using BuildFlow.Platform.Application.Users.DTOs;
using BuildFlow.Platform.Application.Users.Queries;
using FluentAssertions;
using IM.Application.Chat.Commands;
using IM.Application.Chat.Handlers;
using IM.Domain.Enums;
using IM.Infrastructure.Persistence;
using MediatR;
using Microsoft.EntityFrameworkCore;
using Moq;
using Xunit;

namespace BuildFlow.IM.Tests.Chat;

/// <summary>
/// CreatePrivateConversationCommandHandler：幂等创建私聊（A↔B 仅一条），返回 OtherUserId。
/// </summary>
public class CreatePrivateConversationCommandHandlerTests
{
    private static readonly Guid Current = Guid.Parse("22222222-2222-2222-2222-222222222222");
    private static readonly Guid Target = Guid.Parse("33333333-3333-3333-3333-333333333333");

    private static IMediator NewMediator()
    {
        var mediator = new Mock<IMediator>();
        mediator.Setup(m => m.Send(It.IsAny<GetUserSummariesQuery>(), It.IsAny<CancellationToken>()))
               .ReturnsAsync(new Dictionary<Guid, UserSummaryDto> { [Target] = new UserSummaryDto(Target, "Bob", null) });
        return mediator.Object;
    }

    [Fact]
    public async Task Creates_new_private_conversation()
    {
        await using var db = IMTestDb.Create();
        var handler = new CreatePrivateConversationCommandHandler(db, NewMediator());
        var result = await handler.Handle(new CreatePrivateConversationCommand(Current, Target), CancellationToken.None);

        result.Type.Should().Be(ConversationTypeEnum.Private);
        result.OtherUserId.Should().Be(Target);
        (await db.Conversations.CountAsync(c => c.Type == ConversationTypeEnum.Private)).Should().Be(1);
    }

    [Fact]
    public async Task Returns_same_conversation_when_called_again()
    {
        await using var db = IMTestDb.Create();
        var handler = new CreatePrivateConversationCommandHandler(db, NewMediator());
        var first = await handler.Handle(new CreatePrivateConversationCommand(Current, Target), CancellationToken.None);
        var second = await handler.Handle(new CreatePrivateConversationCommand(Current, Target), CancellationToken.None);

        second.Id.Should().Be(first.Id);
        (await db.Conversations.CountAsync(c => c.Type == ConversationTypeEnum.Private)).Should().Be(1);
    }
}