/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License
 */

package com.android.incallui.answer.impl.classifier;

class Point {
  public float x;
  public float y;
  public long timeOffsetNano;

  public Point(float x, float y) {
    this.x = x;
    this.y = y;
    this.timeOffsetNano = 0;
  }

  public Point(float x, float y, long timeOffsetNano) {
    this.x = x;
    this.y = y;
    this.timeOffsetNano = timeOffsetNano;
  }

  @Override
  public boolean equals(Object other) {
    if (!(other instanceof Point)) {
      return false;
    }
    Point otherPoint = ((Point) other);
    return x == otherPoint.x && y == otherPoint.y;
  }

  @Override
  public int hashCode() {
    int result = (x != +0.0f ? Float.floatToIntBits(x) : 0);
    result = 31 * result + (y != +0.0f ? Float.floatToIntBits(y) : 0);
    return result;
  }

  public float dist(Point a) {
    return (float) Math.hypot(a.x - x, a.y - y);
  }

  /**
   * Calculates the cross product of vec(this, a) and vec(this, b) where vec(x,y) is the vector from
   * point x to point y
   */
  public float crossProduct(Point a, Point b) {
    return (a.x - x) * (b.y - y) - (a.y - y) * (b.x - x);
  }

  /**
   * Calculates the dot product of vec(this, a) and vec(this, b) where vec(x,y) is the vector from
   * point x to point y
   */
  public float dotProduct(Point a, Point b) {
    return (a.x - x) * (b.x - x) + (a.y - y) * (b.y - y);
  }

  /**
   * Calculates the angle in radians created by points (a, this, b). If any two of these points are
   * the same, the method will return 0.0f
   *
   * @return the angle in radians
   */
  public float getAngle(Point a, Point b) {
    float dist1 = dist(a);
    float dist2 = dist(b);

    if (dist1 == 0.0f || dist2 == 0.0f) {
      return 0.0f;
    }

    float crossProduct = crossProduct(a, b);
    float dotProduct = dotProduct(a, b);
    float cos = Math.min(1.0f, Math.max(-1.0f, dotProduct / dist1 / dist2));
    float angle = (float) Math.acos(cos);
    if (crossProduct < 0.0) {
      angle = 2.0f * (float) Math.PI - angle;
    }
    return angle;
  }
}