using SharpChat.Events;
using System.Collections.Generic;
using System.Linq;

namespace SharpChat.EventStorage {
    public class VirtualEventStorage : IEventStorage {
        private readonly Dictionary<string, ChatEventInfo> Events = new();

        public void HandleEvent(ChatEventInfo info) {
            Events.Add(info.Id.ToString(), info);

            if(info.Type.Equals("msg:delete") && info.Data is MessageDeleteEventData msgDelete)
                Events.Remove(msgDelete.MessageId);
        }

        public ChatEventInfo? GetEvent(long eventId) {
            return Events.TryGetValue(eventId.ToString(), out ChatEventInfo? evt) ? evt : null;
        }

        public IEnumerable<ChatEventInfo> GetChannelEventLog(string channelName, int amount = 20, int after = 0) {
            IEnumerable<ChatEventInfo> subset = Events.Values.Where(ev => ev.ChannelName == channelName);

            int start = subset.Count() - after - amount;
            if(start < 0) {
                amount += start;
                start = 0;
            }

            return subset.Skip(start).Take(amount).ToArray();
        }
    }
}