using DigitalData.Core.Abstractions.Infrastructure;
using Microsoft.EntityFrameworkCore;
using System.Linq.Expressions;

namespace DigitalData.Core.Infrastructure;

public class DbRepository<TDbContext, TEntity> : IRepository<TEntity> where TDbContext : DbContext where TEntity : class
{
    protected internal readonly TDbContext Context;

    protected internal readonly DbSet<TEntity> Entities;
    public IEntityMapper<TEntity> Mapper { get; }

    public DbRepository(TDbContext context, Func<TDbContext, DbSet<TEntity>> queryFactory, IEntityMapper<TEntity> mapper)
    {
        Context = context;
        Entities = queryFactory(context);
        Mapper = mapper;
    }

    public virtual async Task<TEntity> CreateAsync(TEntity entity, CancellationToken ct = default)
    {
        Entities.Add(entity);
        await Context.SaveChangesAsync(ct);
        return entity;
    }

    public virtual async Task<IEnumerable<TEntity>> CreateAsync(IEnumerable<TEntity> entities, CancellationToken ct = default)
    {
        Entities.AddRange(entities);
        await Context.SaveChangesAsync(ct);
        return entities;
    }

    public virtual Task<TEntity> CreateAsync<TDto>(TDto dto, CancellationToken ct = default)
    {
        var entity = Mapper.Map(dto);
        return CreateAsync(entity, ct);
    }

    public virtual Task<IEnumerable<TEntity>> CreateAsync<TDto>(IEnumerable<TDto> dtos, CancellationToken ct = default)
    {
        var entities = dtos.Select(dto => Mapper.Map(dto));
        return CreateAsync(entities, ct);
    }

    public virtual async Task<IEnumerable<TEntity>> ReadAsync(Expression<Func<TEntity, bool>>? expression = null, CancellationToken ct = default)
        => expression is null
            ? await Entities.AsNoTracking().ToListAsync(ct)
            : await Entities.AsNoTracking().Where(expression).ToListAsync(ct);

    public virtual async Task UpdateAsync<TDto>(TDto dto, Expression<Func<TEntity, bool>> expression, CancellationToken ct = default)
    {
        var entities = await Entities.Where(expression).ToListAsync(ct);

        foreach (var entity in entities)
        {
            Mapper.Map(dto, entity);
            Entities.Add(entity);
        }

        await Context.SaveChangesAsync(ct);
    }

    public virtual async Task DeleteAsync(Expression<Func<TEntity, bool>> expression, CancellationToken ct = default)
    {
        var entities = await Entities.Where(expression).ToListAsync(ct);

        foreach (var entity in entities)
        {
            entities.Remove(entity);
        }

        await Context.SaveChangesAsync(ct);
    }
}