// 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.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Shared.Diagnostics;
 
namespace Microsoft.Extensions.AI.Evaluation.Safety;
 
/// <summary>
/// An <see cref="IEvaluator"/> that utilizes the Azure AI Foundry Evaluation service to evaluate the groundedness of
/// responses produced by an AI model.
/// </summary>
/// <remarks>
/// <para>
/// The <see cref="GroundednessProEvaluator"/> measures the degree to which the response being evaluated is grounded in
/// the information present in the supplied <see cref="GroundednessProEvaluatorContext.GroundingContext"/>. It returns
/// a <see cref="NumericMetric"/> that contains a score for the groundedness. The score is a number between 1 and 5,
/// with 1 indicating a poor score, and 5 indicating an excellent score.
/// </para>
/// <para>
/// Note that <see cref="GroundednessProEvaluator"/> does not support evaluation of multimodal content present in the
/// evaluated responses. Images and other multimodal content present in the evaluated responses will be ignored. Also
/// note that if a multi-turn conversation is supplied as input, <see cref="GroundednessProEvaluator"/> will only
/// evaluate the contents of the last conversation turn. The contents of previous conversation turns will be ignored.
/// </para>
/// <para>
/// The Azure AI Foundry Evaluation service uses a finetuned model to perform this evaluation which is expected to
/// produce more accurate results than similar evaluations performed using a regular (non-finetuned) model.
/// </para>
/// </remarks>
public sealed class GroundednessProEvaluator()
    : ContentSafetyEvaluator(
        contentSafetyServiceAnnotationTask: "groundedness",
        metricNames: new Dictionary<string, string> { ["generic_groundedness"] = GroundednessProMetricName })
{
    /// <summary>
    /// Gets the <see cref="EvaluationMetric.Name"/> of the <see cref="NumericMetric"/> returned by
    /// <see cref="GroundednessProEvaluator"/>.
    /// </summary>
    public static string GroundednessProMetricName => "Groundedness Pro";
 
    /// <inheritdoc/>
    public override async ValueTask<EvaluationResult> EvaluateAsync(
        IEnumerable<ChatMessage> messages,
        ChatResponse modelResponse,
        ChatConfiguration? chatConfiguration = null,
        IEnumerable<EvaluationContext>? additionalContext = null,
        CancellationToken cancellationToken = default)
    {
        _ = Throw.IfNull(chatConfiguration);
        _ = Throw.IfNull(modelResponse);
 
        EvaluationResult result =
            await EvaluateContentSafetyAsync(
                chatConfiguration.ChatClient,
                messages,
                modelResponse,
                additionalContext,
                contentSafetyServicePayloadFormat: ContentSafetyServicePayloadFormat.QuestionAnswer.ToString(),
                cancellationToken: cancellationToken).ConfigureAwait(false);
 
        GroundednessProEvaluatorContext context = GetRelevantContext(additionalContext);
        result.AddOrUpdateContextInAllMetrics(context);
 
        return result;
    }
 
    /// <inheritdoc/>
    protected override IReadOnlyList<EvaluationContext>? FilterAdditionalContext(
        IEnumerable<EvaluationContext>? additionalContext)
    {
        GroundednessProEvaluatorContext context = GetRelevantContext(additionalContext);
        return [context];
    }
 
    private static GroundednessProEvaluatorContext GetRelevantContext(
        IEnumerable<EvaluationContext>? additionalContext)
    {
        if (additionalContext?.OfType<GroundednessProEvaluatorContext>().FirstOrDefault()
                is GroundednessProEvaluatorContext context)
        {
            return context;
        }
 
        throw new InvalidOperationException(
            $"A value of type '{nameof(GroundednessProEvaluatorContext)}' was not found in the '{nameof(additionalContext)}' collection.");
    }
}