From 52718c94d69b40e79f9ba4fd4ff70376bbf8a774 Mon Sep 17 00:00:00 2001
From: Benjamin Auder <benjamin.auder@somewhere>
Date: Fri, 28 Jul 2023 11:38:31 +0200
Subject: [PATCH] Start thinking about Coregal

---
 base_rules.js                |   2 +-
 utils/setupPieces.js         |  24 +++----
 variants/Capablanca/class.js |   2 +-
 variants/Coregal/Coregal.js  | 121 +++++++++++++++++++++++++++++++++++
 variants/Giveaway/class.js   |   2 +-
 5 files changed, 137 insertions(+), 14 deletions(-)
 create mode 100644 variants/Coregal/Coregal.js

diff --git a/base_rules.js b/base_rules.js
index c0d9b60..0b71cf4 100644
--- a/base_rules.js
+++ b/base_rules.js
@@ -233,7 +233,7 @@ export default class ChessRules {
       ['r', 'n', 'b', 'q', 'k', 'b', 'n', 'r'],
       {
         randomness: this.options["randomness"],
-        between: {p1: 'k', p2: 'r'},
+        between: [{p1: 'k', p2: 'r'}],
         diffCol: ['b'],
         flags: ['r']
       }
diff --git a/utils/setupPieces.js b/utils/setupPieces.js
index 2c8ccee..94bbc73 100644
--- a/utils/setupPieces.js
+++ b/utils/setupPieces.js
@@ -38,17 +38,19 @@ export const FenUtil = {
         });
       }
       if (o.between) {
-        // Locate p1. If appearing first, exchange with first p2.
-        // If appearing last, exchange with last p2.
-        const p1 = res.indexOf(o.between["p1"]);
-        const firstP2 = res.indexOf(o.between["p2"]),
-              lastP2 = res.lastIndexOf(o.between["p2"]);
-        if (p1 < firstP2 || p1 > lastP2) {
-          res[p1] = o.between["p2"];
-          if (p1 < firstP2)
-            res[firstP2] = o.between["p1"];
-          else //p1 > lastP2
-            res[lastP2] = o.between["p1"];
+        o.between.forEach(b => {
+          // Locate p1. If appearing first, exchange with first p2.
+          // If appearing last, exchange with last p2.
+          const p1 = res.indexOf(b["p1"]);
+          const firstP2 = res.indexOf(b["p2"]),
+                lastP2 = res.lastIndexOf(b["p2"]);
+          if (p1 < firstP2 || p1 > lastP2) {
+            res[p1] = b["p2"];
+            if (p1 < firstP2)
+              res[firstP2] = b["p1"];
+            else //p1 > lastP2
+              res[lastP2] = b["p1"];
+          }
         }
       }
     }
diff --git a/variants/Capablanca/class.js b/variants/Capablanca/class.js
index c141e1c..5b1c80e 100644
--- a/variants/Capablanca/class.js
+++ b/variants/Capablanca/class.js
@@ -60,7 +60,7 @@ export default class CapablancaRules extends ChessRules {
       ['r', 'n', 's', 'b', 'q', 'k', 'b', 'e', 'n', 'r'],
       {
         randomness: this.options["randomness"],
-        between: {p1: 'k', p2: 'r'},
+        between: [{p1: 'k', p2: 'r'}],
         diffCol: ['b'],
         flags: ['r']
       }
diff --git a/variants/Coregal/Coregal.js b/variants/Coregal/Coregal.js
new file mode 100644
index 0000000..e12a748
--- /dev/null
+++ b/variants/Coregal/Coregal.js
@@ -0,0 +1,121 @@
+import { ChessRules, Move, PiPo } from "@/base_rules";
+import { ArrayFun } from "@/utils/array";
+import { randInt, sample } from "@/utils/alea";
+
+export class CoregalRules extends ChessRules {
+
+// TODO: special symbol (l) for royal queen...
+
+  getPPpath(m) {
+    if (
+      m.vanish.length == 2 &&
+      m.appear.length == 2 &&
+      m.vanish[0].p == V.QUEEN
+    ) {
+      // Large castle: show castle symbol
+      return "Coregal/castle";
+    }
+    return super.getPPpath(m);
+  }
+
+  genRandInitBaseFen() {
+    const s = FenUtil.setupPieces(
+      ['r', 'n', 'b', 'l', 'k', 'b', 'n', 'r'],
+      {
+        randomness: this.options["randomness"],
+        between: [{p1: 'k', p2: 'r'}, {p1: 'l', p2: 'r'}],
+        diffCol: ['b'],
+        flags: ['r', 'k', 'l']
+      }
+    );
+    return {
+      fen: s.b.join("") + "/pppppppp/8/8/8/8/PPPPPPPP/" +
+           s.w.join("").toUpperCase(),
+      o: {flags: s.flags}
+    };
+  }
+
+  pieces() {
+    let res = super.pieces();
+    res['l'] = {...};
+    return res;
+  }
+
+  setFlags(fenflags) {
+    // white pieces positions, then black pieces positions
+    this.castleFlags = { w: [...Array(4)], b: [...Array(4)] };
+    for (let i = 0; i < 8; i++) {
+      this.castleFlags[i < 4 ? "w" : "b"][i % 4] =
+        parseInt(fenflags.charAt(i), 10);
+    }
+  }
+
+  getPotentialQueenMoves([x, y]) {
+    let moves = super.getPotentialQueenMoves([x, y]);
+    const c = this.getColor(x, y);
+    if (this.castleFlags[c].slice(1, 3).includes(y))
+      moves = moves.concat(this.getCastleMoves([x, y]));
+    return moves;
+  }
+
+  getPotentialKingMoves([x, y]) {
+    let moves = this.getSlideNJumpMoves(
+      [x, y], V.steps[V.ROOK].concat(V.steps[V.BISHOP]), 1);
+    const c = this.getColor(x, y);
+    if (this.castleFlags[c].slice(1, 3).includes(y))
+      moves = moves.concat(this.getCastleMoves([x, y]));
+    return moves;
+  }
+
+  getCastleMoves([x, y]) {
+    // Relative position of the selected piece: left or right ?
+    // If left: small castle left, large castle right.
+    // If right: usual situation.
+    const c = this.getColor(x, y);
+    const relPos = (this.castleFlags[c][1] == y ? "left" : "right");
+
+    const finalSquares = [
+      relPos == "left" ? [1, 2] : [2, 3],
+      relPos == "right" ? [6, 5] : [5, 4]
+    ];
+    const saveFlags = JSON.stringify(this.castleFlags[c]);
+    // Alter flags to follow base_rules semantic
+    this.castleFlags[c] = [0, 3].map(i => this.castleFlags[c][i]);
+    const moves = super.getCastleMoves([x, y], finalSquares);
+    this.castleFlags[c] = JSON.parse(saveFlags);
+    return moves;
+  }
+
+  // "twoKings" arg for the similar Twokings variant.
+  updateCastleFlags(move, piece, twoKings) {
+    const c = V.GetOppCol(this.turn);
+    const firstRank = (c == "w" ? V.size.x - 1 : 0);
+    // Update castling flags if castling pieces moved or were captured
+    const oppCol = V.GetOppCol(c);
+    const oppFirstRank = V.size.x - 1 - firstRank;
+    if (move.start.x == firstRank) {
+      if (piece == V.KING || (!twoKings && piece == V.QUEEN)) {
+        if (this.castleFlags[c][1] == move.start.y)
+          this.castleFlags[c][1] = 8;
+        else if (this.castleFlags[c][2] == move.start.y)
+          this.castleFlags[c][2] = 8;
+        // Else: the flag is already turned off
+      }
+    }
+    else if (
+      move.start.x == firstRank && //our rook moves?
+      [this.castleFlags[c][0], this.castleFlags[c][3]].includes(move.start.y)
+    ) {
+      const flagIdx = (move.start.y == this.castleFlags[c][0] ? 0 : 3);
+      this.castleFlags[c][flagIdx] = 8;
+    } else if (
+      move.end.x == oppFirstRank && //we took opponent rook?
+      [this.castleFlags[oppCol][0], this.castleFlags[oppCol][3]]
+        .includes(move.end.y)
+    ) {
+      const flagIdx = (move.end.y == this.castleFlags[oppCol][0] ? 0 : 3);
+      this.castleFlags[oppCol][flagIdx] = 8;
+    }
+  }
+
+};
diff --git a/variants/Giveaway/class.js b/variants/Giveaway/class.js
index 9665835..45f6a34 100644
--- a/variants/Giveaway/class.js
+++ b/variants/Giveaway/class.js
@@ -43,7 +43,7 @@ export default class GiveawayRules extends ChessRules {
       diffCol: ['b']
     };
     if (this.options["mode"] == "losers") {
-      setupOpts["between"] = ['k', 'r'];
+      setupOpts["between"] = [{p1: 'k', p2: 'r'}];
       setupOpts["flags"] = ['r'];
     }
     const s = FenUtil.setupPieces(
-- 
2.44.0