const symbol = Symbol('IS_GEN')
const makeGen = (gen) => gen[symbol] = true

const isGen = (gen) => Boolean(gen[symbol])

function takeLatest(action, fnGenerator) {
	makeGen(fnGenerator)
	return {
		effect: "takeLatest",
		action,
		fnGenerator
	}
}

function take(action, ) {
	return {
		effect: "take",
		action,
	}
}

function put(action) {
	return {
		effect: "put",
		action,
	}
}

function fork(fnGenerator) {
	makeGen(fnGenerator)

	return {
		effect: "fork",
		fnGenerator
	}
}

function cancel(action, fnGenerator) {
	return {
		effect: "cancel",
		action,
		fnGenerator
	}
}


function* actionA(payload) {
	console.log("=> actionA")
	yield put("ACTION-B")
}

function* actionB(payload) {
	console.log("=> actionB")
	const taskId = yield fork(actionC)
	console.log("=> actionB - fim")

	yield take("ACTION-CANCEL")
	console.log("cancelar")
}


function* actionC(payload) {
	console.log("=> actionC")
}

function* main() {
	// console.log("main")
	yield takeLatest("ACTION-A", actionA)
	yield takeLatest("ACTION-B", actionB)
	// yield takeLatest("ACTION-C", actionC)
}

function runGen({ iter, takers, run, gens }) {
	let result = iter.next();
	let yield$;
	while (!result.done) {
		const yieldedValue = result.value;
		if (iter.cancelRequest) {
			return;
		}
		switch (yieldedValue.effect) {
			case "takeLatest":
				takers[yieldedValue.action] = yieldedValue
				break;

			case "put":
				const action = yieldedValue.action
				run(action)
				break;

			case "fork":
				const iter1 = yieldedValue.fnGenerator()
				yield$ = runGen({ iter: iter1, takers, run })
				break;

			case "take":
				const gen = {
					fnGenerator: () => iter,
					yieldedValue
				};

				makeGen(gen.fnGenerator)

				takers[yieldedValue.action] = gen

				return result;

				break;

			default:
				break;
		}

		result = iter.next(yield$);
	}
}

function createRun(saga) {
	const takers = {};
	const gens = {};
	return function run(action) {
		const iter = saga();

		if (!Object.keys(takers).length) {
			runGen({ iter, takers, gens });
		}

		const taker = takers[action];
		if (taker) {
			const fnCall = taker.fnGenerator

			if (isGen(fnCall)) {
				const value = fnCall()
				runGen({ iter: value, takers, run, gens })
			}

			if (taker.yieldedValue) {
				delete takers[taker.yieldedValue.action]
			}
		}
		console.log(takers)

		return iter;
	}
}

const run = createRun(main)
run("ACTION-A")
console.log("ACTION-CANCEL")
run("ACTION-CANCEL")