/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.tooling.procedure.visitors;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.groups.Tuple.tuple;

import com.google.testing.compile.CompilationRule;
import java.util.stream.Stream;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementVisitor;
import javax.lang.model.util.Elements;
import javax.lang.model.util.Types;
import javax.tools.Diagnostic;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.neo4j.procedure.UserFunction;
import org.neo4j.tooling.procedure.compilerutils.CustomNameExtractor;
import org.neo4j.tooling.procedure.compilerutils.TypeMirrorUtils;
import org.neo4j.tooling.procedure.messages.CompilationMessage;
import org.neo4j.tooling.procedure.testutils.ElementTestUtils;
import org.neo4j.tooling.procedure.visitors.examples.UserFunctionsExamples;

public class UserFunctionVisitorTest {
    @Rule
    public CompilationRule compilationRule = new CompilationRule();

    private ElementTestUtils elementTestUtils;
    private ElementVisitor<Stream<CompilationMessage>, Void> visitor;

    @Before
    public void prepare() {
        Types types = compilationRule.getTypes();
        Elements elements = compilationRule.getElements();

        elementTestUtils = new ElementTestUtils(compilationRule);
        final TypeMirrorUtils typeMirrorUtils = new TypeMirrorUtils(types, elements);
        visitor = new UserFunctionVisitor(new FunctionVisitor<>(
                UserFunction.class,
                types,
                elements,
                typeMirrorUtils,
                function -> CustomNameExtractor.getName(function::name, function::value),
                false));
    }

    @Test
    public void functions_with_specified_name_cannot_be_in_root_namespace() {
        Element function = elementTestUtils.findMethodElement(UserFunctionsExamples.class, "functionWithName");

        Stream<CompilationMessage> errors = visitor.visit(function);

        assertThat(errors)
                .hasSize(1)
                .extracting(
                        CompilationMessage::getCategory,
                        CompilationMessage::getElement,
                        CompilationMessage::getContents)
                .contains(
                        tuple(
                                Diagnostic.Kind.ERROR,
                                function,
                                "Function <in_root_namespace> cannot be defined in the root namespace. Valid name example: com.acme.my_function"));
    }

    @Test
    public void functions_with_specified_value_cannot_be_in_root_namespace() {
        Element function = elementTestUtils.findMethodElement(UserFunctionsExamples.class, "functionWithValue");

        Stream<CompilationMessage> errors = visitor.visit(function);

        assertThat(errors)
                .hasSize(1)
                .extracting(
                        CompilationMessage::getCategory,
                        CompilationMessage::getElement,
                        CompilationMessage::getContents)
                .contains(
                        tuple(
                                Diagnostic.Kind.ERROR,
                                function,
                                "Function <in_root_namespace_again> cannot be defined in the root namespace. Valid name example: com.acme.my_function"));
    }

    @Test
    public void functions_in_non_root_namespace_are_valid() {
        Element function = elementTestUtils.findMethodElement(UserFunctionsExamples.class, "ok");

        Stream<CompilationMessage> errors = visitor.visit(function);

        assertThat(errors).isEmpty();
    }

    @Test
    public void functions_with_unsupported_return_types_are_invalid() {
        Element function = elementTestUtils.findMethodElement(UserFunctionsExamples.class, "wrongReturnType");

        Stream<CompilationMessage> errors = visitor.visit(function);

        assertThat(errors)
                .hasSize(1)
                .extracting(
                        CompilationMessage::getCategory,
                        CompilationMessage::getElement,
                        CompilationMessage::getContents)
                .contains(
                        tuple(
                                Diagnostic.Kind.ERROR,
                                function,
                                "Unsupported return type <void> of function defined in "
                                        + "<org.neo4j.tooling.procedure.visitors.examples.UserFunctionsExamples#wrongReturnType>."));
    }

    @Test
    public void functions_with_unsupported_parameter_types_are_invalid() {
        Element function = elementTestUtils.findMethodElement(UserFunctionsExamples.class, "wrongParameterType");

        Stream<CompilationMessage> errors = visitor.visit(function);

        assertThat(errors)
                .hasSize(1)
                .extracting(CompilationMessage::getCategory, CompilationMessage::getContents)
                .contains(tuple(
                        Diagnostic.Kind.ERROR,
                        "Unsupported parameter type <java.lang.Thread> of procedure|function "
                                + "UserFunctionsExamples#wrongParameterType"));
    }

    @Test
    public void functions_with_non_annotated_parameters_are_invalid() {
        Element function =
                elementTestUtils.findMethodElement(UserFunctionsExamples.class, "missingParameterAnnotation");

        Stream<CompilationMessage> errors = visitor.visit(function);

        String errorMessage = "@org.neo4j.procedure.Name usage error: missing on parameter <oops>";
        assertThat(errors)
                .hasSize(1)
                .extracting(CompilationMessage::getCategory, CompilationMessage::getContents)
                .contains(tuple(Diagnostic.Kind.ERROR, errorMessage));
    }
}
