-- states/ingame_dialogue.lua
--
-- Conversations. Two things must be spoken, and they change independently:
--   * the NPC's line (speaker name + message blocks) -- changes when the node does
--   * the currently selected response -- changes as you press up/down
--
-- So this tracks the node itself and announces the full block on a node change,
-- but only the option on a selection change. Repeating the whole speech every
-- time you move between responses would be unusable.
--
-- Responses can also be picked directly with the number keys 1-0, which the game
-- already supports and which is the fastest way to work through a conversation.

local descriptor = {}

local lastNodeKey

local function nodeKeyFor(speakerName, blocks, options)
	local parts = {tostring(speakerName), tostring(#options)}

	for _, block in ipairs(blocks or {}) do
		parts[#parts + 1] = tostring(block.text)
	end

	return table.concat(parts, "|")
end

descriptor.read = function(stateTable, menus)
	local keypressed = stateTable.keypressed

	local options = menus.getUpvalue(keypressed, "options")
	local selected = menus.getUpvalue(keypressed, "selectedOption")

	if type(options) ~= "table" or type(selected) ~= "number" then
		return nil, nil
	end

	-- speakerName / messageTextBlocks are not touched by keypressed directly --
	-- it calls updateText(), so they are upvalues of that function.
	local updateText = menus.getUpvalue(keypressed, "updateText")
	local speakerName, blocks

	if type(updateText) == "function" then
		speakerName = menus.getUpvalue(updateText, "speakerName")
		blocks = menus.getUpvalue(updateText, "messageTextBlocks")
	end

	local nodeKey = nodeKeyFor(speakerName, blocks, options)

	local option = options[selected]
	local optionText = option and option.text or nil

	-- Selection moved within the same node: just the response.
	if nodeKey == lastNodeKey then
		if not optionText then
			return nil, nil
		end
		return string.format("%s, %d of %d", optionText, selected, #options),
			nodeKey .. ":" .. selected
	end

	-- New node: speaker, what they said, then the options.
	lastNodeKey = nodeKey

	local parts = {}

	if speakerName and speakerName ~= "" then
		parts[#parts + 1] = speakerName
	end

	for _, block in ipairs(blocks or {}) do
		if block.text then
			parts[#parts + 1] = block.text
		end
	end

	if #options > 0 then
		parts[#parts + 1] = #options .. (#options == 1 and " response" or " responses")
		for i, entry in ipairs(options) do
			if entry.text then
				-- The game already prefixes response text with its number
				-- ("1. (Continue)"), matching the number keys that select it.
				-- Adding our own gave "1. 1. (Continue)".
				if entry.text:match("^%s*%d+%s*[%.%)]") then
					parts[#parts + 1] = entry.text
				else
					parts[#parts + 1] = i .. ". " .. entry.text
				end
			end
		end
	end

	if #parts == 0 then
		return nil, nil
	end

	return table.concat(parts, ". "), nodeKey .. ":" .. selected
end

return descriptor