local ds = require("DataStructures")
local Stack, Dictionary, WordInfo, Environment = ds.Stack, ds.Dictionary, ds.WordInfo, ds.Environment
local helpers = require("CoreHelpers")
local isNumber, skipWhitespace, parseToken = helpers.isNumber, helpers.skipWhitespace, helpers.parseToken
local istream = require("InputStream")
local CoreWords = require("CoreWords")
local Pointer = ds.Pointer
local type Interpreters = record
	inner: function(Environment)
	outer: function(Environment)
end

function Interpreters.start(input: istream)
	local machineEnvironment = Environment:new()
	machineEnvironment.activeInputStream = input
	machineEnvironment.activeDataStack = Stack:new()
	machineEnvironment.returnStack = Stack:new()

	table.insert(machineEnvironment.dictionaries, CoreWords)
	local interpreterInstructions = {}
	table.insert(interpreterInstructions, Interpreters.outer)
	table.insert(interpreterInstructions, helpers.reset)
	local startPointer = Pointer:new()
	startPointer.referant = interpreterInstructions
	machineEnvironment.instructionPointer = startPointer
	Interpreters.inner(machineEnvironment)
end



function Interpreters.outer(env: Environment)
	skipWhitespace(env)
	local token: string = parseToken(env)
	if isNumber(token) then
		env.activeDataStack:push(tonumber(token))
	else
		for _, dictionary in ipairs(env.dictionaries) do
			local wordinfo = dictionary:lookup(token)
			if wordinfo then
				(wordinfo as WordInfo).func(env)
				goto continue
			end
		end
		print(string.format('%q ?', token))
		::continue::
	end
end

function Interpreters.inner(env: Environment)
	while(true) do
		env.instructionPointer:deref() as function(Environment)(env)
		env.instructionPointer:inc()
	end
end

return Interpreters