Code refactor and api improvements

3 files changed, 156 insertions, 117 deletions

diff --git a/railcart/init.lua b/railcart/init.lua
index c72db24..821971c 100644
--- a/railcart/init.lua
+++ b/railcart/init.lua
@@ -3,6 +3,29 @@ local modpath = minetest.get_modpath(minetest.get_current_modname())
 dofile(modpath.."/railcart.lua")
 
 local worldpath = minetest.get_worldpath()
+
+local function create_detached_inventory(id)
+	local inv = minetest.create_detached_inventory("railcart_"..tostring(id), {
+		on_put = function(inv, listname, index, stack, player)
+			railcart:save()
+		end,
+		on_take = function(inv, listname, index, stack, player)
+			railcart:save()
+		end,
+		allow_put = function(inv, listname, index, stack, player)
+			return 1
+		end,
+		allow_take = function(inv, listname, index, stack, player)
+			return stack:get_count()
+		end,
+		allow_move = function(inv, from_list, from_index, to_list, to_index, count, player)
+			return count
+		end,
+	})
+	inv:set_size("main", 32)
+	return inv
+end
+
 local input = io.open(worldpath.."/railcart.txt", "r")
 if input then
 	local data = input:read('*all')
@@ -10,12 +33,13 @@ if input then
 		local carts = minetest.deserialize(data) or {}
 		for id, ref in pairs(carts) do
 			local cart = railcart.cart:new(ref)
-			local inv = railcart:create_detached_inventory(cart.id)
-			ref.inv = ref.inv or {}
-			for i, stack in pairs(ref.inv) do
-				inv:set_stack("main", i, stack)
+			if ref.inv then
+				local inv = create_detached_inventory(cart.id)
+				for i, stack in pairs(ref.inv) do
+					inv:set_stack("main", i, stack)
+				end
+				cart.inv = inv
 			end
-			cart.inv = inv
 			railcart.allcarts[id] = cart
 		end
 	end
@@ -28,39 +52,7 @@ local function is_valid_player(object)
 	end
 end
 
-minetest.register_globalstep(function(dtime)
-	for _, cart in pairs(railcart.allcarts) do
-		cart:on_step(dtime)
-	end
-	railcart.timer = railcart.timer + dtime
-	if railcart.timer > RAILCART_OBJECT_SAVE_TIME then
-		railcart:save()
-		railcart.timer = 0
-	end
-end)
-
-minetest.register_on_shutdown(function()
-	railcart:save()
-end)
-
-minetest.register_privilege("carts", "Player can pick-up and place carts.")
-
-minetest.register_entity("railcart:cart_entity", {
-	physical = false,
-	collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
-	visual = "mesh",
-	mesh = "railcart.x",
-	visual_size = {x=1, y=1},
-	textures = {"cart.png"},
-	cart = nil,
-	driver = nil,
-	timer = 0,
-	on_activate = function(self, staticdata, dtime_s)
-		self.object:set_armor_groups({immortal=1})
-		if staticdata == "expired" then
-			self.object:remove()
-		end
-	end,
+railcart:register_entity("railcart:cart_entity", {
 	on_punch = function(self, puncher, _, _, direction)
 		if not is_valid_player(puncher) then
 			return
@@ -105,7 +97,7 @@ minetest.register_entity("railcart:cart_entity", {
 			self.timer = 0
 			self.cart.target = nil
 			self.cart.prev = pos
-			self.cart.vel = vector.multiply(dir, RAILCART_SPEED_PUSH)
+			self.cart.vel = vector.multiply(dir, 5)
 			self.cart.accel = railtrack:get_acceleration(pos)
 			self.object:setvelocity(self.cart.vel)
 		end
@@ -138,27 +130,6 @@ minetest.register_entity("railcart:cart_entity", {
 			clicker:set_attach(self.object, "", {x=0,y=5,z=0}, {x=0,y=0,z=0})
 		end
 	end,
-	on_step = function(self, dtime)
-		local cart = self.cart
-		local object = self.object
-		if not cart or not object then
-			return
-		end
-		self.timer = self.timer - dtime
-		if self.timer > 0 then
-			return
-		end
-		self.timer = railcart:update(cart, RAILCART_ENTITY_UPDATE_TIME, object)
-	end,
-	get_staticdata = function(self)
-		if self.cart then
-			if self.cart:is_loaded() == false then
-				self.cart.timer = 0
-				self.object:remove()
-			end
-		end
-		return "expired"
-	end,
 })
 
 minetest.register_craftitem("railcart:cart", {
@@ -184,13 +155,16 @@ minetest.register_craftitem("railcart:cart", {
 		if #carts > 0 then
 			return
 		end
-		local cart = railcart.cart:new()
-		cart.id = railcart:get_new_id()
-		cart.inv = railcart:create_detached_inventory(cart.id)
-		cart.pos = vector.new(pos)
-		cart.prev = vector.new(pos)
-		cart.accel = railtrack:get_acceleration(pos)
-		cart.dir = railcart:get_rail_direction(pos)
+		local id = railcart:get_new_id()
+		local ref = {
+			id = id,
+			inv = create_detached_inventory(id),
+			pos = vector.new(pos),
+			prev = vector.new(pos),
+			accel = railtrack:get_acceleration(pos),
+			dir = railcart:get_rail_direction(pos),
+		}
+		local cart = railcart.cart:new(ref)
 		table.insert(railcart.allcarts, cart)
 		railcart:save()
 		if not minetest.setting_getbool("creative_mode") then
@@ -200,6 +174,8 @@ minetest.register_craftitem("railcart:cart", {
 	end,
 })
 
+minetest.register_privilege("carts", "Player can pick-up and place carts.")
+
 minetest.register_craft({
 	output = "railcart:cart",
 	recipe = {
@@ -209,3 +185,7 @@ minetest.register_craft({
 	},
 })
 
+minetest.register_on_shutdown(function()
+	railcart:save()
+end)
+
diff --git a/railcart/railcart.lua b/railcart/railcart.lua
index 6e5fbd4..dcaa80e 100644
--- a/railcart/railcart.lua
+++ b/railcart/railcart.lua
@@ -1,15 +1,25 @@
-RAILCART_ENTITY_UPDATE_TIME = 1
-RAILCART_OBJECT_UPDATE_TIME = 5
-RAILCART_OBJECT_SAVE_TIME = 10
-RAILCART_RELOAD_DISTANCE = 32
-RAILCART_SNAP_DISTANCE = 0.5
-RAILCART_SPEED_PUSH = 5
-RAILCART_SPEED_MIN = 0.1
-RAILCART_SPEED_MAX = 20
+local ENTITY_UPDATE_TIME = 1
+local OBJECT_UPDATE_TIME = 5
+local OBJECT_SAVE_TIME = 10
+local RELOAD_DISTANCE = 32
+local SNAP_DISTANCE = 0.5
+local SPEED_MIN = 0.1
+local SPEED_MAX = 15
 
 railcart = {
 	timer = 0,
 	allcarts = {},
+	default_entity = {
+		physical = false,
+		collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
+		visual = "mesh",
+		mesh = "railcart.x",
+		visual_size = {x=1, y=1},
+		textures = {"cart.png"},
+		cart = nil,
+		driver = nil,
+		timer = 0,
+	},
 }
 
 railcart.cart = {
@@ -23,6 +33,7 @@ railcart.cart = {
 	vel = {x=0, y=0, z=0},
 	acc = {x=0, y=0, z=0},
 	timer = 0,
+	name = "railcart:cart_entity",
 }
 
 function railcart.cart:new(obj)
@@ -37,7 +48,7 @@ function railcart.cart:is_loaded()
 		local pos = player:getpos()
 		if pos then
 			local dist = railtrack:get_distance(pos, self.pos)
-			if dist <= RAILCART_RELOAD_DISTANCE then
+			if dist <= RELOAD_DISTANCE then
 				return true
 			end
 		end
@@ -50,13 +61,13 @@ function railcart.cart:on_step(dtime)
 	if self.timer > 0 then
 		return
 	end
-	self.timer = RAILCART_OBJECT_UPDATE_TIME
+	self.timer = OBJECT_UPDATE_TIME
 	local entity = railcart:get_cart_entity(self.id)
 	if entity.object then
 		return
 	end
 	if self:is_loaded() then
-		local object = minetest.add_entity(self.pos, "railcart:cart_entity")
+		local object = minetest.add_entity(self.pos, self.name)
 		if object then
 			entity = object:get_luaentity() or {}
 			entity.cart = self
@@ -68,6 +79,56 @@ function railcart.cart:on_step(dtime)
 	end
 end
 
+function railcart:register_entity(name, def)
+	local ref = {}
+	for k, v in pairs(railcart.default_entity) do
+		ref[k] = def[k] or railtrack:copy(v)
+	end
+	ref.on_activate = function(self, staticdata, dtime_s)
+		if type(def.on_activate) == "function" then
+			def.on_activate(self, staticdata, dtime_s)
+		end
+		self.object:set_armor_groups({immortal=1})
+		if staticdata == "expired" then
+			self.object:remove()
+		end
+	end
+	ref.on_step = function(self, dtime)
+		if type(def.on_step) == "function" then
+			def.on_step(self, dtime)
+		end
+		local cart = self.cart
+		local object = self.object
+		if not cart or not object then
+			return
+		end
+		self.timer = self.timer - dtime
+		if self.timer > 0 then
+			return
+		end
+		self.timer = railcart:update(cart, ENTITY_UPDATE_TIME, object)
+		if type(def.on_update) == "function" then
+			def.on_update(self)
+		end
+	end
+	ref.get_staticdata = function(self)
+		if type(def.get_staticdata) == "function" then
+			def.get_staticdata(self)
+		end
+		if self.cart then
+			if self.cart:is_loaded() == false then
+				self.cart.timer = 0
+				self.object:remove()
+			end
+		end
+		return "expired"
+	end
+	for k, v in pairs(def) do
+		ref[k] = ref[k] or v
+	end
+	minetest.register_entity(name, ref)
+end
+
 function railcart:save()
 	local carts = {}
 	for id, cart in pairs(railcart.allcarts) do
@@ -92,28 +153,6 @@ function railcart:save()
 	end
 end
 
-function railcart:create_detached_inventory(id)
-	local inv = minetest.create_detached_inventory("railcart_"..tostring(id), {
-		on_put = function(inv, listname, index, stack, player)
-			railcart:save()
-		end,
-		on_take = function(inv, listname, index, stack, player)
-			railcart:save()
-		end,
-		allow_put = function(inv, listname, index, stack, player)
-			return 1
-		end,
-		allow_take = function(inv, listname, index, stack, player)
-			return stack:get_count()
-		end,
-		allow_move = function(inv, from_list, from_index, to_list, to_index, count, player)
-			return count
-		end,
-	})
-	inv:set_size("main", 32)
-	return inv
-end
-
 function railcart:remove_cart(id)
 	for i, cart in pairs(railcart.allcarts) do
 		if cart.id == id then
@@ -153,6 +192,14 @@ function railcart:get_new_id()
 	return id + 1
 end
 
+function railcart:get_cart_ref(id)
+	for _, cart in pairs(railcart.allcarts) do
+		if cart.id == id then
+			return cart
+		end
+	end
+end
+
 function railcart:get_cart_entity(id)
 	local cart_ref = {}
 	for _, ref in pairs(minetest.luaentities) do
@@ -222,10 +269,10 @@ end
 
 function railcart:velocity_to_speed(vel)
 	local speed = math.max(math.abs(vel.x), math.abs(vel.z))
-	if speed < RAILCART_SPEED_MIN then
+	if speed < SPEED_MIN then
 		speed = 0
-	elseif speed > RAILCART_SPEED_MAX then
-		speed = RAILCART_SPEED_MAX
+	elseif speed > SPEED_MAX then
+		speed = SPEED_MAX
 	end
 	return speed
 end
@@ -234,7 +281,7 @@ function railcart:get_target(pos, vel)
 	local meta = minetest.get_meta(vector.round(pos))
 	local dir = self:velocity_to_dir(vel)
 	local targets = {}
-	local rots = RAILTRACK_ROTATIONS
+	local rots = railtrack.rotations
 	local contype = meta:get_string("contype") or ""
 	local s_junc = meta:get_string("junctions") or ""
 	local s_cons = meta:get_string("connections") or ""
@@ -290,7 +337,7 @@ function railcart:update(cart, time, object)
 	else
 		speed = 0
 	end
-	if speed > RAILCART_SPEED_MIN then
+	if speed > SPEED_MIN then
 		local blocked = false
 		local cis = railcart:get_cart_in_sight(cart.pos, cart.target)
 		if cis then
@@ -316,16 +363,16 @@ function railcart:update(cart, time, object)
 		local d1 = railtrack:get_distance(cart.prev, cart.target)
 		local d2 = railtrack:get_distance(cart.prev, cart.pos)
 		local dist = d1 - d2
-		if dist > RAILCART_SNAP_DISTANCE then
-			local accel = RAILTRACK_ACCEL_FLAT
+		if dist > SNAP_DISTANCE then
+			local accel = railtrack.accel_flat
 			if cart.dir.y == -1 then
-				accel = RAILTRACK_ACCEL_DOWN
+				accel = railtrack.accel_down
 			elseif cart.dir.y == 1 then
-				accel = RAILTRACK_ACCEL_UP
+				accel = railtrack.accel_up
 			end
 			accel = cart.accel or accel
 			if object then
-				dist = math.max(dist - RAILCART_SNAP_DISTANCE, 0)
+				dist = math.max(dist - SNAP_DISTANCE, 0)
 			end
 			local dt = railcart:get_delta_time(speed, accel, dist)
 			if dt < time then
@@ -384,3 +431,14 @@ function railcart:update(cart, time, object)
 	return time
 end
 
+minetest.register_globalstep(function(dtime)
+	for _, cart in pairs(railcart.allcarts) do
+		cart:on_step(dtime)
+	end
+	railcart.timer = railcart.timer + dtime
+	if railcart.timer > OBJECT_SAVE_TIME then
+		railcart:save()
+		railcart.timer = 0
+	end
+end)
+
diff --git a/railtrack/railtrack.lua b/railtrack/railtrack.lua
index 75a62a6..664300f 100644
--- a/railtrack/railtrack.lua
+++ b/railtrack/railtrack.lua
@@ -1,10 +1,11 @@
-RAILTRACK_MAX_SECTION_LEN = 20
-RAILTRACK_ROTATIONS = "FLR"
-RAILTRACK_ACCEL_FLAT = -0.5
-RAILTRACK_ACCEL_UP = -2
-RAILTRACK_ACCEL_DOWN = 2
+local MAX_SECTION_LEN = 20
 
-railtrack = {}
+railtrack = {
+	rotations = "FLR",
+	accel_flat = -0.5,
+	accel_up = -2,
+	accel_down = 2,
+}
 
 railtrack.default_rail = {
 	description = "Rail",
@@ -90,7 +91,7 @@ function railtrack:limit_section_len(player, pos, meta)
 			local junc = minetest.deserialize(s_junc)
 			if #junc == 2 then
 				local dist = railtrack:get_distance(junc[1], junc[2])
-				if dist > RAILTRACK_MAX_SECTION_LEN then
+				if dist > MAX_SECTION_LEN then
 					local node = minetest.get_node(pos) or {}
 					if node.name then
 						minetest.swap_node(pos, {name=node.name.."_union"})