using System.Collections.Generic;
using Newtonsoft.Json.Serialization;
using Xunit;

namespace Microsoft.AspNetCore.JsonPatch.Internal
{
    public class ObjectVisitorTest
    {
        private class Class1
        {
            public IList<string> States { get; set; } = new List<string>();
            public IDictionary<string, string> Countries = new Dictionary<string, string>();
        }

        public static IEnumerable<object[]> ReturnsListAdapterData
        {
            get
            {
                var model = new Class1();
                yield return new object[] { model, "/States/-", model.States };

                yield return new object[] { model.States, "/-", model.States };
            }
        }

        [Theory]
        [MemberData(nameof(ReturnsListAdapterData))]
        public void Visit_ValidPathToArray_ReturnsListAdapter(object targetObject, string path, object expectedTargetObject)
        {
            // Arrange
            var visitor = new ObjectVisitor(new ParsedPath(path), new DefaultContractResolver());
            IAdapter adapter = null;
            string message = null;

            // Act
            var visitStatus = visitor.TryVisit(ref targetObject, out adapter, out message);

            // Assert
            Assert.True(visitStatus);
            Assert.True(string.IsNullOrEmpty(message), "Expected no error message");
            Assert.Same(expectedTargetObject, targetObject);
            Assert.IsType<ListAdapter>(adapter);
        }

        [Fact]
        public void Visit_ValidPathToDictionary_ReturnsDictionaryAdapter()
        {
            // Arrange
            var visitor = new ObjectVisitor(new ParsedPath("/Countries/USA"), new DefaultContractResolver());
            var model = new Class1();
            object targetObject = model;
            IAdapter adapter = null;
            string message = null;

            // Act
            var visitStatus = visitor.TryVisit(ref targetObject, out adapter, out message);

            // Assert
            Assert.True(visitStatus);
            Assert.True(string.IsNullOrEmpty(message), "Expected no error message");
            Assert.Same(model.Countries, targetObject);
            Assert.IsType<DictionaryAdapter>(adapter);
        }

        private class AutomobileDepartment
        {
            public List<Class1> Customers { get; set; } = new List<Class1>();
        }

        [Fact]
        public void Visit_ValidPathToArray_ReturnsListAdapter_ForDeepNestedPath()
        {
            // Arrange
            var visitor = new ObjectVisitor(new ParsedPath("/Customers/0/States/-"), new DefaultContractResolver());
            var customer = new Class1();
            var automobileDepartment = new AutomobileDepartment();
            automobileDepartment.Customers.Add(customer);
            object targetObject = automobileDepartment;
            IAdapter adapter = null;
            string message = null;

            // Act
            var visitStatus = visitor.TryVisit(ref targetObject, out adapter, out message);

            // Assert
            Assert.True(visitStatus);
            Assert.True(string.IsNullOrEmpty(message), "Expected no error message");
            Assert.Same(customer.States, targetObject);
            Assert.IsType<ListAdapter>(adapter);
        }

        [Fact]
        public void Visit_InvalidPathToArray_Fails()
        {
            // Arrange
            var invalidIndex = 2;
            var visitor = new ObjectVisitor(new ParsedPath($"/Customers/{invalidIndex}/States/-"), new DefaultContractResolver());
            var automobileDepartment = new AutomobileDepartment();
            object targetObject = automobileDepartment;
            IAdapter adapter = null;
            string message = null;

            // Act
            var visitStatus = visitor.TryVisit(ref targetObject, out adapter, out message);

            // Assert
            Assert.False(visitStatus);
            Assert.Equal(string.Format(ErrorMessageFormats.IndexOutOfBounds, invalidIndex), message);
        }

        // The adapter takes care of the responsibility of validating the final segment
        [Fact]
        public void Visit_DoesNotValidate_FinalPathSegment()
        {
            // Arrange
            var visitor = new ObjectVisitor(new ParsedPath($"/NonExisting"), new DefaultContractResolver());
            var model = new Class1();
            object targetObject = model;
            IAdapter adapter = null;
            string message = null;

            // Act
            var visitStatus = visitor.TryVisit(ref targetObject, out adapter, out message);

            // Assert
            Assert.True(visitStatus);
            Assert.True(string.IsNullOrEmpty(message), "Expected no error message");
            Assert.IsType<PocoAdapter>(adapter);
        }
    }
}