bibblan/Server/Business/Services/DatabaseService.cs

using Bibblan.Models;
using Bibblan.ViewModels;
using Dapper;
using Microsoft.Extensions.Options;
using Npgsql;

namespace Bibblan.Business.Services
{

    public class BookFilter
    {
        public int? Id;
        public int? Author;
        public string? Query;
    }

    public class DatabaseService(IOptions<BibblanOptions> options)
    {
        readonly BibblanOptions settings = options.Value;

        public List<Books> GetBooks(int count, BookFilter filter = null)
        {
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            var query = "select * from books";
            object parameters = null;
            if (filter != null)
            {
                query += " where ";
                if(filter.Author != null)
                {
                    query += $"id in (select book from books_authors_link where author = {filter.Author})";
                } 
                else if(filter.Id != null)
                {
                    query += $"id = {filter.Id}";
                }
                else if(!String.IsNullOrWhiteSpace(query))
                {
                    filter.Query = filter.Query.ToLowerInvariant();
                    query += $"lower(title) like @query or lower(author_sort) like @query";
                    parameters = new { query = "%" + filter.Query + "%" };
                }
            }
            return conn.Query<Books>(query, parameters).Take(count).ToList();
        }

        public BookDetailVm GetBookDetails(int id)
        {
            var query = @"select * from books where id = @book;
                select * from authors where id in (select author from books_authors_link where book = @book);
                select * from books_languages_link where book = @book;
                select * from publishers where id in (select publisher from books_publishers_link where book = @book);
                select * from books_ratings_link where book = @book;
                select * from series where id in (select series from books_series_link where book = @book);
                select * from tags where id in (select tag from books_tags_link where book = @book);
                select * from comments  where book = @book;
                select * from data where book = @book;";

            using (var conn = new NpgsqlConnection(settings.BibblanConnection))
            {
                var results = conn.QueryMultiple(query, new { book = id });
                var book = results.ReadFirst<Books>();
                var authors = results.Read<Authors>();
                var lang = results.Read<BooksLanguagesLink>();
                var publishers = results.Read<Publishers>();
                var ratings = results.Read<BooksRatingsLink>();
                var series = results.Read<Series>();
                var tags = results.Read<Tags>();
                var comments = results.Read<Comments>();
                var data = results.Read<Data>();

                return new BookDetailVm
                {
                    Book = book,
                    Authors = authors,
                    Language = lang,
                    Publishers = publishers,
                    Ratings = ratings,
                    Series = series,
                    Tags = tags,
                    Comments = comments,
                    Data = data
                };
            }

        }

        public IEnumerable<AuthorVm> GetAuthors(int count, BookFilter filter = null)
        {
            var query = "select a.id, a.name, count(bal.*) as bookcount\r\nfrom authors a\r\nleft join books_authors_link bal on a.id  = bal.author\r\ngroup by a.id , a.name ";
            object parameters = null;
            if (!String.IsNullOrWhiteSpace(filter?.Query))
            {
                filter.Query = filter.Query.ToLowerInvariant();
                query += $" having lower(a.name) like @query";
                parameters = new { query = "%" + filter.Query + "%" };
            }
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            return conn.Query<AuthorVm>(query, parameters).Take(count).ToList();

        }

        internal List<SeriesVm> GetSeries(int count, BookFilter? filter)
        {
            var query = @"select s.id as seriesid, s.name as seriesname, b.*, a.* 
                from series s
                inner join books_series_link bsl on s.id = bsl.series
                inner join books b on bsl.book = b.id
                inner join books_authors_link bal on b.id = bal.book 
                inner join authors a on bal.author = a.id";
            object parameters = null;
            if (!String.IsNullOrWhiteSpace(filter?.Query))
            {
                filter.Query = filter.Query?.ToLowerInvariant().Trim() ?? "";
                query += $" where lower(s.name) like @query";
                parameters = new { query = "%" + filter.Query + "%" };
            }
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            var lookup = new Dictionary<long, SeriesVm>();
            conn.Query<SeriesVm, Books, Authors, SeriesVm>(query, (s,b,a) =>
            {
                if (!lookup.TryGetValue(s.Id, out SeriesVm svm))
                {
                    lookup.Add(s.Id, svm = s);
                }
                svm.Books.Add(new ListBook
                {
                    AuthorId = a.Id,
                    AuthorName = a.Name,
                    Id = b.Id,
                    PubDate = b.Pubdate,
                    HasCover = b.HasCover,
                    Path = b.Path,
                    SeriesIndex = b.SeriesIndex,
                    Title = b.Title
                });
                return svm;
            }, splitOn: "id", param: parameters);
            return lookup.Values.Take(count).ToList();
        }

        internal List<Tag> GetTags(BookFilter? filter)
        {
            var query = @"select t.id, t.name, count(btl.*) as bookcount from tags t
                inner join books_tags_link btl on t.id = btl.tag 
                group by t.id, t.name
                order by bookcount desc";
            object parameters = null;
            if (!String.IsNullOrWhiteSpace(filter?.Query))
            {
                filter.Query = filter.Query.ToLowerInvariant();
                query += $" having lower(name) like @query";
                parameters = new { query = "%" + filter.Query + "%" };
            }
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            return conn.Query<Tag>(query,parameters).ToList();
        }
    }
}