// 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.Linq;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.Extensions.AI;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Testing;
using Xunit;
 
namespace Microsoft.Extensions.DataIngestion.Processors.Tests;
 
public class AlternativeTextEnricherTests
{
    private readonly ReadOnlyMemory<byte> _imageContent = new byte[256];
 
    [Fact]
    public void ThrowsOnNullOptions()
    {
        Assert.Throws<ArgumentNullException>("options", () => new ImageAlternativeTextEnricher(null!));
    }
 
    [Fact]
    public async Task ThrowsOnNullDocument()
    {
        using TestChatClient chatClient = new();
 
        ImageAlternativeTextEnricher sut = new(new(chatClient));
 
        await Assert.ThrowsAsync<ArgumentNullException>("document", async () => await sut.ProcessAsync(null!));
    }
 
    [Fact]
    public async Task CanGenerateImageAltText()
    {
        const string PreExistingAltText = "Pre-existing alt text";
 
        string[] descriptions = { "First alt text", "Second alt text" };
        using TestChatClient chatClient = new()
        {
            GetResponseAsyncCallback = (messages, options, cancellationToken) =>
            {
                var materializedMessages = messages.ToArray();
 
                Assert.Equal(2, materializedMessages.Length);
                Assert.Equal(ChatRole.System, materializedMessages[0].Role);
                Assert.Equal(ChatRole.User, materializedMessages[1].Role);
                Assert.Equal(2, materializedMessages[1].Contents.Count);
 
                Assert.All(materializedMessages[1].Contents, content =>
                {
                    DataContent dataContent = Assert.IsType<DataContent>(content);
                    Assert.Equal("image/png", dataContent.MediaType);
                    Assert.Equal(_imageContent.ToArray(), dataContent.Data.ToArray());
                });
 
                return Task.FromResult(new ChatResponse(new[]
                {
                    new ChatMessage(ChatRole.Assistant, JsonSerializer.Serialize(new Envelope<string[]> { data = descriptions }))
                }));
            }
        };
        ImageAlternativeTextEnricher sut = new(new(chatClient));
 
        IngestionDocumentImage documentImage = new($"![](nonExisting.png)")
        {
            AlternativeText = null,
            Content = _imageContent,
            MediaType = "image/png"
        };
 
        IngestionDocumentImage tableCell = new($"![](another.png)")
        {
            AlternativeText = null,
            Content = _imageContent,
            MediaType = "image/png"
        };
 
        IngestionDocumentImage imageWithAltText = new($"![](noChangesNeeded.png)")
        {
            AlternativeText = PreExistingAltText,
            Content = _imageContent,
            MediaType = "image/png"
        };
 
        IngestionDocumentImage imageWithNoContent = new($"![](noImage.png)")
        {
            AlternativeText = null,
            Content = default,
            MediaType = "image/png"
        };
 
        IngestionDocument document = new("withImage")
        {
            Sections =
            {
                new IngestionDocumentSection
                {
                    Elements =
                    {
                        documentImage,
                        new IngestionDocumentTable("nvm", new[,] { { tableCell } })
                    }
                }
            }
        };
 
        await sut.ProcessAsync(document);
 
        Assert.Equal(descriptions[0], documentImage.AlternativeText);
        Assert.Equal(descriptions[1], tableCell.AlternativeText);
        Assert.Same(PreExistingAltText, imageWithAltText.AlternativeText);
        Assert.Null(imageWithNoContent.AlternativeText);
    }
 
    [Theory]
    [InlineData(1, 3)]
    [InlineData(3, 7)]
    [InlineData(15, 3)]
    public async Task SendsOneRequestPerBatchSize(int batchSize, int batchCount)
    {
        int callsCount = 0;
        using TestChatClient chatClient = new()
        {
            GetResponseAsyncCallback = (messages, options, cancellationToken) =>
            {
                callsCount++;
 
                var materializedMessages = messages.ToArray();
 
                // One system message + one User message with all the contents
                Assert.Equal(2, materializedMessages.Length);
                Assert.Equal(ChatRole.System, materializedMessages[0].Role);
                Assert.Equal(ChatRole.User, materializedMessages[1].Role);
                Assert.Equal(batchSize, materializedMessages[1].Contents.Count);
 
                Assert.All(materializedMessages[1].Contents, content =>
                {
                    DataContent dataContent = Assert.IsType<DataContent>(content);
                    Assert.Equal("image/png", dataContent.MediaType);
                    Assert.Equal(_imageContent.ToArray(), dataContent.Data.ToArray());
                });
 
                Envelope<string[]> data = new() { data = Enumerable.Range(0, batchSize).Select(i => i.ToString()).ToArray() };
                return Task.FromResult(new ChatResponse(new[] { new ChatMessage(ChatRole.Assistant, JsonSerializer.Serialize(data)) }));
            }
        };
 
        ImageAlternativeTextEnricher sut = new(new(chatClient) { BatchSize = batchSize });
 
        IngestionDocument document = CreateDocument(batchSize, batchCount, _imageContent);
 
        await sut.ProcessAsync(document);
        Assert.Equal(batchCount, callsCount);
    }
 
    [Fact]
    public async Task FailureDoesNotStopTheProcessing()
    {
        FakeLogCollector collector = new();
        using ILoggerFactory loggerFactory = LoggerFactory.Create(b => b.AddProvider(new FakeLoggerProvider(collector)));
        using TestChatClient chatClient = new()
        {
            GetResponseAsyncCallback = (messages, options, cancellationToken) => Task.FromException<ChatResponse>(new ExpectedException())
        };
 
        EnricherOptions options = new(chatClient) { LoggerFactory = loggerFactory };
        ImageAlternativeTextEnricher sut = new(options);
 
        const int BatchCount = 2;
        IngestionDocument document = CreateDocument(options.BatchSize, BatchCount, _imageContent);
        IngestionDocument got = await sut.ProcessAsync(document);
 
        Assert.Equal(BatchCount, collector.Count);
        Assert.All(collector.GetSnapshot(), record =>
        {
            Assert.Equal(LogLevel.Error, record.Level);
            Assert.IsType<ExpectedException>(record.Exception);
        });
    }
 
    private static IngestionDocument CreateDocument(int batchSize, int batchCount, ReadOnlyMemory<byte> imageContent)
    {
        IngestionDocumentSection rootSection = new();
        for (int i = 0; i < batchSize * batchCount; i++)
        {
            IngestionDocumentImage image = new($"![](image{i}.png)")
            {
                Content = imageContent,
                MediaType = "image/png",
                AlternativeText = null
            };
 
            rootSection.Elements.Add(image);
        }
 
        return new("batchTest")
        {
            Sections = { rootSection }
        };
    }
}