using System;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using Azure;
using Azure.Storage.Blobs.Models;
using LCU.API.Internal.Document.Exceptions;
using LCU.API.Internal.Document.Services;
using LCU.API.Internal.DocumentLib.DataAccess;
using Moq;
using NUnit.Framework;

namespace LCU.API.Internal.DocumentTest.Services;

public class BlobApiServiceTest
{
    private BlobApiService _blobApiService;
    private Mock<IBlobApiDao> _mockBlobDao;

    [SetUp]
    public void Setup()
    {
        _mockBlobDao = new Mock<IBlobApiDao>();
        _blobApiService = new BlobApiService(_mockBlobDao.Object);
    }

    [Test]
    public async Task GetDocumentContent_Success()
    {
        var docBlobId = Guid.NewGuid();
        await using var testStream = new MemoryStream(Encoding.UTF8.GetBytes("whatever"));
        var mockContent = BlobsModelFactory.BlobDownloadStreamingResult(testStream);
        var mockContentResponse = new Mock<Response<BlobDownloadStreamingResult>>();

        mockContentResponse.Setup(content => content.Value).Returns(mockContent).Verifiable();
        _mockBlobDao
            .Setup(x => x.GetDocumentFromBlob(docBlobId)).ReturnsAsync(mockContentResponse.Object)
            .Verifiable();

        var returnedDocInfo = await _blobApiService.GetDocumentContent(docBlobId);

        Assert.NotNull(returnedDocInfo);
        _mockBlobDao.Verify();
    }

    [Test]
    public void GetDocument_ContentValueIsNull_DocumentBlobServiceExceptionThrown()
    {
        var docBlobId = Guid.NewGuid();

        _mockBlobDao
            .Setup(x => x.GetDocumentFromBlob(docBlobId)).ReturnsAsync((Response<BlobDownloadStreamingResult>)null)
            .Verifiable();

        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.GetDocumentContent(docBlobId));
        _mockBlobDao.Verify();
    }

    [Test]
    public void GetDocument_ExceptionThrown_DocumentBlobServiceExceptionThrown()
    {
        var docBlobId = Guid.NewGuid();

        _mockBlobDao
            .Setup(x => x.GetDocumentFromBlob(docBlobId)).ThrowsAsync(new Exception("Thrown from unit test"))
            .Verifiable();

        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.GetDocumentContent(docBlobId));
        _mockBlobDao.Verify();
    }

    [Test]
    public async Task UploadDocumentContent_Success()
    {
        var docContent = new byte[10];
        _mockBlobDao.Setup(x => x.SaveDocumentToBlob(docContent)).Verifiable();

        await _blobApiService.UploadDocumentContent(docContent);
        _mockBlobDao.Verify();
    }

    [Test]
    public void UploadDocumentContent_Exception_ThrowsBlobApiServiceException()
    {
        var docContent = new byte[10];
        _mockBlobDao.Setup(x => x.SaveDocumentToBlob(docContent)).ThrowsAsync(new Exception("Thrown from unit test")).Verifiable();

        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.UploadDocumentContent(docContent));
        _mockBlobDao.Verify();
    }

    [Test]
    public async Task UpdateDocumentContent_Success()
    {
        var docBlobId = Guid.NewGuid();
        var docContent = new byte[10];
        _mockBlobDao.Setup(x => x.UpdateDocumentInBlob(docBlobId, docContent)).Verifiable();

        await _blobApiService.UpdateDocumentContent(docBlobId, docContent);
        _mockBlobDao.Verify();
    }

    [Test]
    public void UpdateDocumentContent_Exception_ThrowsBlobApiServiceException()
    {
        var docBlobId = Guid.NewGuid();
        var docContent = new byte[10];
        _mockBlobDao.Setup(x => x.UpdateDocumentInBlob(docBlobId, docContent)).ThrowsAsync(new Exception("Thrown from unit test")).Verifiable();

        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.UpdateDocumentContent(docBlobId, docContent));
        _mockBlobDao.Verify();
    }

    [Test]
    public void UpdateDocumentContent_Exception_DocumentBlobIdIsNull()
    {
        Guid? docBlobId = null;
        var docContent = new byte[10];
        
        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.UpdateDocumentContent(docBlobId, docContent));
    }

    
    [Test]
    public async Task DeleteDocumentContent_Success()
    {
        var docBlobId = Guid.NewGuid();
        _mockBlobDao.Setup(x => x.RemoveDocumentFromBlob(docBlobId)).Verifiable();

        await _blobApiService.DeleteDocumentContent(docBlobId);
        _mockBlobDao.Verify();
    }

    [Test]
    public void DeleteDocumentContent_Exception_ThrowsBlobApiServiceException()
    {
        var docBlobId = Guid.NewGuid();
        _mockBlobDao.Setup(x => x.RemoveDocumentFromBlob(docBlobId)).ThrowsAsync(new Exception("Thrown from unit test")).Verifiable();

        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.DeleteDocumentContent(docBlobId));
        _mockBlobDao.Verify();
    }
    
    [Test]
    public void DeleteDocumentContent_Exception_DocumentBlobIdIsNull()
    {
        Guid? docBlobId = null;

        Assert.ThrowsAsync<BlobApiServiceException>(async() => await _blobApiService.DeleteDocumentContent(docBlobId));
    }

    [Test]
    public async Task GetDocument_BlobGuidIsEmpty_ReturnsEmptyContent()
    {
        var docBlobId = Guid.Empty;
        var emptyContent = Array.Empty<byte>();

        var result = await _blobApiService.GetDocumentContent(docBlobId);

        Assert.AreEqual(emptyContent, result);
        _mockBlobDao.Verify(s => s.GetDocumentFromBlob(It.IsAny<Guid>()), Times.Never);
    }
    
    [Test]
    public async Task GetDocument_BlobGuidIsNull_ReturnsEmptyContent()
    {
        Guid? docBlobId = null;
        var emptyContent = Array.Empty<byte>();

        var result = await _blobApiService.GetDocumentContent(docBlobId);

        Assert.AreEqual(emptyContent, result);
        _mockBlobDao.Verify(s => s.GetDocumentFromBlob(It.IsAny<Guid>()), Times.Never);
    }
}