package org.checkerframework.dataflow.cfg.node;

import com.sun.source.tree.Tree;
import com.sun.source.tree.Tree.Kind;
import java.util.Arrays;
import java.util.Collection;
import java.util.Objects;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.javacutil.TreeUtils;

/**
 * A node for the string concatenation compound assignment:
 *
 * <pre>
 *   <em>variable</em> += <em>expression</em>
 * </pre>
 */
public class StringConcatenateAssignmentNode extends Node {
  protected final Tree tree;
  protected final Node left;
  protected final Node right;

  public StringConcatenateAssignmentNode(Tree tree, Node left, Node right) {
    super(TreeUtils.typeOf(tree));
    assert tree.getKind() == Kind.PLUS_ASSIGNMENT;
    this.tree = tree;
    this.left = left;
    this.right = right;
  }

  public Node getLeftOperand() {
    return left;
  }

  public Node getRightOperand() {
    return right;
  }

  @Override
  public Tree getTree() {
    return tree;
  }

  @Override
  public <R, P> R accept(NodeVisitor<R, P> visitor, P p) {
    return visitor.visitStringConcatenateAssignment(this, p);
  }

  @Override
  public Collection<Node> getOperands() {
    return Arrays.asList(getLeftOperand(), getRightOperand());
  }

  @Override
  public String toString() {
    return "(" + getLeftOperand() + " += " + getRightOperand() + ")";
  }

  @Override
  public boolean equals(@Nullable Object obj) {
    if (obj == null || !(obj instanceof StringConcatenateAssignmentNode)) {
      return false;
    }
    StringConcatenateAssignmentNode other = (StringConcatenateAssignmentNode) obj;
    return getLeftOperand().equals(other.getLeftOperand())
        && getRightOperand().equals(other.getRightOperand());
  }

  @Override
  public int hashCode() {
    return Objects.hash(getLeftOperand(), getRightOperand());
  }
}