--!strict

--[[
	Constructs and returns objects which can be used to model independent
	reactive state.
]]

local Types = require "../Types"
-- Logging
local logError = require "../Logging/logError"
-- State
local updateAll = require "../State/updateAll"
-- Utility
local isSimilar = require "../Utility/isSimilar"

local class = {}

local CLASS_METATABLE = { __index = class }
local WEAK_KEYS_METATABLE = { __mode = "k" }

--[[
	Updates the value stored in this State object.

	If `force` is enabled, this will skip equality checks and always update the
	state object and any dependents - use this with care as this can lead to
	unnecessary updates.
]]
function class:set(newValue: any, force: boolean?)
	local oldValue = self._value
	if force or not isSimilar(oldValue, newValue) then
		self._value = newValue
		updateAll(self)
	end
end

--[[
	Returns the interior value of this state object.
]]
function class:_peek(): any
	return self._value
end

function class:get()
	logError "stateGetWasRemoved"
end

local function Value<T>(initialValue: T): Types.State<T>
	local self = setmetatable({
		type = "State",
		kind = "Value",
		-- if we held strong references to the dependents, then they wouldn't be
		-- able to get garbage collected when they fall out of scope
		dependentSet = setmetatable({}, WEAK_KEYS_METATABLE),
		_value = initialValue,
	}, CLASS_METATABLE)

	return self
end

return Value