/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.el;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.annotation.Annotation;

import jakarta.el.ELContext;
import jakarta.el.ELException;
import jakarta.el.MethodExpression;
import jakarta.el.MethodInfo;
import jakarta.el.MethodReference;

import org.apache.el.util.MessageFactory;
import org.apache.el.util.ReflectionUtil;


/**
 * Literal method expression.
 */
public class MethodExpressionLiteral extends MethodExpression implements Externalizable {

    private static final Annotation[] EMPTY_ANNOTATION_ARRAY = new Annotation[0];
    private static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];

    private Class<?> expectedType;

    private String expr;

    private Class<?>[] paramTypes;

    /**
     * Default constructor.
     */
    public MethodExpressionLiteral() {
        // do nothing
    }

    /**
     * Constructor.
     * @param expr the expression
     * @param expectedType the expected type
     * @param paramTypes the parameter types
     */
    public MethodExpressionLiteral(String expr, Class<?> expectedType, Class<?>[] paramTypes) {
        this.expr = expr;
        this.expectedType = expectedType;
        this.paramTypes = paramTypes;
    }

    @Override
    public MethodInfo getMethodInfo(ELContext context) throws ELException {
        context.notifyBeforeEvaluation(getExpressionString());
        MethodInfo result = getMethodInfoInternal();
        context.notifyAfterEvaluation(getExpressionString());
        return result;
    }


    private MethodInfo getMethodInfoInternal() throws ELException {
        return new MethodInfo(this.expr, this.expectedType, this.paramTypes);
    }

    @Override
    public Object invoke(ELContext context, Object[] params) throws ELException {
        context.notifyBeforeEvaluation(getExpressionString());
        Object result;
        if (this.expectedType != null) {
            result = context.convertToType(this.expr, this.expectedType);
        } else {
            result = this.expr;
        }
        context.notifyAfterEvaluation(getExpressionString());
        return result;
    }


    @Override
    public MethodReference getMethodReference(ELContext context) {
        if (context == null) {
            throw new NullPointerException(MessageFactory.get("error.context.null"));
        }
        context.notifyBeforeEvaluation(getExpressionString());
        MethodReference result =
                new MethodReference(null, getMethodInfoInternal(), EMPTY_ANNOTATION_ARRAY, EMPTY_OBJECT_ARRAY);
        context.notifyAfterEvaluation(getExpressionString());
        return result;
    }

    @Override
    public String getExpressionString() {
        return this.expr;
    }

    @Override
    public boolean equals(Object obj) {
        return (obj instanceof MethodExpressionLiteral && this.hashCode() == obj.hashCode());
    }

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

    @Override
    public boolean isLiteralText() {
        return true;
    }

    @Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
        this.expr = in.readUTF();
        String type = in.readUTF();
        if (!type.isEmpty()) {
            this.expectedType = ReflectionUtil.forName(type);
        }
        this.paramTypes = ReflectionUtil.toTypeArray(((String[]) in.readObject()));
    }

    @Override
    public void writeExternal(ObjectOutput out) throws IOException {
        out.writeUTF(this.expr);
        out.writeUTF((this.expectedType != null) ? this.expectedType.getName() : "");
        out.writeObject(ReflectionUtil.toTypeNameArray(this.paramTypes));
    }
}