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>();
		private readonly Iesi.Collections.Generic.ISet<Category> categories = new HashedSet<Category>();

		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 IEnumerable<Category> Categories { get { return categories; } }

		#region adding and removing stuff
		public virtual Quote AddCategory(Category category) {
			categories.Add(category);
			return this;
		}

		public virtual void ClearCategories() {
			categories.Clear();
		}

		public virtual Quote AddFlag(QuoteFlag flag) {
			flags.Add(flag);
			return this;
		}

		public virtual void ClearFlags() {
			flags.Clear();
		}
		#endregion

		public virtual Quote 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 });
			}

			return this;
		}

		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); } }
	}

	public static class QuoteExtensions {
		public static string GetHumanReadableTimeSinceCreated(this Quote quote) {
			var timespan = DateTime.UtcNow.Subtract(quote.Created);
			if (timespan.TotalDays >= 365) {
				var years = (int)Math.Round(timespan.TotalDays / 365);
				return years == 1 ? "1 year ago" : years + " years ago";
			}

			if (timespan.TotalDays >= 50) {
				var months = (int)Math.Round(timespan.TotalDays / 30);
				return months == 1 ? "1 month ago" : months + " months ago";
			}

			if (timespan.TotalDays >= 10) {
				var weeks = (int)Math.Round(timespan.TotalDays / 7);
				return weeks == 1 ? "1 week ago" : weeks + " weeks ago";
			}

			if (timespan.TotalDays >= 1) {
				return (int)timespan.TotalDays == 1 ? "1 day ago" : (int)timespan.TotalDays + " days ago";
			}

			if (timespan.TotalMinutes >= 90) {
				return (int)timespan.TotalHours == 1 ? "1 hour ago" : (int)timespan.TotalHours + " hours ago";
			}

			if (timespan.TotalSeconds >= 90) {
				return (int)timespan.TotalMinutes == 1 ? "1 minute ago" : (int)timespan.TotalMinutes + " minutes ago";
			}

			return (int)timespan.TotalSeconds == 1 ? "1 second ago" : (int)timespan.TotalSeconds + " seconds ago";
		}
	}

}