%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% WAR SIMULATOR
% by: Eric Sorensen
% 10/23/2009
% http://www.esorensen.com
%
% Usage: Adjust variables in the USER SETUP section to run the simulation. 
% After all games are finished (it may take awhile if you run alot) stat-
% istics can be found in the variables starting with g_:
%
% g_rounds: Rounds for the game to end
% g_wars: Wars in the game
% g_nest: Maximum number of "nested" wars in a game 
% g_winner: Winner of the round. In the case of a neverending game, 
%           this is the player with the most cards when the round limit
%           is reached.
%
% g_stuck: 1 if the round limit is reached, 0 otherwise. 
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


format compact;
clear;

%%%%%%%%%%%%%%%%%%%%USER SETUP************************

%how many games to play 
number_of_games = 5000;
   
%number of face-down cards included in each war (usually 2 or 3)
war_cards = 3; 

%point at which a game is declared unwinnable 
round_limit = 5000;

%hand generation: 
cards_in_hand = 26; 

%include random factor? 
random_factor = 1; %0 = NO, 1 = YES

%If the random factor is enabled, the order in which cards are placed on 
%the bottom of the deck is randomly flipped. This simulates how *most*
%people probably play war. If the random factor is disabled, the same
%procedure is used in determining card order on every hand. 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%----------Do not edit below this line-----------------------%


%initialize multi-game stat variables 
g_stuck = zeros(1,number_of_games); 
g_winner = zeros(1,number_of_games); 
g_wars = zeros(1,number_of_games);
g_nest = zeros(1,number_of_games); 
g_rounds = zeros(1,number_of_games); 

for game = 1:number_of_games %setup number of games to play and collect stats for 

    %setup the deck: 
    deck_indexes = randperm(52);  %fifty two random deck locations

    %randomly place all 52 cards
    deck = zeros(1,52); 
    for x = 1:13
        for y = 1:4
            position = (y * 13) - 13 + x; 
            index = deck_indexes(position);
            deck(index) = x; 
        end
    end

    %setup each hand: 
    deal1 = deck(1:cards_in_hand); 
    deal2 = deck(cards_in_hand+1:2*cards_in_hand); 

    %setup hands in working variables
    hand1 = deal1;
    hand2 = deal2;

    %initialize stash as an empty vector
    stash = []; 

    %setup statistic variables
    rounds = 0; 
    wars = 0;
    hand_stats = zeros(round_limit,1);

    in_war = 0; 
    max_war = 0; 
    current_war = 0; 
    if(mod(game, 10) == 0)
        disp(['Calculating game: ', num2str(game)]);
    end
    while(isempty(hand1) == 0 && isempty(hand2) == 0 && rounds < round_limit)
        rounds = rounds + 1;
        
%         if(mod(rounds,26) == 0 && in_war == 0)
%             hand1 = hand1(randperm(length(hand1)));
%             hand2 = hand2(randperm(length(hand2)));
%         end
            
        hand_stats(rounds) = length(hand1); 
        %save action cards

        key1 = hand1(1);  %save action cards to compare
        key2 = hand2(1); 

        %remove action cards from decks 
        hand1(1) = [];
        hand2(1) = [];

        %setup stash
        if(randi(random_factor+1,1) == 1)   %random factor to prevent endless games. 
                             % randi(2,1) :: random :: random_factor = 1
                             % randi(1,1) :: notrandom :: random_factor = 0
            stash(end+1) = key1;
            stash(end+1) = key2; 
        else
            stash(end+1) = key2;
            stash(end+1) = key1;
        end



        if(key1 > key2)  %player 1 wins, add cards to his deck
            hand1 = [hand1, stash]; 
            stash = []; %empty stash
            in_war = 0;

        elseif(key2 > key1)  %player 2 wins, add cards to his deck
            hand2 = [hand2, stash];
            stash = []; %empty stash
            in_war = 0;

        else %WAR  key1 = key2
            wars = wars + 1;  
            if(in_war == 1)
                current_war = current_war + 1;  %track what "nest level" the war is at 
            else
                in_war = 1; 
                current_war = 1;
            end

            if(current_war > max_war)
                    max_war = current_war;  %determine the highest nest achieved in this game 
            end

            %add as many cards as possible (up to war_cards) to the stash
            upper_bound = min(length(hand1),length(hand2));
            upper_bound = upper_bound - 1; %leave room for comparison card
            if(upper_bound > war_cards)
                upper_bound = war_cards;  
            end


            %add the war cards to the stash, remove them from hands
            if(upper_bound > 0)
                stash = [stash, hand1(1:upper_bound), hand2(1:upper_bound)];
                hand1(1:upper_bound) = [];
                hand2(1:upper_bound) = [];
            end
        end
    end

      if(length(hand1) > length(hand2))
     
          g_winner(game) = 1; 
      else
         %disp('Player 2 wins!');
          g_winner(game) = 2; 
      end
      
      if(rounds == round_limit)
     
          g_stuck(game) = 1; 
      else 
          g_stuck(game) = 0;
      end
      
      %update stats
      g_rounds(game) = rounds; 
      g_wars(game) = wars; 
      g_nest(game) = max_war; 
      
%UNCOMMENT TO SEE CONSOLE SUMMARY OF EACH GAME

%       disp(['WINNER:', num2str(g_winner(game))]);
%       disp(['GAME: ', num2str(game)]);
%       disp(['Rounds: ', num2str(rounds)]); 
%       disp(['Wars: ', num2str(wars)]); 
%       disp(['Largest Nested War:', num2str(max_war)]);

%UNCOMMENT TO SEE GRAPH OF EACH GAME: 
      
%       close all;   
%       midline(1:rounds) = cards_in_hand; 
%       plot(hand_stats(1:rounds)); 
%       xlabel('Rounds'); 
%       ylabel('Cards in Player 1''s Hand');
%       title('War'); 
%       hold on; 
%       plot(midline, 'r'); 
%       ylim([0 cards_in_hand*2]); 
%       xlim([1 rounds]);
%       pause


end

 %update for the final round
 rounds = rounds + 1;
 hand_stats(rounds) = length(hand1); 
  
 %final recap: 
 
 disp(' '); 
 disp(['Average Rounds: ', num2str(mean(g_rounds(:,g_rounds(1,:)~=round_limit)))]); %doesn't average games which reached the round limit; 
 disp(['Average Victor: ', num2str(mean(g_winner))]); %should approach 1.5 
 disp(['Average Wars: ', num2str(mean(g_wars))]); 
 disp(['Stuck Percentage: ', num2str(mean(g_stuck) * 100)]);
 disp(['Longest Game: ', num2str(max(g_rounds(:,g_rounds(1,:)~=round_limit)))]); %doesn't include stuck games