using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using ErsatzTV.Core.Interfaces.Repositories;
using ErsatzTV.Infrastructure.Data;
using ErsatzTV.Infrastructure.Extensions;
using LanguageExt;
using MediatR;
using Microsoft.EntityFrameworkCore;

namespace ErsatzTV.Application.MediaItems.Queries
{
    public class GetAllLanguageCodesHandler : IRequestHandler<GetAllLanguageCodes, List<CultureInfo>>
    {
        private readonly IDbContextFactory<TvContext> _dbContextFactory;
        private readonly IMediaItemRepository _mediaItemRepository;

        public GetAllLanguageCodesHandler(
            IDbContextFactory<TvContext> dbContextFactory,
            IMediaItemRepository mediaItemRepository)
        {
            _dbContextFactory = dbContextFactory;
            _mediaItemRepository = mediaItemRepository;
        }

        public async Task<List<CultureInfo>> Handle(GetAllLanguageCodes request, CancellationToken cancellationToken)
        {
            await using TvContext dbContext = _dbContextFactory.CreateDbContext();
            
            var result = new System.Collections.Generic.HashSet<CultureInfo>();

            CultureInfo[] allCultures = CultureInfo.GetCultures(CultureTypes.NeutralCultures);
            List<string> mediaCodes = await _mediaItemRepository.GetAllLanguageCodes();
            foreach (string mediaCode in mediaCodes)
            {
                foreach (string code in await dbContext.LanguageCodes.GetAllLanguageCodes(mediaCode))
                {
                    Option<CultureInfo> maybeCulture = allCultures.Find(
                        c => string.Equals(code, c.ThreeLetterISOLanguageName, StringComparison.OrdinalIgnoreCase));
                    foreach (CultureInfo culture in maybeCulture)
                    {
                        result.Add(culture);
                    }
                }
            }

            return result.ToList();
        }
    }
}