// Copyright (c) Microsoft Open Technologies, Inc. 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;
using System.Collections.Generic;
using Microsoft.AspNet.Http;
using Moq;
using Xunit;

namespace Microsoft.AspNet.Mvc
{
    public class SessionStateTempDataProviderTest
    {
        [Fact]
        public void Load_NullSession_ReturnsEmptyDictionary()
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act
            var tempDataDictionary = testProvider.LoadTempData(
                GetHttpContext(session: null, sessionEnabled: true));

            // Assert
            Assert.Empty(tempDataDictionary);
        }

        [Fact]
        public void Load_NonNullSession_NoSessionData_ReturnsEmptyDictionary()
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act
            var tempDataDictionary = testProvider.LoadTempData(
                GetHttpContext(Mock.Of<ISessionCollection>()));

            // Assert
            Assert.Empty(tempDataDictionary);
        }

        [Fact]
        public void Save_NullSession_NullDictionary_DoesNotThrow()
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act & Assert (does not throw)
            testProvider.SaveTempData(GetHttpContext(session: null, sessionEnabled: false), null);
        }

        [Fact]
        public void Save_NullSession_EmptyDictionary_DoesNotThrow()
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act & Assert (does not throw)
            testProvider.SaveTempData(
                GetHttpContext(session: null, sessionEnabled: false), new Dictionary<string, object>());
        }

        [Fact]
        public void Save_NullSession_NonEmptyDictionary_Throws()
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act & Assert
            Assert.Throws<InvalidOperationException>(() =>
            {
                testProvider.SaveTempData(
                    GetHttpContext(session: null, sessionEnabled: false),
                    new Dictionary<string, object> { { "foo", "bar" } }
                );
            });
        }

        public static TheoryData<object, Type> InvalidTypes
        {
            get
            {
                return new TheoryData<object, Type>
                {
                    { new object(), typeof(object) },
                    { new object[3], typeof(object) },
                    { new TestItem(), typeof(TestItem) },
                    { new List<TestItem>(), typeof(TestItem) },
                    { new Dictionary<string, TestItem>(), typeof(TestItem) },
                };
            }
        }

        [Theory]
        [MemberData(nameof(InvalidTypes))]
        public void EnsureObjectCanBeSerialized_InvalidType_Throws(object value, Type type)
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act & Assert
            var exception = Assert.Throws<InvalidOperationException>(() =>
            {
                testProvider.EnsureObjectCanBeSerialized(value);
            });
            Assert.Equal($"The '{typeof(SessionStateTempDataProvider).FullName}' cannot serialize an object of type '{type}' to session state.",
                exception.Message);
        }

        public static TheoryData<object, Type> InvalidDictionaryTypes
        {
            get
            {
                return new TheoryData<object, Type>
                {
                    { new Dictionary<int, string>(), typeof(int) },
                    { new Dictionary<Uri, Guid>(), typeof(Uri) },
                    { new Dictionary<object, string>(), typeof(object) },
                    { new Dictionary<TestItem, TestItem>(), typeof(TestItem) }
                };
            }
        }

        [Theory]
        [MemberData(nameof(InvalidDictionaryTypes))]
        public void EnsureObjectCanBeSerialized_InvalidDictionaryType_Throws(object value, Type type)
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act & Assert
            var exception = Assert.Throws<InvalidOperationException>(() =>
            {
                testProvider.EnsureObjectCanBeSerialized(value);
            });
            Assert.Equal($"The '{typeof(SessionStateTempDataProvider).FullName}' cannot serialize a dictionary with a key of type '{type}' to session state.",
                exception.Message);
        }

        public static TheoryData<object> ValidTypes
        {
            get
            {
                return new TheoryData<object>
                {
                    { 10 },
                    { new int[]{ 10, 20 } },
                    { "FooValue" },
                    { new Uri("http://Foo") },
                    { Guid.NewGuid() },
                    { new List<string> { "foo", "bar" } },
                    { new DateTimeOffset() },
                    { 100.1m },
                    { new Dictionary<string, int>() },
                    { new Uri[] { new Uri("http://Foo"), new Uri("http://Bar") } }
                };
            }
        }

        [Theory]
        [MemberData(nameof(ValidTypes))]
        public void EnsureObjectCanBeSerialized_ValidType_DoesNotThrow(object value)
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();

            // Act & Assert (Does not throw)
            testProvider.EnsureObjectCanBeSerialized(value);
        }

        [Fact]
        public void SaveAndLoad_SimpleTypesCanBeStoredAndLoaded()
        {
            // Arrange
            var testProvider = new SessionStateTempDataProvider();
            var inputGuid = Guid.NewGuid();
            var inputDictionary = new Dictionary<string, string>
            {
                { "Hello", "World" },
            };
            var input = new Dictionary<string, object>
            {
                { "string", "value" },
                { "int", 10 },
                { "bool", false },
                { "DateTime", new DateTime() },
                { "Guid", inputGuid },
                { "List`string", new List<string> { "one", "two" } },
                { "Dictionary", inputDictionary },
                { "EmptyDictionary", new Dictionary<string, int>() }
            };
            var context = GetHttpContext(new TestSessionCollection(), true);

            // Act
            testProvider.SaveTempData(context, input);
            var TempData = testProvider.LoadTempData(context);

            // Assert
            var stringVal = Assert.IsType<string>(TempData["string"]);
            Assert.Equal("value", stringVal);
            var intVal = Convert.ToInt32(TempData["int"]);
            Assert.Equal(10, intVal);
            var boolVal = Assert.IsType<bool>(TempData["bool"]);
            Assert.Equal(false, boolVal);
            var datetimeVal = Assert.IsType<DateTime>(TempData["DateTime"]);
            Assert.Equal(new DateTime().ToString(), datetimeVal.ToString());
            var guidVal = Assert.IsType<Guid>(TempData["Guid"]);
            Assert.Equal(inputGuid.ToString(), guidVal.ToString());
            var list = (IList<string>)TempData["List`string"];
            Assert.Equal(2, list.Count);
            Assert.Equal("one", list[0]);
            Assert.Equal("two", list[1]);
            var dictionary = Assert.IsType<Dictionary<string, string>>(TempData["Dictionary"]);
            Assert.Equal("World", dictionary["Hello"]);
            var emptyDictionary = (IDictionary<string, int>)TempData["EmptyDictionary"];
            Assert.Null(emptyDictionary);
        }

        private class TestItem
        {
            public int DummyInt { get; set; }
        }

        private HttpContext GetHttpContext(ISessionCollection session, bool sessionEnabled=true)
        {
            var httpContext = new Mock<HttpContext>();
            if (session != null)
            {
                httpContext.Setup(h => h.Session).Returns(session);
            }
            else if (!sessionEnabled)
            {
                httpContext.Setup(h => h.Session).Throws<InvalidOperationException>();
            }
            else
            {
                httpContext.Setup(h => h.Session[It.IsAny<string>()]);
            }
            if (sessionEnabled)
            {
                httpContext.Setup(h => h.GetFeature<ISessionFeature>()).Returns(Mock.Of<ISessionFeature>());
            }
            return httpContext.Object;
        }

        private class TestSessionCollection : ISessionCollection
        {
            private Dictionary<string, byte[]> _innerDictionary = new Dictionary<string, byte[]>();

            public byte[] this[string key]
            {
                get
                {
                    return _innerDictionary[key];
                }

                set
                {
                    _innerDictionary[key] = value;
                }
            }

            public void Clear()
            {
                _innerDictionary.Clear();
            }

            public IEnumerator<KeyValuePair<string, byte[]>> GetEnumerator()
            {
                return _innerDictionary.GetEnumerator();
            }

            public void Remove(string key)
            {
                _innerDictionary.Remove(key);
            }

            public void Set(string key, ArraySegment<byte> value)
            {
                _innerDictionary[key] = value.AsArray();
            }

            public bool TryGetValue(string key, out byte[] value)
            {
                return _innerDictionary.TryGetValue(key, out value);
            }

            IEnumerator IEnumerable.GetEnumerator()
            {
                return _innerDictionary.GetEnumerator();
            }
        }
    }
}