-- Button hints as a shared module rather than a firmware paint routine: what the strip looks
-- like is composition, and only the device knows which roles exist to label.

local hints = {}

-- Reading order across the strip, so a device showing three of them still reads left to right.
local ORDER = { "back", "left", "up", "down", "right", "confirm" }

local function available()
	local roles = {}
	if input and input.getButtons then
		for _, role in ipairs(input.getButtons()) do roles[role] = true end
	end
	return roles
end

---Paints the labels this device can actually act on, and returns the height it used.
---@param actions table<string, string> Label per Button role; roles the device lacks are skipped.
---@param options table|nil `y`, `font`, `color`, and `background` overrides.
function hints.draw(actions, options)
	options = options or {}
	local font = options.font or gui.FONT_SMALL
	local color = options.color or gui.color(0, 0, 0)
	local background = options.background or gui.color(255, 255, 255)
	local height = gui.getFontHeight(font) + 6
	local y = options.y or (gui.getHeight() - height)

	local roles = available()
	local labels = {}
	for _, role in ipairs(ORDER) do
		if roles[role] and actions[role] then labels[#labels + 1] = actions[role] end
	end

	gui.fillRect(0, y, gui.getWidth(), height, background)
	if #labels == 0 then return height end

	local slot = gui.getWidth() // #labels
	for index, label in ipairs(labels) do
		local left = slot * (index - 1) + (slot - gui.getTextWidth(font, label)) // 2
		gui.drawText(font, left, y + 3, label, color, gui.STYLE_NORMAL, background)
	end
	return height
end

return hints