import { useEffect, useMemo, useRef, useState } from 'react';
import {
  Map,
  NavigationControl,
  type GeoJSONSource,
} from 'maplibre-gl';
import { Alert, LoadingBlock, errorMessage } from '../../components/Feedback';
import { Icon } from '../../components/Icon';
import {
  getAssetGeometry,
  removeAssetGeometry,
  upsertAssetGeometry,
} from '../../lib/api';
import type {
  AssetGeometry,
  AssetGeometryType,
  GeoJsonGeometry,
  Position,
} from '../../lib/api';
import { formatDate } from '../../lib/format';

const osmStyle = {
  version: 8 as const,
  sources: {
    osm: {
      type: 'raster' as const,
      tiles: ['https://tile.openstreetmap.org/{z}/{x}/{y}.png'],
      tileSize: 256,
      attribution: '© OpenStreetMap contributors',
    },
  },
  layers: [{ id: 'osm', type: 'raster' as const, source: 'osm' }],
};

function localDateTime(value: string | number | Date): string {
  const date = new Date(value);
  if (Number.isNaN(date.getTime())) return '';
  const local = new Date(date.getTime() - date.getTimezoneOffset() * 60_000);
  return local.toISOString().slice(0, 16);
}

function geometryVertices(geometry: GeoJsonGeometry | null): Position[] {
  if (!geometry) return [];
  if (geometry.type === 'Point') return [geometry.coordinates];
  if (geometry.type === 'LineString') return geometry.coordinates;
  return geometry.coordinates[0]?.slice(0, -1) ?? [];
}

function draftGeometry(type: AssetGeometryType, vertices: Position[]): GeoJsonGeometry | null {
  if (type === 'POINT') return vertices[0] ? { type: 'Point', coordinates: vertices[0] } : null;
  if (type === 'LINESTRING') return vertices.length >= 2 ? { type: 'LineString', coordinates: vertices } : null;
  if (vertices.length < 3) return null;
  return { type: 'Polygon', coordinates: [[...vertices, vertices[0]!]] };
}

function drawingCollection(geometry: GeoJsonGeometry | null, vertices: Position[]) {
  const features: unknown[] = [];
  if (geometry) features.push({ type: 'Feature', properties: { kind: 'shape' }, geometry });
  if (geometry?.type !== 'Point') {
    vertices.forEach((coordinates, index) => features.push({
      type: 'Feature', properties: { kind: 'vertex', index: index + 1 },
      geometry: { type: 'Point', coordinates },
    }));
  }
  return { type: 'FeatureCollection', features };
}

function geometryBounds(geometry: GeoJsonGeometry | null) {
  const points = geometryVertices(geometry);
  if (!points.length) return null;
  return points.reduce<[number, number, number, number]>((result, point) => [
    Math.min(result[0], point[0]), Math.min(result[1], point[1]),
    Math.max(result[2], point[0]), Math.max(result[3], point[1]),
  ], [points[0]![0], points[0]![1], points[0]![0], points[0]![1]]);
}

function GeometryDrawingMap({
  geometry,
  vertices,
  editable,
  onAddVertex,
}: {
  geometry: GeoJsonGeometry | null;
  vertices: Position[];
  editable: boolean;
  onAddVertex: (position: Position) => void;
}) {
  const containerRef = useRef<HTMLDivElement | null>(null);
  const mapRef = useRef<Map | null>(null);
  const addVertexRef = useRef(onAddVertex);
  const dataRef = useRef(drawingCollection(geometry, vertices));
  addVertexRef.current = onAddVertex;
  dataRef.current = drawingCollection(geometry, vertices);

  useEffect(() => {
    if (!containerRef.current) return;
    const bounds = geometryBounds(geometry);
    const map = new Map({
      container: containerRef.current,
      style: osmStyle,
      center: bounds ? [bounds[0], bounds[1]] : [-68.8458, -32.8895],
      zoom: bounds ? 12 : 6,
    });
    mapRef.current = map;
    map.addControl(new NavigationControl(), 'top-right');
    map.on('load', () => {
      map.addSource('drawing', { type: 'geojson', data: dataRef.current as never });
      map.addLayer({
        id: 'drawing-fill', type: 'fill', source: 'drawing',
        filter: ['==', ['geometry-type'], 'Polygon'],
        paint: { 'fill-color': '#2864dc', 'fill-opacity': 0.2 },
      });
      map.addLayer({
        id: 'drawing-line', type: 'line', source: 'drawing',
        filter: ['in', ['geometry-type'], ['literal', ['LineString', 'Polygon']]],
        paint: { 'line-color': '#2864dc', 'line-width': 3 },
      });
      map.addLayer({
        id: 'drawing-points', type: 'circle', source: 'drawing',
        filter: ['==', ['geometry-type'], 'Point'],
        paint: {
          'circle-radius': ['case', ['==', ['get', 'kind'], 'vertex'], 5, 8],
          'circle-color': ['case', ['==', ['get', 'kind'], 'vertex'], '#f59e0b', '#2864dc'],
          'circle-stroke-color': '#ffffff', 'circle-stroke-width': 2,
        },
      });
      if (bounds) {
        if (bounds[0] === bounds[2] && bounds[1] === bounds[3]) {
          map.flyTo({ center: [bounds[0], bounds[1]], zoom: 14 });
        } else {
          map.fitBounds([[bounds[0], bounds[1]], [bounds[2], bounds[3]]], { padding: 45, maxZoom: 16 });
        }
      }
    });
    if (editable) {
      map.getCanvas().style.cursor = 'crosshair';
      map.on('click', (event) => addVertexRef.current([
        Number(event.lngLat.lng.toFixed(7)),
        Number(event.lngLat.lat.toFixed(7)),
      ]));
    }
    return () => {
      mapRef.current = null;
      map.remove();
    };
  }, [editable]);

  useEffect(() => {
    const source = mapRef.current?.getSource('drawing') as GeoJSONSource | undefined;
    source?.setData(drawingCollection(geometry, vertices) as never);
  }, [geometry, vertices]);

  return <div ref={containerRef} className="geometry-map" />;
}

const geometryNames: Record<AssetGeometryType, string> = {
  POINT: 'Punto',
  LINESTRING: 'Línea',
  POLYGON: 'Polígono',
};

export function AssetGeometryEditor({
  assetId,
  assetName,
  canEdit,
  onChanged,
}: {
  assetId: string;
  assetName: string;
  canEdit: boolean;
  onChanged?: () => void;
}) {
  const [stored, setStored] = useState<AssetGeometry | null>(null);
  const [type, setType] = useState<AssetGeometryType>('POINT');
  const [vertices, setVertices] = useState<Position[]>([]);
  const [accuracyM, setAccuracyM] = useState('');
  const [capturedAt, setCapturedAt] = useState('');
  const [deviceLabel, setDeviceLabel] = useState('');
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [locating, setLocating] = useState(false);
  const [error, setError] = useState('');
  const [success, setSuccess] = useState('');

  const geometry = useMemo(() => draftGeometry(type, vertices), [type, vertices]);

  const applyStored = (value: AssetGeometry | null) => {
    setStored(value);
    if (value) {
      setType(value.geometryType);
      setVertices(geometryVertices(value.geometry));
      setAccuracyM(value.accuracyM == null ? '' : String(value.accuracyM));
      setCapturedAt(value.capturedAt ? localDateTime(value.capturedAt) : '');
      setDeviceLabel(value.deviceLabel ?? '');
    }
  };

  useEffect(() => {
    getAssetGeometry(assetId)
      .then(applyStored)
      .catch((requestError) => setError(errorMessage(requestError)))
      .finally(() => setLoading(false));
  }, [assetId]);

  const changeType = (next: AssetGeometryType) => {
    setType(next); setVertices([]); setSuccess(''); setError('');
  };

  const addVertex = (position: Position) => {
    if (!canEdit) return;
    setVertices((current) => type === 'POINT' ? [position] : [...current, position]);
    setSuccess('');
  };

  const useDeviceLocation = () => {
    if (!navigator.geolocation) {
      setError('Este navegador no permite obtener la ubicación del dispositivo.');
      return;
    }
    setLocating(true); setError('');
    navigator.geolocation.getCurrentPosition(
      (position) => {
        setType('POINT');
        setVertices([[
          Number(position.coords.longitude.toFixed(7)),
          Number(position.coords.latitude.toFixed(7)),
        ]]);
        setAccuracyM(Number(position.coords.accuracy.toFixed(3)).toString());
        setCapturedAt(localDateTime(position.timestamp));
        setDeviceLabel('Navegador web');
        setLocating(false);
      },
      (locationError) => {
        setError(locationError.code === 1
          ? 'No se otorgó permiso para acceder a la ubicación.'
          : 'No fue posible obtener una ubicación precisa.');
        setLocating(false);
      },
      { enableHighAccuracy: true, timeout: 15_000, maximumAge: 0 },
    );
  };

  const save = async () => {
    if (!geometry) return;
    setSaving(true); setError(''); setSuccess('');
    try {
      const updated = await upsertAssetGeometry(assetId, {
        geometry,
        accuracyM: accuracyM ? Number(accuracyM) : null,
        capturedAt: capturedAt ? new Date(capturedAt).toISOString() : null,
        deviceLabel: deviceLabel.trim() || null,
      });
      applyStored(updated);
      setSuccess('Ubicación guardada correctamente');
      onChanged?.();
    } catch (requestError) { setError(errorMessage(requestError)); }
    finally { setSaving(false); }
  };

  const remove = async () => {
    if (!window.confirm(`¿Quitar la geometría actual de ${assetName}? El cambio quedará auditado.`)) return;
    setSaving(true); setError(''); setSuccess('');
    try {
      await removeAssetGeometry(assetId);
      setStored(null); setVertices([]); setAccuracyM(''); setCapturedAt(''); setDeviceLabel('');
      setSuccess('La geometría fue retirada y el cambio quedó auditado');
      onChanged?.();
    } catch (requestError) { setError(errorMessage(requestError)); }
    finally { setSaving(false); }
  };

  if (loading) return <div className="panel"><LoadingBlock label="Cargando ubicación…" /></div>;

  const minimum = type === 'POINT' ? 1 : type === 'LINESTRING' ? 2 : 3;
  return <article className="panel geometry-editor">
    <div className="panel-heading"><div><span className="eyebrow">POSTGIS · WGS 84</span><h2>Ubicación geográfica</h2></div>{stored ? <span className="tag">{geometryNames[stored.geometryType]}</span> : <span className="tag">Sin geometría</span>}</div>
    {error && <Alert>{error}</Alert>}{success && <Alert type="success">{success}</Alert>}
    <p className="section-copy">Elegí el tipo y marcá {type === 'POINT' ? 'la posición' : 'los vértices'} directamente sobre el mapa. Las coordenadas se guardan en EPSG:4326.</p>

    {canEdit && <div className="geometry-toolbar"><div className="geometry-type-buttons">{(['POINT', 'LINESTRING', 'POLYGON'] as AssetGeometryType[]).map((item) => <button type="button" key={item} className={`button ${type === item ? 'primary' : 'secondary'}`} onClick={() => changeType(item)}>{geometryNames[item]}</button>)}</div><button type="button" className="button secondary" onClick={useDeviceLocation} disabled={locating}><Icon name="map" />{locating ? 'Ubicando…' : 'Usar mi ubicación'}</button></div>}

    <GeometryDrawingMap geometry={geometry} vertices={vertices} editable={canEdit} onAddVertex={addVertex} />

    <div className="geometry-progress"><strong>{vertices.length} vértice{vertices.length === 1 ? '' : 's'}</strong><span>{geometry ? 'Geometría lista para guardar' : `Faltan ${Math.max(0, minimum - vertices.length)} vértices`}</span>{canEdit && vertices.length > 0 && <div><button type="button" className="button text" onClick={() => setVertices((current) => current.slice(0, -1))}>Deshacer último</button><button type="button" className="button text" onClick={() => setVertices([])}>Limpiar</button></div>}</div>

    <div className="form-grid geometry-metadata"><label className="field"><span>Precisión GPS <em>metros · opcional</em></span><input type="number" min="0" max="100000" step="0.001" value={accuracyM} onChange={(event) => setAccuracyM(event.target.value)} disabled={!canEdit} /></label><label className="field"><span>Fecha y hora de captura <em>opcional</em></span><input type="datetime-local" value={capturedAt} onChange={(event) => setCapturedAt(event.target.value)} disabled={!canEdit} /></label><label className="field"><span>Dispositivo <em>opcional</em></span><input value={deviceLabel} onChange={(event) => setDeviceLabel(event.target.value)} disabled={!canEdit} maxLength={255} placeholder="Tablet, navegador, GPS…" /></label></div>

    {stored && <div className="geometry-audit-note"><span>Fuente: {stored.source}</span><span>Actualizada: {formatDate(stored.updatedAt)}</span>{stored.accuracyM != null && <span>Precisión: {stored.accuracyM} m</span>}</div>}
    {canEdit && <div className="form-actions">{stored && <button type="button" className="button danger-outline" onClick={remove} disabled={saving}>Quitar geometría</button>}<button type="button" className="button primary" onClick={save} disabled={!geometry || saving}><Icon name="check" />{saving ? 'Guardando…' : 'Guardar ubicación'}</button></div>}
  </article>;
}