#nullable enable
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using UserService.DatabaseLayer.DataModels;

namespace UserService.DatabaseLayer.Repository
{
    public class BaseRepository<T> where T : Node
    {
        protected readonly Func<UserServiceDbContext, DbSet<T>> Context;

        protected BaseRepository(Func<UserServiceDbContext, DbSet<T>> context)
        {
            Context = context;
        }

        public virtual async Task<IReadOnlyList<T>> GetAllAsync(Expression<Func<T, bool>>? predicate = null, CancellationToken token = default)
        {
            await using var db = new UserServiceDbContext();

            IQueryable<T> queryable = Context(db).Include(x => x.Parent);
            if(queryable != null) queryable = queryable.Where(predicate);
            return await queryable.ToListAsync(token);
        }

        public async Task<T?> GetAsync(Expression<Func<T, bool>> predicate, CancellationToken token = default)
        {
            await using var db = new UserServiceDbContext();
            return await Context(db).FirstOrDefaultAsync(predicate, token);
        }

        public async Task AddAsync(T entity, CancellationToken token = default)
        {
            await using var db = new UserServiceDbContext();
            await Context(db).AddAsync(@entity, token);
            await db.SaveChangesAsync(token);
        }

        public async Task UpdateAsync(T entity, CancellationToken token = default)
        {
            await using var db = new UserServiceDbContext();
            Context(db).Update(entity);
            await db.SaveChangesAsync(token);
        }

        public async Task DeleteAsync(T entity, CancellationToken token = default)
        {
            await using var db = new UserServiceDbContext();
            Context(db).Remove(entity);
            await db.SaveChangesAsync(token);
        }
    }
}