Create Lua frontend UI code

builtin/ui/context.lua

@@ -0,0 +1,143 @@
+-- Luanti
+-- SPDX-License-Identifier: LGPL-2.1-or-later
+-- Copyright (C) 2025 v-rob, Vincent Robinson <robinsonvincent89@gmail.com>
+
+ui.Context = core.class()
+
+local open_contexts = {}
+
+local OPEN_WINDOW   = 0x00
+local REOPEN_WINDOW = 0x01
+local UPDATE_WINDOW = 0x02
+local CLOSE_WINDOW  = 0x03
+
+function ui.Context:new(builder, player, state)
+	self._builder = ui._req(builder, "function")
+	self._player = ui._req(player, "string")
+	self._state = ui._opt(state, "table", {})
+
+	self._id = nil
+	self._window = nil
+end
+
+function ui.Context:open(param)
+	if self:is_open() then
+		return self
+	end
+
+	self:_open_window()
+	self:_build_window(ui._opt(param, "table", {}))
+
+	local data = ui._encode("BL Z", OPEN_WINDOW, self._id,
+			self._window:_encode(self._player, true))
+
+	core.send_ui_message(self._player, data)
+	return self
+end
+
+function ui.Context:reopen(param)
+	if not self:is_open() then
+		return self
+	end
+
+	local close_id = self:_close_window()
+	self:_open_window()
+	self:_build_window(ui._opt(param, "table", {}))
+
+	local data = ui._encode("BLL Z", REOPEN_WINDOW, self._id, close_id,
+			self._window:_encode(self._player, true))
+
+	core.send_ui_message(self._player, data)
+	return self
+end
+
+function ui.Context:update(param)
+	if not self:is_open() then
+		return self
+	end
+
+	self:_build_window(ui._opt(param, "table", {}))
+
+	local data = ui._encode("BL Z", UPDATE_WINDOW, self._id,
+			self._window:_encode(self._player, false))
+
+	core.send_ui_message(self._player, data)
+	return self
+end
+
+function ui.Context:close()
+	if not self:is_open() then
+		return self
+	end
+
+	local close_id = self:_close_window()
+	local data = ui._encode("BL", CLOSE_WINDOW, close_id)
+
+	core.send_ui_message(self._player, data)
+	return self
+end
+
+function ui.Context:is_open()
+	return self._id ~= nil
+end
+
+function ui.Context:get_builder()
+	return self._builder
+end
+
+function ui.Context:get_player()
+	return self._player
+end
+
+function ui.Context:get_state()
+	return self._state
+end
+
+function ui.Context:set_state(state)
+	self._state = ui._req(state, "table")
+	return self
+end
+
+local last_id = 0
+
+function ui.Context:_open_window()
+	self._id = last_id
+	last_id = last_id + 1
+
+	open_contexts[self._id] = self
+end
+
+function ui.Context:_build_window(param)
+	self._window = self._builder(self, self._player, self._state, param)
+
+	ui._req(self._window, ui.Window)
+	assert(not self._window._context, "Window object has already been used")
+
+	self._window._context = self
+end
+
+function ui.Context:_close_window()
+	local close_id = self._id
+
+	self._id = nil
+	self._window = nil
+
+	open_contexts[close_id] = nil
+	return close_id
+end
+
+function ui.get_open_contexts()
+	local contexts = {}
+	for _, context in pairs(open_contexts) do
+		table.insert(contexts, context)
+	end
+	return contexts
+end
+
+core.register_on_leaveplayer(function(player)
+	for _, context in pairs(open_contexts) do
+		if context:get_player() == player:get_player_name() then
+			context:_close_window()
+		end
+	end
+end)