package expression;

/*
 * Seda klassi ei pea muutma, aga esita see ka siis, kui sa seda ei muutnud!
 */
public class ExprNode {

    public boolean containsVariable(String name) {
        if (this instanceof BinOp) {
            if (((BinOp)this).getLeft().containsVariable(name)) {
                return true;
            }

            if (((BinOp)this).getRight().containsVariable(name)) {
                return true;
            }
        } else if (this instanceof Variable) {
            if (((Variable)this).getName().equals(name)){
                return true;
            }
        }

        return false;
    }
    public ExprNode renameVariable(String oldName, String newName) {
        if (this instanceof BinOp) {
            BinOp oldNode = (BinOp) this;
            return new BinOp(oldNode.getOperator(),
                    oldNode.getLeft().renameVariable(oldName, newName),
                    oldNode.getRight().renameVariable(oldName, newName));
        }
        if (this instanceof Variable) {
            Variable oldNode = (Variable) this;
            if (oldNode.getName().equals(oldName)) {
                return new Variable(newName);
            } else {
                return new Variable(oldNode.getName());
            }
        }
        if (this instanceof IntLiteral) {
            IntLiteral oldNode = (IntLiteral) this;
            return new IntLiteral(oldNode.getValue());
        }

        throw new RuntimeException("Unknown node");
    }

    public ExprNode renameVariableSafely(String oldName, String newName) {
        String temp = newName;
        while (this.containsVariable(temp)) {
            temp += "a";
        }
        ExprNode unique = renameVariable(newName, temp);
        return unique.renameVariable(oldName, newName);
    }

    @Override
    public boolean equals(Object that) {
        return this.getClass().equals(that.getClass())
                && this.toString().equals(that.toString());
    }

    @Override
    public int hashCode() {
        return this.toString().hashCode();
    }
}