elepower/elepower_papi/machine.lua

-- Machine definitions

--[[
	Groups:
		ele_machine			Any machine that does something with power
			ele_provider	Any machine that can provide power (generator, storage, etc)
			ele_user		Any machine that uses power
			ele_storage		Any machine that stores power
		ele_conductor		A node that is used to connect ele_machine nodes together

	Custom nodedef variables:
		ele_capacity = 12000
			Static capacitor for nodes.
			** Can be overridden by metadata: `capacity`

		ele_inrush = 32
			Decides how much power can be inserted into this machine's internal capacitor.
			** Can be overridden by metadata: `inrush`

		ele_output = 64
			Decides how much power a `ele_provider` node can output.
			** SHOULD be overridden by metadata: `output`

		ele_sides = nil
			All sides of providers currently output power. All sides of other nodes accept power.
			** SHOULD be overridden by metadata: `sides`

		ele_usage = 16
			How much power this machine uses or generates.
			** Can be overridden by metadata: `usage`

		ele_active_node = nil
			Set to true or a string to also register an active variant of this node.
			If the parameter is a boolean, "_active" will be appended to the `node_name`

		ele_active_nodedef = nil
			If set, the `ele_active_node` will have this table in its nodedef.
			Intended use: to set textures or light output.
]]

local function can_dig(pos, player)
	local meta = minetest.get_meta(pos);
	local inv = meta:get_inventory()
	return inv:is_empty("dst") and inv:is_empty("src")
end

local function allow_metadata_inventory_put(pos, listname, index, stack, player)
	if minetest.is_protected(pos, player:get_player_name()) then
		return 0
	end

	if listname == "dst" then
		return 0
	end

	return stack:get_count()
end

local function allow_metadata_inventory_move(pos, from_list, from_index, to_list, to_index, count, player)
	local meta = minetest.get_meta(pos)
	local inv = meta:get_inventory()
	local stack = inv:get_stack(from_list, from_index)
	return allow_metadata_inventory_put(pos, to_list, to_index, stack, player)
end

local function allow_metadata_inventory_take(pos, listname, index, stack, player)
	if minetest.is_protected(pos, player:get_player_name()) then
		return 0
	end

	return stack:get_count()
end

function metadata_inventory_changed(pos)
	local t = minetest.get_node_timer(pos)

	if not t:is_started() then
		t:start(1.0)
	end
end

-- Preserve power storage in the item stack dropped
local function preserve_metadata(pos, oldnode, oldmeta, drops)
	local meta     = minetest.get_meta(pos)
	local capacity = ele.helpers.get_node_property(meta, pos, "capacity")
	local storage  = ele.helpers.get_node_property(meta, pos, "storage")

	local nodedesc  = minetest.registered_nodes[oldnode.name].description

	if storage == 0 then
		return drops
	end

	for i,stack in pairs(drops) do
		local stack_meta = stack:get_meta()
		stack_meta:set_int("storage", storage)
		stack_meta:set_string("description", nodedesc.."\nCharge: " .. storage .. "/" .. capacity .. " " .. ele.unit)
		drops[i] = stack
	end

	return drops
end

-- Retrieve power storage from itemstack when placed
local function retrieve_metadata(pos, placer, itemstack, pointed_thing)
	local item_meta = itemstack:get_meta()
	local storage   = item_meta:get_int("storage")
	
	if storage and storage > 0 then
		local meta = minetest.get_meta(pos)
		meta:set_int("storage", storage)
		minetest.get_node_timer(pos):start(1.0)
	end

	return false
end

function ele.capacity_text(capacity, storage)
	return "Charge: " .. storage .. "/" .. capacity .. " " ..ele.unit
end

-- Register a base device
function ele.register_base_device(nodename, nodedef)
	-- Override construct callback
	local original_on_construct = nodedef.on_construct
	nodedef.on_construct = function (pos)
		if nodedef.groups and nodedef.groups["ele_machine"] then
			local meta = minetest.get_meta(pos)
			meta:set_int("storage", 0)
		end

		ele.clear_networks(pos)
		if original_on_construct then
			original_on_construct(pos)
		end
	end

	-- Override destruct callback
	local original_after_destruct = nodedef.after_destruct
	nodedef.after_destruct = function (pos)
		ele.clear_networks(pos)
		if original_after_destruct then
			original_after_destruct(pos)
		end
	end

	-- Save storage amount when picked up
	nodedef.preserve_metadata = preserve_metadata
	nodedef.after_place_node  = retrieve_metadata

	-- Prevent digging when there's items inside
	if not nodedef.can_dig then
		nodedef.can_dig = can_dig
	end

	-- Finally, register the damn thing already
	minetest.register_node(nodename, nodedef)

	-- Register an active variant if configured.
	if nodedef.ele_active_node then
		local active_nodedef = ele.helpers.table_copy(nodedef)
		local active_name = nodename.."_active"
		
		if nodedef.ele_active_node ~= true then
			active_name = nodedef.ele_active_node
		end

		if nodedef.ele_active_nodedef then
			for k,v in pairs(nodedef.ele_active_nodedef) do
				active_nodedef[k] = v
			end

			nodedef.ele_active_nodedef        = nil
			active_nodedef.ele_active_nodedef = nil
		end

		active_nodedef.groups["ele_active"] = 1
		active_nodedef.groups["not_in_creative_inventory"] = 1
		active_nodedef.drop = nodename
		minetest.register_node(active_name, active_nodedef)
	end
end

function ele.register_machine(nodename, nodedef)
	if not nodedef.groups then
		nodedef.groups = {}
	end

	-- Start cleaning up the nodedef
	local defaults = {
		ele_capacity = 1600,
		ele_inrush   = 64,
		ele_usage    = 64,
		ele_output   = 64,
		ele_sides    = nil,
		paramtype2   = "facedir"
	}

	-- Ensure everything that's required is present
	for k,v in pairs(defaults) do
		if not nodedef[k] then
			nodedef[k] = v
		end
	end

	-- Ensure machine group is used properly
	if not nodedef.groups["ele_conductor"] and not nodedef.groups["ele_machine"] then
		nodedef.groups["ele_machine"] = 1
	elseif nodedef.groups["ele_conductor"] and nodedef.groups["ele_machine"] then
		nodedef.groups["ele_machine"] = 0
	end

	if not nodedef.ele_no_automatic_ports then
		-- Add ports to the device's faces
		if nodedef.tiles and #nodedef.tiles == 6 then
			for i = 1, 5 do
				nodedef.tiles[i] = nodedef.tiles[i] .. "^elepower_power_port.png"
			end
		end

		-- Add ports to the device's active faces
		if nodedef.ele_active_nodedef and nodedef.ele_active_nodedef.tiles and #nodedef.ele_active_nodedef.tiles == 6 then
			for i = 1, 5 do
				nodedef.ele_active_nodedef.tiles[i] = nodedef.ele_active_nodedef.tiles[i] .. "^elepower_power_port.png"
			end
		end
	end
	nodedef.ele_no_automatic_ports = nil

	-- Default metadata handlers for "src" and "dst"
	if not nodedef.allow_metadata_inventory_put then
		nodedef.allow_metadata_inventory_put  = allow_metadata_inventory_put
		nodedef.allow_metadata_inventory_move = allow_metadata_inventory_move
	end

	if not nodedef.allow_metadata_inventory_take then
		nodedef.allow_metadata_inventory_take = allow_metadata_inventory_take
	end

	-- Default metadata changed handlers for inventories
	-- Starts the timer on the node
	if not nodedef.on_metadata_inventory_move then
		nodedef.on_metadata_inventory_move = metadata_inventory_changed
	end

	if not nodedef.on_metadata_inventory_put then
		nodedef.on_metadata_inventory_put  = metadata_inventory_changed
	end

	if not nodedef.on_metadata_inventory_take then
		nodedef.on_metadata_inventory_take = metadata_inventory_changed
	end

	ele.register_base_device(nodename, nodedef)
end