// deck.gl-community
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

import turfBearing from '@turf/bearing';
import turfDistance from '@turf/distance';
import turfTransformTranslate from '@turf/transform-translate';
import {point} from '@turf/helpers';
import {SimpleFeatureCollection, Position} from '../utils/geojson-types';
import {PointerMoveEvent, StartDraggingEvent, StopDraggingEvent} from '../edit-modes/types';
import {EditAction, ModeHandler} from './mode-handler';

// TODO edit-modes: delete handlers once EditMode fully implemented
export class TranslateHandler extends ModeHandler {
  _geometryBeforeTranslate: SimpleFeatureCollection | null | undefined;
  _isTranslatable: boolean = undefined!;

  handlePointerMove(event: PointerMoveEvent): {
    editAction: EditAction | null | undefined;
    cancelMapPan: boolean;
  } {
    let editAction: EditAction | null | undefined = null;

    this._isTranslatable =
      Boolean(this._geometryBeforeTranslate) || this.isSelectionPicked(event.picks);

    if (!this._isTranslatable || !event.pointerDownMapCoords) {
      // Nothing to do
      return {editAction: null, cancelMapPan: false};
    }

    if (event.isDragging && this._geometryBeforeTranslate) {
      // Translate the geometry
      editAction = this.getTranslateAction(
        event.pointerDownMapCoords,
        event.mapCoords,
        'translating'
      );
    }

    return {editAction, cancelMapPan: true};
  }

  handleStartDragging(event: StartDraggingEvent): EditAction | null | undefined {
    if (!this._isTranslatable) {
      return null;
    }

    this._geometryBeforeTranslate = this.getSelectedFeaturesAsFeatureCollection();
    return null;
  }

  handleStopDragging(event: StopDraggingEvent): EditAction | null | undefined {
    let editAction: EditAction | null | undefined = null;

    if (this._geometryBeforeTranslate) {
      // Translate the geometry
      editAction = this.getTranslateAction(
        event.pointerDownMapCoords,
        event.mapCoords,
        'translated'
      );
      this._geometryBeforeTranslate = null;
    }

    return editAction;
  }

  getCursor({isDragging}: {isDragging: boolean}): string {
    if (this._isTranslatable) {
      return 'move';
    }
    return isDragging ? 'grabbing' : 'grab';
  }

  getTranslateAction(
    startDragPoint: Position,
    currentPoint: Position,
    editType: string
  ): EditAction | null | undefined {
    if (!this._geometryBeforeTranslate) {
      return null;
    }
    const p1 = point(startDragPoint);
    const p2 = point(currentPoint);

    const distanceMoved = turfDistance(p1, p2);
    const direction = turfBearing(p1, p2);

    const movedFeatures: SimpleFeatureCollection = turfTransformTranslate(
      this._geometryBeforeTranslate,
      distanceMoved,
      direction
    );

    let updatedData = this.getImmutableFeatureCollection();

    const selectedIndexes = this.getSelectedFeatureIndexes();
    for (let i = 0; i < selectedIndexes.length; i++) {
      const selectedIndex = selectedIndexes[i];
      const movedFeature = movedFeatures.features[i];
      updatedData = updatedData.replaceGeometry(selectedIndex, movedFeature.geometry);
    }

    return {
      updatedData: updatedData.getObject(),
      editType,
      featureIndexes: selectedIndexes,
      editContext: null
    };
  }
}