import { useContext, useCallback, useState } from 'react';
import { HackleContext } from '../components';
import { Decision, DEFAULT_VARIATION, DecisionReason } from '../models';
import { InputUtil } from '../utils';

export function useVariationDetail(experimentKey: number): Decision {
  const { hackle, userVersion } = useContext(HackleContext);
  const getVariationDetail = useCallback(() => {
    if (!hackle) {
      return Decision.of(DEFAULT_VARIATION, DecisionReason.SDK_NOT_READY);
    }
    return Decision.withReactNativeDecision(
      hackle.variationDetailSync(experimentKey)
    );
  }, [experimentKey, hackle]);

  const [variationDetail, setVariationDetail] = useState(() => {
    if (!hackle) {
      return Decision.of(DEFAULT_VARIATION, DecisionReason.SDK_NOT_READY);
    }
    return getVariationDetail();
  });

  const currentInput = {
    key: experimentKey,
    userVersion,
  };

  const [prevInput, setPrevInput] = useState(currentInput);

  if (!InputUtil.isInputEqual(prevInput, currentInput)) {
    setPrevInput(currentInput);
    setVariationDetail(getVariationDetail());
  }

  return variationDetail;
}