-- states/narration.lua
--
-- The intro and interlude screens. Text is revealed one line at a time: pressing
-- enter advances `currentLoadedLine` within `displayData[currentPage]`, and rolls
-- over to the next page at the end.
--
-- Not a list menu, so this uses a custom read(). The "focus" is the most recently
-- revealed line, keyed by page:line so each newly revealed line is announced once.

return {
	read = function(stateTable, menus)
		-- Two-level probe. narration.keypressed does not touch these locals
		-- directly -- it just calls continueNarration(), so they are upvalues of
		-- THAT function. We reach continueNarration as an upvalue of keypressed,
		-- then read through it.
		local probeFn = menus.getUpvalue(stateTable.keypressed, "continueNarration")

		if type(probeFn) ~= "function" then
			return nil, nil
		end

		local displayData = menus.getUpvalue(probeFn, "displayData")
		local page = menus.getUpvalue(probeFn, "currentPage")
		local line = menus.getUpvalue(probeFn, "currentLoadedLine")

		if type(displayData) ~= "table" or type(page) ~= "number" or type(line) ~= "number" then
			return nil, nil
		end

		local pageData = displayData[page]
		if type(pageData) ~= "table" then
			return nil, nil
		end

		local entry = pageData[line]
		if type(entry) ~= "table" or not entry.text then
			return nil, nil
		end

		return entry.text, page .. ":" .. line
	end,
}