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 or ""
	if image == "none" then
		image = ""
	end
	if image == "" and speaker ~= nil then
		image = speaker.__cfg.profile
	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 message_user_choice(msg_cfg)
	return function()
		local dlg_result, option_chosen, ti_content = wesnoth.show_message_dialog(msg_cfg)
		
		if dlg_result == -1 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 ti_element ~= nil then
			result_cfg.text = ti_content
		end
		return result_cfg
	end
end

local function build_message_dialog(cfg, speaker, options, ti_element)
	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
	
	-- Parse input text, if not available all fields are empty
	if ti_element ~= nil then
		local ti_label = ti_element.label or ""
		local ti_content = ti_element.text or ""
		local input_max_size = tonumber(ti_element.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
	end
	
	local msg_cfg = {
		left_side = left_side,
		title = caption,
		message = cfg.message,
		portrait = image,
	}
	if ti_element ~= nil then
		table.insert(msg_cfg, {"text_input", {
			label = ti_label,
			text = ti_content,
			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

local function message_get_speaker(cfg)
	local speaker
	if cfg.speaker == "unit" then
		speaker = wesnoth.get_unit(wesnoth.current.event_context.x1, wesnoth.current.event_context.x2)
	elseif cfg.speaker == "second_unit" then
		speaker = wesnoth.get_unit(wesnoth.current.event_context.x1, wesnoth.current.event_context.x2)
	elseif cfg.speaker ~= "narrator" then
		speaker = wesnoth.get_units(cfg)[1]
	end
	if speaker ~= nil then
		-- LOG_NG << "Set speaker to '" << speaker->name() << "'"
		wesnoth.select_hex(speaker.x, speaker.y)
		if cfg["scroll"] then
			-- LOG_DP << "Scrolling to speaker..."
			local offset_from_center = math.max(0, speaker.y - 1)
			wesnoth.scroll_to_tile(speaker.x, offset_from_center)
		end
		wesnoth.select_hex(speaker.x, speaker.y)
	elseif cfg.speaker == "narrator" then
		-- LOG_NG << "No speaker"
		wesnoth.select_hex(-1000, -1000)
	end
	return speaker
end

function wml_actions.message(cfg)
	-- Check if there is any input to be made, if not the message may be skipped
	local has_ti = helper.get_child(cfg, "text_input") ~= nil
	local has_input = has_ti or helper.get_child("text_input") ~= nil
	if not has_input and (wesnoth.is_skipping_replay or wesnoth.context_skip_messages) then return end
	
	local side_for_raw = cfg.side_for
	if side_for then
		local side_for_show = has_input
		for side in string.gmatch(side_for_raw, '[^,]+') do
			side = tonumber(side)
			-- Make sanity check that side number is good
			-- then check if this side is human controlled
			if side > 0 and side < #wesnoth.sides and wesnoth.sides[side].controller == "human" then
				side_for_show = true
				break
			end
		end
		if not side_for_show then
			-- DBG_NG << "Player isn't controlling side which should get message"
			return
		end
	end
	
	local speaker = message_get_speaker(cfg)
	-- screen.draw(false)
	-- LOG_DP << "Done scrolling to speaker..."
	if speaker == nil and cfg.speaker ~= "narrator" then
		-- No matching unit found, so the dialog can't come up.
		-- Continue onto the next message.
		-- WRN_NG << "Cannot show message"
		return
	end
	
	local options, option_events = {}, {}
	for opt_cfg in helper.child_range(cfg, "option") do
		local msg_str = opt_cfg.message
		local condition = helper.get_child(cfg, "show_if")
		if condition == nil or wesnoth.eval_conditional(condition) then
			table.insert(options, msg_str)
			table.insert(option_events, {})
			for cmd in helper.child_range(opt_cfg, "command") do
				table.insert(option_events[#option_events])
			end
		end
	end
	
	has_input = #options > 0 or has_ti
	if not has_input and wesnoth.is_skipping_replay then
		-- No input to get and the user is not interested either.
		return
	end
	
	if cfg.sound then wesnoth.play_sound(cfg.sound) end
	
	local ti_element
	for ti_cfg in helper.child_range(cfg, "text_input") do
		if ti_element ~= nil then
			-- lg::wml_error << "Too many text_unput tags, only one accepted"
			break
		end
		ti_element = ti_cfg
	end
	
	local option_chosen, ti_result
	-- DBG_DP << "Showing dialog..."
	
	local msg_cfg = build_message_dialog(cfg, speaker, options, ti_element)
	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))
		option_chosen = tonumber(choice.value)
		ti_result = choice.text
	end
	
	-- Implement the consequences of the choice
	if has_ti then
		local var_name = ti_element.variable or "input"
		wesnoth.set_variable(var_name, ti_result)
	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