AIsOfCatan.StarterAgent.HandleTrade C# (CSharp) Method

        public ITrade HandleTrade(IGameState state, ITrade offer, int proposingPlayerId)
        {
            // accept if convert extras to needed and opponent < 7 points
            List<Resource> extras = new List<Resource>();
            foreach (Resource r in Enum.GetValues(typeof(Resource)))
            {
                int extra = state.GetOwnResources().Count(res => res == r) - 1;
                for (int i = 0; i < extra; i++) extras.Add(r);
            }

            // good offer?
            var valid = offer.Give.Where(o => o.All(r => o.Count(cur => cur == r) <= extras.Count(e => e == r)));

            if (valid.Count() == 0) return offer.Decline();

            // take the one with least cards to give, and then by most duplicates
            List<Resource> bestGive = valid.OrderBy(o => o.Count)
                .ThenByDescending(o => state.GetOwnResources().Sum(r => state.GetOwnResources().Count(res => res == r)))
                .First();

            // find best "take" (cards we get) kind of the opposite of above
            List<Resource> bestTake = offer.Take.OrderBy(o => o.Count)
                .ThenBy(o => state.GetOwnResources().Sum(r => state.GetOwnResources().Count(res => res == r)))
                .First();

            return offer.Respond(bestGive, bestTake);
        }