Fix rand init pos for Antiking (no cornered bishops)

diff --git a/public/javascripts/variants/Antiking.js b/public/javascripts/variants/Antiking.js
index 71e01ff..b22cbd7 100644 (file)
--- a/public/javascripts/variants/Antiking.js
+++ b/public/javascripts/variants/Antiking.js
@@ -157,15 +157,56 @@ class AntikingRules extends ChessRules
 
        static GenRandInitFen()
        {
-               let randFen = ChessRules.GenRandInitFen();
-               // Black side
-               let antikingPos = _.random(7);
-               let ranks23 = "pppppppp/" + (antikingPos>0?antikingPos:"") + "A" + (antikingPos<7?7-antikingPos:"");
-               randFen = randFen.replace("pppppppp/8", ranks23);
-               // White side
-               antikingPos = _.random(7);
-               ranks23 = (antikingPos>0?antikingPos:"") + "a" + (antikingPos<7?7-antikingPos:"") + "/PPPPPPPP";
-               randFen = randFen.replace("8/PPPPPPPP", ranks23);
-               return randFen;
+               let pieces = { "w": new Array(8), "b": new Array(8) };
+               let antikingPos = { "w": -1, "b": -1 };
+               for (let c of ["w","b"])
+               {
+                       let positions = _.range(8);
+
+                       // Get random squares for bishops, but avoid corners; because,
+                       // if an antiking blocks a cornered bishop, it can never be checkmated
+                       let randIndex = 2 * _.random(1,3);
+                       const bishop1Pos = positions[randIndex];
+                       let randIndex_tmp = 2 * _.random(2) + 1;
+                       const bishop2Pos = positions[randIndex_tmp];
+                       positions.splice(Math.max(randIndex,randIndex_tmp), 1);
+                       positions.splice(Math.min(randIndex,randIndex_tmp), 1);
+
+                       randIndex = _.random(5);
+                       const knight1Pos = positions[randIndex];
+                       positions.splice(randIndex, 1);
+                       randIndex = _.random(4);
+                       const knight2Pos = positions[randIndex];
+                       positions.splice(randIndex, 1);
+
+                       randIndex = _.random(3);
+                       const queenPos = positions[randIndex];
+                       positions.splice(randIndex, 1);
+
+                       const rook1Pos = positions[0];
+                       const kingPos = positions[1];
+                       const rook2Pos = positions[2];
+
+                       // Random squares for antikings
+                       antikingPos[c] = _.random(7);
+
+                       pieces[c][rook1Pos] = 'r';
+                       pieces[c][knight1Pos] = 'n';
+                       pieces[c][bishop1Pos] = 'b';
+                       pieces[c][queenPos] = 'q';
+                       pieces[c][kingPos] = 'k';
+                       pieces[c][bishop2Pos] = 'b';
+                       pieces[c][knight2Pos] = 'n';
+                       pieces[c][rook2Pos] = 'r';
+               }
+               const ranks23_black = "pppppppp/" + (antikingPos["w"]>0?antikingPos["w"]:"")
+                       + "A" + (antikingPos["w"]<7?7-antikingPos["w"]:"");
+               const ranks23_white = (antikingPos["b"]>0?antikingPos["b"]:"") + "a"
+                       + (antikingPos["b"]<7?7-antikingPos["b"]:"") + "/PPPPPPPP";
+               let fen = pieces["b"].join("") + "/" + ranks23_black +
+                       "/8/8/" +
+                       ranks23_white + "/" + pieces["w"].join("").toUpperCase() +
+                       " 1111"; //add flags
+               return fen;
        }
 }