local C={}local g=newproxy(true)local function q(C,q)local h={[g]=true,name=C;validate=q}setmetatable(h,{__call=function(C,...)return q(...)end})return h end function C.args(...)local C={...}return function(...)if select("\035",...)>#C then local g=("\084\111\111 \109\097\110\121 \097\114\103\117\109\101\110\116\115 \112\097\115\115\101\100 \105\110\046 \069\120\112\101\099\116\101\100 \037\100 \097\114\103\117\109\101\110\116\115 \111\114 \102\101\119\101\114\044 \103\111\116 \037\100"):format(#C,select("\035",...))error(g,3)end for C,g in ipairs(C)do local q=g[1]local h=g[2]local x=select(C,...)local t,e=h.validate(x)if not t then local g=("\066\097\100 \097\114\103\117\109\101\110\116 \037\115 \040\035\037\100\041\044 \101\120\112\101\099\116\101\100 \037\115\044 \098\117\116 \037\115"):format(q,C,h.name,e)error(g,3)end end end end function C.instance(C)assert(typeof(C)=="\115\116\114\105\110\103","\101\120\112\101\099\116\101\100\073\110\115\116\097\110\099\101\067\108\097\115\115 \109\117\115\116 \098\101 \097 \115\116\114\105\110\103")local g=("\073\110\115\116\097\110\099\101\040\037\115\041"):format(C)return q(g,function(g)local q=typeof(g)if q~="\073\110\115\116\097\110\099\101"then local C=("\103\111\116 \118\097\108\117\101 \111\102 \116\121\112\101 \037\115"):format(q)return false,C end if g:IsA(C)then return true else local C=("\103\111\116 \105\110\115\116\097\110\099\101 \111\102 \099\108\097\115\115 \037\115"):format(g.ClassName)return false,C end end)end function C.type(C)assert(typeof(C)=="\115\116\114\105\110\103","\101\120\112\101\099\116\101\100\084\121\112\101 \109\117\115\116 \098\101 \097 \115\116\114\105\110\103")return q(C,function(g)local q=typeof(g)if q==C then return true else local C=("\103\111\116 \118\097\108\117\101 \111\102 \116\121\112\101 \037\115"):format(q)return false,C end end)end function C.any()return q("\097\110\121",function(C)return true end)end function C.optional(C)assert(typeof(C)=="\116\097\098\108\101"and C[g])local h=("\111\112\116\105\111\110\097\108\040\037\115\041"):format(C.name)return q(h,function(g)if g==nil then return true else return C(g)end end)end function C.listOf(C)assert(typeof(C)=="\116\097\098\108\101"and C[g])local h=("\108\105\115\116\040\037\115\041"):format(C.name)return q(h,function(g)local q=typeof(g)if q~="\116\097\098\108\101"then return false,("\103\111\116 \118\097\108\117\101 \111\102 \116\121\112\101 \037\115"):format(q)end for g,q in pairs(g)do local h=typeof(g)if h~="\110\117\109\098\101\114"then return false,("\103\111\116 \110\111\110-\110\117\109\098\101\114 \107\101\121 \037\115 \040\111\102 \116\121\112\101 \037\115\041"):format(tostring(g),h)end local x,t=C(q)if not x then return false,("\104\097\100 \098\097\100 \118\097\108\117\101 \097\116 \107\101\121 \037\100\044 \037\115"):format(g,t)end end return true end)end function C.mapOf(h,x)assert(typeof(h)=="\116\097\098\108\101"and h[g])assert(typeof(x)=="\116\097\098\108\101"and x[g])local t=("\109\097\112\040\037\115\044 \037\115\041"):format(h.name,x.name)local e=C.type("\116\097\098\108\101")return q(t,function(C)local g,q=e(C)if not g then return false,q end for C,g in pairs(C)do local q,x=h(C)if not q then return false,("\104\097\100 \098\097\100 \107\101\121 \037\115\058 \037\115"):format(tostring(C),x)end local t,e=h(g)if not t then return false,("\104\097\100 \098\097\100 \118\097\108\117\101 \037\115 \097\116 \107\101\121 \037\115"):format(tostring(g),tostring(C),e)end end return true end)end function C.object(C,h)assert(typeof(h)=="\116\097\098\108\101"and not h[g])return q(C,function(C)for g,q in pairs(h)do local h=C[g]local x,t=q(h)if not x then return false,("\104\097\100 \098\097\100 \107\101\121 \037\115\058 \037\115"):format(tostring(g),t)end end for C,g in pairs(C)do if h[C]==nil then return false,("\104\097\100 \117\110\107\110\111\119\110 \107\101\121 \037\115 \119\105\116\104 \118\097\108\117\101 \037\115"):format(tostring(C),tostring(g))end end return true end)end return C
--[[
	This is a prototype module that helps encode strong runtime type checks for
	functions.

	It's used in a couple different functions, as well as in ApiSpec to define
	the correct arguments for use in RemoteEvent objects.

	Typer is a prototype and won't make it into an official library in its
	current form.

	Check out "t" by Osyris for a more fleshed out approach:

		https://github.com/osyrisrblx/t
]] local Typer
= {}

local IS_SCHEMA = newproxy(true)

local function makeSchema(name, fn)
	local check = {
		[IS_SCHEMA] = true,
		name = name,
		validate = fn,
	}

	setmetatable(check, { __call = function(_, ...)
		return fn(...)
	end })

	return check
end

function Typer.args(...)
	local argsSchema = { ... }

	return function(...)
		if select('#', ...) > #argsSchema then
			local message =
				('Too many arguments passed in. Expected %d arguments or fewer, got %d'):format(
					#argsSchema,
					select('#', ...)
				)
			error(message, 3)
		end

		for index, arg in ipairs(argsSchema) do
			local argName = arg[1]
			local argSchema = arg[2]
			local value = select(index, ...)

			local success, err = argSchema.validate(value)

			if not success then
				local message =
					('Bad argument %s (#%d), expected %s, but %s'):format(
						argName,
						index,
						argSchema.name,
						err
					)
				error(message, 3)
			end
		end
	end
end

function Typer.instance(expectedInstanceClass)
	assert(typeof(expectedInstanceClass) == 'string', 'expectedInstanceClass must be a string')

	local name = ('Instance(%s)'):format(expectedInstanceClass)

	return makeSchema(name, function(value)
		local actualType = typeof(value)

		if actualType ~= 'Instance' then
			local message = ('got value of type %s'):format(actualType)

			return false, message
		end

		if value:IsA(expectedInstanceClass) then
			return true
		else
			local message = ('got instance of class %s'):format(value.ClassName)

			return false, message
		end
	end)
end

function Typer.type(expectedType)
	assert(typeof(expectedType) == 'string', 'expectedType must be a string')

	return makeSchema(expectedType, function(value)
		local actualType = typeof(value)
		if actualType == expectedType then
			return true
		else
			local message = ('got value of type %s'):format(actualType)

			return false, message
		end
	end)
end

function Typer.any()
	return makeSchema('any', function(value)
		return true
	end)
end

function Typer.optional(innerCheck)
	assert(typeof(innerCheck) == 'table' and innerCheck[IS_SCHEMA])

	local name = ('optional(%s)'):format(innerCheck.name)

	return makeSchema(name, function(value)
		if value == nil then
			return true
		else
			return innerCheck(value)
		end
	end)
end

function Typer.listOf(innerCheck)
	assert(typeof(innerCheck) == 'table' and innerCheck[IS_SCHEMA])

	local name = ('list(%s)'):format(innerCheck.name)

	return makeSchema(name, function(list)
		local actualType = typeof(list)

		if actualType ~= 'table' then
			return false, ('got value of type %s'):format(actualType)
		end

		for key, value in pairs(list) do
			local keyType = typeof(key)

			if keyType ~= 'number' then
				return false, ('got non-number key %s (of type %s)'):format(tostring(key), keyType)
			end

			local success, err = innerCheck(value)

			if not success then
				return false, ('had bad value at key %d, %s'):format(key, err)
			end
		end

		return true
	end)
end

function Typer.mapOf(keyCheck, valueCheck)
	assert(typeof(keyCheck) == 'table' and keyCheck[IS_SCHEMA])
	assert(typeof(valueCheck) == 'table' and valueCheck[IS_SCHEMA])

	local name = ('map(%s, %s)'):format(keyCheck.name, valueCheck.name)

	local tableTypeCheck = Typer.type('table')

	return makeSchema(name, function(map)
		local mapOk, mapErr = tableTypeCheck(map)

		if not mapOk then
			return false, mapErr
		end

		for key, value in pairs(map) do
			local keyOk, keyErr = keyCheck(key)

			if not keyOk then
				return false, ('had bad key %s: %s'):format(tostring(key), keyErr)
			end

			local valueOk, valueErr = keyCheck(value)

			if not valueOk then
				return false, ('had bad value %s at key %s'):format(
					tostring(value),
					tostring(key),
					valueErr
				)
			end
		end

		return true
	end)
end

function Typer.object(name, shape)
	assert(typeof(shape) == 'table' and not shape[IS_SCHEMA])

	return makeSchema(name, function(object)
		for key, valueCheck in pairs(shape) do
			local value = object[key]

			local ok, err = valueCheck(value)

			if not ok then
				return false, ('had bad key %s: %s'):format(tostring(key), err)
			end
		end

		for key, value in pairs(object) do
			if shape[key] == nil then
				return false, ('had unknown key %s with value %s'):format(
					tostring(key),
					tostring(value)
				)
			end
		end

		return true
	end)
end

return Typer