-- Player-facing HUD drawn into gameCanvas. Keeping it here (rather than in
-- the editor sidebar) means its RGB circles use the same screen blend as the
-- room, so their overlaps are the real additive colour combinations.
local GameUI = {}

local channelColor = {
	red = {1, 0, 0},
	green = {0, 1, 0},
	blue = {0, 0, 1},
}

local vennSize = 32
local vennLayout = {
	red = {x = 12, y = 10},
	green = {x = 20, y = 10},
	blue = {x = 16, y = 18},
}

local function drawDottedCircle(x, y, radius, color, dotRadius)
	local dots = math.max(14, math.floor((2 * math.pi * radius) / (dotRadius * 4)))
	love.graphics.setColor(color[1], color[2], color[3], 1)
	for index = 0, dots - 1 do
		local angle = index / dots * math.pi * 2
		love.graphics.circle("fill", x + math.cos(angle) * radius, y + math.sin(angle) * radius, dotRadius)
	end
end

function GameUI.init()
	uiVennCanvas = love.graphics.newCanvas(vennSize, vennSize)
	uiVennCanvas:setFilter("nearest", "nearest")
end

function GameUI.drawBacking()
	if not gameUiBox then return end
	love.graphics.setBlendMode("alpha")
	love.graphics.setColor(0, 0, 0, 1)
	love.graphics.rectangle("fill", gameUiBox.x, gameUiBox.y, gameUiBox.w, gameUiBox.h)
end

function GameUI.drawVennOverlay()
	if not gameUiBox or not uiVennCanvas then return end
	local cellSize = width / gridWidth
	local sidebarWidth = cellSize * 2
	if gameUiBox.w < sidebarWidth then return end

	love.graphics.setBlendMode("screen")
	love.graphics.setColor(1, 1, 1, 1)
	local scale = cellSize / 22
	local vennWidth = vennSize * scale
	local left = gameUiBox.x + (gameUiBox.w - vennWidth) / 2
	love.graphics.draw(uiVennCanvas, left, cellSize * 1.1, 0, scale, scale)
end

-- Render the venn from explicit colour sets: `has` are the channels the player
-- possesses (drawn as a circle), `active` the subset shown filled (the rest
-- dotted). Restores whatever canvas was bound, so callers drawing straight to
-- the screen (e.g. the map overlay) work as well as the in-game HUD pass.
function GameUI.drawColorVennChannels(has, active)
	if not gameUiBox then return end
	GameUI.drawBacking()

	local cellSize = width / gridWidth
	local sidebarWidth = cellSize * 2
	if gameUiBox.w < sidebarWidth or not uiVennCanvas then return end

	local previousCanvas = love.graphics.getCanvas()
	love.graphics.setCanvas(uiVennCanvas)
	love.graphics.clear(0, 0, 0, 0)
	love.graphics.setBlendMode("screen")
	local radius = 9
	local dotRadius = 1

	for _, color in ipairs({"red", "green", "blue"}) do
		if has[color] then
			local layout = vennLayout[color]
			local rgb = channelColor[color]
			if active[color] then
				love.graphics.setColor(rgb[1], rgb[2], rgb[3], 1)
				love.graphics.circle("fill", layout.x, layout.y, radius)
			else
				drawDottedCircle(layout.x, layout.y, radius, rgb, dotRadius)
			end
		end
	end

	love.graphics.setCanvas(previousCanvas)
	GameUI.drawVennOverlay()
end

function GameUI.drawColorVenn(room)
	if not room or not gameUiBox then return end
	local has, active = {}, {}
	for _, color in ipairs({"red", "green", "blue"}) do
		if room.player[color] then has[color] = true end
	end
	for _, color in ipairs(room:getActiveColors()) do active[color] = true end
	GameUI.drawColorVennChannels(has, active)
end

return GameUI