using FastEndpoints;
using MetaCourse.Api.Data;
using MetaCourse.Api.Entities;
using Microsoft.EntityFrameworkCore;

namespace MetaCourse.Api.Endpoints.Topics;

public class LinkResourceRequest
{
    public Guid TopicId { get; set; }
    public Guid ResourceId { get; set; }
    public int Position { get; set; } = 1;
}

public class LinkResourceToTopicEndpoint(AppDbContext db) : Endpoint<LinkResourceRequest>
{
    public override void Configure()
    {
        Post("api/topics/{topicId}/resources/{resourceId}");
        AllowAnonymous();
        Summary(s => s.Summary = "Associe une ressource à un sujet");
    }

    public override async Task HandleAsync(LinkResourceRequest req, CancellationToken ct)
    {
        var topicExists = await db.Topics.AnyAsync(t => t.Id == req.TopicId, ct);
        if (!topicExists)
        {
            AddError("Le sujet n'existe pas.");
            await SendErrorsAsync(404, ct);
            return;
        }

        var resourceExists = await db.Resources.AnyAsync(r => r.Id == req.ResourceId, ct);
        if (!resourceExists)
        {
            AddError("La ressource n'existe pas.");
            await SendErrorsAsync(404, ct);
            return;
        }

        var alreadyLinked = await db.TopicResources
            .AnyAsync(tr => tr.TopicId == req.TopicId && tr.ResourceId == req.ResourceId, ct);

        if (alreadyLinked)
        {
            AddError("Cette ressource est déjà associée à ce sujet.");
            await SendErrorsAsync(409, ct);
            return;
        }

        db.TopicResources.Add(new TopicResource
        {
            TopicId = req.TopicId,
            ResourceId = req.ResourceId,
            Position = req.Position
        });
        await db.SaveChangesAsync(ct);
        await SendNoContentAsync(ct);
    }
}