4 then
		return fields[4]
	else
		return "???"
	end
end

-- API ENTRY POINT
-- Returns the name for each additional channel (starting from 2).
-- Called at the start of the program, and then each frame for live
-- channels in case they change resolution.
function channel_name(channel)
	local signal_num = channel - 2
	if signal_num == INPUT0_SIGNAL_NUM then
		return "Main (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == INPUT1_SIGNAL_NUM then
		return "Secondary (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == INPUT2_SIGNAL_NUM then
		return "Goal L (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == INPUT3_SIGNAL_NUM then
		return "Goal R (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == INPUT4_SIGNAL_NUM then
		return "Commentators (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == INPUT5_SIGNAL_NUM then
		return "Hall A2 (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == INPUT6_SIGNAL_NUM then
		return "Hall A1 (" .. get_channel_resolution(signal_num) .. ")"
	elseif signal_num == VIDEO_SIGNAL_NUM then
		local res = last_resolution[iptv_video:get_signal_num()]
		if (not res) or res.last_subtitle == nil then
			return "Futatabi"
		else
			return "Futatabi (" .. get_futatabi_status(res.last_subtitle) .. ")"
		end
	elseif signal_num == SBS_SIGNAL_NUM then
		return "Side-by-side"
	elseif signal_num == STATIC_SIGNAL_NUM then
		return "Static picture"
	elseif signal_num == OVERLAY_SIGNAL_NUM then
		return "Overlay"
	end
end

-- API ENTRY POINT
-- Returns, given a channel number, which signal it corresponds to (starting from 0).
-- Should return -1 if the channel does not correspond to a simple signal.
-- (The information is used for whether right-click on the channel should bring up
-- an input selector or not.)
-- Called once for each channel, at the start of the program.
-- Will never be called for live (0) or preview (1).
function channel_signal(channel)
	if channel - 2 == VIDEO_SIGNAL_NUM then
		return iptv_video:get_signal_num()
	elseif is_plain_signal(channel - 2) then
		return channel - 2
	else
		return -1
	end
end

-- API ENTRY POINT
-- Called every frame. Returns the color (if any) to paint around the given
-- channel. Returns a CSS color (typically to mark live and preview signals);
-- "transparent" is allowed.
-- Will never be called for live (0) or preview (1).
function channel_color(channel)
	if state.transition_type ~= NO_TRANSITION then
		if channel_involved_in(channel, state.transition_src_signal) or
		   channel_involved_in(channel, state.transition_dst_signal) then
			return "#f00"
		end
	else
		if channel_involved_in(channel, state.live_signal_num) then
			return "#f00"
		end
	end
	if channel_involved_in(channel, state.preview_signal_num) then
		return "#0f0"
	end
	return "transparent"
end

function channel_involved_in(channel, signal_num)
	if is_plain_signal(signal_num) then
		return channel == (signal_num + 2)
	end
	if signal_num == SBS_SIGNAL_NUM then
		return is_sbs_participating_signal(channel - 2)
	end
	if signal_num == STATIC_SIGNAL_NUM then
		return (channel == NUM_CAMERAS)
	end
	if signal_num == VIDEO_SIGNAL_NUM then
		return (channel == NUM_CAMERAS + 1)
	end
	return false
end

-- API ENTRY POINT
-- Returns if a given channel supports setting white balance (starting from 2).
-- Called only once for each channel, at the start of the program.
function supports_set_wb(channel)
	return is_plain_signal(channel - 2)
end

function finish_transitions(t)
	if state.transition_type ~= NO_TRANSITION and t >= state.transition_end then
		state.live_signal_num = state.transition_dst_signal
		state.transition_type = NO_TRANSITION
	end

	-- Disable the overlay if it is no longer visible.
	if state.overlay_enabled and t > state.overlay_transition_end and state.overlay_alpha_dst == 0.0 then
		state.overlay_enabled = false
		print("Turning off overlay")
	end
end

function in_transition(t)
	return t >= state.transition_start and t <= state.transition_end
end

function is_sbs_participating_signal(signal_num)
	return signal_num == INPUT0_SIGNAL_NUM or signal_num == COMMENTATOR_SIGNAL_NUM
end

function simple_signal_has_overlay(signal_num)
	-- The commentator output has no overlay on it.
	return signal_num ~= COMMENTATOR_SIGNAL_NUM
end

-- API ENTRY POINT
-- Called every frame.
function get_transitions(t)
	if state.preview_signal_num == OVERLAY_SIGNAL_NUM then
		if t < state.overlay_transition_end then
			-- Fade in progress.
			return {}
		end
		if state.overlay_enabled then
			return {"Overlay off", "", "Fade ovl out"}
		else
			return {"Overlay on", "", "Fade ovl in"}
		end
	end

	if in_transition(t) then
		-- Transition already in progress, the only thing we can do is really
		-- cut to the preview. (TODO: Make an “abort” and/or “finish”, too?)
		return {"Cut"}
	end

	if state.live_signal_num == state.preview_signal_num then
		-- No transitions possible.
		return {}
	end

	if (is_plain_signal(state.live_signal_num) and state.preview_signal_num == VIDEO_SIGNAL_NUM) or
	   (is_plain_signal(state.preview_signal_num) and state.live_signal_num == VIDEO_SIGNAL_NUM) then
		return {"Cut", "Sting", "Fade"}
	end

	if (is_plain_signal(state.live_signal_num) or state.live_signal_num == STATIC_SIGNAL_NUM) and
	   (is_plain_signal(state.preview_signal_num) or state.preview_signal_num == STATIC_SIGNAL_NUM) then
		return {"Cut", "", "Fade"}
	end

	-- Various zooms.
	if state.live_signal_num == SBS_SIGNAL_NUM and is_sbs_participating_signal(state.preview_signal_num) then
		return {"Cut", "Zoom in"}
	elseif is_sbs_participating_signal(state.live_signal_num) and state.preview_signal_num == SBS_SIGNAL_NUM then
		return {"Cut", "Zoom out"}
	end

	return {"Cut"}
end

function swap_preview_live()
	local temp = state.live_signal_num
	state.live_signal_num = state.preview_signal_num
	state.preview_signal_num = temp
end

function start_transition(type_, t, duration)
	state.transition_start = t
	state.transition_end = t + duration
	state.transition_type = type_
	state.transition_src_signal = state.live_signal_num
	state.transition_dst_signal = state.preview_signal_num
	state.stinger_in_progress = false
	swap_preview_live()
end

-- API ENTRY POINT
-- Called when the user clicks a transition button.
function transition_clicked(num, t)
	if state.preview_signal_num == OVERLAY_SIGNAL_NUM then
		if num == 0 then
			-- Cut.
			state.overlay_transition_start = -2.0
			state.overlay_transition_end = -1.0
			if state.overlay_enabled then
				state.overlay_enabled = false
				state.overlay_alpha_src = 0.0
				state.overlay_alpha_dst = 0.0
			else
				state.overlay_enabled = true
				state.overlay_alpha_src = 1.0
				state.overlay_alpha_dst = 1.0
			end
		elseif num == 2 then
			-- Fade.
			state.overlay_transition_start = t
			state.overlay_transition_end = t + 1.0
			if state.overlay_enabled then
				state.overlay_alpha_src = 1.0
				state.overlay_alpha_dst = 0.0
			else
				state.overlay_alpha_src = 0.0
				state.overlay_alpha_dst = 1.0
			end
			state.overlay_enabled = true
		end
		return
	end

	if num == 0 then
		-- Cut.
		if in_transition(t) then
			-- Ongoing transition; finish it immediately before the cut.
			finish_transitions(state.transition_end)
		end

		swap_preview_live()
		state.stinger_in_progress = false
	elseif num == 1 then
		-- Zoom or sting.
		finish_transitions(t)

		if state.live_signal_num == state.preview_signal_num then
			-- Nothing to do.
			return
		end

		if (is_plain_signal(state.live_signal_num) and state.preview_signal_num == VIDEO_SIGNAL_NUM) or
		   (is_plain_signal(state.preview_signal_num) and state.live_signal_num == VIDEO_SIGNAL_NUM) then
			-- Sting.
			if stinger_in_progress then
				return
			end

			state.stinger_in_progress = true
			state.stinger_frame = 0
			state.stinger_src_signal = state.live_signal_num
			state.stinger_dst_signal = state.preview_signal_num
			return
		end

		if is_plain_signal(state.live_signal_num) and is_plain_signal(state.preview_signal_num) then
			-- We can't zoom between these. Just make a cut.
			io.write("Cutting from " .. state.live_signal_num .. " to " .. state.live_signal_num .. "\n")
			swap_preview_live()
			state.stinger_in_progress = false
			return
		end

		if (state.live_signal_num == SBS_SIGNAL_NUM and is_sbs_participating_signal(state.preview_signal_num)) or
		   (state.preview_signal_num == SBS_SIGNAL_NUM and is_sbs_participating_signal(state.live_signal_num)) then
			start_transition(ZOOM_TRANSITION, t, 1.0)
		end
	elseif num == 2 then
		finish_transitions(t)

		-- Fade.
		if (state.live_signal_num ~= state.preview_signal_num) and
		   (is_plain_signal(state.live_signal_num) or
		    state.live_signal_num == STATIC_SIGNAL_NUM) and
		   (is_plain_signal(state.preview_signal_num) or
		    state.preview_signal_num == STATIC_SIGNAL_NUM) then
			start_transition(FADE_TRANSITION, t, 1.0)
		else
			-- Fades involving SBS are ignored (we have no scene for it).
		end
	end
end

-- API ENTRY POINT
function channel_clicked(num)
	state.preview_signal_num = num
end

function setup_fade_input(state, input, signals, signal_num, width, height)
	if signal_num == STATIC_SIGNAL_NUM then
		input.input:display(static_image)

		-- We assume this is already correctly scaled at load time.
		input.resample_effect:disable()
	else
		input.input:display(signal_num)

		if (signals:get_width(signal_num) ~= width or signals:get_height(signal_num) ~= height) then
			input.resample_effect:enable()
			input.resample_effect:set_int("width", width)
			input.resample_effect:set_int("height", height)
		else
			input.resample_effect:disable()
		end
	end
end

function get_fade_scene(state, signals, t, width, height, input_resolution)
	local scene = fade_scene
	setup_fade_input(state, scene.input0, signals, state.transition_src_signal, width, height)
	setup_fade_input(state, scene.input1, signals, state.transition_dst_signal, width, height)

	local tt = calc_fade_progress(t, state.transition_start, state.transition_end)
	scene.mix_effect:set_float("strength_first", 1.0 - tt)
	scene.mix_effect:set_float("strength_second", tt)

	-- The commentator output has no overlay on it.
	local extra_alpha_factor = 1.0
	if not simple_signal_has_overlay(state.transition_src_signal) and
	   not simple_signal_has_overlay(state.transition_dst_signal) then
		extra_alpha_factor = 0.0
	elseif not simple_signal_has_overlay(state.transition_src_signal) then
		extra_alpha_factor = tt
	elseif not simple_signal_has_overlay(state.transition_dst_signal) then
		extra_alpha_factor = 1.0 - tt
	end

	-- If fading between two live inputs, the overlay is put on top.
	-- If fading between the static picture and a live input,
	-- the overlay is put on the live input.
	scene.input0.overlay.overlay_effect:disable()
	scene.input1.overlay.overlay_effect:disable()
	scene.overlay.overlay_effect:disable()
	if state.overlay_enabled then
		local input0_live = (state.transition_src_signal ~= STATIC_SIGNAL_NUM)
		local input1_live = (state.transition_dst_signal ~= STATIC_SIGNAL_NUM)
		if input0_live and not input1_live then
			scene.input0.overlay.overlay_effect:enable()
			prepare_overlay_live(state, scene.input0, t, extra_alpha_factor)
		elseif input1_live and not input0_live then
			scene.input1.overlay.overlay_effect:enable()
			prepare_overlay_live(state, scene.input1, t, extra_alpha_factor)
		else
			scene.overlay.overlay_effect:enable()
			prepare_overlay_live(state, scene, t, extra_alpha_factor)
		end
	end
	return scene.scene
end

function fetch_input_resolution(signals, signal_num)
	local res = {
		width = signals:get_width(signal_num),
		height = signals:get_height(signal_num),
		interlaced = signals:get_interlaced(signal_num),
		has_signal = signals:get_has_signal(signal_num),
		is_connected = signals:get_is_connected(signal_num),
		frame_rate_nom = signals:get_frame_rate_nom(signal_num),
		frame_rate_den = signals:get_frame_rate_den(signal_num),
		last_subtitle = signals:get_last_subtitle(signal_num)
	}

	if res.interlaced then
		-- Convert height from frame height to field height.
		-- (Needed for e.g. place_rectangle.)
		res.height = res.height * 2

		-- Show field rate instead of frame rate; really for cosmetics only
		-- (and actually contrary to EBU recommendations, although in line
		-- with typical user expectations).
		res.frame_rate_nom = res.frame_rate_nom * 2
	end
	return res
end

local last_alsa_sound_shark_volume = -1   -- Always update on the first frame.

function update_volume()
	if Nageru.get_num_audio_buses() < 3 or
	   Nageru.get_audio_bus_name(2) ~= 'Sound Shark' then
		-- We haven't loaded the right audio mapping.
		return
	end

	if first_frame then
		Nageru.set_audio_bus_fader_level_db(2, -math.huge)
		first_frame = false
	end

	local volume_db = Nageru.get_audio_bus_fader_level_db(2)
	if Nageru.get_audio_bus_mute(2) or volume_db < -100.0 then
		volume_db = -100.0
	end
	cef_input:execute_javascript_async("set_sound_shark_volume_db(" .. volume_db .. ")")

	local desired_alsa_sound_shark_volume = (volume_db < -40.0) and 0 or 154  -- 154 corresponds to 70% in alsamixer for this input.
	if desired_alsa_sound_shark_volume ~= last_alsa_sound_shark_volume then
		os.execute("amixer -D hw:CARD=USB sset 'Mix A Input 04' " .. desired_alsa_sound_shark_volume .. " &")
		os.execute("amixer -D hw:CARD=USB sset 'Mix B Input 04' " .. desired_alsa_sound_shark_volume .. " &")
		last_alsa_sound_shark_volume = desired_alsa_sound_shark_volume
	end
end

local last_rate = 0.0

-- API ENTRY POINT
-- Called every frame. Get the scene 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).
--
-- <signals> is basically an exposed InputState, which you can use to
-- query for information about the signals at the point of the current
-- frame. In particular, you can call get_width() and get_height()
-- for any signal number, and use that to e.g. assist in scene selection.
--
-- You should return scene to use, after having set any parameters you
-- want to set (through set_int() etc.). The parameters will be snapshot
-- at return time and used during rendering.
function get_scene(num, t, width, height, signals)
	if num == 0 then
		update_volume()
	end

	local input_resolution = {}
	for signal_num=0,(NUM_CAMERAS-1) do
		input_resolution[signal_num] = fetch_input_resolution(signals, signal_num)
	end
	input_resolution[iptv_video:get_signal_num()] = fetch_input_resolution(signals, iptv_video:get_signal_num())
	last_resolution = input_resolution

	-- Save some CPU time if we're not having SBS on live.
	local new_rate
	if state.live_signal_num == SBS_SIGNAL_NUM or
	   state.preview_signal_num == SBS_SIGNAL_NUM or
	   state.transition_type == ZOOM_TRANSITION then
		new_rate = 1.0
	else
		new_rate = 0.0001
	end
	if new_rate ~= last_rate then
		-- Avoid waking up the video thread (which may be sleeping) if the rate is the same.
		bg_video:change_rate(new_rate)
		last_rate = new_rate
	end

	if num == 0 and multiviewer_enabled then  -- Live, with debugging on.
		return multiview_scene_hq
	end

	if num == 0 then  -- Live.
		-- See if we're in a transition.
		finish_transitions(t)
		if state.transition_type == ZOOM_TRANSITION then
			-- Transition in or out of SBS.
			sbs_scene.input0.overlay.overlay_effect:enable_if(state.overlay_enabled)
			prepare_sbs_scene(state, sbs_scene, calc_zoom_progress(t), state.transition_type, state.transition_src_signal, state.transition_dst_signal, width, height, input_resolution, true)
			prepare_overlay_live(state, sbs_scene, t, 1.0)
			return sbs_scene.scene
		elseif state.transition_type == NO_TRANSITION and state.live_signal_num == SBS_SIGNAL_NUM then
			-- Static SBS view.
			sbs_scene.input0.overlay.overlay_effect:enable_if(state.overlay_enabled)
			prepare_sbs_scene(state, sbs_scene, 0.0, NO_TRANSITION, 0, SBS_SIGNAL_NUM, width, height, input_resolution, true)
			prepare_overlay_live(state, sbs_scene, t, 1.0)
			return sbs_scene.scene
		elseif state.transition_type == FADE_TRANSITION then
			return get_fade_scene(state, signals, t, width, height, input_resolution)
		elseif is_plain_signal(state.live_signal_num) then
			local overlay_really_enabled = state.overlay_enabled and simple_signal_has_overlay(state.live_signal_num)
			if state.stinger_in_progress then
				stinger_scene.overlay.overlay_effect:enable_if(overlay_really_enabled)
				if state.live_signal_num == VIDEO_SIGNAL_NUM then
					stinger_scene.input:display(iptv_video)
				else
					stinger_scene.input:display(state.live_signal_num)
				end
				set_scale_parameters_if_needed(stinger_scene, signals, state.live_signal_num, width, height, true)

				stinger_scene.stinger_input:display(stinger_images[state.stinger_frame])
				state.stinger_frame = state.stinger_frame + 1
				if state.stinger_frame >= 25 then
					state.stinger_in_progress = false
					state.preview_signal_num = state.stinger_src_signal
					state.live_signal_num = state.stinger_dst_signal

					if state.stinger_dst_signal == VIDEO_SIGNAL_NUM then
						-- Turn off the overlay when playing video.
						state.stinger_save_overlay = state.overlay_enabled
						state.overlay_enabled = false
					else
						-- Restore the state.
						state.overlay_enabled = state.stinger_save_overlay
					end
				end

				if overlay_really_enabled then
					prepare_overlay_live(state, stinger_scene, t, 1.0)
				end
				return stinger_scene.scene
			else
				simple_scene.overlay.overlay_effect:enable_if(overlay_really_enabled)
				if state.live_signal_num == VIDEO_SIGNAL_NUM then
					simple_scene.input:display(iptv_video)
				else
					simple_scene.input:display(state.live_signal_num)
				end
				set_scale_parameters_if_needed(simple_scene, signals, state.live_signal_num, width, height, true)
				prepare_overlay_live(state, simple_scene, t, 1.0)
				return simple_scene.scene
			end
		elseif state.live_signal_num == STATIC_SIGNAL_NUM then  -- Static picture.
			return static_scene
		else
			assert(false)
		end
	end

	-- We do not show overlays on the individual preview inputs.
	-- The M/E preview matches what we'd put live by doing a transition, as always.
	local show_overlay = false
	if num == 1 then  -- Preview.
		if state.preview_signal_num == OVERLAY_SIGNAL_NUM then
			num = state.live_signal_num + 2
			show_overlay = not state.overlay_enabled

			if state.transition_type ~= NO_TRANSITION then
				num = state.transition_dst_signal + 2
			end
		else
			num = state.preview_signal_num + 2
			show_overlay = state.overlay_enabled and simple_signal_has_overlay(state.preview_signal_num)
		end
	end

	-- Individual preview inputs (usually without overlay).
	if is_plain_signal(num - 2) then
		local signal_num = num - 2
		simple_scene.overlay.overlay_effect:enable_if(show_overlay)
		if signal_num == VIDEO_SIGNAL_NUM then
			simple_scene.input:display(iptv_video)
		else
			simple_scene.input:display(signal_num)
		end
		set_scale_parameters_if_needed(simple_scene, signals, signal_num, width, height, false)
		prepare_overlay_static(simple_scene, t)
		return simple_scene.scene
	end
	if num == SBS_SIGNAL_NUM + 2 then
		sbs_scene.input0.overlay.overlay_effect:enable_if(show_overlay)
		prepare_sbs_scene(state, sbs_scene, 0.0, NO_TRANSITION, 0, SBS_SIGNAL_NUM, width, height, input_resolution, false)
		return sbs_scene.scene
	end
	if num == STATIC_SIGNAL_NUM + 2 then
		return static_scene
	end
	if num == OVERLAY_SIGNAL_NUM + 2 then
		return overlay_scene_lq
	end
end

-- This is broken, of course (even for positive numbers), but Lua doesn't give us access to real rounding.
function round(x)
	return math.floor(x + 0.5)
end

function lerp(a, b, t)
	return a + (b - a) * t
end

function lerp_pos(a, b, t)
	return {
		x0 = lerp(a.x0, b.x0, t),
		y0 = lerp(a.y0, b.y0, t),
		x1 = lerp(a.x1, b.x1, t),
		y1 = lerp(a.y1, b.y1, t)
	}
end

function pos_from_top_left(x, y, width, height, screen_width, screen_height)
	local xs = screen_width / 1280.0
	local ys = screen_height / 720.0
	return {
		x0 = round(xs * x),
		y0 = round(ys * y),
		x1 = round(xs * (x + width)),
		y1 = round(ys * (y + height))
	}
end

function prepare_sbs_scene(state, scene, t, transition_type, src_signal, dst_signal, screen_width, screen_height, input_resolution, hq)
	scene.input0.input:display(0)
	scene.input1.input:display(COMMENTATOR_SIGNAL_NUM)

	-- Both inputs are the same size (true side-by-side).
	local pos0 = pos_from_top_left(1280 - 616 - 16, 186, 616, 347, screen_width, screen_height)
	local pos1 = pos_from_top_left(16, 186, 616, 347, screen_width, screen_height)

	local pos_fs = { x0 = 0, y0 = 0, x1 = screen_width, y1 = screen_height }
	local affine_param
	if transition_type == NO_TRANSITION then
		-- Static SBS view.
		affine_param = { sx = 1.0, sy = 1.0, tx = 0.0, ty = 0.0 }   -- Identity.
	else
		-- Zooming to/from SBS view into or out of a single view.
		assert(transition_type == ZOOM_TRANSITION)
		local signal, real_t
		if src_signal == SBS_SIGNAL_NUM then
			signal = dst_signal
			real_t = t
		else
			assert(dst_signal == SBS_SIGNAL_NUM)
			signal = src_signal
			real_t = 1.0 - t
		end

		if signal == INPUT0_SIGNAL_NUM then
			affine_param = find_affine_param(pos0, lerp_pos(pos0, pos_fs, real_t))
		elseif signal == COMMENTATOR_SIGNAL_NUM then
			affine_param = find_affine_param(pos1, lerp_pos(pos1, pos_fs, real_t))
		end
	end

	-- NOTE: input_resolution is not 1-indexed, unlike usual Lua arrays.
	place_rectangle_with_affine(scene.input0, pos0, affine_param, screen_width, screen_height, input_resolution[0].width, input_resolution[0].height, hq)
	place_rectangle_with_affine(scene.input1, pos1, affine_param, screen_width, screen_height, input_resolution[1].width, input_resolution[1].height, hq)
end

-- Find the transformation that changes the first rectangle to the second one.
function find_affine_param(a, b)
	local sx = (b.x1 - b.x0) / (a.x1 - a.x0)
	local sy = (b.y1 - b.y0) / (a.y1 - a.y0)
	return {
		sx = sx,
		sy = sy,
		tx = b.x0 - a.x0 * sx,
		ty = b.y0 - a.y0 * sy
	}
end

function place_rectangle_with_affine(input, pos, aff, screen_width, screen_height, input_width, input_height, hq)
	local x0 = pos.x0 * aff.sx + aff.tx
	local x1 = pos.x1 * aff.sx + aff.tx
	local y0 = pos.y0 * aff.sy + aff.ty
	local y1 = pos.y1 * aff.sy + aff.ty

	place_rectangle(input, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height, hq)
end

function place_rectangle(input, x0, y0, x1, y1, screen_width, screen_height, input_width, input_height, hq)
	input.padding_effect:set_int("width", screen_width)
	input.padding_effect:set_int("height", screen_height)

	-- Cull.
	if x0 > screen_width or x1 < 0.0 or y0 > screen_height or y1 < 0.0 then
		input.resample_effect:choose(ResizeEffect)  -- Low-quality resizing.
		input.resample_effect:set_int("width", 1)
		input.resample_effect:set_int("height", 1)
		input.padding_effect:set_int("left", screen_width + 100)
		input.padding_effect:set_int("top", screen_height + 100)
		return
	end

	local srcx0 = 0.0
	local srcx1 = 1.0
	local srcy0 = 0.0
	local srcy1 = 1.0

	-- Clip.
	if x0 < 0 then
		srcx0 = -x0 / (x1 - x0)
		x0 = 0
	end
	if y0 < 0 then
		srcy0 = -y0 / (y1 - y0)
		y0 = 0
	end
	if x1 > screen_width then
		srcx1 = (screen_width - x0) / (x1 - x0)
		x1 = screen_width
	end
	if y1 > screen_height then
		srcy1 = (screen_height - y0) / (y1 - y0)
		y1 = screen_height
	end

	if hq then
		-- High-quality resampling.
		local resample_effect = input.resample_effect:choose(ResampleEffect)

		local x_subpixel_offset = x0 - math.floor(x0)
		local y_subpixel_offset = y0 - math.floor(y0)

		-- Resampling must be to an integral number of pixels. Round up,
		-- and then add an extra pixel so we have some leeway for the border.
		local width = math.ceil(x1 - x0) + 1
		local height = math.ceil(y1 - y0) + 1
		input.resample_effect:set_int("width", width)
		input.resample_effect:set_int("height", height)

		-- Correct the discrepancy with zoom. (This will leave a small
		-- excess edge of pixels and subpixels, which we'll correct for soon.)
		local zoom_x = (x1 - x0) / (width * (srcx1 - srcx0))
		local zoom_y = (y1 - y0) / (height * (srcy1 - srcy0))
		resample_effect:set_float("zoom_x", zoom_x)  -- Use the actual effect specialization; specific to ResampleEffect.
		resample_effect:set_float("zoom_y", zoom_y)
		resample_effect:set_float("zoom_center_x", 0.0)
		resample_effect:set_float("zoom_center_y", 0.0)

		-- Padding must also be to a whole-pixel offset.
		input.padding_effect:set_int("left", math.floor(x0))
		input.padding_effect:set_int("top", math.floor(y0))

		-- Correct _that_ discrepancy by subpixel offset in the resampling.
		resample_effect:set_float("left", srcx0 * input_width - x_subpixel_offset / zoom_x)
		resample_effect:set_float("top", srcy0 * input_height - y_subpixel_offset / zoom_y)

		-- Finally, adjust the border so it is exactly where we want it.
		input.padding_effect:set_float("border_offset_left", x_subpixel_offset)
		input.padding_effect:set_float("border_offset_right", x1 - (math.floor(x0) + width))
		input.padding_effect:set_float("border_offset_top", y_subpixel_offset)
		input.padding_effect:set_float("border_offset_bottom", y1 - (math.floor(y0) + height))
	else
		-- Lower-quality simple resizing.
		input.resample_effect:choose(ResizeEffect)

		local width = round(x1 - x0)
		local height = round(y1 - y0)
		input.resample_effect:set_int("width", width)
		input.resample_effect:set_int("height", height)

		-- Padding must also be to a whole-pixel offset.
		input.padding_effect:set_int("left", math.floor(x0))
		input.padding_effect:set_int("top", math.floor(y0))

		-- No subpixel stuff.
		input.padding_effect:set_float("border_offset_left", 0.0)
		input.padding_effect:set_float("border_offset_right", 0.0)
		input.padding_effect:set_float("border_offset_top", 0.0)
		input.padding_effect:set_float("border_offset_bottom", 0.0)
	end
end

function prepare_overlay_live(state, scene, t, extra_alpha_factor)
	if scene.overlay then
		local tt = calc_fade_progress(t, state.overlay_transition_start, state.overlay_transition_end)
		local overlay_alpha = state.overlay_alpha_src + tt * (state.overlay_alpha_dst - state.overlay_alpha_src)
		overlay_alpha = overlay_alpha * extra_alpha_factor
		--print("overlay_alpha=" .. overlay_alpha .. " [" .. state.overlay_alpha_src .. "," .. state.overlay_alpha_dst .. "]@" .. tt)
		if t > state.overlay_transition_end and state.overlay_alpha_dst == 0.0 then
			state.overlay_enabled = false  -- Takes effect next frame.
	--		print("Turning off overlay")
		end
		scene.overlay.multiply_effect:set_vec4("factor", overlay_alpha, overlay_alpha, overlay_alpha, overlay_alpha)
	end
end

function prepare_overlay_static(scene)
	if scene.overlay then
		scene.overlay.multiply_effect:set_vec4("factor", 1.0, 1.0, 1.0, 1.0)
	end
end

function calc_zoom_progress(t)
	if t < state.transition_start then
		return 0.0
	elseif t > state.transition_end then
		return 1.0
	else
		local tt = (t - state.transition_start) / (state.transition_end - state.transition_start)
		-- Smooth it a bit.
		return math.sin(tt * 3.14159265358 * 0.5)
	end
end

function calc_fade_progress(t, transition_start, transition_end)
	local tt = (t - transition_start) / (transition_end - transition_start)
	if tt < 0.0 then
		return 0.0
	elseif tt > 1.0 then
		return 1.0
	end

	-- Make the fade look maybe a tad more natural, by pumping it
	-- through a sigmoid function.
	tt = 10.0 * tt - 5.0
	tt = 1.0 / (1.0 + math.exp(-tt))

	return tt
end

ThemeMenu.set(
	{ "Reload overlay", reload_cef },
	{ "Disconnect IPTV", disconnect_iptv },
	{ "Toggle multiviewer", toggle_multiviewer }
)