/*
 * 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.procedure.impl;

import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.fail;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;
import static org.neo4j.internal.kernel.api.procs.UserFunctionSignature.functionSignature;
import static org.neo4j.kernel.api.procedure.BasicContext.buildContext;
import static org.neo4j.values.storable.Values.NO_VALUE;
import static org.neo4j.values.storable.Values.longValue;
import static org.neo4j.values.storable.Values.stringValue;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.neo4j.collection.Dependencies;
import org.neo4j.common.DependencyResolver;
import org.neo4j.configuration.Config;
import org.neo4j.configuration.GraphDatabaseSettings;
import org.neo4j.exceptions.KernelException;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.internal.kernel.api.exceptions.ProcedureException;
import org.neo4j.internal.kernel.api.procs.Neo4jTypes;
import org.neo4j.kernel.api.procedure.CallableUserFunction;
import org.neo4j.kernel.impl.coreapi.InternalTransaction;
import org.neo4j.kernel.impl.util.DefaultValueMapper;
import org.neo4j.kernel.impl.util.ValueUtils;
import org.neo4j.logging.InternalLog;
import org.neo4j.logging.NullLog;
import org.neo4j.procedure.Context;
import org.neo4j.procedure.Name;
import org.neo4j.procedure.UserFunction;
import org.neo4j.values.AnyValue;
import org.neo4j.values.ValueMapper;
import org.neo4j.values.storable.LongValue;
import org.neo4j.values.storable.StringValue;
import org.neo4j.values.virtual.MapValue;

@SuppressWarnings({"WeakerAccess", "unused"})
public class UserFunctionTest {
    private ProcedureCompiler procedureCompiler;
    private ComponentRegistry components;
    private final DependencyResolver dependencyResolver = new Dependencies();
    private final ValueMapper<Object> valueMapper = new DefaultValueMapper(mock(InternalTransaction.class));

    @BeforeEach
    void setUp() {
        components = new ComponentRegistry();
        procedureCompiler = new ProcedureCompiler(
                new TypeCheckers(), components, components, NullLog.getInstance(), ProcedureConfig.DEFAULT);
    }

    @Test
    void shouldInjectLogging() throws KernelException {
        // Given
        InternalLog log = spy(InternalLog.class);
        components.register(InternalLog.class, ctx -> log);
        CallableUserFunction function =
                procedureCompiler.compileFunction(LoggingFunction.class, false).get(0);

        // When
        function.apply(prepareContext(), new AnyValue[0]);

        // Then
        verify(log).debug("1");
        verify(log).info("2");
        verify(log).warn("3");
        verify(log).error("4");
    }

    @Test
    void shouldCompileFunction() throws Throwable {
        // When
        List<CallableUserFunction> function = compile(SingleReadOnlyFunction.class);

        // Then
        assertEquals(1, function.size());
        assertThat(function.get(0).signature())
                .isEqualTo(functionSignature("org", "neo4j", "procedure", "impl", "listCoolPeople")
                        .out(Neo4jTypes.NTList(Neo4jTypes.NTAny))
                        .build());
    }

    @Test
    void shouldRunSimpleReadOnlyFunction() throws Throwable {
        // Given
        CallableUserFunction func = compile(SingleReadOnlyFunction.class).get(0);

        // When
        Object out = func.apply(prepareContext(), new AnyValue[0]);

        // Then
        assertThat(out).isEqualTo(ValueUtils.of(Arrays.asList("Bonnie", "Clyde")));
    }

    @Test
    void shouldIgnoreClassesWithNoFunctions() throws Throwable {
        // When
        List<CallableUserFunction> functions = compile(PrivateConstructorButNoFunctions.class);

        // Then
        assertEquals(0, functions.size());
    }

    @Test
    void shouldRunClassWithMultipleFunctionsDeclared() throws Throwable {
        // Given
        List<CallableUserFunction> compiled = compile(UserFunctionTest.MultiFunction.class);
        CallableUserFunction bananaPeople = compiled.get(0);
        CallableUserFunction coolPeople = compiled.get(1);

        // When
        Object coolOut = coolPeople.apply(prepareContext(), new AnyValue[0]);
        Object bananaOut = bananaPeople.apply(prepareContext(), new AnyValue[0]);

        // Then
        assertThat(coolOut).isEqualTo(ValueUtils.of(Arrays.asList("Bonnie", "Clyde")));

        assertThat(((MapValue) bananaOut).get("foo")).isEqualTo(ValueUtils.of(Arrays.asList("bar", "baz")));
    }

    @Test
    void shouldGiveHelpfulErrorOnConstructorThatRequiresArgument() {
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> compile(WeirdConstructorFunction.class));
        assertThat(exception.getMessage())
                .isEqualTo(
                        "Unable to find a usable public no-argument constructor in the class `WeirdConstructorFunction`. Please add a "
                                + "valid, public constructor, recompile the class and try again.");
    }

    @Test
    void shouldGiveHelpfulErrorOnNoPublicConstructor() {
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> compile(PrivateConstructorFunction.class));
        assertThat(exception.getMessage())
                .isEqualTo(
                        "Unable to find a usable public no-argument constructor in the class `PrivateConstructorFunction`. Please add "
                                + "a valid, public constructor, recompile the class and try again.");
    }

    @Test
    void shouldNotAllowVoidOutput() {
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> compile(FunctionWithVoidOutput.class));
        assertThat(exception.getMessage()).startsWith("Don't know how to map `void` to the Neo4j Type System.");
    }

    @Test
    void shouldGiveHelpfulErrorOnFunctionReturningInvalidType() {

        // When
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> compile(FunctionWithInvalidOutput.class));
        assertThat(exception.getMessage())
                .isEqualTo(String.format("Don't know how to map `char[]` to the Neo4j Type System.%n"
                        + "Please refer to to the documentation for full details.%n"
                        + "For your reference, known types are: [boolean, byte[], double, java.lang.Boolean, "
                        + "java.lang.Double, java.lang.Long, java.lang.Number, java.lang.Object, "
                        + "java.lang.String, java.time.LocalDate, java.time.LocalDateTime, "
                        + "java.time.LocalTime, java.time.OffsetTime, java.time.ZonedDateTime, "
                        + "java.time.temporal.TemporalAmount, java.util.List, java.util.Map, long]"));
    }

    @Test
    void shouldGiveHelpfulErrorOnContextAnnotatedStaticField() {
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> compile(FunctionWithStaticContextAnnotatedField.class));
        assertThat(exception.getMessage())
                .isEqualTo(String.format(
                        "The field `gdb` in the class named `FunctionWithStaticContextAnnotatedField` is annotated as a @Context field,%n"
                                + "but it is static. @Context fields must be public, non-final and non-static,%n"
                                + "because they are reset each time a procedure is invoked."));
    }

    @Test
    void shouldAllowOverridingProcedureName() throws Throwable {
        // When
        CallableUserFunction proc = compile(FunctionWithOverriddenName.class).get(0);

        // Then
        assertEquals(
                "org.mystuff.thisisActuallyTheName", proc.signature().name().toString());
    }

    @Test
    void shouldNotAllowOverridingFunctionNameWithoutNamespace() {
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> compile(FunctionWithSingleName.class));
        assertThat(exception.getMessage())
                .isEqualTo("It is not allowed to define functions in the root namespace please use a "
                        + "namespace, e.g. `@UserFunction(\"org.example.com.singleName\")");
    }

    @Test
    void shouldGiveHelpfulErrorOnNullMessageException() throws Throwable {
        // Given
        CallableUserFunction proc =
                compile(FunctionThatThrowsNullMsgExceptionAtInvocation.class).get(0);

        // When
        ProcedureException exception =
                assertThrows(ProcedureException.class, () -> proc.apply(prepareContext(), new AnyValue[0]));
        assertThat(exception.getMessage())
                .isEqualTo(
                        "Failed to invoke function `org.neo4j.procedure.impl.throwsAtInvocation`: Caused by: java.lang.IndexOutOfBoundsException");
    }

    @Test
    void shouldLoadWhiteListedFunction() throws Throwable {
        // Given
        procedureCompiler = new ProcedureCompiler(
                new TypeCheckers(),
                components,
                new ComponentRegistry(),
                NullLog.getInstance(),
                new ProcedureConfig(Config.defaults(
                        GraphDatabaseSettings.procedure_allowlist,
                        List.of("org.neo4j.procedure.impl.listCoolPeople"))));

        CallableUserFunction method = compile(SingleReadOnlyFunction.class).get(0);

        // Expect
        Object out = method.apply(prepareContext(), new AnyValue[0]);
        assertThat(out).isEqualTo(ValueUtils.of(Arrays.asList("Bonnie", "Clyde")));
    }

    @Test
    void shouldNotLoadNoneWhiteListedFunction() throws Throwable {
        // Given
        InternalLog log = spy(InternalLog.class);
        procedureCompiler = new ProcedureCompiler(
                new TypeCheckers(),
                components,
                new ComponentRegistry(),
                log,
                new ProcedureConfig(Config.defaults(GraphDatabaseSettings.procedure_allowlist, List.of("WrongName"))));

        List<CallableUserFunction> method = compile(SingleReadOnlyFunction.class);
        verify(log)
                .warn(
                        "The function 'org.neo4j.procedure.impl.listCoolPeople' is not on the allowlist and won't be loaded.");
        assertThat(method.size()).isEqualTo(0);
    }

    @Test
    void shouldNotLoadAnyFunctionIfConfigIsEmpty() throws Throwable {
        // Given
        InternalLog log = spy(InternalLog.class);
        procedureCompiler = new ProcedureCompiler(
                new TypeCheckers(),
                components,
                new ComponentRegistry(),
                log,
                new ProcedureConfig(Config.defaults(GraphDatabaseSettings.procedure_allowlist, List.of(""))));

        List<CallableUserFunction> method = compile(SingleReadOnlyFunction.class);
        verify(log)
                .warn(
                        "The function 'org.neo4j.procedure.impl.listCoolPeople' is not on the allowlist and won't be loaded.");
        assertThat(method.size()).isEqualTo(0);
    }

    @Test
    void shouldSupportFunctionDeprecation() throws Throwable {
        // Given
        InternalLog log = mock(InternalLog.class);
        ProcedureCompiler procedureCompiler = new ProcedureCompiler(
                new TypeCheckers(), components, new ComponentRegistry(), log, ProcedureConfig.DEFAULT);

        // When
        List<CallableUserFunction> funcs = procedureCompiler.compileFunction(FunctionWithDeprecation.class, false);

        // Then
        verify(log).warn("Use of @UserFunction(deprecatedBy) without @Deprecated in org.neo4j.procedure.impl.badFunc");
        verifyNoMoreInteractions(log);
        for (CallableUserFunction func : funcs) {
            String name = func.signature().name().name();
            func.apply(prepareContext(), new AnyValue[0]);
            switch (name) {
                case "newFunc":
                    assertFalse(func.signature().deprecated().isPresent(), "Should not be deprecated");
                    break;
                case "oldFunc":
                case "badFunc":
                    assertTrue(func.signature().deprecated().isPresent(), "Should be deprecated");
                    assertThat(func.signature().deprecated().get()).isEqualTo("newFunc");
                    break;
                default:
                    fail("Unexpected function: " + name);
            }
        }
    }

    @Test
    void shouldSupportInternalTypes() throws Throwable {
        // Given
        CallableUserFunction func = compile(FunctionsWithInternalTypes.class).get(0);

        // When
        Object out = func.apply(prepareContext(), new AnyValue[] {stringValue("hello")});

        // Then
        assertThat(out).isEqualTo(longValue(5));
    }

    @Test
    void shouldSupportInternalTypesWithNull() throws Throwable {
        // Given
        CallableUserFunction func = compile(FunctionsWithInternalTypes.class).get(1);

        // When
        Object out = func.apply(prepareContext(), new AnyValue[] {stringValue("hello")});

        // Then
        assertThat(out).isEqualTo(NO_VALUE);
    }

    private org.neo4j.kernel.api.procedure.Context prepareContext() {
        return buildContext(dependencyResolver, valueMapper).context();
    }

    public static class LoggingFunction {
        @Context
        public InternalLog log;

        @UserFunction
        public long logAround() {
            log.debug("1");
            log.info("2");
            log.warn("3");
            log.error("4");
            return -1L;
        }
    }

    public static class SingleReadOnlyFunction {
        @UserFunction
        public List<String> listCoolPeople() {
            return Arrays.asList("Bonnie", "Clyde");
        }
    }

    public static class FunctionWithVoidOutput {
        @UserFunction
        public void voidOutput() {}
    }

    public static class MultiFunction {
        @UserFunction
        public List<String> listCoolPeople() {
            return Arrays.asList("Bonnie", "Clyde");
        }

        @UserFunction
        public Map<String, Object> listBananaOwningPeople() {
            Map<String, Object> map = new HashMap<>();
            map.put("foo", Arrays.asList("bar", "baz"));
            return map;
        }
    }

    public static class WeirdConstructorFunction {
        public WeirdConstructorFunction(WeirdConstructorFunction wat) {}

        @UserFunction
        public List<String> listCoolPeople() {
            return Arrays.asList("Bonnie", "Clyde");
        }
    }

    public static class FunctionWithInvalidOutput {
        @UserFunction
        public char[] test() {
            return "Testing".toCharArray();
        }
    }

    public static class FunctionWithStaticContextAnnotatedField {
        @Context
        public static GraphDatabaseService gdb;

        @UserFunction
        public Object test() {
            return null;
        }
    }

    public static class FunctionThatThrowsNullMsgExceptionAtInvocation {
        @UserFunction
        public String throwsAtInvocation() {
            throw new IndexOutOfBoundsException();
        }
    }

    public static class PrivateConstructorFunction {
        private PrivateConstructorFunction() {}

        @UserFunction
        public List<String> listCoolPeople() {
            return Arrays.asList("Bonnie", "Clyde");
        }
    }

    public static class PrivateConstructorButNoFunctions {
        private PrivateConstructorButNoFunctions() {}

        public String thisIsNotAFunction() {
            return null;
        }
    }

    public static class FunctionWithOverriddenName {
        @UserFunction("org.mystuff.thisisActuallyTheName")
        public Object somethingThatShouldntMatter() {
            return null;
        }
    }

    public static class FunctionWithSingleName {
        @UserFunction("singleName")
        public String blahDoesntMatterEither() {
            return null;
        }
    }

    public static class FunctionWithDeprecation {
        @UserFunction
        public Object newFunc() {
            return null;
        }

        @Deprecated
        @UserFunction(deprecatedBy = "newFunc")
        public String oldFunc() {
            return null;
        }

        @UserFunction(deprecatedBy = "newFunc")
        public Object badFunc() {
            return null;
        }
    }

    public static class FunctionsWithInternalTypes {

        @UserFunction
        public LongValue countLetters(@Name(value = "text") StringValue text) {
            return longValue(text.length());
        }

        @UserFunction
        public LongValue nullMethod(@Name(value = "text") StringValue text) {
            return null;
        }
    }

    private List<CallableUserFunction> compile(Class<?> clazz) throws KernelException {
        return procedureCompiler.compileFunction(clazz, false);
    }
}
