------------------------------------------------------------
-- Copyright (c) 2016 tacigar
-- https://github.com/tacigar/maidroid
------------------------------------------------------------

-- maidroid.animation_frames represents the animation frame data
-- of "models/maidroid.b3d".
maidroid.animation_frames = {
	STAND     = {x =   0, y =  79},
	SIT       = {x =  81, y = 160},
	LAY       = {x = 162, y = 166},
	WALK      = {x = 168, y = 187},
	MINE      = {x = 189, y = 198},
	WALK_MINE = {x = 200, y = 219},
}

-- maidroid.registered_maidroids represents a table that contains
-- definitions of maidroid registered by maidroid.register_maidroid.
maidroid.registered_maidroids = {}

-- maidroid.registered_cores represents a table that contains
-- definitions of core registered by maidroid.register_core.
maidroid.registered_cores = {}

-- maidroid.is_core reports whether a item is a core item by the name.
function maidroid.is_core(item_name)
	if maidroid.registered_cores[item_name] then
		return true
	end
	return false
end

---------------------------------------------------------------------

-- maidroid.maidroid represents a table that contains common methods
-- for maidroid object.
-- this table must be a metatable of maidroid self tables.
maidroid.maidroid = {}
maidroid.maidroid.__index = maidroid

-- maidroid.maidroid.get_inventory returns a inventory of a maidroid.
function maidroid.maidroid.get_inventory(self)
	return minetest.get_inventory {
		type = "detached",
		name = self.inventory_name,
	}
end

-- maidroid.maidroid.get_core_name returns a name of a maidroid's current core.
function maidroid.maidroid.get_core_name(self)
	return self.core_name
end

-- maidroid.maidroid.get_core returns a maidroid's current core definition.
function maidroid.maidroid.get_core(self)
	local name = self:get_core_name(self)
	if name ~= "" then
		return maidroid.registered_cores[name]
	end
	return nil
end

---------------------------------------------------------------------

-- maidroid.register_core registers a definition of a new core.
function maidroid.register_core(core_name, def)
	maidroid.registered_cores[core_name] = def

	minetest.register_craftitem(core_name, {
		stack_max       = 1,
		description     = def.description,
		inventory_image = def.inventory_image,
	})
end

-- maidroid.register_maidroid registers a definition of a new maidroid.
function maidroid.register_maidroid(product_name, def)

	-- create_inventory creates a new inventory, and returns it.
	function create_inventory(self)
		self.inventory_name = self.product_name .. tostring(self.manufacturing_number)

		local inventory = minetest.create_detached_inventory(self.inventory_name, {
			on_put = function(inv, listname, index, stack, player)
				if listname == "core" then
					local core_name = stack:get_name()
					local core = registered_cores[core_name]
					core.initialize(self)
					self.core_name = core_name
				end
			end,

			allow_put = function(inv, listname, index, stack, player)
				-- only cores can put to a core inventory.
				if listname == "main" then
					return stack:get_count()
				elseif listname == "core" and maidroid.is_core(stack:get_name()) then
					return stack:get_count()
				end
				return 0
			end,

			on_take = function(inv, listname, index, stack, player)
				if listname == "core" then
					local core = registered_cores[self.core_name]
					self.core_name = ""
					core.finalize(self)
				end
			end,
		})
		inventory:set_size("main", 16)
		inventory:set_size("core",  1)

		return inventory
	end

	-- create_formspec_string returns a string that represents a formspec definition.
	function create_formspec_string(self)
		return "size[8,9]"
			.. "list[detached:"..self.inventory_name..";main;0,0;4,4;]"
			.. "label[5,0;core]"
			.. "list[detached:"..self.inventory_name..";core;6,0;1,1;]"
			.. "list[current_player;main;0,5;8,1;]"
			.. "list[current_player;main;0,6.2;8,3;8]"
	end

	-- on_activate is a callback function that is called when the object is created or recreated.
	function on_activate(self, staticdata)
		-- first, set maidroid metatable to self table.
		if getmetatable(self) == nil then
			setmetatable(self, maidroid.maidroid)
		end

		if staticdata == "" then
			self.product_name = product_name
			create_inventory(self)
		else
			-- if static data is not empty string, this object has beed already created.
			local data = minetest.deserialize(staticdata)

			self.product_name = data["product_name"]
			self.manufacturing_number = data["manufacturing_number"]

			local inventory = create_inventory(self)

			if data["inventory"]["core"] ~= "" then

			end

		end

		self.formspec_string = create_formspec_string(self)
	end

	-- get_staticdata is a callback function that is called when the object is destroyed.
	function get_staticdata(self)
		local inventory = maidroid.get_inventory(self)
		local data = {
			["product_name"] = self.product_name,
			["manufacturing_number"] = self.manufacturing_number,
			["inventory"] = {
				["main"] = {},
				["core"] = self.core_name,
			},
		}

		for _, item in ipairs(inventory:get_list("main")) do
			local count = item:get_count()
			local itemname = item:get_name()
			if count ~= 0 then
				local itemdata = {count = count, name = itemname}
				table.insert(data["inventory"]["main"], itemdata)
			end
		end
		return minetest.serialize(data)
	end

	-- on_step is a callback function that is called every delta times.
	function on_step(self, dtime)
		if (not self.pause) and self.core_name ~= "" then
			local core = registered_cores[self.core_name]
			core.on_step(self, dtime)
		end
	end

	-- on_rightclick is a callback function that is called when a player right-click them.
	function on_rightclick(self, clicker)
		minetest.show_formspec(
			clicker:get_player_name(),
			self.inventory_name,
			self.formspec_string
		)
	end

	-- on_punch is a callback function that is called when a player punch then.
	function on_punch(self, puncher, time_from_last_punch, tool_capabilities, dir)
		if self.pause == true then
			self.pause = false
			if self.core_name ~= "" then
				local core = registered_cores[self.core_name]
				core.on_pause(self)
			end
		else
			self.pause = true
			if self.core_name ~= "" then
				local core = registered_cores[self.core_name]
				core.on_resume(self)
			end
		end
	end

	-- register a definition of a new maidroid.
	minetest.register_entity(product_name, {
		-- basic initial properties
		hp_max               = def.hp_max,
		weight               = def.weight,
		mesh                 = def.mesh,
		textures             = def.textures,

		physical             = true,
		visual               = "mesh",
		visual_size          = {x = 10, y = 10},
		is_visible           = true,
		makes_footstep_sound = true,

		-- extra initial properties
		pause                = false,
		product_name         = "",
		manufacturing_number = -1,
		core_name            = "",

		-- callback methods.
		on_activate          = on_activate,
		on_step              = on_step,
		on_rightclick        = on_rightclick,
		on_punch             = on_punch,
		get_staticdata       = get_staticdata,
	})

	minetest.register_craftitem(product_name .. "_spawner", {
		description     = " Spawner",
		inventory_image = def.inventory_image,
		stack_max       = 1,
		on_use          = function(item_stack, user, pointed_thing)
			if pointed_thing.above ~= nil then
				minetest.add_entity(pointed_thing.above, product_name)
				return itemstack
			end
			return nil
		end,
	})
end