import React, { useState, useEffect, useRef, useImperativeHandle, forwardRef } from 'react';

import { Platform, ViewPropTypes, View } from 'react-native';

import PropTypes from 'prop-types';

import { WebView } from 'react-native-webview';

import { reduceData, getWidth, isSizeChanged, shouldUpdate } from './utils';

const AutoHeightWebView = React.memo(
  forwardRef((props, ref) => {
    const { style, onMessage, onSizeUpdated, scrollEnabledWithZoomedin, scrollEnabled, source } = props;

    if (!source) {
      return null;
    }

    const webView = useRef();
    useImperativeHandle(ref, () => ({
      stopLoading: () => webView.current.stopLoading(),
      goForward: () => webView.current.goForward(),
      goBack: () => webView.current.goBack(),
      reload: () => webView.current.reload(),
      injectJavaScript: script => webView.current.injectJavaScript(script),
    }));

    const [size, setSize] = useState({
      height: style && style.height ? style.height : 0,
      width: getWidth(style),
    });
    const [scrollable, setScrollable] = useState(false);
    const handleMessage = (event) => {
      onMessage && onMessage(event);
      if (!event.nativeEvent) {
        return;
      }
      let data = {};
      // Sometimes the message is invalid JSON, so we ignore that case
      try {
        data = JSON.parse(event.nativeEvent.data);
      } catch (error) {
        console.error(error);
        return;
      }
      const { height, width, zoomedin } = data;
      !scrollEnabled && scrollEnabledWithZoomedin && setScrollable(!!zoomedin);
      const { height: previousHeight, width: previousWidth } = size;
      isSizeChanged({ height, previousHeight, width, previousWidth })
        && setSize({
          height,
          width,
        });
    };

    const currentScrollEnabled = scrollEnabled === false && scrollEnabledWithZoomedin ? scrollable : scrollEnabled;

    const { currentSource, script } = reduceData(props);

    const { width, height } = size;
    useEffect(
      () => onSizeUpdated
        && onSizeUpdated({
          height,
          width,
        }),
      [width, height, onSizeUpdated]
    );
    return (
      <View style={[props.style, { height: height || 50, transform: [{ translateX: -1 }] }]}>
        <WebView
          {...props}
          style={{ transform: [{ translateX: 1 }] }}
          ref={webView}
          onMessage={handleMessage}
          injectedJavaScript={script}
          source={currentSource}
          scrollEnabled={currentScrollEnabled}
        />
      </View>
    );
  }),
  (prevProps, nextProps) => !shouldUpdate({ prevProps, nextProps })
);

AutoHeightWebView.propTypes = {
  onSizeUpdated: PropTypes.func,
  files: PropTypes.arrayOf(
    PropTypes.shape({
      href: PropTypes.string,
      type: PropTypes.string,
      rel: PropTypes.string,
    })
  ),
  style: ViewPropTypes.style,
  customScript: PropTypes.string,
  customStyle: PropTypes.string,
  viewportContent: PropTypes.string,
  scrollEnabledWithZoomedin: PropTypes.bool,
  // webview props
  originWhitelist: PropTypes.arrayOf(PropTypes.string),
  onMessage: PropTypes.func,
  scalesPageToFit: PropTypes.bool,
  source: PropTypes.object,
};

const defaultProps = {
  showsVerticalScrollIndicator: false,
  showsHorizontalScrollIndicator: false,
  originWhitelist: ['*'],
};

Platform.OS === 'android'
  && Object.assign(defaultProps, {
    scalesPageToFit: false,
  });

Platform.OS === 'ios'
  && Object.assign(defaultProps, {
    viewportContent: 'width=device-width',
  });

AutoHeightWebView.defaultProps = defaultProps;

export default AutoHeightWebView;