Deal the straddle, instead of leaving the dealer to fake it

A straddle is a blind raise put out before the cards by the player left of the
big blind, for twice it. Home games run them constantly, and the tool had no
idea they existed — so a dealer's only way through was to deal the hand and have
the straddler "raise" to $4, which gets the money right and the other two rules
wrong.

There are three at once:

  - the amount doubles as it goes left, and re-straddles carry on doubling;
  - first to act is left of the *straddler*, not left of the big blind, and the
    straddler keeps the option when it comes back round even if nobody raised;
  - the minimum raise is twice the straddle. Measured off the big blind
    underneath it, a $2/$4 game prices the next raise at $6, and every player at
    the table will argue — correctly.

Tap Straddle on the deal prompt and the tool posts it, puts the right player on
the clock and prices the raise. The seat wears an STR badge for the hand, read
off what the deal actually posted rather than off the count, so the badge can't
outlive the chips it stands for. It's a one-hand decision, like posting in, and
it clears when the button moves.

The control sits on the deal row rather than a line of its own: measured at
390x844, its own line cost 44px of felt on every deal prompt, straddle or no
straddle, and this bar is docked over the seats. Three buttons across a 360px
phone want to wrap, which made the bar 64px taller and put the bottom seat three
fifths behind it — this layout deliberately doesn't shrink the felt to suit, so
the deal button is given a 7rem floor instead, which keeps the row to one line
and the cost to nothing.

20 new tests, checked by breaking each of the three rules on purpose first: the
wrong first-to-act, the minimum measured off the big blind, and a flat rather
than doubling chain each fail a different one.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_015bnp7xKUPFFSpwkYNFaPgb

tests/holdem/straddle.test.js

@@ -0,0 +1,188 @@
+// The straddle: a blind raise put out before the cards by the player left of the big
+// blind, for twice it.
+//
+// Home games run them constantly, and it is three rules at once — the amount, who is
+// first to act, and what the minimum raise becomes. Faking one by dealing and having
+// the straddler "raise" gets the last of those right and the other two wrong.
+const test = require("node:test");
+const { describe } = require("node:test");
+const assert = require("node:assert");
+const { Betting, HoldemState, makeTable, chipsOnTable } = require("./load");
+
+// Six seats, everyone in, button on seat 0: small blind seat 1, big blind seat 2,
+// straddle seat 3.
+const table = (straddles = 0, extra = {}) => {
+    const state = makeTable({ seatCount: 6, stack: 200, smallBlind: 1, bigBlind: 2, dealerSeatIndex: 0, ...extra });
+    state.straddleCount = straddles;
+    return state;
+};
+
+const dealt = (straddles = 0, extra = {}) => {
+    const state = table(straddles, extra);
+    Betting.beginHand(state);
+    return state;
+};
+
+describe("what goes in the middle", () => {
+    test("the seat left of the big blind puts out twice it", () => {
+        const state = dealt(1);
+        assert.deepEqual(state.seats.map(p => p.committed), [0, 1, 2, 4, 0, 0]);
+    });
+
+    test("a re-straddle doubles again, one seat further round", () => {
+        const state = dealt(2);
+        assert.deepEqual(state.seats.map(p => p.committed), [0, 1, 2, 4, 8, 0]);
+    });
+
+    test("none of it comes from anywhere but the straddler's stack", () => {
+        const before = chipsOnTable(table(2));
+        assert.equal(chipsOnTable(dealt(2)), before);
+    });
+
+    test("the felt is told who straddled, not left to work it out", () => {
+        assert.deepEqual(dealt(2).postedStraddles, [3, 4]);
+        assert.deepEqual(dealt(0).postedStraddles, []);
+    });
+});
+
+describe("who is on the clock", () => {
+    test("action starts left of the straddler, not left of the big blind", () => {
+        assert.equal(dealt(0).actingSeatIndex, 3, "without a straddle it is the seat after the big blind");
+        assert.equal(dealt(1).actingSeatIndex, 4);
+        assert.equal(dealt(2).actingSeatIndex, 5);
+    });
+
+    test("the straddler still has the option when it comes back to them", () => {
+        const state = dealt(1);
+        // Everyone calls the straddle round to the big blind.
+        [4, 5, 0, 1, 2].forEach(seat => {
+            assert.equal(state.actingSeatIndex, seat, `expected seat ${seat} to be up`);
+            Betting.call(state, seat);
+        });
+        assert.equal(state.actingSeatIndex, 3, "back to the straddler");
+        assert.equal(Betting.toCall(state, state.seats[3]), 0, "nothing to call");
+        assert.equal(Betting.isStreetComplete(state), false, "and the street isn't over until they say so");
+    });
+
+    test("the straddler checking closes it", () => {
+        const state = dealt(1);
+        [4, 5, 0, 1, 2].forEach(seat => Betting.call(state, seat));
+        Betting.check(state, 3);
+        assert.equal(Betting.isStreetComplete(state), true);
+        assert.equal(state.actingSeatIndex, null);
+    });
+
+    test("the big blind acts in turn, not last", () => {
+        const state = dealt(1);
+        Betting.call(state, 4);
+        Betting.call(state, 5);
+        Betting.call(state, 0);
+        Betting.call(state, 1);
+        assert.equal(state.actingSeatIndex, 2, "the big blind is up before the straddler");
+        assert.equal(Betting.toCall(state, state.seats[2]), 2, "and owes the difference to the straddle");
+    });
+});
+
+describe("what it costs to raise", () => {
+    test("the minimum raise is twice the straddle, not the straddle plus a blind", () => {
+        // $2 blinds, $4 straddle: the next raise is to $8. Measured off the big blind
+        // instead it comes out at $6, and every player at the table would argue.
+        assert.equal(Betting.minRaiseTo(dealt(1)), 8);
+        assert.equal(Betting.minRaiseTo(dealt(2)), 16);
+        assert.equal(Betting.minRaiseTo(dealt(0)), 4);
+    });
+
+    test("what the table owes is measured off the straddle", () => {
+        const state = dealt(1);
+        assert.equal(state.currentBet, 4);
+        assert.equal(Betting.toCall(state, state.seats[4]), 4, "a fresh player calls the straddle");
+        assert.equal(Betting.toCall(state, state.seats[1]), 3, "the small blind owes the rest");
+        assert.equal(Betting.toCall(state, state.seats[2]), 2, "so does the big blind");
+        assert.equal(Betting.toCall(state, state.seats[3]), 0, "the straddler is already good");
+    });
+
+    test("a raise over the straddle is a raise, and the straddler can still re-raise", () => {
+        const state = dealt(1);
+        Betting.raiseTo(state, 4, 12);
+        assert.equal(state.currentBet, 12);
+        assert.equal(Betting.minRaiseTo(state), 20, "twice again over a raise of eight");
+        assert.equal(state.seats[3].hasActed, false, "the straddler has not acted yet");
+    });
+});
+
+describe("how many a table can take", () => {
+    test("everyone but the two blinds", () => {
+        assert.equal(Betting.maxStraddles(table(0)), 4);
+        assert.equal(Betting.maxStraddles(table(0, { seatCount: 3, seated: [0, 1, 2] })), 1);
+    });
+
+    test("heads-up, none — there is no seat left of the big blind to straddle from", () => {
+        const heads = table(1, { seatCount: 6, seated: [0, 1] });
+        assert.equal(Betting.maxStraddles(heads), 0);
+        assert.deepEqual(Betting.straddleSeats(heads), []);
+        Betting.beginHand(heads);
+        assert.deepEqual(heads.seats.map(p => p.committed), [1, 2, 0, 0, 0, 0]);
+    });
+
+    test("asking for more than the table has stops at the last seat", () => {
+        const state = table(0, { seatCount: 4, seated: [0, 1, 2, 3] });
+        state.straddleCount = 99;
+        assert.equal(Betting.straddleSeats(state).length, 2);
+        Betting.beginHand(state);
+        assert.deepEqual(state.seats.map(p => p.committed), [8, 1, 2, 4]);
+        assert.equal(state.actingSeatIndex, 1, "round to the small blind, who is first to act");
+    });
+
+    test("a seat with no chips is never handed one", () => {
+        const state = table(1);
+        state.seats[3].stack = 0;
+        // Seat 3 is sat out for the deal, so the straddle passes to seat 4.
+        assert.deepEqual(Betting.straddleSeats(state), [{ index: 4, amount: 4 }]);
+    });
+});
+
+describe("what it doesn't outlive", () => {
+    test("the hand it was called for", () => {
+        const state = dealt(1);
+        HoldemState.startNextHand(state);
+        assert.equal(state.straddleCount, 0, "nobody straddles again by accident");
+        assert.deepEqual(state.postedStraddles, []);
+    });
+
+    test("but it survives the button being pushed around before the deal", () => {
+        // repostBlinds takes every posted chip back and deals again; a straddle that
+        // vanished there would have been paid once and never returned.
+        const state = dealt(1);
+        const before = chipsOnTable(state);
+        Betting.repostBlinds(state);
+        assert.deepEqual(state.seats.map(p => p.committed), [0, 1, 2, 4, 0, 0]);
+        assert.equal(chipsOnTable(state), before);
+    });
+
+    test("a table saved before straddles existed reads as having none", () => {
+        const parsed = JSON.parse(JSON.stringify(makeTable({ seatCount: 6 })));
+        delete parsed.straddleCount;
+        delete parsed.postedStraddles;
+        const migrated = HoldemState.migrate(parsed);
+        assert.equal(migrated.straddleCount, 0);
+        assert.deepEqual(migrated.postedStraddles, []);
+    });
+});
+
+describe("what the dealer is shown before dealing", () => {
+    test("the straddles that are coming, and how many more it could take", () => {
+        const preview = Betting.blindPreview(table(1));
+        assert.deepEqual(preview.straddles, [{ index: 3, amount: 4 }]);
+        assert.equal(preview.maxStraddles, 4);
+    });
+
+    test("and the preview matches what dealing actually does", () => {
+        const state = table(2);
+        const preview = Betting.blindPreview(state);
+        Betting.beginHand(state);
+        assert.deepEqual(preview.straddles.map(s => s.index), state.postedStraddles);
+        preview.straddles.forEach(({ index, amount }) => {
+            assert.equal(state.seats[index].committed, amount, `seat ${index + 1}`);
+        });
+    });
+});