package de.ph87.data.view.tree;

import de.ph87.data.point.Point;
import de.ph87.data.view.ViewScope;
import jakarta.persistence.*;
import lombok.*;

import java.util.ArrayList;
import java.util.List;
import java.util.function.BiFunction;

@Entity
@Getter
@Setter
@NoArgsConstructor
@ToString(callSuper = true)
@DiscriminatorValue("binary")
public class ViewBinary extends View {

  @NonNull
  @Enumerated(EnumType.STRING)
  private Operation operation;

  @NonNull
  @OneToOne(optional = false, orphanRemoval = true, cascade = CascadeType.ALL)
  private View view0;

  @NonNull
  @OneToOne(optional = false, orphanRemoval = true, cascade = CascadeType.ALL)
  private View view1;

  public ViewBinary(@NonNull final Operation operation, @NonNull final View view0, @NonNull final View view1) {
    this.operation = operation;
    this.view0 = view0;
    this.view1 = view1;
  }

  public enum Operation {
    PLUS(Double::sum),
    MINUS((a, b) -> a - b),
    MULTIPLY((a, b) -> a * b),
    DIVIDE((a, b) -> a / b),
    MODULO((a, b) -> a % b),
    PERCENT((a, b) -> a / b * 100),
    ;

    public final BiFunction<Double, Double, Double> function;

    Operation(final BiFunction<Double, Double, Double> function) {
      this.function = function;
    }

    @NonNull
    public Point apply(@NonNull final Point a, @NonNull final Point b) {
      return new Point(a.date, function.apply(a.value, b.value));
    }

  }

  @Override
  public List<Point> getPoints(final @NonNull ViewScope scope) {
    final List<Point> pointsA = view0.getPoints(scope);
    final List<Point> pointsB = view1.getPoints(scope);
    final List<Point> result = new ArrayList<>(pointsA.size() + pointsB.size());
    int indexA = 0;
    int indexB = 0;
    while (indexA < pointsA.size() && indexB < pointsB.size()) {
      final Point pointA = pointsA.get(indexA);
      final Point pointB = pointsB.get(indexB);
      int cmp = pointA.date.compareTo(pointB.date);
      if (cmp < 0) {
        indexA++;
      } else if (cmp > 0) {
        indexB++;
      } else {
        result.add(operation.apply(pointA, pointB));
        indexA++;
        indexB++;
      }
    }
    return result;
  }

}