Physics: Refactoring: add API; ability to :set()|:get() for player;…

… store localy & merge new velues in `:set()`. Relates to #1666

mods/lord/Core/physics/src/physics.lua

@@ -1,12 +1,41 @@
 local ipairs
     = ipairs
 
+local PlayerPhysics = require('physics.PlayerPhysics')
+local Event         = require('physics.Event')
+
 
 --- @type table<number,string>|string[]
 local PHYSICS_TYPES = { "jump", "speed", "gravity" }
 
---- @type table<string,{jump:number,speed:number,gravity:number}>
-local player_physics = {} -- luacheck: ignore variable player_physics is mutated but never accessed
+--- @type physics.PlayerPhysics[]|table<string,physics.PlayerPhysics>
+local player_physics = {}
+
+
+physics = {} -- luacheck: ignore unused global variable physics
+
+local function register_api()
+	_G.physics = {
+		--- @param player Player
+		--- @return physics.PlayerPhysics
+		for_player = function(player)
+			local name = player:get_player_name()
+			if not player_physics[name] then
+				player_physics[name] = PlayerPhysics:new(player)
+			else
+				player_physics[name]:refresh_player(player)
+			end
+
+			return player_physics[name]
+		end,
+
+		--- @type fun(callback:physics.callback)
+		on_change = Event:on(Event.Type.on_change),
+
+		--- @type fun(callback:physics.callback)
+		on_init   = Event:on(Event.Type.on_init),
+	}
+end
 
 --- @param player        Player
 local function collect_physics(player)
@@ -17,7 +46,7 @@ local function collect_physics(player)
 			for _, type in ipairs(PHYSICS_TYPES) do
 				local value = item_groups["physics_" .. type]
 				if value then
-					physics[type] = physics[type] + value
+					physics[type] = (physics[type] or 1) + value
 				end
 			end
 		end
@@ -28,29 +57,18 @@ end
 
 --- @param player Player
 local function set_player_physics(player)
-	local name = player:get_player_name()
-	if not name then
-		return
-	end
-
 	local physics_o = collect_physics(player)
-	player:set_physics_override(physics_o)
-	player_physics[name].jump    = physics_o.jump
-	player_physics[name].speed   = physics_o.speed
-	player_physics[name].gravity = physics_o.gravity
+
+	physics.for_player(player):set(physics_o)
 end
 
 
 return {
 	--- @param mod minetest.Mod
 	init = function(mod)
-		equipment.on_load(equipment.Kind.ARMOR, function(player)
-			player_physics[player:get_player_name()] = {
-				jump      = 1,
-				speed     = 1,
-				gravity   = 1,
-			}
+		register_api()
 
+		equipment.on_load(equipment.Kind.ARMOR, function(player)
 			set_player_physics(player)
 		end)
 		equipment.on_change(equipment.Kind.ARMOR, function(player)

mods/lord/Core/physics/src/physics/Event.lua

@@ -0,0 +1,22 @@
+--- @alias physics.callback fun(player:Player,physics:physics.PlayerPhysics)
+
+--- @class physics.Event: base_classes.Event
+--- @field on      fun(self:self,event:string|physics.Event.Type): fun(callback:physics.callback)
+--- @field trigger fun(self:self,event:string|physics.Event.Type, ...): void
+local Event = base_classes.Event:extended()
+
+--- @class physics.Event.Type
+Event.Type = {
+	on_init   = 'on_init',
+	on_change = 'on_change',
+}
+--- @type table<string,physics.callback[]>
+Event.subscribers = {
+	--- @type physics.callback[]
+	on_init   = {},
+	--- @type physics.callback[]
+	on_change = {},
+}
+
+
+return Event

mods/lord/Core/physics/src/physics/PlayerPhysics.lua

@@ -0,0 +1,61 @@
+local table_merge, setmetatable
+	= table.merge, setmetatable
+
+local Event = require('physics.Event')
+
+
+--- @class physics.PlayerPhysics
+local PlayerPhysics = {
+	--- @type Player
+	player = nil,
+
+	--- @private
+	--- @type table<string,number>
+	physics = nil,
+}
+
+--- Constructor
+--- @public
+--- @param player  Player
+--- @param physics table<string,number>
+--- @return physics.PlayerPhysics
+function PlayerPhysics:new(player, physics)
+	local class = self
+
+	self = {}
+	self.player  = player
+	self.physics = physics or {}
+
+	return setmetatable(self, { __index = class })
+end
+
+--- @param player Player
+--- @return physics.PlayerPhysics
+function PlayerPhysics:refresh_player(player)
+	self.player = player
+
+	return self
+end
+
+--- @param physics table
+function PlayerPhysics:set(physics)
+	self.physics = table_merge(self.physics, physics)
+
+	self.player:set_physics_override(table_merge(
+		self.player:get_physics_override(), self.physics
+	))
+
+	Event:trigger(Event.Type.on_change, self.player, self)
+end
+
+--- @overload fun()
+--- @param name string
+--- @return number|table<string,number>
+function PlayerPhysics:get(name)
+	return name
+		and (self.physics[name] or nil)
+		or  self.physics
+end
+
+
+return PlayerPhysics