/traderous

-- Class: Storage

-- Allows your app to save data between sessions -- high scores or game

-- progress, for example. A single storage instance corresponds to a

-- file on disk. If you'd like to maintain individual files (e.g. so

-- a user can email a save game to a friend), you'll need to create a

-- separate storage instance for each one.

--

-- Your data is saved on disk in Lua format. This means that if someone

-- figures out where your data files are saved, it is very trivial for them

-- to change the data. If saving or loading fails, then this class still

-- retains your data across a single app session. If you want to be notified

-- when errors occur, check the <save()> and <load()> methods' arguments.

--

-- Make sure to set your app's identity in conf.lua, so that your 

-- files don't clobber some other app's. See https://love2d.org/wiki/Config_Files

-- for details.

--

--

-- Extends:

--		<Class>

Storage = Class:extend{

	-- Property: data

	-- Use this property to store whatever data you like. You can

	-- nest tables inside this.

	data = {},

	-- Property: filename

	-- What filename to store the data on disk under. See

	-- https://love2d.org/wiki/love.filesystem for where exactly this

	-- will be saved. Make sure to set this if your app is using

	-- multiple storage objects -- otherwise they will overwrite

	-- each other.

	filename = 'storage.dat',

	new = function (self, obj)

		obj = obj or {}

		self:extend(obj)

		if obj.filename then obj:load() end

		if obj.onNew then obj:onNew() end

		return obj

	end,

	-- Method: save

	-- Saves data to disk.

	--

	-- Arguments:

	--		none

	--

	-- Returns:

	--		nothing

	save = function (self, ignoreError)

		if ignoreError ~= false then ignoreError = true end

		local ok, message = pcall(love.filesystem.write, self.filename, dump(self.data))

		if not ok and not ignoreError then

			error("could not save storage from disk: " .. message)

		end

	end,

	-- Method: load

	-- Loads data from disk.

	--

	-- Arguments:

	--		ignoreError - silently ignore any errors loading, default to true

	--

	-- Returns:

	--		whether loading actually worked, boolean

	load = function (self, ignoreError)

		if ignoreError ~= false then ignoreError = true end

		local ok, data = pcall(love.filesystem.read, self.filename)

		if ok then

			ok, self.data = pcall(loadstring('return ' .. data))

			if not ok then

				if ignoreError then

					self.data = {}

				else

					error("could not deserialize storage data: " .. self.data)

				end

			end

		else

			if not ignoreError then

				error("could not load storage from disk: " .. data)

			end

		end

		return ok

	end

}