text: import {
    getIdByType,
    getProxyByType,
    getSignature,
    isColdType,
    isRegisteredComponent,
    updateProxyById,
  } from './proxies';
  import { hotComparisonOpen } from '../global/generation';
  import { isForwardType, isMemoType, isReactClass, isReloadableComponent } from '../internal/reactUtils';
  import { areSwappable } from './utils';
  import { PROXY_KEY, UNWRAP_PROXY } from '../proxy';
  import { resolveType } from './resolver';
  import logger from '../logger';
  import configuration from '../configuration';
  
  const getInnerComponentType = component => {
    const unwrapper = component[UNWRAP_PROXY];
    return unwrapper ? unwrapper() : component;
  };
  
  function haveEqualSignatures(prevType, nextType) {
    const prevSignature = getSignature(prevType);
    const nextSignature = getSignature(nextType);
  
    if (prevSignature === undefined && nextSignature === undefined) {
      return true;
    }
    if (prevSignature === undefined || nextSignature === undefined) {
      return false;
    }
    if (prevSignature.key !== nextSignature.key) {
      return false;
    }
  
    // TODO: we might need to calculate previous signature earlier in practice,
    // such as during the first time a component is resolved. We'll revisit this.
    const prevCustomHooks = prevSignature.getCustomHooks();
    const nextCustomHooks = nextSignature.getCustomHooks();
    if (prevCustomHooks.length !== nextCustomHooks.length) {
      return false;
    }
  
    for (let i = 0; i < nextCustomHooks.length; i++) {
      if (!haveEqualSignatures(prevCustomHooks[i], nextCustomHooks[i])) {
        return false;
      }
    }
  
    return true;
  }
  
  const areSignaturesCompatible = (a, b) => {
    // compare signatures of two components
    // non-equal component have to remount and there is two options to do it
    // - fail the comparison, remounting all tree below
    // - fulfill it, but set `_debugNeedsRemount` on a fiber to drop only local state
    // the second way is not published yet, so going with the first one
    if (!haveEqualSignatures(a, b)) {
      logger.warn('⚛️🔥🎣 Hook order change detected: component', a, 'has been remounted');
      return false;
    }
    return true;
  };
  
  const compareRegistered = (a, b) => {
    if (isRegisteredComponent(a) || isRegisteredComponent(b)) {
      if (resolveType(a) !== resolveType(b)) {
        return false;
      }
    }
  
    return areSignaturesCompatible(a, b);
  };
  
  const compareComponents = (oldType, newType, setNewType, baseType) => {
    let defaultResult = oldType === newType;
  
    if ((oldType && !newType) || (!oldType && newType)) {
      return false;
    }
  
    if (isRegisteredComponent(oldType) || isRegisteredComponent(newType)) {
      if (!compareRegistered(oldType, newType)) {
        return false;
      }
      defaultResult = true;
    }
  
    if (isForwardType({ type: oldType }) && isForwardType({ type: newType })) {
      if (!compareRegistered(oldType.render, newType.render)) {
        return false;
      }
      if (oldType.render === newType.render || areSwappable(oldType.render, newType.render)) {
        setNewType(newType);
        return true;
      }
      return defaultResult;
    }
  
    if (isMemoType({ type: oldType }) && isMemoType({ type: newType })) {
      if (!compareRegistered(oldType.type, newType.type)) {
        return false;
      }
      if (oldType.type === newType.type || areSwappable(oldType.type, newType.type)) {
        if (baseType) {
          // memo form different fibers, why?
          if (baseType.$$typeof === newType.$$typeof) {
            setNewType(newType);
          } else {
            setNewType(newType.type);
          }
        } else {
          logger.warn('Please update hot-loader/react-dom');
          if (isReactClass(newType.type)) {
            setNewType(newType);
          } else {
            setNewType(newType.type);
          }
        }
  
        return true;
      }
      return defaultResult;
    }
  
    if (newType !== oldType && areSignaturesCompatible(newType, oldType) && areSwappable(newType, oldType)) {
      const unwrapFactory = newType[UNWRAP_PROXY];
      const oldProxy = unwrapFactory && getProxyByType(unwrapFactory());
      if (oldProxy) {
        oldProxy.dereference();
        updateProxyById(oldType[PROXY_KEY] || getIdByType(oldType), getInnerComponentType(newType));
      } else {
        setNewType(newType);
      }
      return true;
    }
  
    return defaultResult;
  };
  
  const knownPairs = new WeakMap();
  const emptyMap = new WeakMap();
  
  export const hotComponentCompare = (oldType, preNewType, setNewType, baseType) => {
    const hotActive = hotComparisonOpen();
    const newType = configuration.intergratedResolver ? resolveType(preNewType) : preNewType;
    let result = oldType === newType;
  
    if (
      result ||
      !isReloadableComponent(oldType) ||
      !isReloadableComponent(newType) ||
      isColdType(oldType) ||
      isColdType(oldType) ||
      !oldType ||
      !newType ||
      0
    ) {
      return result;
    }
  
    // comparison should be active only if hot update window
    // or it would merge components it shall not
    if (hotActive) {
      result = compareComponents(oldType, newType, setNewType, baseType);
      const pair = knownPairs.get(oldType) || new WeakMap();
      pair.set(newType, result);
      knownPairs.set(oldType, pair);
      return result;
    }
  
    if (result) {
      return result;
    }
  
    const pair = knownPairs.get(oldType) || emptyMap;
    return pair.get(newType) || false;
  };
  