using FastEndpoints;
using MetaCourse.Api.Data;
using MetaCourse.Api.DTOs.Progress;
using Microsoft.EntityFrameworkCore;

namespace MetaCourse.Api.Endpoints.Progress;

public class GetCourseProgressRequest
{
    public Guid CourseId { get; set; }
    public Guid UserId { get; set; }
}

public class GetCourseProgressEndpoint(AppDbContext db) : Endpoint<GetCourseProgressRequest, CourseProgressDto>
{
    public override void Configure()
    {
        Get("api/courses/{courseId}/progress");
        AllowAnonymous();
        Summary(s => s.Summary = "Retourne la progression d'un utilisateur dans un cours");
    }

    public override async Task HandleAsync(GetCourseProgressRequest req, CancellationToken ct)
    {
        var course = await db.Courses
            .AsNoTracking()
            .Include(c => c.Topics)
                .ThenInclude(t => t.TopicResources)
            .FirstOrDefaultAsync(c => c.Id == req.CourseId, ct);

        if (course is null)
        {
            await SendNotFoundAsync(ct);
            return;
        }

        var topicIds = course.Topics.Select(t => t.Id).ToList();
        var resourceIds = course.Topics
            .SelectMany(t => t.TopicResources.Select(tr => tr.ResourceId))
            .Distinct()
            .ToList();

        var completedTopics = await db.UserTopicProgresses
            .CountAsync(p => p.UserId == req.UserId && topicIds.Contains(p.TopicId) && p.Completed, ct);

        var completedResources = await db.UserResourceProgresses
            .CountAsync(p => p.UserId == req.UserId && resourceIds.Contains(p.ResourceId) && p.Completed, ct);

        var totalTopics = topicIds.Count;
        var totalResources = resourceIds.Count;

        var percentage = totalTopics == 0 ? 0 :
            Math.Round((completedTopics + completedResources) / (double)(totalTopics + totalResources) * 100, 1);

        await SendOkAsync(new CourseProgressDto
        {
            CourseId = req.CourseId,
            UserId = req.UserId,
            TotalTopics = totalTopics,
            CompletedTopics = completedTopics,
            TotalResources = totalResources,
            CompletedResources = completedResources,
            ProgressPercentage = percentage
        }, ct);
    }
}