// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.DataAnnotations.Internal
{
    public class ValidatableObjectAdapterTest
    {
        private static readonly ModelMetadataProvider _metadataProvider
            = TestModelMetadataProvider.CreateDefaultProvider();

        // Inspired by DataAnnotationsModelValidatorTest.Validate_SetsMemberName_AsExpectedData but using a type that
        // implements IValidatableObject. Values are metadata, expected DisplayName, and expected MemberName.
        public static TheoryData<ModelMetadata, string, string> Validate_PassesExpectedNamesData
        {
            get
            {
                var method = typeof(SampleModel).GetMethod(nameof(SampleModel.IsLovely));
                var parameter = method.GetParameters()[0]; // IsLovely(SampleModel other)
                return new TheoryData<ModelMetadata, string, string>
                {
                    {
                        // Validating a property.
                        _metadataProvider.GetMetadataForProperty(
                            typeof(SampleModelContainer),
                            nameof(SampleModelContainer.SampleModel)),
                        nameof(SampleModelContainer.SampleModel),
                        nameof(SampleModelContainer.SampleModel)
                    },
                    {
                        // Validating a property with [Display(Name = "...")].
                        _metadataProvider.GetMetadataForProperty(
                            typeof(SampleModelContainer),
                            nameof(SampleModelContainer.SampleModelWithDisplay)),
                        "sample model",
                        nameof(SampleModelContainer.SampleModelWithDisplay)
                    },
                    {
                        // Validating a parameter.
                        _metadataProvider.GetMetadataForParameter(parameter),
                        "other",
                        "other"
                    },
                    {
                        // Validating a top-level parameter when using old-fashioned metadata provider.
                        // Or, validating an element of a collection.
                        _metadataProvider.GetMetadataForType(typeof(SampleModel)),
                        nameof(SampleModel),
                        null
                    },
                };
            }
        }

        public static TheoryData<ValidationResult[], ModelValidationResult[]> Validate_ReturnsExpectedResultsData
        {
            get
            {
                return new TheoryData<ValidationResult[], ModelValidationResult[]>
                {
                    {
                        new[] { new ValidationResult("Error message") },
                        new[] { new ModelValidationResult(memberName: null, message: "Error message") }
                    },
                    {
                        new[] { new ValidationResult("Error message", new[] { nameof(SampleModel.FirstName) }) },
                        new[] { new ModelValidationResult(nameof(SampleModel.FirstName), "Error message") }
                    },
                    {
                        new[]
                        {
                            new ValidationResult("Error message1"),
                            new ValidationResult("Error message2", new[] { nameof(SampleModel.FirstName) }),
                            new ValidationResult("Error message3", new[] { nameof(SampleModel.LastName) }),
                            new ValidationResult("Error message4", new[] { nameof(SampleModel) }),
                        },
                        new[]
                        {
                            new ModelValidationResult(memberName: null, message: "Error message1"),
                            new ModelValidationResult(nameof(SampleModel.FirstName), "Error message2"),
                            new ModelValidationResult(nameof(SampleModel.LastName), "Error message3"),
                            // No special case for ValidationContext.MemberName==ValidationResult.MemberName
                            new ModelValidationResult(nameof(SampleModel), "Error message4"),
                        }
                    },
                    {
                        new[]
                        {
                            new ValidationResult("Error message1", new[]
                            {
                                nameof(SampleModel.FirstName),
                                nameof(SampleModel.LastName),
                            }),
                            new ValidationResult("Error message2"),
                        },
                        new[]
                        {
                            new ModelValidationResult(nameof(SampleModel.FirstName), "Error message1"),
                            new ModelValidationResult(nameof(SampleModel.LastName), "Error message1"),
                            new ModelValidationResult(memberName: null, message: "Error message2"),
                        }
                    },
                };
            }
        }


        [Theory]
        [MemberData(nameof(Validate_PassesExpectedNamesData))]
        public void Validate_PassesExpectedNames(
            ModelMetadata metadata,
            string expectedDisplayName,
            string expectedMemberName)
        {
            // Arrange
            var adapter = new ValidatableObjectAdapter();
            var model = new SampleModel();
            var validationContext = new ModelValidationContext(
                new ActionContext(),
                metadata,
                _metadataProvider,
                container: new SampleModelContainer(),
                model: model);

            // Act
            var results = adapter.Validate(validationContext);

            // Assert
            Assert.NotNull(results);
            Assert.Empty(results);

            Assert.Equal(expectedDisplayName, model.DisplayName);
            Assert.Equal(expectedMemberName, model.MemberName);
            Assert.Equal(model, model.ObjectInstance);
        }

        [Theory]
        [MemberData(nameof(Validate_ReturnsExpectedResultsData))]
        public void Validate_ReturnsExpectedResults(
            ValidationResult[] innerResults,
            ModelValidationResult[] expectedResults)
        {
            // Arrange
            var adapter = new ValidatableObjectAdapter();
            var model = new SampleModel();
            foreach (var result in innerResults)
            {
                model.ValidationResults.Add(result);
            }

            var metadata = _metadataProvider.GetMetadataForProperty(
                typeof(SampleModelContainer),
                nameof(SampleModelContainer.SampleModel));
            var validationContext = new ModelValidationContext(
                new ActionContext(),
                metadata,
                _metadataProvider,
                container: null,
                model: model);

            // Act
            var results = adapter.Validate(validationContext);

            // Assert
            Assert.NotNull(results);
            Assert.Equal(expectedResults, results, ModelValidationResultComparer.Instance);
        }

        private class SampleModel : IValidatableObject
        {
            // "Real" properties.

            public string FirstName { get; set; }

            public string LastName { get; set; }

            // ValidationContext members passed to Validate(...)

            public string DisplayName { get; private set; }

            public string MemberName { get; private set; }

            public object ObjectInstance { get; private set; }

            // What Validate(...) should return.

            public IList<ValidationResult> ValidationResults { get; } = new List<ValidationResult>();

            // Test method.

            public bool IsLovely(SampleModel other)
            {
                return true;
            }

            // IValidatableObject for realz.

            public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
            {
                DisplayName = validationContext.DisplayName;
                MemberName = validationContext.MemberName;
                ObjectInstance = validationContext.ObjectInstance;

                return ValidationResults;
            }
        }

        private class SampleModelContainer
        {
            [Display(Name = "sample model")]
            public SampleModel SampleModelWithDisplay { get; set; }

            public SampleModel SampleModel { get; set; }
        }
    }
}