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

namespace Bibblan.Business.Services
{

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

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

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

        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 ";
            if(!String.IsNullOrWhiteSpace(filter?.Query))
            {
                filter.Query = filter.Query.ToLowerInvariant();
                query += $" having lower(a.name) like '%{filter.Query}%'";
            }
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            return conn.Query<AuthorVm>(query).Take(count).ToList();

        }

        internal List<SeriesVm> GetSeries(int count, BookFilter? filter)
        {
            var query = @"select s.id as seriesid, s.name as seriesname, b.*, a.* 
                --b.id as bookid, b.title, b.pubdate, b.series_index, 
                --a.id as authorid, a.name as authorname 
                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";
            if (!String.IsNullOrWhiteSpace(filter?.Query))
            {
                filter.Query = filter.Query?.ToLowerInvariant().Trim() ?? "";
                query += $" where lower(s.name) like '%{filter.Query}%'";
            }
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            var lookup = new Dictionary<long, SeriesVm>();
            conn.Query<SeriesVm, Books, Authors, SeriesVm>(query, (s,b,a) =>
            {
                SeriesVm svm;
                if (!lookup.TryGetValue(s.Id, out svm))
                {
                    lookup.Add(s.Id, svm = s);
                }
                svm.Books.Add(new ListBook
                {
                    AuthorId = a.Id,
                    AuthorName = a.Name,
                    Id = b.Id,
                    PubDate = b.Pubdate,
                    SeriesIndex = b.SeriesIndex,
                    Title = b.Title
                    
                });
                return svm;
            }, splitOn: "id").Take(count).ToList();
            return lookup.Values.AsList();
        }

        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";
            if (!String.IsNullOrWhiteSpace(filter?.Query))
            {
                filter.Query = filter.Query.ToLowerInvariant();
                query += $" having lower(name) like '%{filter.Query}%'";
            }
            var conn = new NpgsqlConnection(settings.BibblanConnection);
            return conn.Query<Tag>(query).ToList();
        }
    }
}