luanti/builtin/fstk/dialog.lua

-- Luanti
-- Copyright (C) 2014 sapier
-- SPDX-License-Identifier: LGPL-2.1-or-later

local function dialog_event_handler(self,event)
	if self.user_eventhandler == nil or
		self.user_eventhandler(event) == false then

		--close dialog on esc
		if event == "MenuQuit" then
			self:delete()
			return true
		end
	end
end

local dialog_metatable = {
	eventhandler = dialog_event_handler,
	get_formspec = function(self)
				if not self.hidden then return self.formspec(self.data) end
			end,
	handle_buttons = function(self,fields)
				if not self.hidden then return self.buttonhandler(self,fields) end
			end,
	handle_events  = function(self,event)
				if not self.hidden then return self.eventhandler(self,event) end
			end,
	hide = function(self)
		if not self.hidden then
			self.hidden = true
			self.eventhandler(self, "DialogHide")
		end
	end,
	show = function(self)
		if self.hidden then
			self.hidden = false
			self.eventhandler(self, "DialogShow")
		end
	end,
	delete = function(self)
			if self.parent ~= nil then
				self.parent:show()
			end
			ui.delete(self)
		end,
	set_parent = function(self,parent) self.parent = parent end
}
dialog_metatable.__index = dialog_metatable

function dialog_create(name,get_formspec,buttonhandler,eventhandler)
	local self = {}

	self.name = name
	self.type = "toplevel"
	self.hidden = true
	self.data = {}

	self.formspec      = get_formspec
	self.buttonhandler = buttonhandler
	self.user_eventhandler  = eventhandler

	setmetatable(self,dialog_metatable)

	ui.add(self)
	return self
end

-- "message" must already be formspec-escaped, e.g. via fgettext or
-- core.formspec_escape.
function messagebox(name, message)
	return dialog_create(name,
			function()
				return ui.get_message_formspec("", message, "ok")
			end,
			function(this, fields)
				if fields.ok then
					this:delete()
					return true
				end
			end,
			nil)
end