--[[
	Create a new Store whose state is transformed by the given reducer function.

	Each time an action is dispatched to the store, the new state of the store
	is given by:

		state = reducer(state, action)

	Reducers do not mutate the state object, so the original state is still
	valid.
]]

function Store.new(reducer, initialState, middlewares)
	assert(typeof(reducer) == "function", "Bad argument #1 to Store.new, expected function.")
	assert(middlewares == nil or typeof(middlewares) == "table", "Bad argument #3 to Store.new, expected nil or table.")

	local self = {}

	self._reducer = reducer
	self._state = reducer(initialState, {
		type = "@@INIT",
	})
	self._lastState = self._state

	self._mutatedSinceFlush = false
	self._connections = {}

	self.changed = Signal.new()

	setmetatable(self, Store)

	local connection = self._flushEvent:Connect(function()
		self:flush()
	end)
	table.insert(self._connections, connection)

	if middlewares then
		local unboundDispatch = self.dispatch
		local dispatch = function(...)
			return unboundDispatch(self, ...)
		end

		for i = #middlewares, 1, -1 do
			local middleware = middlewares[i]
			dispatch = middleware(dispatch, self)
		end

		self.dispatch = function(self, ...)
			return dispatch(...)
		end
	end

	return self
end
