using GermanApp.Domain.Entities;
using GermanApp.Domain.Interfaces;
using GermanApp.Infrastructure.Data.DbContext;
using Microsoft.EntityFrameworkCore;

namespace GermanApp.Infrastructure.Data.Repositories;

/// <summary>
/// Entity Framework Core implementation of ILessonRepository.
/// This is part of the Infrastructure layer.
/// </summary>
public class LessonRepository : ILessonRepository
{
    private readonly AppDbContext _context;

    public LessonRepository(AppDbContext context)
    {
        _context = context;
    }

    public async Task<Lesson?> GetByIdAsync(int id, CancellationToken cancellationToken = default)
    {
        return await _context.Lessons
            .FirstOrDefaultAsync(l => l.Id == id, cancellationToken);
    }

    public async Task<IReadOnlyList<Lesson>> GetAllAsync(CancellationToken cancellationToken = default)
    {
        return await _context.Lessons
            .AsNoTracking()
            .ToListAsync(cancellationToken);
    }

    public async Task<Lesson> AddAsync(Lesson entity, CancellationToken cancellationToken = default)
    {
        await _context.Lessons.AddAsync(entity, cancellationToken);
        await _context.SaveChangesAsync(cancellationToken);
        return entity;
    }

    public async Task UpdateAsync(Lesson entity, CancellationToken cancellationToken = default)
    {
        _context.Lessons.Update(entity);
        await _context.SaveChangesAsync(cancellationToken);
    }

    public async Task DeleteAsync(Lesson entity, CancellationToken cancellationToken = default)
    {
        _context.Lessons.Remove(entity);
        await _context.SaveChangesAsync(cancellationToken);
    }

    public async Task<bool> ExistsAsync(int id, CancellationToken cancellationToken = default)
    {
        return await _context.Lessons
            .AnyAsync(l => l.Id == id, cancellationToken);
    }

    public async Task<IReadOnlyList<Lesson>> GetByLevelAsync(int level, CancellationToken cancellationToken = default)
    {
        return await _context.Lessons
            .Where(l => l.Level == level)
            .AsNoTracking()
            .ToListAsync(cancellationToken);
    }

    public async Task<IReadOnlyList<Lesson>> GetBeginnerLessonsAsync(CancellationToken cancellationToken = default)
    {
        return await _context.Lessons
            .Where(l => l.Level <= 2)
            .AsNoTracking()
            .ToListAsync(cancellationToken);
    }

    public async Task<IReadOnlyList<Lesson>> GetAdvancedLessonsAsync(CancellationToken cancellationToken = default)
    {
        return await _context.Lessons
            .Where(l => l.Level >= 4)
            .AsNoTracking()
            .ToListAsync(cancellationToken);
    }
}