DeFiCh/wallet

import {
  SimplifiedAppStateStatus,
  useAppStateContext,
} from "@contexts/AppStateContext";
import {
  PrivacyLockContextI,
  usePrivacyLockContext,
} from "@contexts/LocalAuthContext";
import { EnvironmentName, getEnvironment } from "@waveshq/walletkit-core";
import { useEffect } from "react";
import { BackHandler } from "react-native";
import { ThemedView } from "@components/themed";
import { tailwind } from "@tailwind";
import {
  NativeLoggingProps,
  useLogger,
} from "@shared-contexts/NativeLoggingProvider";
import { getReleaseChannel } from "@api/releaseChannel";

const APP_LAST_ACTIVE: { force: boolean; timestamp?: number } = {
  force: false,
};

function shouldReauthenticate(): boolean {
  if (APP_LAST_ACTIVE.force) {
    return true;
  }

  const lastActive = APP_LAST_ACTIVE.timestamp;
  if (lastActive === undefined) {
    return true;
  }

  const env = getEnvironment(getReleaseChannel());
  const timeout = env.name === EnvironmentName.Development ? 3000 : 60000;
  return lastActive + timeout < Date.now();
}

export function PrivacyLock(): JSX.Element {
  const privacyLock = usePrivacyLockContext();
  const appState = useAppStateContext();
  const logger = useLogger();

  const handler = (nextState: SimplifiedAppStateStatus): void => {
    if (nextState === "background") {
      APP_LAST_ACTIVE.timestamp = Date.now();
    } else if (privacyLock.isEnabled) {
      if (shouldReauthenticate()) {
        authenticateOrExit(privacyLock, logger);
      }
    }
  };

  // authenticate once during cold start
  useEffect(() => {
    const id = appState.addListener(handler);
    return () => appState.removeListener(id);
  }, [handler]);

  // this run only ONCE on fresh start
  // isPrivacyLock change in-app should not re-triggered
  useEffect(() => {
    if (privacyLock.isEnabled) {
      authenticateOrExit(privacyLock, logger);
    }
  }, []);

  if (privacyLock.isAuthenticating || APP_LAST_ACTIVE.force) {
    return (
      <ThemedView
        style={tailwind("h-full w-full")}
        light={tailwind("bg-gray-200")}
        dark={tailwind("bg-gray-900")}
      />
    );
  } else {
    return <></>;
  }
}

function authenticateOrExit(
  privacyLockContext: PrivacyLockContextI,
  logger: NativeLoggingProps
): void {
  const backHandler = BackHandler.addEventListener(
    "hardwareBackPress",
    () => null
  );
  privacyLockContext
    .prompt()
    .then(async () => {
      try {
        APP_LAST_ACTIVE.force = false;
      } catch (e) {
        /* value not found in secure-store, unable to delete */
        logger.error(e);
      }
    })
    .catch(async (e) => {
      logger.error(e);
      APP_LAST_ACTIVE.force = true;
    })
    .finally(() => {
      privacyLockContext.setIsAuthenticating(false);
      backHandler.remove();
    });
}