1 files changed, 90 insertions, 2 deletions

diff --git a/server/hand.cpp b/server/hand.cpp
index 393a6c0..abdeb4b 100644
--- a/server/hand.cpp
+++ b/server/hand.cpp
@@ -4,6 +4,10 @@ bool Hand::agari(const Tiles& tiles) {
 	return basic_format(tiles);
 }
 
+bool Hand::tenpai(const Tiles& tiles) {
+	return basic_format_tenpai(tiles);
+}
+
 bool Hand::basic_format(const Tiles& tiles, bool pair_eaten) {
 	if(!tiles) {
 		return true; // All tiles eaten.
@@ -34,6 +38,90 @@ bool Hand::basic_format(const Tiles& tiles, bool pair_eaten) {
 	return false;
 }
 
+bool Hand::basic_format_tenpai(const Tiles& tiles, bool pair_eaten, bool wait_eaten) {
+	if(!tiles) {
+		return true;
+	}
+	
+	if(!pair_eaten && !wait_eaten) {
+		if(basic_format_tenpai(eat_tanki(tiles), true, true)) {
+			return true;
+		}
+	}
+	
+	if(tiles.size() < 2) {
+		return false;
+	}
+	
+	if(!pair_eaten) {
+		if(Tiles rest = eat_pair(tiles)) {
+			if(basic_format_tenpai(rest, true, wait_eaten)) {
+				return true;
+			}
+		}
+	}
+	
+	if(!wait_eaten) {
+		if(Tiles rest = eat_chi_wait(tiles)) {
+			if(basic_format_tenpai(rest, pair_eaten, true)) {
+				return true;
+			}
+		}
+	}
+	
+	if(tiles.size() < 3) {
+		return false;
+	}
+	
+	if(Tiles rest = eat_pon(tiles)) {
+		if(basic_format_tenpai(rest, pair_eaten, wait_eaten)) {
+			return true;
+		}
+	}
+	
+	if(Tiles rest = eat_chi(tiles)) {
+		return basic_format_tenpai(rest, pair_eaten, wait_eaten);
+	}
+	
+	return false;
+}
+
+Tiles Hand::eat_tanki(Tiles tiles) {
+	tiles.erase(tiles.begin());
+	return tiles;
+}
+
+Tiles Hand::eat_chi_wait(Tiles tiles) {
+	Tile::Set set = tiles.front().get_set();
+	int num = tiles.front().get_num();
+	
+	if(set == Tile::Honor || num > 8) {
+		return Tiles();
+	}
+	
+	// Look for T+1.
+	Tiles::iterator it = std::find(tiles.begin(), tiles.end(), Tile(set, num + 1));
+	if(it != tiles.end()) {
+		tiles.erase(it);
+		tiles.erase(tiles.begin());
+		return tiles;
+	}
+	
+	if(num > 7) {
+		return Tiles();
+	}
+	
+	// Look for T+2.
+	it = std::find(tiles.begin(), tiles.end(), Tile(set, num + 2));
+	if(it != tiles.end()) {
+		tiles.erase(it);
+		tiles.erase(tiles.begin());
+		return tiles;
+	}
+	
+	return Tiles();
+}
+
 Tiles Hand::eat_pair(Tiles tiles) {
 	if(tiles[0] == tiles[1]) {
 		tiles.erase(tiles.begin(), tiles.begin() + 2);
@@ -51,8 +139,8 @@ Tiles Hand::eat_pon(Tiles tiles) {
 }
 
 Tiles Hand::eat_chi(Tiles tiles) {
-	Tile::Set set = tiles[0].get_set();
-	int num = tiles[0].get_num();
+	Tile::Set set = tiles.front().get_set();
+	int num = tiles.front().get_num();
 	
 	if(set == Tile::Honor || num > 7) {
 		// Can't be chi-ed.