using Application.Abstractions.Data;
using Application.Abstractions.Messaging;
using Application.Abstractions.YouTube;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Admin.Channel.YouTubePubSub.GetLiveStatus;

internal sealed class Handler(
    IAppDbContext db,
    IYouTubeLiveStateStore liveStateStore
) : IQueryHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var liveInfos = await liveStateStore.GetAllLiveAsync();
        if (liveInfos.Count == 0)
        {
            return new Response([]);
        }

        var ytIds = liveInfos.Select(x => x.ChannelId).ToList();

        var channelNames = await db.Channel.AsNoTracking()
            .Where(c => c.YouTubeChannelID != null && ytIds.Contains(c.YouTubeChannelID))
            .Select(c => new { c.YouTubeChannelID, c.Name })
            .ToDictionaryAsync(x => x.YouTubeChannelID!, x => x.Name, ct);

        var items = liveInfos.Select(info => new LiveItem(
            info.ChannelId,
            channelNames.TryGetValue(info.ChannelId, out var name) ? name : null,
            info.VideoId,
            info.Title,
            info.ActualStartTime
        )).ToList();

        return new Response(items);
    }
}