import React, { useRef, useCallback, useEffect } from 'react';
import { StyleSheet } from 'react-native';
import { WebView } from 'react-native-webview';
import type { LatLng } from '../../types/location';
import { getLeafletMapHtml } from './LeafletMapHtml';
import type { LeafletMapMarker, LeafletMapPolyline } from './LeafletMapHtml';

export interface LeafletMapProps {
  /** Center coordinate of the map */
  center: LatLng;
  /** Initial zoom level (default 14) */
  zoom?: number;
  /** Markers to display on the map */
  markers?: LeafletMapMarker[];
  /** Polylines to draw on the map */
  polylines?: LeafletMapPolyline[];
  /** Whether to show the pulsing user-location marker */
  showCurrentLocation?: boolean;
  /** Whether the map is interactive (default true) */
  interactive?: boolean;
  /** Fired when a marker is tapped */
  onMarkerTap?: (data: { lat: number; lng: number; title?: string; type?: string }) => void;
  /** Fired once the Leaflet map is ready */
  onMapReady?: () => void;
  /** Fired on map move (center / zoom change) */
  onMapMove?: (data: { lat: number; lng: number; zoom: number }) => void;
  /** Optional style override for the WebView container */
  style?: object;
}

/**
 * WebView wrapper that renders a Leaflet.js map via injected HTML.
 * Handles two-way communication (postMessage / onMessage) between the
 * WebView and React Native.
 */
export function LeafletMap({
  center,
  zoom = 14,
  markers = [],
  polylines = [],
  showCurrentLocation = false,
  interactive = true,
  onMarkerTap,
  onMapReady,
  onMapMove,
  style,
}: LeafletMapProps) {
  const webViewRef = useRef<WebView>(null);

  // Regenerate HTML when core options change
  const html = getLeafletMapHtml({
    centerLat: center.lat,
    centerLng: center.lng,
    zoom,
    markers,
    polylines,
    showCurrentLocation,
    interactive,
  });

  const handleMessage = useCallback(
    (event: { nativeEvent: { data: string } }) => {
      try {
        const msg = JSON.parse(event.nativeEvent.data);
        switch (msg.event) {
          case 'map_ready':
            onMapReady?.();
            break;
          case 'marker_tap':
            onMarkerTap?.(msg.data);
            break;
          case 'map_move':
            onMapMove?.(msg.data);
            break;
        }
      } catch {
        // ignore malformed messages
      }
    },
    [onMapReady, onMarkerTap, onMapMove],
  );

  // Public imperative methods exposed via ref-forwarding
  // These are called by injecting JS into the WebView.
  const runJS = useCallback((js: string) => {
    webViewRef.current?.injectJavaScript(js);
  }, []);

  // Expose updateCurrentLocation as a side-effect (if needed)
  // The parent can call `webViewRef.current.injectJavaScript(...)` directly.
  useEffect(() => {
    // No-op on mount; the map is fully rendered via the html prop.
  }, [center.lat, center.lng]);

  return (
    <WebView
      ref={webViewRef}
      source={{ html }}
      style={[styles.webview, style]}
      originWhitelist={['*']}
      onMessage={handleMessage}
      javaScriptEnabled
      domStorageEnabled
      scrollEnabled={false}
      bounces={false}
      showsHorizontalScrollIndicator={false}
      showsVerticalScrollIndicator={false}
      cacheEnabled
      cacheMode="LOAD_DEFAULT"
      androidLayerType="hardware"
      // @ts-expect-error – mixed content mode needed for OSM tiles
      mixedContentMode="always"
      pointerEvents={interactive ? 'auto' : 'none'}
    />
  );
}

const styles = StyleSheet.create({
  webview: {
    flex: 1,
    backgroundColor: 'transparent',
  },
});