using System;
using System.Collections.Generic;
using System.Linq;
using Iesi.Collections.Generic;
using Portoa.Persistence;

namespace VideoGameQuotes.Api {
	public class Quote : Entity<Quote, int> {
		private readonly Iesi.Collections.Generic.ISet<Vote> votes = new HashedSet<Vote>();
		private readonly Iesi.Collections.Generic.ISet<QuoteFlag> flags = new HashedSet<QuoteFlag>();

		public Quote() {
			Created = DateTime.UtcNow;
		}

		public virtual User Creator { get; set; }
		public virtual DateTime Created { get; set; }
		public virtual DateTime? Modified { get; set; }

		public virtual string Text { get; set; }
		public virtual Game Game { get; set; }

		public virtual IEnumerable<Vote> Votes { get { return votes; } }
		public virtual IEnumerable<QuoteFlag> Flags { get { return flags; } }

		public virtual void VoteFor(User user, VoteDirection direction) {
			var currentVote = votes.SingleOrDefault(vote => vote.Voter == user);
			if (currentVote != null) {
				if (currentVote.Direction == direction) {
					throw new CannotVoteTwiceException();
				}

				votes.Remove(currentVote);
				currentVote.Direction = direction;
				currentVote.Created = DateTime.UtcNow;
				votes.Add(currentVote);
			} else {
				votes.Add(new Vote { Direction = direction, Quote = this, Voter = user });
			}
		}

		public virtual int UpVotes { get { return Votes.Count(vote => vote.Direction == VoteDirection.Up); } }
		public virtual int DownVotes { get { return Votes.Count(vote => vote.Direction == VoteDirection.Down); } }
		public virtual int NetVotes { get { return Votes.Sum(vote => (int)vote); } }
	}
}