A Lua implementation of Wesnoth's [message] WML tag

wml_action_message.lua

local helper = wesnoth.require "lua/helper.lua"
local location_set = wesnoth.require "lua/location_set.lua"
local wml_actions = wesnoth.wml_actions

local function get_image(cfg, speaker)
	local image = cfg.image

	if speaker and image == nil then
		image = speaker.profile
	end

	if image == "none" or image == nil then
		return ""
	end

	return image
end

local function get_caption(cfg, speaker)
	local caption = cfg.caption

	if not caption and speaker ~= nil then
		caption = speaker.name or speaker.type_name
	end

	return caption
end

local function get_speaker(cfg)
	local speaker
	local context = wesnoth.current.event_context

	if cfg.speaker == "narrator" then
		speaker = "narrator"
	elseif cfg.speaker == "unit" then
		speaker = wesnoth.get_unit(context.x1, context.y1)
	elseif cfg.speaker == "second_unit" then
		speaker = wesnoth.get_unit(context.x2, context.y2)
	else
		speaker = wesnoth.get_units(cfg)[1].__cfg
	end

	return speaker
end

local function message_user_choice(msg_cfg)
	return function()
		local dlg_result, option_chosen, ti_content = wesnoth.show_message_dialog(msg_cfg)
		
		if dlg_result == -2 then -- Cancelled (not quite sure of the right value)
			wesnoth.context_skip_messages = true
		end
		
		local result_cfg = {}

		if #options > 0 then
			result_cfg.value = option_chosen
		end

		if text_input ~= nil then
			result_cfg.text = ti_content
		end

		return result_cfg
	end
end

local function build_message_dialog(cfg, speaker, options, text_input)
	local image = get_image(cfg, speaker)
	local caption = get_caption(cfg, speaker)

	local left_side = true
	-- If this doesn't work, might need tostring()
	if string.find(image, "~RIGHT()") then
		left_side = false
		image = string.gsub(image, "~RIGHT()", "")
	end

	local msg_cfg = {
		left_side = left_side,
		title = caption,
		message = cfg.message,
		portrait = image,
	}

	-- Parse input text, if not available all fields are empty
	if text_input then
		local input_max_size = tonumber(text_input.max_length) or 256
		if input_max_size > 1024 or input_max_size < 1 then
			-- lg::wml_error << "Invalid maximum size for input " << input_max_size
			input_max_size = 256
		end

		table.insert(msg_cfg, {"text_input", {
			label = text_input.label or "",
			text  = text_input.text  or "",
			max_length = input_max_size,
		}})
	end

	for i,opt in ipairs(options) do
		table.insert(msg_cfg, {"option", {value = opt}})
	end

	return msg_cfg
end

function wml_actions.message(cfg)
	-- Only the first text_input tag is considered
	local text_input = helper.get_child(cfg, "text_input") or nil

	local options, option_events = {}, {}
	for option in helper.child_range(cfg, "option") do
		local condition = helper.get_child(cfg, "show_if") or {}

		if wesnoth.eval_conditional(condition) then
			table.insert(options, option.message)
			table.insert(option_events, {})

			for cmd in helper.child_range(option, "command") do
				table.insert(option_events[#option_events])
			end
		end
	end

	-- Check if there is any input to be made, if not the message may be skipped
	local has_input = text_input ~= nil and options ~= nil 

	if not (#options > 0 or has_input) and (wesnoth.is_skipping_replay or wesnoth.context_skip_messages) then
		-- No input to get and the user is not interested either
		return
	end

	local sides_for = cfg.side_for
	if sides_for and not has_input then
		local show_for_side = false

		-- Sanity checks on side number and controller
		for tonumber(side) in split(sides_for) do
			if side > 0 and side < #wesnoth.sides and wesnoth.sides[side].controller == "human" then
				show_for_side = true
				break
			end
		end

		if not show_for_side then
			-- Player isn't controlling side which should see the message
			return
		end
	end

	local speaker = get_speaker(cfg)
	if not speaker then
		-- No matching unit found, continue onto the next message
		return
	elseif speaker == "narrator" then
		-- Narrator, so deselect units
		wesnoth.select_hex(-1000, -1000)
	else
		if cfg.scroll then
			wesnoth.scroll_to_tile(speaker.x, speaker.y)
		end

		wesnoth.select_hex(speaker.x, speaker.y, false)
	end

	if cfg.sound then wesnoth.play_sound(cfg.sound) end

	local msg_cfg = build_message_dialog(cfg, speaker, options, text_input)

	local option_chosen
	if not has_input then
		-- Always show the dialog if it has no input, whether we are replaying or not
		message_user_choice(msg_cfg)
	else
		local choice = wesnoth.synchronize_choice(message_user_choice(msg_cfg))
		local var_name = text_input.variable or "input"

		option_chosen = tonumber(choice.value)
		
		-- Implement the consequences of the choice
		wesnoth.set_variable(var_name, choice.text)
	end

	if #options > 0 then
		if option_chosen > #options then
			--[[ replace::process_error("invalid choice (" .. option_chosen ..
				 ") was specified, choice 1 to " .. #options ..
				 " was expected") ]]
			return
		end

		for i, cmd in ipairs(option_events[option_chosen]) do
			local action = handle_event_commands(cmd)

			if action == "continue" then
				helper.wml_error("[continue] encountered outside a loop scope")
			elseif action == "break" then
				return
			end
		end
	end
end