// 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;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Internal;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using Microsoft.Extensions.Primitives;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.ModelBinding.Binders
{
    public class DictionaryModelBinderTest
    {
        [Theory]
        [InlineData(false)]
        [InlineData(true)]
        public async Task BindModel_Succeeds(bool isReadOnly)
        {
            // Arrange
            var values = new Dictionary<string, string>()
            {
                { "someName[0].Key", "42" },
                { "someName[0].Value", "forty-two" },
                { "someName[1].Key", "84" },
                { "someName[1].Value", "eighty-four" },
            };

            // Value Provider

            var bindingContext = GetModelBindingContext(isReadOnly, values);
            bindingContext.ValueProvider = CreateEnumerableValueProvider("{0}", values);

            var binder = new DictionaryModelBinder<int, string>(
                new SimpleTypeModelBinder(typeof(int)), 
                new SimpleTypeModelBinder(typeof(string)));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            var dictionary = Assert.IsAssignableFrom<IDictionary<int, string>>(bindingContext.Result.Model);
            Assert.NotNull(dictionary);
            Assert.Equal(2, dictionary.Count);
            Assert.Equal("forty-two", dictionary[42]);
            Assert.Equal("eighty-four", dictionary[84]);

            // This uses the default IValidationStrategy
            Assert.DoesNotContain(bindingContext.Result.Model, bindingContext.ValidationState.Keys);
        }

        [Theory]
        [InlineData(false)]
        [InlineData(true)]
        public async Task BindModel_WithExistingModel_Succeeds(bool isReadOnly)
        {
            // Arrange
            var values = new Dictionary<string, string>()
            {
                { "someName[0].Key", "42" },
                { "someName[0].Value", "forty-two" },
                { "someName[1].Key", "84" },
                { "someName[1].Value", "eighty-four" },
            };

            var bindingContext = GetModelBindingContext(isReadOnly, values);
            bindingContext.ValueProvider = CreateEnumerableValueProvider("{0}", values);

            var dictionary = new Dictionary<int, string>();
            bindingContext.Model = dictionary;

            var binder = new DictionaryModelBinder<int, string>(
                new SimpleTypeModelBinder(typeof(int)), 
                new SimpleTypeModelBinder(typeof(string)));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            Assert.Same(dictionary, bindingContext.Result.Model);
            Assert.NotNull(dictionary);
            Assert.Equal(2, dictionary.Count);
            Assert.Equal("forty-two", dictionary[42]);
            Assert.Equal("eighty-four", dictionary[84]);

            // This uses the default IValidationStrategy
            Assert.DoesNotContain(bindingContext.Result.Model, bindingContext.ValidationState.Keys);
        }

        // modelName, keyFormat, dictionary
        public static TheoryData<string, string, IDictionary<string, string>> StringToStringData
        {
            get
            {
                var dictionaryWithOne = new Dictionary<string, string>(StringComparer.Ordinal)
                {
                    { "one", "one" },
                };
                var dictionaryWithThree = new Dictionary<string, string>(StringComparer.Ordinal)
                {
                    { "one", "one" },
                    { "two", "two" },
                    { "three", "three" },
                };

                return new TheoryData<string, string, IDictionary<string, string>>
                {
                    { string.Empty, "[{0}]", dictionaryWithOne },
                    { string.Empty, "[{0}]", dictionaryWithThree },
                    { "prefix", "prefix[{0}]", dictionaryWithOne },
                    { "prefix", "prefix[{0}]", dictionaryWithThree },
                    { "prefix.property", "prefix.property[{0}]", dictionaryWithOne },
                    { "prefix.property", "prefix.property[{0}]", dictionaryWithThree },
                };
            }
        }

        [Theory]
        [MemberData(nameof(StringToStringData))]
        public async Task BindModel_FallsBackToBindingValues(
            string modelName,
            string keyFormat,
            IDictionary<string, string> dictionary)
        {
            // Arrange
            var binder = new DictionaryModelBinder<string, string>(
                new SimpleTypeModelBinder(typeof(string)), 
                new SimpleTypeModelBinder(typeof(string)));

            var bindingContext = CreateContext();
            bindingContext.ModelName = modelName;
            bindingContext.ValueProvider = CreateEnumerableValueProvider(keyFormat, dictionary);
            bindingContext.FieldName = modelName;

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithDictionaryProperties),
                nameof(ModelWithDictionaryProperties.DictionaryProperty));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            var resultDictionary = Assert.IsAssignableFrom<IDictionary<string, string>>(bindingContext.Result.Model);
            Assert.Equal(dictionary, resultDictionary);
        }

        // Similar to one BindModel_FallsBackToBindingValues case but without an IEnumerableValueProvider.
        [Fact]
        public async Task BindModel_DoesNotFallBack_WithoutEnumerableValueProvider()
        {
            // Arrange
            var dictionary = new Dictionary<string, string>(StringComparer.Ordinal)
            {
                { "one", "one" },
                { "two", "two" },
                { "three", "three" },
            };

            var binder = new DictionaryModelBinder<string, string>(
                new SimpleTypeModelBinder(typeof(string)), 
                new SimpleTypeModelBinder(typeof(string)));

            var bindingContext = CreateContext();
            bindingContext.ModelName = "prefix";
            bindingContext.ValueProvider = CreateTestValueProvider("prefix[{0}]", dictionary);
            bindingContext.FieldName = bindingContext.ModelName;

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithDictionaryProperties),
                nameof(ModelWithDictionaryProperties.DictionaryProperty));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            var resultDictionary = Assert.IsAssignableFrom<IDictionary<string, string>>(bindingContext.Result.Model);
            Assert.Empty(resultDictionary);
        }

        public static TheoryData<IDictionary<long, int>> LongToIntData
        {
            get
            {
                var dictionaryWithOne = new Dictionary<long, int>
                {
                    { 0L, 0 },
                };
                var dictionaryWithThree = new Dictionary<long, int>
                {
                    { -1L, -1 },
                    { long.MaxValue, int.MaxValue },
                    { long.MinValue, int.MinValue },
                };

                return new TheoryData<IDictionary<long, int>> { dictionaryWithOne, dictionaryWithThree };
            }
        }

        [Theory]
        [MemberData(nameof(LongToIntData))]
        public async Task BindModel_FallsBackToBindingValues_WithValueTypes(IDictionary<long, int> dictionary)
        {
            // Arrange
            var stringDictionary = dictionary.ToDictionary(kvp => kvp.Key.ToString(), kvp => kvp.Value.ToString());

            var binder = new DictionaryModelBinder<long, int>(
                new SimpleTypeModelBinder(typeof(long)), 
                new SimpleTypeModelBinder(typeof(int)));

            var bindingContext = CreateContext();
            bindingContext.ModelName = "prefix";
            bindingContext.ValueProvider = CreateEnumerableValueProvider("prefix[{0}]", stringDictionary);
            bindingContext.FieldName = bindingContext.ModelName;

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithDictionaryProperties),
                nameof(ModelWithDictionaryProperties.DictionaryWithValueTypesProperty));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            var resultDictionary = Assert.IsAssignableFrom<IDictionary<long, int>>(bindingContext.Result.Model);
            Assert.Equal(dictionary, resultDictionary);
        }

        [Fact]
        public async Task BindModel_FallsBackToBindingValues_WithComplexValues()
        {
            // Arrange
            var dictionary = new Dictionary<int, ModelWithProperties>
            {
                { 23, new ModelWithProperties { Id = 43, Name = "Wilma" } },
                { 27, new ModelWithProperties { Id = 98, Name = "Fred" } },
            };
            var stringDictionary = new Dictionary<string, string>
            {
                { "prefix[23].Id", "43" },
                { "prefix[23].Name", "Wilma" },
                { "prefix[27].Id", "98" },
                { "prefix[27].Name", "Fred" },
            };

            var bindingContext = CreateContext();
            bindingContext.ModelName = "prefix";
            bindingContext.ValueProvider = CreateEnumerableValueProvider("{0}", stringDictionary);
            bindingContext.FieldName = bindingContext.ModelName;

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithDictionaryProperties),
                nameof(ModelWithDictionaryProperties.DictionaryWithComplexValuesProperty));

            var valueMetadata = metadataProvider.GetMetadataForType(typeof(ModelWithProperties));

            var binder = new DictionaryModelBinder<int, ModelWithProperties>(
                new SimpleTypeModelBinder(typeof(int)),
                new ComplexTypeModelBinder(new Dictionary<ModelMetadata, IModelBinder>()
                {
                    { valueMetadata.Properties["Id"], new SimpleTypeModelBinder(typeof(int)) },
                    { valueMetadata.Properties["Name"], new SimpleTypeModelBinder(typeof(string)) },
                }));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            var resultDictionary = Assert.IsAssignableFrom<IDictionary<int, ModelWithProperties>>(bindingContext.Result.Model);
            Assert.Equal(dictionary, resultDictionary);

            // This requires a non-default IValidationStrategy
            Assert.Contains(bindingContext.Result.Model, bindingContext.ValidationState.Keys);
            var entry = bindingContext.ValidationState[bindingContext.Result.Model];
            var strategy = Assert.IsType<ShortFormDictionaryValidationStrategy<int, ModelWithProperties>>(entry.Strategy);
            Assert.Equal(
                new KeyValuePair<string, int>[]
                {
                    new KeyValuePair<string, int>("23", 23),
                    new KeyValuePair<string, int>("27", 27),
                }.OrderBy(kvp => kvp.Key),
                strategy.KeyMappings.OrderBy(kvp => kvp.Key));
        }

        [Theory]
        [MemberData(nameof(StringToStringData))]
        public async Task BindModel_FallsBackToBindingValues_WithCustomDictionary(
            string modelName,
            string keyFormat,
            IDictionary<string, string> dictionary)
        {
            // Arrange
            var expectedDictionary = new SortedDictionary<string, string>(dictionary);
            var binder = new DictionaryModelBinder<string, string>(
                new SimpleTypeModelBinder(typeof(string)), 
                new SimpleTypeModelBinder(typeof(string)));

            var bindingContext = CreateContext();
            bindingContext.ModelName = modelName;

            bindingContext.ValueProvider = CreateEnumerableValueProvider(keyFormat, dictionary);
            bindingContext.FieldName = bindingContext.ModelName;

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithDictionaryProperties),
                nameof(ModelWithDictionaryProperties.CustomDictionaryProperty));

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.True(bindingContext.Result.IsModelSet);

            var resultDictionary = Assert.IsAssignableFrom<SortedDictionary<string, string>>(bindingContext.Result.Model);
            Assert.Equal(expectedDictionary, resultDictionary);
        }

        [Fact]
        public async Task DictionaryModelBinder_CreatesEmptyCollection_IfIsTopLevelObject()
        {
            // Arrange
            var binder = new DictionaryModelBinder<string, string>(
                new SimpleTypeModelBinder(typeof(string)), 
                new SimpleTypeModelBinder(typeof(string)));

            var bindingContext = CreateContext();
            bindingContext.IsTopLevelObject = true;

            // Lack of prefix and non-empty model name both ignored.
            bindingContext.ModelName = "modelName";

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForType(typeof(Dictionary<string, string>));

            bindingContext.ValueProvider = new TestValueProvider(new Dictionary<string, object>());

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.Empty(Assert.IsType<Dictionary<string, string>>(bindingContext.Result.Model));
            Assert.True(bindingContext.Result.IsModelSet);
        }

        [Theory]
        [InlineData("")]
        [InlineData("param")]
        public async Task DictionaryModelBinder_DoesNotCreateCollection_IfNotIsTopLevelObject(string prefix)
        {
            // Arrange
            var binder = new DictionaryModelBinder<int, int>(
                new SimpleTypeModelBinder(typeof(int)), 
                new SimpleTypeModelBinder(typeof(int)));

            var bindingContext = CreateContext();
            bindingContext.ModelName = ModelNames.CreatePropertyModelName(prefix, "ListProperty");

            var metadataProvider = new TestModelMetadataProvider();
            bindingContext.ModelMetadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithDictionaryProperties),
                nameof(ModelWithDictionaryProperties.DictionaryProperty));

            bindingContext.ValueProvider = new TestValueProvider(new Dictionary<string, object>());

            // Act
            await binder.BindModelAsync(bindingContext);

            // Assert
            Assert.False(bindingContext.Result.IsModelSet);
        }

        // Model type -> can create instance.
        public static TheoryData<Type, bool> CanCreateInstanceData
        {
            get
            {
                return new TheoryData<Type, bool>
                {
                    { typeof(IEnumerable<KeyValuePair<int, int>>), true },
                    { typeof(ICollection<KeyValuePair<int, int>>), true },
                    { typeof(IDictionary<int, int>), true },
                    { typeof(Dictionary<int, int>), true },
                    { typeof(SortedDictionary<int, int>), true },
                    { typeof(IList<KeyValuePair<int, int>>), true },
                    { typeof(ISet<KeyValuePair<int, int>>), false },
                };
            }
        }

        [Theory]
        [MemberData(nameof(CanCreateInstanceData))]
        public void CanCreateInstance_ReturnsExpectedValue(Type modelType, bool expectedResult)
        {
            // Arrange
            var binder = new DictionaryModelBinder<int, int>(
                new SimpleTypeModelBinder(typeof(int)), 
                new SimpleTypeModelBinder(typeof(int)));

            // Act
            var result = binder.CanCreateInstance(modelType);

            // Assert
            Assert.Equal(expectedResult, result);
        }

        private static DefaultModelBindingContext CreateContext()
        {
            var modelBindingContext = new DefaultModelBindingContext()
            {
                ActionContext = new ActionContext()
                {
                    HttpContext = new DefaultHttpContext(),
                },
                ModelState = new ModelStateDictionary(),
                ValidationState = new ValidationStateDictionary(),
            };

            return modelBindingContext;
        }

        private static IValueProvider CreateEnumerableValueProvider(
            string keyFormat,
            IDictionary<string, string> dictionary)
        {
            // Convert to an IDictionary<string, StringValues> then wrap it up.
            var backingStore = dictionary.ToDictionary(
                kvp => string.Format(keyFormat, kvp.Key),
                kvp => (StringValues)kvp.Value);

            var formCollection = new FormCollection(backingStore);

            return new FormValueProvider(
                BindingSource.Form,
                formCollection,
                CultureInfo.InvariantCulture);
        }

        // Like CreateEnumerableValueProvider except returned instance does not implement IEnumerableValueProvider.
        private static IValueProvider CreateTestValueProvider(string keyFormat, IDictionary<string, string> dictionary)
        {
            // Convert to an IDictionary<string, object> then wrap it up.
            var backingStore = dictionary.ToDictionary(
                kvp => string.Format(keyFormat, kvp.Key),
                kvp => (object)kvp.Value);

            return new TestValueProvider(BindingSource.Form, backingStore);
        }

        private static DefaultModelBindingContext GetModelBindingContext(
            bool isReadOnly,
            IDictionary<string, string> values = null)
        {
            var metadataProvider = new TestModelMetadataProvider();
            metadataProvider
                .ForProperty<ModelWithIDictionaryProperty>(nameof(ModelWithIDictionaryProperty.DictionaryProperty))
                .BindingDetails(bd => bd.IsReadOnly = isReadOnly);
            var metadata = metadataProvider.GetMetadataForProperty(
                typeof(ModelWithIDictionaryProperty),
                nameof(ModelWithIDictionaryProperty.DictionaryProperty));

            var valueProvider = new SimpleValueProvider();
            foreach (var kvp in values)
            {
                valueProvider.Add(kvp.Key, string.Empty);
            }

            var bindingContext = new DefaultModelBindingContext
            {
                ModelMetadata = metadata,
                ModelName = "someName",
                ModelState = new ModelStateDictionary(),
                ValueProvider = valueProvider,
                ValidationState = new ValidationStateDictionary(),
            };

            return bindingContext;
        }

        private class ModelWithIDictionaryProperty
        {
            public IDictionary<int, string> DictionaryProperty { get; set; }
        }

        private class ModelWithDictionaryProperties
        {
            // A Dictionary<string, string> instance cannot be assigned to this property.
            public SortedDictionary<string, string> CustomDictionaryProperty { get; set; }

            public Dictionary<string, string> DictionaryProperty { get; set; }

            public Dictionary<int, ModelWithProperties> DictionaryWithComplexValuesProperty { get; set; }

            public Dictionary<long, int> DictionaryWithValueTypesProperty { get; set; }
        }

        private class ModelWithProperties
        {
            public int Id { get; set; }

            public string Name { get; set; }

            public override bool Equals(object obj)
            {
                var other = obj as ModelWithProperties;
                return other != null &&
                    Id == other.Id &&
                    string.Equals(Name, other.Name, StringComparison.Ordinal);
            }

            public override int GetHashCode()
            {
                int nameCode = Name == null ? 0 : Name.GetHashCode();
                return nameCode ^ Id.GetHashCode();
            }

            public override string ToString()
            {
                return $"{{{ Id }, '{ Name }'}}";
            }
        }
    }
}
