using System;
using Xunit;

namespace Microsoft.AspNet.Mvc.ModelBinding.Test
{
    public class ModelBindingContextTest
    {
        [Fact]
        public void CopyConstructor()
        {
            // Arrange
            var originalBindingContext = new ModelBindingContext
            {
                ModelMetadata = new EmptyModelMetadataProvider().GetMetadataForType(null, typeof(object)),
                ModelName = "theName",
                ModelState = new ModelStateDictionary(),
                ValueProvider = new SimpleHttpValueProvider()
            };

            // Act
            var newBindingContext = new ModelBindingContext(originalBindingContext);

            // Assert
            Assert.Null(newBindingContext.ModelMetadata);
            Assert.Equal("", newBindingContext.ModelName);
            Assert.Equal(originalBindingContext.ModelState, newBindingContext.ModelState);
            Assert.Equal(originalBindingContext.ValueProvider, newBindingContext.ValueProvider);
        }

        [Fact]
        public void ModelProperty_ThrowsIfModelMetadataDoesNotExist()
        {
            // Arrange
            var bindingContext = new ModelBindingContext();

            // Act & assert
            ExceptionAssert.Throws<InvalidOperationException>(
                () => bindingContext.Model = null,
                "The ModelMetadata property must be set before accessing this property.");
        }

        [Fact]
        public void ModelAndModelTypeAreFedFromModelMetadata()
        {
            // Act
            var bindingContext = new ModelBindingContext
            {
                ModelMetadata = new EmptyModelMetadataProvider().GetMetadataForType(() => 42, typeof(int))
            };

            // Assert
            Assert.Equal(42, bindingContext.Model);
            Assert.Equal(typeof(int), bindingContext.ModelType);
        }

        [Fact]
        public void ValidationNodeProperty_DefaultValues()
        {
            // Act
            var bindingContext = new ModelBindingContext
            {
                ModelMetadata = new EmptyModelMetadataProvider().GetMetadataForType(() => 42, typeof(int)),
                ModelName = "theInt"
            };

            // Act
            var validationNode = bindingContext.ValidationNode;

            // Assert
            Assert.NotNull(validationNode);
            Assert.Equal(bindingContext.ModelMetadata, validationNode.ModelMetadata);
            Assert.Equal(bindingContext.ModelName, validationNode.ModelStateKey);
        }
    }
}