components/LiteCharms.Features.MidrandBooks/Authors/AuthorService.cs

using LiteCharms.Features.MidrandBooks.Abstractions;
using LiteCharms.Features.MidrandBooks.AuthorBooks.Models;
using LiteCharms.Features.MidrandBooks.Authors.Models;
using LiteCharms.Features.MidrandBooks.Extensions;
using LiteCharms.Features.MidrandBooks.Postgres;
using LiteCharms.Features.Models;

namespace LiteCharms.Features.MidrandBooks.Authors;

public sealed class AuthorService(IDbContextFactory<MidrandBooksDbContext> contextFactory) : IService
{
    public async ValueTask<Result<AuthorBook[]>> GetAuthorBooksAsync(long authorId, CancellationToken cancellationToken)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var author = await context.Authors.FirstOrDefaultAsync(a => a.Id == authorId, cancellationToken);

            if (author is null)
                return Result.Fail<AuthorBook[]>(new Error($"Author with ID {authorId} not found"));

            var books = await context.Books
                .AsNoTracking()
                .Include(b => b.Author)
                .Include(b => b.Product!.Price)
                .OrderByDescending(b => b.CreatedAt)
                .Where(p => p.AuthorId == authorId)
                .AsSplitQuery()                
                .ToArrayAsync(cancellationToken);

            return books?.Length > 0
                ? Result.Ok(books.Select(b => b.ToModel()).ToArray())
                : Result.Fail<AuthorBook[]>(new Error($"No books found for author with ID {authorId}"));
        }
        catch (Exception ex)
        {
            return Result.Fail<AuthorBook[]>(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> UpdateAuthorStatusAsync(long authorId, bool isEnabled, CancellationToken cancellationToken)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var author = await context.Authors.FirstOrDefaultAsync(a => a.Id == authorId, cancellationToken);

            if (author is null)
                return Result.Fail(new Error($"Author with ID {authorId} not found"));

            author.UpdatedAt = DateTime.UtcNow;
            author.Enabled = isEnabled;

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail(new Error($"Failed to change status of author with ID {authorId}"));
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Author>> GetAuthorAsync(long authorId, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var author = await context.Authors.FirstOrDefaultAsync(a => a.Id == authorId, cancellationToken);

            return author is not null
                ? Result.Ok(author.ToModel())
                : Result.Fail<Author>(new Error($"Author with ID {authorId} not found"));
        }
        catch (Exception ex)
        {
            return Result.Fail<Author>(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Author[]>> GetAuthors(DateRange range, CancellationToken cancellationToken)
    {
        try
        {
            var fromDate = range.From.ToDateTime(TimeOnly.MinValue);
            var toDate = range.To.ToDateTime(TimeOnly.MaxValue);

            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var authors = await context.Authors.AsNoTracking()
               .OrderByDescending(o => o.CreatedAt)
                .ThenByDescending(o => o.UpdatedAt)
               .Where(a => a.CreatedAt >= fromDate && a.CreatedAt <= toDate)
               .Take(range.MaxRecords)
               .ToArrayAsync(cancellationToken);

            return authors?.Length > 0
                ? Result.Ok(authors.Select(a => a.ToModel()).ToArray())
                : Result.Fail<Author[]>(new Error("No authors found in the specified date range."));
        }
        catch (Exception ex)
        {
            return Result.Fail<Author[]>(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> UpdateAuthorAsync(long authorId, UpdateAuthor request, CancellationToken cancellationToken)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (await context.Authors.AnyAsync(a => a.Name == request.Name && a.LastName == request.LastName, cancellationToken))
                return Result.Fail(new Error($"An author with the name {request.Name} {request.LastName} already exists"));

            if (await context.Authors.AnyAsync(a => a.Email == request.Email, cancellationToken))
                return Result.Fail(new Error($"An author with the email {request.Email} already exists"));

            var author = await context.Authors.FirstOrDefaultAsync(a => a.Id == authorId, cancellationToken);

            if (author is null)
                return Result.Fail(new Error($"Author with ID {authorId} not found"));

            author.UpdatedAt = DateTime.UtcNow;
            author.PublisherType = request.PublisherType;
            author.Company = request.Company;
            author.VatNumber = request.VatNumber;
            author.Name = request.Name;
            author.LastName = request.LastName;
            author.Biography = request.Biography;
            author.Email = request.Email;
            author.Website = request.Website;
            author.ImageUrl = request.ImageUrl;
            author.ThumbnailImageUrl = request.ThumbnailImageUrl;
            author.SocialMedia = request.SocialMedia;

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail(new Error($"Failed to update author with ID {authorId}"));
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<long>> CreateAuthorAsync(CreateAuthor request, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if(await context.Authors.AnyAsync(a => a.Name == request.Name && a.LastName == request.LastName, cancellationToken))
                return Result.Fail<long>(new Error($"An author with the name {request.Name} {request.LastName} already exists"));

            if(await context.Authors.AnyAsync(a => a.Email == request.Email, cancellationToken))
                return Result.Fail<long>(new Error($"An author with the email {request.Email} already exists"));

            var newAuthor = context.Authors.Add(new Entities.Author
            {
                Company = request.Company,
                VatNumber = request.VatNumber,
                PublisherType = request.PublisherType,
                Name = request.Name,
                LastName = request.LastName,
                Biography = request.Biography,
                Email = request.Email,
                Website = request.Website,
                ImageUrl = request.ImageUrl,
                ThumbnailImageUrl = request.ThumbnailImageUrl,
                SocialMedia = request.SocialMedia
            });

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok(newAuthor.Entity.Id)
                : Result.Fail<long>(new Error($"Failed to create author {request.Name} {request.LastName}"));
        }
        catch (Exception ex)
        {
            return Result.Fail<long>(new Error(ex.Message).CausedBy(ex));
        }
    }
}