/*
 * 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.parser;

import jakarta.el.ELException;
import jakarta.el.ELProcessor;

import org.junit.Assert;
import org.junit.Test;

public class TestAstLambdaExpression {

    @Test
    public void testSpec01() {
        ELProcessor processor = new ELProcessor();
        Object result = processor.getValue("(x->x+1)(1)", Integer.class);
        Assert.assertEquals(Integer.valueOf(2), result);
    }


    @Test
    public void testSpec02() {
        ELProcessor processor = new ELProcessor();
        Object result = processor.getValue("((x,y)->x+y)(1,2)", Integer.class);
        Assert.assertEquals(Integer.valueOf(3), result);
    }


    @Test
    public void testSpec03() {
        ELProcessor processor = new ELProcessor();
        Object result = processor.getValue("(()->64)", Integer.class);
        Assert.assertEquals(Integer.valueOf(64), result);
    }


    @Test
    public void testSpec04() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (x,y)->x+y; v(3,4)", Integer.class);
        Assert.assertEquals(Integer.valueOf(7), result);
    }


    @Test
    public void testSpec05() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("fact = n -> n==0? 1: n*fact(n-1); fact(5)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(120), result);
    }


    @Test
    public void testSpec06() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(x->y->x-y)(2)(1)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testInvocation01() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(()->2)()",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(2), result);
    }


    @Test
    public void testNested01() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(()->y->2-y)()(1)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testNested02() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(()->y->()->2-y)()(1)()",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test(expected=ELException.class)
    public void testNested03() {
        ELProcessor processor = new ELProcessor();
        // More method parameters than there are nested lambda expressions
        processor.getValue("(()->y->()->2-y)()(1)()()",
                    Integer.class);
    }


    @Test
    public void testNested04() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(()->y->()->x->x-y)()(1)()(2)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testNested05() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(()->y->()->()->x->x-y)()(1)()()(2)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testNested06() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("(()->y->()->()->x->x-y)()(1)()(3)(2)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testNested07() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("()->()->()->42",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(42), result);
    }


    @Test
    public void testLambdaAsFunction01() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (x->y->x-y); v(2)(1)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testLambdaAsFunction02() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (()->y->2-y); v()(1)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testLambdaAsFunction03() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (()->y->()->2-y); v()(1)()",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test(expected=ELException.class)
    public void testLambdaAsFunction04() {
        ELProcessor processor = new ELProcessor();
        // More method parameters than there are nested lambda expressions
        processor.getValue("v = (()->y->()->2-y); v()(1)()()",
                    Integer.class);
    }


    @Test
    public void testLambdaAsFunction05() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (()->y->()->x->x-y); v()(1)()(2)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testLambdaAsFunction06() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (()->y->()->()->x->x-y); v()(1)()()(2)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test
    public void testLambdaAsFunction07() {
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("v = (()->y->()->()->x->x-y); v()(1)()(3)(2)",
                        Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }


    @Test(expected=ELException.class)
    public void testLambdaAsFunction08() {
        // Using a name space for the function is not allowed
        ELProcessor processor = new ELProcessor();
        Object result =
                processor.getValue("foo:v = (x)->x+1; foo:v(0)", Integer.class);
        Assert.assertEquals(Integer.valueOf(1), result);
    }
}