// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.IO;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Primitives;
using Xunit;

namespace Microsoft.AspNetCore.Mvc.Formatters
{
    public class StreamOutputFormatterTest
    {
        [Theory]
        [InlineData(typeof(Stream), "text/plain")]
        [InlineData(typeof(Stream), null)]
        public void CanWriteResult_ReturnsTrue_ForStreams(Type type, string contentType)
        {
            // Arrange
            var formatter = new StreamOutputFormatter();
            var contentTypeHeader = new StringSegment(contentType);

            var context = new OutputFormatterWriteContext(
                new DefaultHttpContext(),
                new TestHttpResponseStreamWriterFactory().CreateWriter,
                type,
                new MemoryStream())
            {
                ContentType = contentTypeHeader,
            };

            // Act
            var canWrite = formatter.CanWriteResult(context);

            // Assert
            Assert.True(canWrite);
        }

        [Theory]
        [InlineData(typeof(SimplePOCO), "text/plain")]
        [InlineData(typeof(SimplePOCO), null)]
        public void CanWriteResult_OnlyActsOnStreams_IgnoringContentType(Type type, string contentType)
        {
            // Arrange
            var formatter = new StreamOutputFormatter();
            var contentTypeHeader = contentType == null ? new StringSegment() : new StringSegment(contentType);

            var context = new OutputFormatterWriteContext(
                new DefaultHttpContext(),
                new TestHttpResponseStreamWriterFactory().CreateWriter,
                type,
                new SimplePOCO())
            {
                ContentType = contentTypeHeader,
            };

            // Act
            var canWrite = formatter.CanWriteResult(context);

            // Assert
            Assert.False(canWrite);
        }

        [Theory]
        [InlineData(typeof(object))]
        [InlineData(typeof(SimplePOCO))]
        [InlineData(null)]
        public void CanWriteResult_OnlyActsOnStreams(Type type)
        {
            // Arrange
            var formatter = new StreamOutputFormatter();
            var @object = type != null ? Activator.CreateInstance(type) : null;

            var context = new OutputFormatterWriteContext(
                new DefaultHttpContext(),
                new TestHttpResponseStreamWriterFactory().CreateWriter,
                type,
                @object);

            // Act
            var result = formatter.CanWriteResult(context);

            // Assert
            Assert.False(result);
        }

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