// Copyright (c) Microsoft. All rights reserved.

using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Agents.AI;
using Microsoft.Extensions.AI;
using Moq;

namespace Microsoft.Agents.Orchestration.UnitTest;

/// <summary>
/// Mock definition of <see cref="AIAgent"/>.
/// </summary>
internal sealed class MockAgent(int index) : AIAgent
{
    public static MockAgent CreateWithResponse(int index, string response) => new(index)
    {
        Response = [new(ChatRole.Assistant, response)]
    };

    public int InvokeCount { get; private set; }

    public IReadOnlyList<ChatMessage> Response { get; set; } = [];

    public override string? Name => $"testagent{index}";

    public override string? Description => $"test {index}";

    public override AgentThread GetNewThread()
        => new Mock<AgentThread>().Object;

    public override AgentThread DeserializeThread(System.Text.Json.JsonElement serializedThread, System.Text.Json.JsonSerializerOptions? jsonSerializerOptions = null)
        => new Mock<AgentThread>().Object;

    public override Task<AgentRunResponse> RunAsync(IEnumerable<ChatMessage> messages, AgentThread? thread = null, AgentRunOptions? options = null, CancellationToken cancellationToken = default)
    {
        this.InvokeCount++;

        return Task.FromResult(new AgentRunResponse(messages: [.. this.Response]));
    }

    public override IAsyncEnumerable<AgentRunResponseUpdate> RunStreamingAsync(IEnumerable<ChatMessage> messages, AgentThread? thread = null, AgentRunOptions? options = null, CancellationToken cancellationToken = default)
    {
        this.InvokeCount++;

        return this.Response.Select(message => new AgentRunResponseUpdate(message.Role, message.Text)).ToAsyncEnumerable();
    }
}