/**
 * @module ol/geom/SimpleGeometry
 */
import {FALSE} from '../functions.js';
import {createOrUpdateFromFlatCoordinates, getCenter} from '../extent.js';
import Geometry from '../geom/Geometry.js';
import GeometryLayout from '../geom/GeometryLayout.js';
import {rotate, scale, translate, transform2D} from '../geom/flat/transform.js';
import {clear} from '../obj.js';

/**
 * @classdesc
 * Abstract base class; only used for creating subclasses; do not instantiate
 * in apps, as cannot be rendered.
 *
 * @abstract
 * @api
 */
class SimpleGeometry extends Geometry {
  constructor() {

    super();

    /**
     * @protected
     * @type {GeometryLayout}
     */
    this.layout = GeometryLayout.XY;

    /**
     * @protected
     * @type {number}
     */
    this.stride = 2;

    /**
     * @protected
     * @type {Array<number>}
     */
    this.flatCoordinates = null;

  }

  /**
   * @inheritDoc
   */
  computeExtent(extent) {
    return createOrUpdateFromFlatCoordinates(this.flatCoordinates,
      0, this.flatCoordinates.length, this.stride, extent);
  }

  /**
   * @abstract
   * @return {Array} Coordinates.
   */
  getCoordinates() {}

  /**
   * Return the first coordinate of the geometry.
   * @return {import("../coordinate.js").Coordinate} First coordinate.
   * @api
   */
  getFirstCoordinate() {
    return this.flatCoordinates.slice(0, this.stride);
  }

  /**
   * @return {Array<number>} Flat coordinates.
   */
  getFlatCoordinates() {
    return this.flatCoordinates;
  }

  /**
   * Return the last coordinate of the geometry.
   * @return {import("../coordinate.js").Coordinate} Last point.
   * @api
   */
  getLastCoordinate() {
    return this.flatCoordinates.slice(this.flatCoordinates.length - this.stride);
  }

  /**
   * Return the {@link module:ol/geom/GeometryLayout~GeometryLayout layout} of the geometry.
   * @return {GeometryLayout} Layout.
   * @api
   */
  getLayout() {
    return this.layout;
  }

  /**
   * @inheritDoc
   */
  getSimplifiedGeometry(squaredTolerance) {
    if (this.simplifiedGeometryRevision != this.getRevision()) {
      clear(this.simplifiedGeometryCache);
      this.simplifiedGeometryMaxMinSquaredTolerance = 0;
      this.simplifiedGeometryRevision = this.getRevision();
    }
    // If squaredTolerance is negative or if we know that simplification will not
    // have any effect then just return this.
    if (squaredTolerance < 0 ||
        (this.simplifiedGeometryMaxMinSquaredTolerance !== 0 &&
         squaredTolerance <= this.simplifiedGeometryMaxMinSquaredTolerance)) {
      return this;
    }
    const key = squaredTolerance.toString();
    if (this.simplifiedGeometryCache.hasOwnProperty(key)) {
      return this.simplifiedGeometryCache[key];
    } else {
      const simplifiedGeometry =
          this.getSimplifiedGeometryInternal(squaredTolerance);
      const simplifiedFlatCoordinates = simplifiedGeometry.getFlatCoordinates();
      if (simplifiedFlatCoordinates.length < this.flatCoordinates.length) {
        this.simplifiedGeometryCache[key] = simplifiedGeometry;
        return simplifiedGeometry;
      } else {
        // Simplification did not actually remove any coordinates.  We now know
        // that any calls to getSimplifiedGeometry with a squaredTolerance less
        // than or equal to the current squaredTolerance will also not have any
        // effect.  This allows us to short circuit simplification (saving CPU
        // cycles) and prevents the cache of simplified geometries from filling
        // up with useless identical copies of this geometry (saving memory).
        this.simplifiedGeometryMaxMinSquaredTolerance = squaredTolerance;
        return this;
      }
    }
  }

  /**
   * @param {number} squaredTolerance Squared tolerance.
   * @return {SimpleGeometry} Simplified geometry.
   * @protected
   */
  getSimplifiedGeometryInternal(squaredTolerance) {
    return this;
  }

  /**
   * @return {number} Stride.
   */
  getStride() {
    return this.stride;
  }

  /**
   * @param {GeometryLayout} layout Layout.
   * @param {Array<number>} flatCoordinates Flat coordinates.
    */
  setFlatCoordinates(layout, flatCoordinates) {
    this.stride = getStrideForLayout(layout);
    this.layout = layout;
    this.flatCoordinates = flatCoordinates;
  }

  /**
   * @abstract
   * @param {!Array} coordinates Coordinates.
   * @param {GeometryLayout=} opt_layout Layout.
   */
  setCoordinates(coordinates, opt_layout) {}

  /**
   * @param {GeometryLayout|undefined} layout Layout.
   * @param {Array} coordinates Coordinates.
   * @param {number} nesting Nesting.
   * @protected
   */
  setLayout(layout, coordinates, nesting) {
    /** @type {number} */
    let stride;
    if (layout) {
      stride = getStrideForLayout(layout);
    } else {
      for (let i = 0; i < nesting; ++i) {
        if (coordinates.length === 0) {
          this.layout = GeometryLayout.XY;
          this.stride = 2;
          return;
        } else {
          coordinates = /** @type {Array} */ (coordinates[0]);
        }
      }
      stride = coordinates.length;
      layout = getLayoutForStride(stride);
    }
    this.layout = layout;
    this.stride = stride;
  }

  /**
   * @inheritDoc
   * @api
   */
  applyTransform(transformFn) {
    if (this.flatCoordinates) {
      transformFn(this.flatCoordinates, this.flatCoordinates, this.stride);
      this.changed();
    }
  }

  /**
   * @inheritDoc
   * @api
   */
  rotate(angle, anchor) {
    const flatCoordinates = this.getFlatCoordinates();
    if (flatCoordinates) {
      const stride = this.getStride();
      rotate(
        flatCoordinates, 0, flatCoordinates.length,
        stride, angle, anchor, flatCoordinates);
      this.changed();
    }
  }

  /**
   * @inheritDoc
   * @api
   */
  scale(sx, opt_sy, opt_anchor) {
    let sy = opt_sy;
    if (sy === undefined) {
      sy = sx;
    }
    let anchor = opt_anchor;
    if (!anchor) {
      anchor = getCenter(this.getExtent());
    }
    const flatCoordinates = this.getFlatCoordinates();
    if (flatCoordinates) {
      const stride = this.getStride();
      scale(
        flatCoordinates, 0, flatCoordinates.length,
        stride, sx, sy, anchor, flatCoordinates);
      this.changed();
    }
  }

  /**
   * @inheritDoc
   * @api
   */
  translate(deltaX, deltaY) {
    const flatCoordinates = this.getFlatCoordinates();
    if (flatCoordinates) {
      const stride = this.getStride();
      translate(
        flatCoordinates, 0, flatCoordinates.length, stride,
        deltaX, deltaY, flatCoordinates);
      this.changed();
    }
  }
}


/**
 * @param {number} stride Stride.
 * @return {GeometryLayout} layout Layout.
 */
function getLayoutForStride(stride) {
  let layout;
  if (stride == 2) {
    layout = GeometryLayout.XY;
  } else if (stride == 3) {
    layout = GeometryLayout.XYZ;
  } else if (stride == 4) {
    layout = GeometryLayout.XYZM;
  }
  return (
    /** @type {GeometryLayout} */ (layout)
  );
}


/**
 * @param {GeometryLayout} layout Layout.
 * @return {number} Stride.
 */
export function getStrideForLayout(layout) {
  let stride;
  if (layout == GeometryLayout.XY) {
    stride = 2;
  } else if (layout == GeometryLayout.XYZ || layout == GeometryLayout.XYM) {
    stride = 3;
  } else if (layout == GeometryLayout.XYZM) {
    stride = 4;
  }
  return /** @type {number} */ (stride);
}


/**
 * @inheritDoc
 */
SimpleGeometry.prototype.containsXY = FALSE;


/**
 * @param {SimpleGeometry} simpleGeometry Simple geometry.
 * @param {import("../transform.js").Transform} transform Transform.
 * @param {Array<number>=} opt_dest Destination.
 * @return {Array<number>} Transformed flat coordinates.
 */
export function transformGeom2D(simpleGeometry, transform, opt_dest) {
  const flatCoordinates = simpleGeometry.getFlatCoordinates();
  if (!flatCoordinates) {
    return null;
  } else {
    const stride = simpleGeometry.getStride();
    return transform2D(
      flatCoordinates, 0, flatCoordinates.length, stride,
      transform, opt_dest);
  }
}

export default SimpleGeometry;