2 files changed, 74 insertions, 1 deletions

diff --git a/server/game.cpp b/server/game.cpp
index 268439f..65d5cf2 100644
--- a/server/game.cpp
+++ b/server/game.cpp
@@ -324,6 +324,10 @@ Actions Game::Player::get_actions_draw() {
 	
 	// Check if player can force a draw.
 	// Check if player can tsumo.
+	if(can_tsumo()) {
+		possible_actions.push_back(Action(Action::Tsumo));
+	}
+	
 	// Check if player can declare a concealed kan or extend an open pon. List all possibilities.
 	
 	if(!riichi) {
@@ -369,6 +373,9 @@ Actions Game::Player::get_actions_discard(Tile tile, PlayerNum discarder) {
 	}
 	
 	// Check if tile can be ron-ed.
+	if(can_ron(tile)) {
+		possible_actions.push_back(Action(Action::Ron));
+	}
 	
 	// If any action is possible, add option to pass.
 	if(possible_actions) {
@@ -442,6 +449,66 @@ bool Game::Player::can_kan(Tile tile, int target) {
 	return false;
 }
 
+//! Recursive function that eats away sets from a hand to determine if it's valid or not.
+bool complete_hand(Tiles tiles, bool pair_eaten = false) {
+	if(!tiles) {
+		return true; // All tiles eaten.
+	}
+	
+	if(tiles[0] == tiles[1]) {
+		if(!pair_eaten) {
+			// We can eat a pair of tiles.
+			Tiles t = tiles;
+			t.erase(t.begin(), t.begin() + 2);
+			if(complete_hand(t, true)) {
+				return true;
+			}
+		}
+		
+		if(tiles[1] == tiles[2]) {
+			// We can eat a pon of tiles.
+			Tiles t = tiles;
+			t.erase(t.begin(), t.begin() + 3);
+			if(complete_hand(t, pair_eaten)) {
+				return true;
+			}
+		}
+	}
+	
+	Tile::Set set = tiles[0].get_set();
+	int num = tiles[0].get_num();
+	
+	if(set == Tile::Honor || num > 7) {
+		// Can't be chi-ed.
+		return false;
+	}
+	
+	Tiles::iterator it1 = std::find(tiles.begin(), tiles.end(), Tile(set, num + 1));
+	if(it1 != tiles.end()) {
+		Tiles::iterator it2 = std::find(tiles.begin(), tiles.end(), Tile(set, num + 2));
+		if(it2 != tiles.end()) {
+			// We can eat a chi of tiles.
+			tiles.erase(it2);
+			tiles.erase(it1);
+			tiles.erase(tiles.begin());
+			return complete_hand(tiles, pair_eaten);
+		}
+	}
+	
+	return false;
+}
+
+bool Game::Player::can_tsumo() {
+	return complete_hand(hand);
+}
+
+bool Game::Player::can_ron(Tile tile) {
+	Tiles tiles = hand;
+	tiles.push_back(tile);
+	tiles.sort();
+	return complete_hand(tiles);
+}
+
 void Game::Player::draw(Tile tile) {
 	hand.push_back(tile);
 }
diff --git a/server/game.h b/server/game.h
index 5613751..8bf89e8 100644
--- a/server/game.h
+++ b/server/game.h
@@ -59,9 +59,15 @@ class Game : public boost::enable_shared_from_this<Game> {
 				//! Check if it's possible to make a concealed kan or extend an open kan.
 				Targets can_kan();
 				
-				// Check if tile can be called to kan target.
+				//! Check if tile can be called to kan target.
 				bool can_kan(Tile tile, int target);
 				
+				//! Check if hand is complete.
+				bool can_tsumo();
+				
+				//! Check if tile can be called to complete hand.
+				bool can_ron(Tile tile);
+				
 				//! Draw tile.
 				void draw(Tile tile);