/*

 * Copyright (C) 2007-2010 Júlio Vilmar Gesser.

 * Copyright (C) 2011, 2013-2021 The JavaParser Team.

 *

 * This file is part of JavaParser.

 *

 * JavaParser can be used either under the terms of

 * a) the GNU Lesser General Public License as published by

 *     the Free Software Foundation, either version 3 of the License, or

 *     (at your option) any later version.

 * b) the terms of the Apache License

 *

 * You should have received a copy of both licenses in LICENCE.LGPL and

 * LICENCE.APACHE. Please refer to those files for details.

 *

 * JavaParser is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 */

package com.github.javaparser.ast.expr;

import com.github.javaparser.TokenRange;

import com.github.javaparser.ast.AllFieldsConstructor;

import com.github.javaparser.ast.Generated;

import com.github.javaparser.ast.Node;

import com.github.javaparser.ast.NodeList;

import com.github.javaparser.ast.nodeTypes.NodeWithIdentifier;

import com.github.javaparser.ast.nodeTypes.NodeWithTypeArguments;

import com.github.javaparser.ast.observer.ObservableProperty;

import com.github.javaparser.ast.type.Type;

import com.github.javaparser.ast.visitor.CloneVisitor;

import com.github.javaparser.ast.visitor.GenericVisitor;

import com.github.javaparser.ast.visitor.VoidVisitor;

import com.github.javaparser.metamodel.JavaParserMetaModel;

import com.github.javaparser.metamodel.MethodReferenceExprMetaModel;

import com.github.javaparser.metamodel.NonEmptyProperty;

import com.github.javaparser.metamodel.OptionalProperty;

import com.github.javaparser.resolution.Resolvable;

import com.github.javaparser.resolution.declarations.ResolvedMethodDeclaration;

import java.util.Optional;

import java.util.function.Consumer;

import static com.github.javaparser.utils.Utils.assertNonEmpty;

import static com.github.javaparser.utils.Utils.assertNotNull;

/**

 * Method reference expressions introduced in Java 8 specifically designed to simplify lambda Expressions.

 * Note that the field "identifier", indicating the word to the right of the ::, is not always a method name,

 * it can be "new".

 * <br>In {@code System.out::println;} the scope is System.out and the identifier is "println"

 * <br>{@code (test ? stream.map(String::trim) : stream)::toArray;}

 * <br>In {@code Bar<String>::<Integer>new} the String type argument is on the scope,

 * and the Integer type argument is on this MethodReferenceExpr.

 *

 * @author Raquel Pau

 */

public class MethodReferenceExpr extends Expression implements NodeWithTypeArguments<MethodReferenceExpr>, NodeWithIdentifier<MethodReferenceExpr>, Resolvable<ResolvedMethodDeclaration> {

    private Expression scope;

    @OptionalProperty

    private NodeList<Type> typeArguments;

    @NonEmptyProperty

    private String identifier;

    public MethodReferenceExpr() {

        this(null, new ClassExpr(), null, "empty");

    }

    @AllFieldsConstructor

    public MethodReferenceExpr(Expression scope, NodeList<Type> typeArguments, String identifier) {

        this(null, scope, typeArguments, identifier);

    }

    /**

     * This constructor is used by the parser and is considered private.

     */

    @Generated("com.github.javaparser.generator.core.node.MainConstructorGenerator")

    public MethodReferenceExpr(TokenRange tokenRange, Expression scope, NodeList<Type> typeArguments, String identifier) {

        super(tokenRange);

        setScope(scope);

        setTypeArguments(typeArguments);

        setIdentifier(identifier);

        customInitialization();

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.AcceptGenerator")

    public <R, A> R accept(final GenericVisitor<R, A> v, final A arg) {

        return v.visit(this, arg);

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.AcceptGenerator")

    public <A> void accept(final VoidVisitor<A> v, final A arg) {

        v.visit(this, arg);

    }

    @Generated("com.github.javaparser.generator.core.node.PropertyGenerator")

    public Expression getScope() {

        return scope;

    }

    @Generated("com.github.javaparser.generator.core.node.PropertyGenerator")

    public MethodReferenceExpr setScope(final Expression scope) {

        assertNotNull(scope);

        if (scope == this.scope) {

            return this;

        }

        notifyPropertyChange(ObservableProperty.SCOPE, this.scope, scope);

        if (this.scope != null)

            this.scope.setParentNode(null);

        this.scope = scope;

        setAsParentNodeOf(scope);

        return this;

    }

    @Generated("com.github.javaparser.generator.core.node.PropertyGenerator")

    public Optional<NodeList<Type>> getTypeArguments() {

        return Optional.ofNullable(typeArguments);

    }

    /**

     * Sets the typeArguments

     *

     * @param typeArguments the typeArguments, can be null

     * @return this, the MethodReferenceExpr

     */

    @Generated("com.github.javaparser.generator.core.node.PropertyGenerator")

    public MethodReferenceExpr setTypeArguments(final NodeList<Type> typeArguments) {

        if (typeArguments == this.typeArguments) {

            return this;

        }

        notifyPropertyChange(ObservableProperty.TYPE_ARGUMENTS, this.typeArguments, typeArguments);

        if (this.typeArguments != null)

            this.typeArguments.setParentNode(null);

        this.typeArguments = typeArguments;

        setAsParentNodeOf(typeArguments);

        return this;

    }

    @Generated("com.github.javaparser.generator.core.node.PropertyGenerator")

    public String getIdentifier() {

        return identifier;

    }

    @Generated("com.github.javaparser.generator.core.node.PropertyGenerator")

    public MethodReferenceExpr setIdentifier(final String identifier) {

        assertNonEmpty(identifier);

        if (identifier == this.identifier) {

            return this;

        }

        notifyPropertyChange(ObservableProperty.IDENTIFIER, this.identifier, identifier);

        this.identifier = identifier;

        return this;

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.RemoveMethodGenerator")

    public boolean remove(Node node) {

        if (node == null)

            return false;

        if (typeArguments != null) {

            for (int i = 0; i < typeArguments.size(); i++) {

                if (typeArguments.get(i) == node) {

                    typeArguments.remove(i);

                    return true;

                }

            }

        }

        return super.remove(node);

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.CloneGenerator")

    public MethodReferenceExpr clone() {

        return (MethodReferenceExpr) accept(new CloneVisitor(), null);

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.GetMetaModelGenerator")

    public MethodReferenceExprMetaModel getMetaModel() {

        return JavaParserMetaModel.methodReferenceExprMetaModel;

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.ReplaceMethodGenerator")

    public boolean replace(Node node, Node replacementNode) {

        if (node == null)

            return false;

        if (node == scope) {

            setScope((Expression) replacementNode);

            return true;

        }

        if (typeArguments != null) {

            for (int i = 0; i < typeArguments.size(); i++) {

                if (typeArguments.get(i) == node) {

                    typeArguments.set(i, (Type) replacementNode);

                    return true;

                }

            }

        }

        return super.replace(node, replacementNode);

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")

    public boolean isMethodReferenceExpr() {

        return true;

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")

    public MethodReferenceExpr asMethodReferenceExpr() {

        return this;

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")

    public void ifMethodReferenceExpr(Consumer<MethodReferenceExpr> action) {

        action.accept(this);

    }

    @Override

    @Generated("com.github.javaparser.generator.core.node.TypeCastingGenerator")

    public Optional<MethodReferenceExpr> toMethodReferenceExpr() {

        return Optional.of(this);

    }

    /**

     * @return the method declaration this method reference is referencing.

     */

    @Override

    public ResolvedMethodDeclaration resolve() {

        return getSymbolResolver().resolveDeclaration(this, ResolvedMethodDeclaration.class);

    }

    /*

     * Method reference expressions are always poly expressions

     * (https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html 15.13. Method Reference Expressions)

     */

    @Override

    public boolean isPolyExpression() {

        return true;

    }

}