Notice when the same table is open twice

Opening the tool in a second tab -- tapping the bookmark again rather than hunting for
the tab you already had -- silently throws away whatever the first one is doing.

Each tab holds its own copy in memory and each save writes the whole table, so the
second one to act wins. Driven with two tabs on one profile:

  tab A: deal, and Ann calls    stored -> bettingOpen true, committed [0,1,2,2]
  tab B: type a name in seat 5  stored -> bettingOpen false, committed [0,0,0,0]

The deal, the blinds and the call are gone, and neither tab said anything. That is the
same silent shape as the save and load failures either side of this change.

The browser already tells us: a storage event fires in every other tab when the key
changes, and never in the one that wrote. So a tab that sees its table move underneath
it now says so, once, with the way out attached:

  toast:  "This table is open in another tab. Whichever acts last wins."  [Reload]
  panel:  "This table is open in another tab, and both are writing to it — whichever
           acts last wins, so work done in the other one can vanish. Close one, then
           reload this tab to pick up the table as it stands."

Watched rather than merged, deliberately. Replacing the table under a dealer's hands
in the middle of a hand would be its own hazard, and reloading is the only resolution
that does not throw somebody's work away -- so it is offered rather than taken.

6 tests (269 total): a write from elsewhere is noticed, another app's key and our own
recovery key are not our business, ten writes produce one warning, watching twice
listens once, no listener is not an error, and no window at all is not an error.

Driven with two live tabs: both quiet at first, A deals and B warns with the reload
offer, A stays quiet about its own writes, two more actions in A add no further toasts
in B, and reloading B picks up A's table -- bettingOpen true, committed [2,1,2,2] --
with the warning cleared. Audit and contrast clean, no console errors.

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

JoshHeaps.Net/Pages/Casino/TexasHoldem.cshtml

@@ -103,6 +103,7 @@
             <details class="sidebarPanel">
                 <summary>Session</summary>
                 <div class="panelBody">
+                    <p id="storageWarning" class="storageWarning" hidden></p>
                     <h3 class="panelSubhead">Standings</h3>
                     <div class="standingsTableWrap">
                         <div id="standingsTable">
@@ -156,6 +157,14 @@
                 </div>
             </details>
 
+            <details class="sidebarPanel" id="keyboardPanel">
+                <summary>Keyboard</summary>
+                <div class="panelBody">
+                    <dl id="shortcutLegend" class="shortcutLegend"></dl>
+                    <p class="fieldHint">Nothing fires while you're typing in a field, or while a sheet is open over the table.</p>
+                </div>
+            </details>
+
             <details class="sidebarPanel">
                 <summary>Table Notes</summary>
                 <div class="panelBody">
@@ -294,7 +303,9 @@
             not during it.
         </p>
 
-        <section class="ruling">
+        <nav id="rulingsIndex" class="rulingsIndex" aria-label="Jump to a ruling"></nav>
+
+        <section class="ruling" data-short="Misdeal">
             <h3>Redeal it — misdeal</h3>
             <ul>
                 <li>The first card goes to the wrong seat.</li>
@@ -304,7 +315,7 @@
             </ul>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Board card early">
             <h3>A board card turned too early</h3>
             <p>
                 If the fourth board card gets turned before the betting round is finished,
@@ -313,7 +324,7 @@
             </p>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Out of turn">
             <h3>Acting out of turn</h3>
             <p>
                 A one-off is usually just backed up if no one has acted behind them.
@@ -321,7 +332,7 @@
             </p>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Short all-in">
             <h3>A short all-in doesn't reopen the betting</h3>
             <p>
                 Somebody shoving in less than a full raise — say $3 more when the last
@@ -336,7 +347,7 @@
             </p>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Uncalled bet">
             <h3>Chips nobody called come back</h3>
             <p>
                 Bet more than anyone was able to call and the excess is returned to you
@@ -346,7 +357,7 @@
             </p>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Oversized chip">
             <h3>One big chip, nothing said</h3>
             <p>
                 The most common argument at a home table. A player facing a bet who
@@ -362,7 +373,7 @@
             </p>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Minimum raise">
             <h3>A raise has to be a full raise</h3>
             <p>
                 At least as much again as the last raise, or the big blind if there
@@ -373,7 +384,7 @@
             </p>
         </section>
 
-        <section class="ruling">
+        <section class="ruling" data-short="Odd chip">
             <h3>The odd chip in a split pot</h3>
             <p>
                 When a chopped pot won't divide evenly, the odd chip goes to the first
@@ -383,6 +394,22 @@
             </p>
         </section>
 
+        <section class="ruling" data-short="String bet">
+            <h3>Betting in one motion — the string bet</h3>
+            <p>
+                A bet is whatever goes in on the first trip to the stack, unless the
+                amount was said out loud first. Reaching back for more chips without
+                having said "raise" is a string bet, and only the first motion stands.
+                Saying the number is always enough on its own: "raise to sixty" binds
+                whatever order the chips arrive in.
+            </p>
+            <p>
+                It's the rule home games invoke most and enforce least, and both are
+                fine — the point is that a player can't watch the table react and then
+                decide how much to bet. Say it, or push it all at once.
+            </p>
+        </section>
+
         <p class="rulingsSource">
             Follows the Tournament Directors Association rules, which most rooms and
             home games take their lead from.

JoshHeaps.Net/wwwroot/css/casino/holdem.css

@@ -1095,6 +1095,104 @@ button,
     line-height: 1.5;
 }
 
+/* Amber, like the bank check's disagreement — both are "your record of the night is
+   wrong and you can still do something about it". */
+.storageWarning {
+    margin: 0;
+    padding: 0.5rem 0.6rem;
+    border: 1px solid rgba(240, 180, 106, 0.45);
+    border-radius: 7px;
+    background: rgba(240, 180, 106, 0.08);
+    color: #f0b46a;
+    font-size: 0.76rem;
+    line-height: 1.4;
+}
+
+/* The shortcut legend. A touch device has no keys to press, so it doesn't get a panel
+   telling it about them — the same pointer question the touch-target rules ask. */
+@media (pointer: coarse) {
+    #keyboardPanel {
+        display: none;
+    }
+}
+
+.shortcutLegend {
+    display: grid;
+    grid-template-columns: auto 1fr;
+    gap: 0.45rem 0.6rem;
+    margin: 0;
+    align-items: baseline;
+}
+
+.shortcutLegend dt {
+    display: flex;
+    gap: 0.2rem;
+}
+
+.shortcutLegend dd {
+    margin: 0;
+    color: #b8b8b8;
+    font-size: 0.78rem;
+    line-height: 1.35;
+}
+
+.shortcutKey {
+    background: #232323;
+    border: 1px solid #3f3f3f;
+    border-bottom-width: 2px;
+    border-radius: 4px;
+    padding: 0.05rem 0.32rem;
+    font-family: inherit;
+    font-size: 0.68rem;
+    color: #d8b46a;
+    white-space: nowrap;
+}
+
+/* One chip per ruling, wrapped across the top of the sheet. Names rather than icons:
+   a dealer scanning this is looking for the words somebody at the table just said. */
+.rulingsIndex {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.35rem;
+    margin: 0 0 1rem;
+}
+
+.rulingsIndexBtn {
+    box-sizing: border-box;
+    min-height: 32px;
+    padding: 0.3rem 0.6rem;
+    border-radius: 999px;
+    border: 1px solid #3a3a3a;
+    background: #232323;
+    color: #d8b46a;
+    font-family: inherit;
+    font-size: 0.72rem;
+    line-height: 1.25;
+    text-align: left;
+    cursor: pointer;
+}
+
+@media (hover: hover) {
+    .rulingsIndexBtn:hover {
+        background: #2e2e2e;
+        border-color: #4a4a4a;
+    }
+}
+
+/* A thumb needs the same 44px here as everywhere else. */
+@media (pointer: coarse) {
+    .rulingsIndexBtn {
+        min-height: 44px;
+        font-size: 0.78rem;
+    }
+}
+
+/* The heading the index jumps to takes focus, and a focus ring on a heading that the
+   dealer just asked for reads as noise rather than as help. */
+.ruling h3:focus {
+    outline: none;
+}
+
 .ruling {
     margin-bottom: 1rem;
     padding-left: 0.7rem;
@@ -2072,6 +2170,20 @@ body.hasActionBar #holdemSidebar {
     font-variant-numeric: tabular-nums;
 }
 
+/* The undo pill's key, inline rather than pinned to a corner — see actionBar.js. */
+.actionUndoKey {
+    margin-left: 0.4rem;
+    padding: 0 0.25rem;
+    border-radius: 4px;
+    border: 1px solid currentColor;
+    opacity: 0.55;
+    font-family: inherit;
+    font-size: 0.6rem;
+    line-height: 1.4;
+    text-transform: uppercase;
+    pointer-events: none;
+}
+
 .actionKey {
     position: absolute;
     top: 5px;
@@ -2603,6 +2715,16 @@ body.hasActionBar #toastHost {
     color: #d6ffe0;
 }
 
+/* The chips to push, under the amount they add up to. Quieter than the payout it
+   belongs to — the dealer reads the name and the money first, then counts. */
+.payoutChips {
+    display: block;
+    margin-top: 0.15rem;
+    font-size: 0.76rem;
+    color: #9fb8a6;
+    font-variant-numeric: tabular-nums;
+}
+
 .potWizardActions {
     display: flex;
     gap: 0.6rem;

JoshHeaps.Net/wwwroot/js/casino/holdem/actionBar.js

@@ -176,6 +176,17 @@ const ActionBar = {
             undo.className = "actionUndo";
             undo.title = `Undo ${undoLabel}`;
             undo.textContent = `↶ ${undoLabel}`;
+            // U undoes, and nothing said so — this control was the only place a dealer
+            // could have learned it, and it was the one action bar control without its
+            // key printed on it.
+            const key = document.createElement("kbd");
+            // Its own class, not .actionKey: that one pins itself to the top-right
+            // corner of a big action button, and this control is a 30px pill with
+            // overflow hidden and no positioning context — the cap escaped it and
+            // floated above the bar. Here the key belongs inline, after the label.
+            key.className = "actionUndoKey";
+            key.textContent = this.KEY_HINTS.actionUndo;
+            undo.appendChild(key);
             undo.addEventListener("click", () => this.hooks.undoLast());
             row.appendChild(undo);
         }
@@ -281,6 +292,8 @@ const ActionBar = {
         actionAdvance: "↵",
         raiseConfirm: "↵",
         raiseCancel: "esc",
+        raiseAllIn: "A",
+        actionUndo: "U",
     },
 
     button(label, className, onClick, sublabel) {
@@ -293,7 +306,10 @@ const ActionBar = {
         main.textContent = label;
         btn.appendChild(main);
 
-        const hint = this.KEY_HINTS[className];
+        // Looked up by any of the button's classes, so a button can carry a shared
+        // class for its looks and a specific one for its key — the raise pad's four
+        // quick amounts are all raiseQuickBtn, but only All-in has a key.
+        const hint = className.split(/\s+/).map(name => this.KEY_HINTS[name]).find(Boolean);
         if (hint) {
             const kbd = document.createElement("kbd");
             kbd.className = "actionKey";
@@ -397,7 +413,7 @@ const ActionBar = {
         ];
         options.forEach(option => {
             const value = Math.max(minTo, Math.min(option.value, maxTo));
-            const btn = this.button(option.label, "raiseQuickBtn", () => {
+            const btn = this.button(option.label, `raiseQuickBtn${option.label === "All-in" ? " raiseAllIn" : ""}`, () => {
                 this.raiseDraft = value;
                 this.render();
             }, Money.format(value));

JoshHeaps.Net/wwwroot/js/casino/holdem/main.js

@@ -96,6 +96,19 @@ document.addEventListener("DOMContentLoaded", () => {
             });
         },
 
+        // Two players change chairs. Undoable like every other seat action, because a
+        // swap is easy to aim wrong and the seats look alike at a glance.
+        swapSeats: (from, to) => {
+            const movedName = nameOf(from);
+            const intoName = nameOf(to);
+            const wasEmpty = Render.isEmptySeat(state.seats[to]);
+            runUndoable(
+                wasEmpty
+                    ? `${movedName} moved to seat ${to + 1}.`
+                    : `${movedName} and ${intoName} changed seats.`,
+                () => HoldemState.swapSeats(state, from, to));
+        },
+
         makeDealer: index => {
             // Before the deal there's nothing posted, so this is just moving a marker.
             // After it, the blinds have to follow the button or the badges and the
@@ -445,7 +458,90 @@ document.addEventListener("DOMContentLoaded", () => {
     // Escape is Modal's job now, for this sheet and the five others that never had it.
     const rulingsOverlay = document.getElementById("rulingsOverlay");
     const closeRulings = () => { rulingsOverlay.hidden = true; };
-    document.getElementById("openRulingsBtn").addEventListener("click", () => { rulingsOverlay.hidden = false; });
+    // The one time the browser refuses to save, say so out loud as well as leaving the
+    // standing warning in the Session panel. Set before the first render so a failure
+    // during start-up is caught too.
+    // Another tab writing to the same table. Said once, with the way out attached —
+    // reloading here adopts whatever that tab has done, which is the only resolution
+    // that doesn't throw somebody's work away.
+    HoldemState.onOtherTab = () => {
+        Toast.show(
+            "This table is open in another tab. Whichever acts last wins.",
+            { actionLabel: "Reload", onAction: () => window.location.reload(), duration: 20000 });
+        Render.renderStorageWarning();
+    };
+    HoldemState.watchOtherTabs();
+
+    HoldemState.onSaveFailed = () => {
+        Toast.show(
+            "This table isn't being saved — refreshing would lose it. Keep this tab open.",
+            { duration: 12000 });
+        Render.renderStorageWarning();
+    };
+
+    // The shortcut legend, built from the same list the handlers are keyed off, so a
+    // shortcut can't exist without a line here saying what it does.
+    const legend = document.getElementById("shortcutLegend");
+    if (legend) {
+        Shortcuts.LEGEND.forEach(entry => {
+            const term = document.createElement("dt");
+            entry.keys.forEach(key => {
+                const kbd = document.createElement("kbd");
+                kbd.className = "shortcutKey";
+                kbd.textContent = key;
+                term.appendChild(kbd);
+            });
+            const detail = document.createElement("dd");
+            detail.textContent = entry.what;
+            legend.appendChild(term);
+            legend.appendChild(detail);
+        });
+    }
+
+    // An index across the top of the rulings sheet, one chip per ruling.
+    //
+    // This is opened mid-argument with players waiting, and it was nine rulings of
+    // prose with no way in: reaching the last one meant scrolling 1.6 screens on a
+    // desktop, 2.1 on a phone and 3.5 on a phone held sideways. A dealer looking for
+    // the odd-chip rule had to read past seven others to find it.
+    //
+    // Built from the sections rather than written out beside them, so a ruling added
+    // later turns up in the index without anyone having to remember to add it twice.
+    const buildRulingsIndex = () => {
+        const index = document.getElementById("rulingsIndex");
+        if (!index || index.childElementCount > 0) return;
+        [...rulingsOverlay.querySelectorAll(".ruling")].forEach((section, i) => {
+            const heading = section.querySelector("h3");
+            if (!heading) return;
+            if (!section.id) section.id = `ruling${i + 1}`;
+
+            const jump = document.createElement("button");
+            jump.type = "button";
+            jump.className = "rulingsIndexBtn";
+            // A short label where the ruling gives one. The headings are sentences —
+            // "A short all-in doesn't reopen the betting" — and nine of those stacked
+            // one per row made the index 342px tall on a phone, which is most of the
+            // sheet before the first ruling. "Short all-in" says the same thing to
+            // somebody who is looking for it, and three fit on a line.
+            jump.textContent = section.dataset.short || heading.textContent;
+            // The full heading is still what it announces, so the short label never
+            // costs a screen reader the sentence.
+            if (section.dataset.short) jump.setAttribute("aria-label", heading.textContent);
+            jump.addEventListener("click", () => {
+                section.scrollIntoView({ block: "start", behavior: "smooth" });
+                // The heading is what the dealer is now reading, so that is where the
+                // keyboard and a screen reader should be too.
+                heading.setAttribute("tabindex", "-1");
+                heading.focus({ preventScroll: true });
+            });
+            index.appendChild(jump);
+        });
+    };
+
+    document.getElementById("openRulingsBtn").addEventListener("click", () => {
+        buildRulingsIndex();
+        rulingsOverlay.hidden = false;
+    });
     document.getElementById("closeRulingsBtn").addEventListener("click", closeRulings);
     rulingsOverlay.addEventListener("click", e => {
         if (e.target === rulingsOverlay) closeRulings();
@@ -486,4 +582,14 @@ document.addEventListener("DOMContentLoaded", () => {
         if ((state.handHistory || []).length === 0) return;
         HandHistoryExport.download(state.handHistory, HoldemState.sessionStandings(state));
     });
+
+    // The load happens on the first line of this file, long before there's a Toast to
+    // show it in, so this is checked here rather than wired as a callback. The standing
+    // warning in the Session panel doesn't need it — that reads the flag every render —
+    // but an empty table is a thing a dealer needs told, not left to notice.
+    if (HoldemState.loadFailed) {
+        Toast.show(
+            "The saved table couldn't be read, so this one started empty.",
+            { duration: 12000 });
+    }
 });

JoshHeaps.Net/wwwroot/js/casino/holdem/money.js

@@ -48,6 +48,58 @@ const Money = {
         return (this.toCents(amount) / 100).toFixed(2);
     },
 
+    // The chips to actually push, for an amount.
+    //
+    // A payout figure is the answer to the arithmetic, not to the dealer's job: they
+    // still have to work out that $132 is two blacks, a green, a red and two whites
+    // while six people watch. The chip legend already knows the denominations.
+    //
+    // Largest first, which is greedy and therefore not optimal for an arbitrary set of
+    // values — but poker chips are not arbitrary. Every real set is canonical (each
+    // denomination divides the next: 1, 5, 25, 100, 500), and greedy is exactly optimal
+    // on those. A dealer who invents a 3-and-7 chip set gets a valid answer that might
+    // use one chip more than it had to.
+    //
+    // Anything the smallest chip can't make comes back as `remainder` rather than being
+    // rounded away: a 50c share in a game whose smallest chip is a dollar is a real
+    // problem for the dealer to solve, not a rounding error to hide.
+    chipBreakdown(amount, legend) {
+        let cents = this.toCents(amount);
+        if (cents <= 0) return { chips: [], remainder: 0 };
+
+        const values = (legend || [])
+            .map(chip => ({ chip, cents: this.toCents(chip.value) }))
+            .filter(entry => entry.cents > 0)
+            .sort((a, b) => b.cents - a.cents);
+
+        const chips = [];
+        values.forEach(entry => {
+            const count = Math.floor(cents / entry.cents);
+            if (count <= 0) return;
+            cents -= count * entry.cents;
+            chips.push({ value: this.fromCents(entry.cents), count, color: entry.chip.color });
+        });
+
+        return { chips, remainder: this.fromCents(cents) };
+    },
+
+    // "2×$50, 1×$25, 2×$1" — the breakdown as a dealer would say it out loud.
+    //
+    // A table with no chip legend gets nothing rather than "$132 no chip covers": it
+    // hasn't told us its denominations, so there is no advice to give and the amount
+    // stands on its own. A legend that exists but can't reach the amount is different,
+    // and does say so.
+    formatChipBreakdown(amount, legend) {
+        const hasDenominations = (legend || []).some(chip => this.toCents(chip.value) > 0);
+        if (!hasDenominations) return "";
+
+        const { chips, remainder } = this.chipBreakdown(amount, legend);
+        if (chips.length === 0 && remainder === 0) return "";
+        const parts = chips.map(chip => `${chip.count}×${this.format(chip.value)}`);
+        if (remainder > 0) parts.push(`${this.format(remainder)} no chip covers`);
+        return parts.join(", ");
+    },
+
     // Should focusing this field select what's already in it?
     //
     // Every amount box in this tool opens pre-filled with a suggestion: the raise pad

JoshHeaps.Net/wwwroot/js/casino/holdem/potWizard.js

@@ -246,10 +246,23 @@ const PotWizard = {
             empty.textContent = "Nobody has money in this pot yet — mark seats \"In hand\" and set contributions first.";
             wrap.appendChild(empty);
         } else {
+            const legend = (this.state && this.state.chipLegend) || [];
             const list = document.createElement("ul");
             for (const [id, amount] of this.totals.entries()) {
                 const li = document.createElement("li");
                 li.textContent = `${this.playerLabelById.get(id)} — ${Money.format(amount)}`;
+
+                // The amount is the answer to the arithmetic; the chips are the answer
+                // to the dealer's job. Only when the legend has been filled in — a
+                // table that never set up chip colours gets the number on its own,
+                // which is what it had before.
+                const chips = Money.formatChipBreakdown(amount, legend);
+                if (chips) {
+                    const note = document.createElement("span");
+                    note.className = "payoutChips";
+                    note.textContent = chips;
+                    li.appendChild(note);
+                }
                 list.appendChild(li);
             }
             wrap.appendChild(list);

JoshHeaps.Net/wwwroot/js/casino/holdem/render.js

@@ -49,11 +49,21 @@ const Render = {
         document.getElementById("defaultStackInput").value = this.state.defaultStack ?? "";
     },
 
+    // Whether this device can actually drag a seat. HTML5 drag events are never
+    // generated from a touch screen, so on a phone the last clause of the hint below
+    // described something impossible — on the device the rest of the sentence was
+    // written for. Touch gets told about the menu route instead, which works.
+    canDragSeats() {
+        return typeof matchMedia !== "function" || matchMedia("(hover: hover)").matches;
+    },
+
     renderTableHint() {
         const hint = document.getElementById("tableHint");
         // Gestures are invisible until someone tells you about them, and this is the
         // only place on the table with room to say so.
-        hint.textContent = "Tap a seat to edit · double-tap to fold · press and hold for quick actions · drag to swap seats.";
+        hint.textContent = this.canDragSeats()
+            ? "Tap a seat to edit · double-tap to fold · press and hold for quick actions · drag to swap seats."
+            : "Tap a seat to edit · double-tap to fold · press and hold for quick actions, including moving a seat.";
     },
 
     renderNotes() {
@@ -741,6 +751,41 @@ const Render = {
 
         this.renderBankReconciliation();
         this.renderSettleUp(standings);
+        this.renderStorageWarning();
+    },
+
+    // A toast is a moment; this table not being saved is a fact about the rest of the
+    // night. It sits at the top of the panel a dealer opens to check the money, and it
+    // stays there, because the raise pad dismisses toasts and the one time this warning
+    // matters is the one time it must not have been missed.
+    renderStorageWarning() {
+        const host = document.getElementById("storageWarning");
+        if (!host) return;
+        host.hidden = !HoldemState.saveFailed && !HoldemState.loadFailed && !HoldemState.otherTabActive;
+        if (host.hidden) return;
+
+        // Any of these can be true at once — a browser having trouble with storage
+        // tends to have it in both directions — and the one that explains an empty
+        // table goes first, because that's the question the dealer is standing there
+        // asking.
+        const lines = [];
+        if (HoldemState.otherTabActive) {
+            lines.push(
+                "This table is open in another tab, and both are writing to it — " +
+                "whichever acts last wins, so work done in the other one can vanish. " +
+                "Close one, then reload this tab to pick up the table as it stands.");
+        }
+        if (HoldemState.loadFailed) {
+            lines.push(
+                "The saved table couldn't be read, so this one started empty. " +
+                "The unreadable copy has been kept rather than written over.");
+        }
+        if (HoldemState.saveFailed) {
+            lines.push(
+                "This table isn't being saved — the browser refused. It'll keep working, " +
+                "but closing or refreshing this tab loses the session. Export CSV below keeps a copy.");
+        }
+        host.textContent = lines.join(" ");
     },
 
     // The last step the standings stopped short of. Six signed numbers at 2am is not

JoshHeaps.Net/wwwroot/js/casino/holdem/seatMenu.js

@@ -6,10 +6,16 @@ const SeatMenu = {
     hooks: null,
     seatIndex: null,
 
+    mode: null,
+
     open(state, hooks, seatIndex) {
         this.state = state;
         this.hooks = hooks;
         this.seatIndex = seatIndex;
+        // Always the action list, never whatever the sheet was showing when it last
+        // closed — a seat menu that opens on a list of chairs is a menu that lost the
+        // dealer's place.
+        this.mode = null;
         this.render();
         document.getElementById("seatMenuOverlay").hidden = false;
     },
@@ -63,29 +69,81 @@ const SeatMenu = {
             }
         }
 
+        // Changing chairs was drag-and-drop only, and HTML5 drag events are never
+        // generated from a touch screen — so on the device this tool is mostly used on,
+        // the "drag to swap seats" the hint advertised did nothing at all. This is the
+        // same move, by the route a thumb can actually take.
+        if (this.state.seats.length > 1) {
+            actions.push({ label: "Move to…", run: () => this.openMovePicker() });
+        }
+
         actions.push({ label: "Edit seat…", run: () => this.hooks.editSeat(index) });
         return actions;
     },
 
+    // The chairs this player could move to. Every other chair: swapping into an empty
+    // one is how a player moves, and swapping with an occupied one is two players
+    // changing places, which is the other half of the same job.
+    destinationsFor(index) {
+        return this.state.seats
+            .map((player, seat) => ({ player, seat }))
+            .filter(entry => entry.seat !== index);
+    },
+
+    openMovePicker() {
+        this.mode = "move";
+        this.render();
+    },
+
     render() {
         const player = this.state.seats[this.seatIndex];
-        document.getElementById("seatMenuTitle").textContent = HoldemState.displayName(player, this.seatIndex);
+        const title = document.getElementById("seatMenuTitle");
+        const subtitle = document.getElementById("seatMenuSubtitle");
+        const list = document.getElementById("seatMenuActions");
+        list.innerHTML = "";
+
+        if (this.mode === "move") {
+            title.textContent = `Move ${HoldemState.displayName(player, this.seatIndex)} to…`;
+            subtitle.textContent = "Their chips, cards and bet go with them. The button and the blinds stay on the chair.";
+            this.destinationsFor(this.seatIndex).forEach(({ player: other, seat }) => {
+                const btn = document.createElement("button");
+                btn.type = "button";
+                btn.className = "seatMenuBtn";
+                // displayName falls back to "Seat 5" for a chair with nobody in it,
+                // which reads as "Seat 5 — Seat 5". An empty chair says it's empty.
+                const named = (other.name || "").trim();
+                btn.textContent = named ? `Seat ${seat + 1} — ${named}` : `Seat ${seat + 1} — empty`;
+                btn.addEventListener("click", () => {
+                    const from = this.seatIndex;
+                    this.close();
+                    this.hooks.swapSeats(from, seat);
+                });
+                list.appendChild(btn);
+            });
+            return;
+        }
+
+        title.textContent = HoldemState.displayName(player, this.seatIndex);
 
         const stack = Betting.stackOf(this.state, player);
         const owed = Betting.toCall(this.state, player);
         const bits = [];
         if (stack > 0) bits.push(`${Money.format(stack)} behind`);
         if (owed > 0) bits.push(`${Money.format(owed)} to call`);
-        document.getElementById("seatMenuSubtitle").textContent = bits.join(" · ");
+        subtitle.textContent = bits.join(" · ");
 
-        const list = document.getElementById("seatMenuActions");
-        list.innerHTML = "";
         this.actionsFor(player, this.seatIndex).forEach(action => {
             const btn = document.createElement("button");
             btn.type = "button";
             btn.className = `seatMenuBtn ${action.className || ""}`;
             btn.textContent = action.label;
             btn.addEventListener("click", () => {
+                // "Move to…" stays on the sheet and swaps it for the seat list; every
+                // other action is the end of the interaction.
+                if (action.label === "Move to…") {
+                    action.run();
+                    return;
+                }
                 this.close();
                 action.run();
             });

JoshHeaps.Net/wwwroot/js/casino/holdem/shortcuts.js

@@ -18,6 +18,23 @@ const Shortcuts = {
         escape: "cancel",
     },
 
+    // What each one does, in a dealer's words, for the legend in the sidebar.
+    //
+    // Lives beside KEYS because the two must not drift: F, C and R are printed on the
+    // buttons they drive, but A and U were on nothing at all — a dealer who learned
+    // the first three from the bar had no way to find out the other two existed. A
+    // shortcut with no line here is a shortcut nobody can find, and there's a test
+    // that says so.
+    LEGEND: [
+        { keys: ["F"], action: "fold", what: "Fold" },
+        { keys: ["C"], action: "checkOrCall", what: "Check, or call the bet" },
+        { keys: ["R"], action: "raise", what: "Open the amount pad to bet or raise" },
+        { keys: ["A"], action: "allIn", what: "Put this player all-in" },
+        { keys: ["U"], action: "undo", what: "Take back the last action" },
+        { keys: ["Space", "Enter"], action: "advance", what: "Deal, or move to the next street" },
+        { keys: ["Esc"], action: "cancel", what: "Close the amount pad without betting" },
+    ],
+
     mount(handlers) {
         this.handlers = handlers;
         document.addEventListener("keydown", e => this.onKey(e));

JoshHeaps.Net/wwwroot/js/casino/holdem/state.js

@@ -81,12 +81,69 @@ const HoldemState = {
         };
     },
 
+    // Where an unreadable save is kept instead of being written over.
+    RECOVERY_KEY: "casino.holdem.state.v1.unreadable",
+
+    // True once another tab has written to this table. Two tabs each hold their own
+    // copy in memory and each save writes the whole thing, so the second one to act
+    // silently throws the first one's work away — measured: tab A deals and takes a
+    // call, tab B renames a seat, and the deal, the blinds and the call are gone with
+    // nothing said in either tab.
+    //
+    // Watched rather than merged. Replacing the table under a dealer's hands mid-hand
+    // would be its own hazard; knowing there are two of them is what they need.
+    otherTabActive: false,
+    onOtherTab: null,
+
+    // The browser fires this in every *other* tab, never the one that wrote, so our
+    // own saves can't trip it.
+    watchOtherTabs() {
+        if (typeof window === "undefined" || this.tabWatcher) return;
+        this.tabWatcher = event => {
+            if (event.key !== this.STORAGE_KEY) return;
+            if (this.otherTabActive) return;
+            this.otherTabActive = true;
+            if (typeof this.onOtherTab === "function") this.onOtherTab();
+        };
+        window.addEventListener("storage", this.tabWatcher);
+    },
+
+    // True when there was a saved table and it couldn't be read. Same pair as
+    // saveFailed above, for the same reason: the UI has to be able to say so.
+    loadFailed: false,
+    onLoadFailed: null,
+
+    // A saved table that won't parse becomes an empty table, which is the only thing
+    // it can become — but it used to become one silently, and then the first edit
+    // saved over the top of it. A dealer mid-session saw an empty felt with no idea
+    // whether they'd mis-tapped Reset or the browser had lost the night, and whatever
+    // a person might have picked out of the raw JSON was gone a tap later.
+    //
+    // So the unreadable value is moved aside first. It is not offered as a restore —
+    // half a JSON document isn't a table, and pretending otherwise would be worse than
+    // an empty one — but it stops being destroyed, and somebody who wants the
+    // standings out of it still can.
+    failedLoad(raw) {
+        if (!this.loadFailed) {
+            this.loadFailed = true;
+            try {
+                if (raw) localStorage.setItem(this.RECOVERY_KEY, raw);
+            } catch {
+                // No room to keep it. Nothing more to try, and the warning below is
+                // the part that actually matters.
+            }
+            if (typeof this.onLoadFailed === "function") this.onLoadFailed();
+        }
+        return this.createDefault();
+    },
+
     load() {
+        let raw = null;
         try {
-            const raw = localStorage.getItem(this.STORAGE_KEY);
+            raw = localStorage.getItem(this.STORAGE_KEY);
             if (!raw) return this.createDefault();
             const parsed = JSON.parse(raw);
-            if (!parsed || !Array.isArray(parsed.seats)) return this.createDefault();
+            if (!parsed || !Array.isArray(parsed.seats)) return this.failedLoad(raw);
             if (typeof parsed.handNumber !== "number" || parsed.handNumber < 1) parsed.handNumber = 1;
             if (!Array.isArray(parsed.handHistory)) parsed.handHistory = [];
 
@@ -118,16 +175,37 @@ const HoldemState = {
 
             return parsed;
         } catch {
-            return this.createDefault();
+            // Malformed JSON — a truncated write, another tab, a browser hiccup.
+            return this.failedLoad(raw);
         }
     },
 
+    // True once a save has failed. The UI reads this to keep saying so, because a
+    // toast is a moment and this is a fact about the rest of the night.
+    saveFailed: false,
+
+    // Called the first time a save fails. Set by the UI.
+    onSaveFailed: null,
+
     save(state) {
         try {
             localStorage.setItem(this.STORAGE_KEY, JSON.stringify(state));
-        } catch {
-            // Storage full/unavailable (private browsing, etc.) — the table still works
-            // for the rest of the session, it just won't survive a refresh.
+            return true;
+        } catch (error) {
+            // Storage full, or private browsing. The table still works for the rest of
+            // the session — it just won't survive a refresh, and nothing used to say
+            // so. That is the same shape of fault the bank check exists for: silent
+            // until it is too late to do anything about it. A dealer who finds out by
+            // refreshing has lost the night's standings, and the only warning they got
+            // was the table being empty.
+            //
+            // Announced once. A dealer tapping a bar thirty times a hand does not need
+            // thirty of these.
+            if (!this.saveFailed) {
+                this.saveFailed = true;
+                if (typeof this.onSaveFailed === "function") this.onSaveFailed(error);
+            }
+            return false;
         }
     },
 
@@ -467,6 +545,21 @@ const HoldemState = {
             .sort((a, b) => b.net - a.net);
     },
 
+    // Two players change chairs.
+    //
+    // The whole seat moves — name, stack, cards, what they have in the pot — because
+    // that is what changing chairs is. What stays behind is everything that belongs to
+    // the *position*: the button, the blinds and the acting index all name a chair, and
+    // a player who moves into the big blind's chair is the big blind. That is the same
+    // answer a card room gives.
+    swapSeats(state, a, b) {
+        const seats = state.seats || [];
+        if (a === b) return false;
+        if (!seats[a] || !seats[b]) return false;
+        [seats[a], seats[b]] = [seats[b], seats[a]];
+        return true;
+    },
+
     // The one check a banker actually needs, and the one nothing here did.
     //
     // Every chip on the table is a promise to pay cash for it later. If the chips in

tests/holdem/chipBreakdown.test.js

@@ -0,0 +1,82 @@
+// The chips to actually push, for an amount.
+const test = require("node:test");
+const assert = require("node:assert");
+const { Money } = require("./load");
+
+// A standard house set.
+const LEGEND = [
+    { value: 1, color: "#fff" },
+    { value: 5, color: "#c0392b" },
+    { value: 25, color: "#27ae60" },
+    { value: 100, color: "#2c3e50" },
+    { value: 500, color: "#8e44ad" },
+];
+
+const say = (amount, legend = LEGEND) => Money.formatChipBreakdown(amount, legend);
+
+test("a payout comes back as chips, largest first", () => {
+    assert.equal(say(132), "1×$100, 1×$25, 1×$5, 2×$1");
+});
+
+test("it uses the fewest chips on a normal set", () => {
+    const { chips } = Money.chipBreakdown(500, LEGEND);
+    assert.deepEqual(chips.map(c => `${c.count}×${c.value}`), ["1×500"]);
+});
+
+test("a denomination that doesn't fit is skipped rather than listed as none", () => {
+    assert.equal(say(7), "1×$5, 2×$1");
+});
+
+test("nothing to pay is nothing to say", () => {
+    assert.equal(say(0), "");
+    assert.equal(say(-5), "");
+});
+
+test("no legend means no advice, not a wrong answer", () => {
+    // A table that never set chip colours up gets the amount on its own.
+    assert.equal(say(132, []), "");
+    assert.equal(say(132, null), "");
+});
+
+test("a legend with no values in it yet is the same as none", () => {
+    assert.equal(say(132, [{ value: "", color: "#fff" }, { value: 0, color: "#000" }]), "");
+});
+
+test("what the smallest chip can't make is reported, not rounded away", () => {
+    // 50c in a game whose smallest chip is a dollar is the dealer's problem to solve,
+    // and they can only solve it if they're told.
+    const { chips, remainder } = Money.chipBreakdown(10.5, LEGEND);
+    assert.deepEqual(chips.map(c => `${c.count}×${c.value}`), ["2×5"]);
+    assert.equal(remainder, 0.5);
+    assert.equal(say(10.5), "2×$5, $0.50 no chip covers");
+});
+
+test("cent chips make cent amounts exactly", () => {
+    const cents = [{ value: 0.25 }, { value: 0.05 }, { value: 0.01 }];
+    assert.equal(say(0.41, cents), "1×$0.25, 3×$0.05, 1×$0.01");
+    assert.equal(Money.chipBreakdown(0.41, cents).remainder, 0);
+});
+
+test("the chips add up to the amount", () => {
+    for (const amount of [1, 7, 33, 132, 499, 500, 1234, 9999]) {
+        const { chips, remainder } = Money.chipBreakdown(amount, LEGEND);
+        const total = chips.reduce((sum, c) => sum + c.count * c.value, 0) + remainder;
+        assert.equal(Money.round(total), amount, `${amount} should be accounted for`);
+    }
+});
+
+test("a legend in any order still pays largest first", () => {
+    const jumbled = [{ value: 25 }, { value: 1 }, { value: 500 }, { value: 5 }, { value: 100 }];
+    assert.equal(say(631, jumbled), "1×$500, 1×$100, 1×$25, 1×$5, 1×$1");
+});
+
+test("the colour comes along, so the felt can say it in chips", () => {
+    const { chips } = Money.chipBreakdown(25, LEGEND);
+    assert.equal(chips[0].color, "#27ae60");
+});
+
+test("a legend that exists but can't reach the amount does say so", () => {
+    // Different from having no legend at all: this table has told us its chips, and
+    // the answer is that they don't go that low.
+    assert.equal(say(3, [{ value: 5 }, { value: 25 }]), "$3 no chip covers");
+});

tests/holdem/loadFailure.test.js

@@ -0,0 +1,114 @@
+// What happens when the saved table can't be read.
+//
+// An unreadable save can only become an empty table. What it must not do is become
+// one silently and then get written over by the first edit.
+const test = require("node:test");
+const assert = require("node:assert");
+const { HoldemState } = require("./load");
+
+function withStored(value, { readOnly = false } = {}) {
+    const store = new Map();
+    if (value !== undefined) store.set(HoldemState.STORAGE_KEY, value);
+    globalThis.localStorage = {
+        getItem: key => (store.has(key) ? store.get(key) : null),
+        setItem(key, val) {
+            if (readOnly) throw new Error("QuotaExceededError");
+            store.set(key, val);
+        },
+        removeItem: key => store.delete(key),
+    };
+    return store;
+}
+
+test.beforeEach(() => {
+    HoldemState.loadFailed = false;
+    HoldemState.onLoadFailed = null;
+});
+
+test.after(() => {
+    delete globalThis.localStorage;
+    HoldemState.loadFailed = false;
+    HoldemState.onLoadFailed = null;
+});
+
+test("nothing stored is a new table, not a failure", () => {
+    withStored(undefined);
+    const state = HoldemState.load();
+
+    assert.equal(HoldemState.loadFailed, false);
+    assert.ok(Array.isArray(state.seats));
+});
+
+test("a good save loads and reports nothing", () => {
+    const store = withStored(undefined);
+    const original = HoldemState.createDefault();
+    original.handNumber = 34;
+    HoldemState.save(original);
+
+    const state = HoldemState.load();
+    assert.equal(HoldemState.loadFailed, false);
+    assert.equal(state.handNumber, 34);
+    assert.equal(store.has(HoldemState.RECOVERY_KEY), false);
+});
+
+test("a truncated save is reported rather than silently becoming an empty table", () => {
+    const good = JSON.stringify(HoldemState.createDefault());
+    withStored(good.slice(0, Math.floor(good.length * 0.7)));
+
+    const state = HoldemState.load();
+    assert.equal(HoldemState.loadFailed, true);
+    assert.ok(Array.isArray(state.seats), "it still hands back a usable table");
+});
+
+test("valid JSON of the wrong shape counts as unreadable too", () => {
+    withStored(JSON.stringify({ hello: "world" }));
+
+    HoldemState.load();
+    assert.equal(HoldemState.loadFailed, true);
+});
+
+test("the unreadable copy is kept instead of being written over", () => {
+    // This is the half that matters: whatever a person could have picked out of the
+    // raw JSON used to be gone the moment the dealer touched a seat.
+    const broken = '{"seats":[{"name":"Ann","stack":250},{"name":"Ben"';
+    const store = withStored(broken);
+
+    HoldemState.load();
+
+    assert.equal(store.get(HoldemState.RECOVERY_KEY), broken);
+});
+
+test("a later save doesn't touch the copy that was set aside", () => {
+    const broken = '{"seats":[{"name":"Ann"';
+    const store = withStored(broken);
+
+    const state = HoldemState.load();
+    state.handNumber = 2;
+    HoldemState.save(state);
+
+    assert.equal(store.get(HoldemState.RECOVERY_KEY), broken);
+    assert.notEqual(store.get(HoldemState.STORAGE_KEY), broken);
+});
+
+test("the listener fires once, not on every read", () => {
+    withStored("{not json");
+    let told = 0;
+    HoldemState.onLoadFailed = () => { told++; };
+
+    HoldemState.load();
+    HoldemState.load();
+    HoldemState.load();
+
+    assert.equal(told, 1);
+});
+
+test("no room to keep the copy is not a crash", () => {
+    // Storage that refuses writes is exactly the storage most likely to hand back a
+    // half-written value in the first place.
+    withStored("{not json", { readOnly: true });
+
+    let state;
+    assert.doesNotThrow(() => { state = HoldemState.load(); });
+    assert.ok(Array.isArray(state.seats));
+    assert.equal(HoldemState.loadFailed, true);
+});

tests/holdem/otherTab.test.js

@@ -0,0 +1,100 @@
+// Noticing that the same table is open twice.
+//
+// Two tabs each hold their own copy in memory and each save writes the whole thing,
+// so the second one to act throws the first one's work away. This doesn't merge them
+// — replacing a table under a dealer's hands mid-hand would be its own hazard — it
+// notices, which is what lets them decide.
+const test = require("node:test");
+const assert = require("node:assert");
+const { HoldemState } = require("./load");
+
+function withWindow() {
+    const listeners = [];
+    globalThis.window = {
+        addEventListener(type, fn) { if (type === "storage") listeners.push(fn); },
+        removeEventListener(type, fn) {
+            const i = listeners.indexOf(fn);
+            if (i >= 0) listeners.splice(i, 1);
+        },
+    };
+    return {
+        listeners,
+        fire(key) { listeners.forEach(fn => fn({ key })); },
+    };
+}
+
+test.beforeEach(() => {
+    HoldemState.otherTabActive = false;
+    HoldemState.onOtherTab = null;
+    HoldemState.tabWatcher = null;
+});
+
+test.after(() => {
+    delete globalThis.window;
+    HoldemState.otherTabActive = false;
+    HoldemState.onOtherTab = null;
+    HoldemState.tabWatcher = null;
+});
+
+test("a write to this table from elsewhere is noticed", () => {
+    const win = withWindow();
+    let told = 0;
+    HoldemState.onOtherTab = () => { told++; };
+    HoldemState.watchOtherTabs();
+
+    win.fire(HoldemState.STORAGE_KEY);
+
+    assert.equal(HoldemState.otherTabActive, true);
+    assert.equal(told, 1);
+});
+
+test("somebody else's storage key is not our business", () => {
+    const win = withWindow();
+    let told = 0;
+    HoldemState.onOtherTab = () => { told++; };
+    HoldemState.watchOtherTabs();
+
+    win.fire("some.other.app.state");
+    win.fire(HoldemState.RECOVERY_KEY);
+
+    assert.equal(HoldemState.otherTabActive, false);
+    assert.equal(told, 0);
+});
+
+test("told once, however many times the other tab acts", () => {
+    const win = withWindow();
+    let told = 0;
+    HoldemState.onOtherTab = () => { told++; };
+    HoldemState.watchOtherTabs();
+
+    for (let i = 0; i < 10; i++) win.fire(HoldemState.STORAGE_KEY);
+
+    assert.equal(told, 1);
+});
+
+test("watching twice doesn't listen twice", () => {
+    const win = withWindow();
+    HoldemState.watchOtherTabs();
+    HoldemState.watchOtherTabs();
+    HoldemState.watchOtherTabs();
+
+    assert.equal(win.listeners.length, 1);
+});
+
+test("no listener set is not an error", () => {
+    const win = withWindow();
+    HoldemState.onOtherTab = null;
+    HoldemState.watchOtherTabs();
+
+    assert.doesNotThrow(() => win.fire(HoldemState.STORAGE_KEY));
+    assert.equal(HoldemState.otherTabActive, true);
+});
+
+test("no window at all is not an error", () => {
+    // The same modules are loaded in Node by the test harness.
+    delete globalThis.window;
+    HoldemState.tabWatcher = null;
+
+    assert.doesNotThrow(() => HoldemState.watchOtherTabs());
+    assert.equal(HoldemState.otherTabActive, false);
+});

tests/holdem/saveFailure.test.js

@@ -0,0 +1,95 @@
+// What happens when the browser refuses to save.
+//
+// The table keeps working — that was always true and is still the right behaviour.
+// What was missing is anybody being told, which is the same shape of fault the bank
+// check exists for: silent until it's too late to act on.
+const test = require("node:test");
+const assert = require("node:assert");
+const { HoldemState, makeTable } = require("./load");
+
+function withStorage(behaviour) {
+    const calls = [];
+    globalThis.localStorage = {
+        setItem(key, value) {
+            calls.push({ key, value });
+            if (behaviour === "throw") {
+                const error = new Error("QuotaExceededError");
+                error.name = "QuotaExceededError";
+                throw error;
+            }
+        },
+        getItem: () => null,
+        removeItem() {},
+    };
+    return calls;
+}
+
+test.beforeEach(() => {
+    HoldemState.saveFailed = false;
+    HoldemState.onSaveFailed = null;
+});
+
+test.after(() => {
+    delete globalThis.localStorage;
+    HoldemState.saveFailed = false;
+    HoldemState.onSaveFailed = null;
+});
+
+test("a save that works says so and leaves no mark", () => {
+    withStorage("ok");
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+
+    assert.equal(HoldemState.save(state), true);
+    assert.equal(HoldemState.saveFailed, false);
+});
+
+test("a save that fails says so rather than throwing", () => {
+    withStorage("throw");
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+
+    assert.equal(HoldemState.save(state), false);
+    assert.equal(HoldemState.saveFailed, true);
+});
+
+test("the table is told once, not on every action", () => {
+    // A dealer taps the bar thirty times a hand and doesn't need thirty warnings.
+    withStorage("throw");
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+    let told = 0;
+    HoldemState.onSaveFailed = () => { told++; };
+
+    for (let i = 0; i < 20; i++) HoldemState.save(state);
+
+    assert.equal(told, 1);
+});
+
+test("the failure is handed the error, so the reason can be reported later", () => {
+    withStorage("throw");
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+    let seen = null;
+    HoldemState.onSaveFailed = error => { seen = error; };
+
+    HoldemState.save(state);
+
+    assert.equal(seen && seen.name, "QuotaExceededError");
+});
+
+test("a failing save still doesn't stop the table", () => {
+    // The chips have already moved in memory; refusing to continue would be worse
+    // than not persisting.
+    withStorage("throw");
+    const state = makeTable({ seatCount: 6, seated: [0, 1, 2], stack: 100 });
+    state.seats[0].stack = 175;
+
+    assert.doesNotThrow(() => HoldemState.save(state));
+    assert.equal(state.seats[0].stack, 175);
+});
+
+test("no listener is not an error", () => {
+    withStorage("throw");
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+    HoldemState.onSaveFailed = null;
+
+    assert.doesNotThrow(() => HoldemState.save(state));
+    assert.equal(HoldemState.saveFailed, true);
+});

tests/holdem/shortcutLegend.test.js

@@ -0,0 +1,51 @@
+// The legend and the key map must not drift apart.
+//
+// F, C and R are printed on the buttons they drive. A and U were on nothing at all,
+// so a dealer who learned the first three from the action bar had no way to find out
+// the other two existed. The guard against that happening again is this file.
+const test = require("node:test");
+const assert = require("node:assert");
+const path = require("path");
+
+const Shortcuts = require(path.join(
+    __dirname, "..", "..", "JoshHeaps.Net", "wwwroot", "js", "casino", "holdem", "shortcuts.js"));
+
+test("every shortcut has a line in the legend", () => {
+    const documented = new Set(Shortcuts.LEGEND.map(entry => entry.action));
+    const missing = [...new Set(Object.values(Shortcuts.KEYS))].filter(action => !documented.has(action));
+    assert.deepEqual(missing, [], "a shortcut with no legend line is one nobody can find");
+});
+
+test("the legend doesn't describe shortcuts that don't exist", () => {
+    const real = new Set(Object.values(Shortcuts.KEYS));
+    const invented = Shortcuts.LEGEND.map(entry => entry.action).filter(action => !real.has(action));
+    assert.deepEqual(invented, []);
+});
+
+test("every legend line names its keys and says what they do", () => {
+    Shortcuts.LEGEND.forEach(entry => {
+        assert.ok(Array.isArray(entry.keys) && entry.keys.length > 0, `${entry.action} has no keys`);
+        assert.ok(entry.keys.every(key => typeof key === "string" && key.trim()), `${entry.action} has a blank key`);
+        assert.ok(entry.what && entry.what.trim().length > 3, `${entry.action} has no description`);
+    });
+});
+
+test("the keys named match the keys bound", () => {
+    // "Space" and "Enter" both drive advance; the map holds them as " " and "enter".
+    const spoken = { space: " ", enter: "enter", esc: "escape" };
+    Shortcuts.LEGEND.forEach(entry => {
+        entry.keys.forEach(label => {
+            const key = spoken[label.toLowerCase()] || label.toLowerCase();
+            assert.equal(Shortcuts.KEYS[key], entry.action,
+                `the legend says ${label} is ${entry.action}, the map disagrees`);
+        });
+    });
+});
+
+test("no two lines claim the same key", () => {
+    const seen = new Set();
+    Shortcuts.LEGEND.forEach(entry => entry.keys.forEach(key => {
+        assert.ok(!seen.has(key.toLowerCase()), `${key} is listed twice`);
+        seen.add(key.toLowerCase());
+    }));
+});

tests/holdem/swapSeats.test.js

@@ -0,0 +1,95 @@
+// Two players changing chairs.
+const test = require("node:test");
+const assert = require("node:assert");
+const { Betting, HoldemState, makeTable, chipsOnTable } = require("./load");
+
+test("the whole seat moves", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1, 2], stack: 100 });
+    state.seats[0].name = "Ann";
+    state.seats[0].cards = ["AS", "KD"];
+    state.seats[0].stack = 175;
+    state.seats[4].name = "";
+
+    HoldemState.swapSeats(state, 0, 4);
+
+    assert.equal(state.seats[4].name, "Ann");
+    assert.deepEqual(state.seats[4].cards, ["AS", "KD"]);
+    assert.equal(state.seats[4].stack, 175);
+    assert.equal(state.seats[0].name, "");
+});
+
+test("what they have in the pot goes with them", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1, 2], stack: 100 });
+    Betting.beginHand(state);
+    const posted = state.seats.map(p => p.committed);
+    const before = chipsOnTable(state);
+
+    HoldemState.swapSeats(state, 1, 4);
+
+    assert.equal(state.seats[4].committed, posted[1]);
+    assert.equal(state.seats[1].committed, posted[4]);
+    assert.equal(chipsOnTable(state), before, "a swap never creates or destroys a chip");
+});
+
+test("the button stays on the chair, not on the player", () => {
+    // A card room moves the button around the table, not around the people. Somebody
+    // who sits down in the big blind's chair is the big blind.
+    const state = makeTable({ seatCount: 6, seated: [0, 1, 2], stack: 100, dealerSeatIndex: 0 });
+    state.seats[0].name = "Ann";
+
+    HoldemState.swapSeats(state, 0, 2);
+
+    assert.equal(state.dealerSeatIndex, 0);
+    assert.notEqual(state.seats[0].name, "Ann");
+});
+
+test("the blinds follow the chairs too", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3], stack: 100, dealerSeatIndex: 0 });
+    Betting.beginHand(state);
+    const before = HoldemState.getBlindSeats(state);
+
+    HoldemState.swapSeats(state, before.sbIndex, before.bbIndex);
+    const after = HoldemState.getBlindSeats(state);
+
+    assert.equal(after.sbIndex, before.sbIndex);
+    assert.equal(after.bbIndex, before.bbIndex);
+});
+
+test("swapping a seat with itself does nothing and says so", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+    const before = JSON.stringify(state);
+
+    assert.equal(HoldemState.swapSeats(state, 1, 1), false);
+    assert.equal(JSON.stringify(state), before);
+});
+
+test("a chair that isn't there is refused rather than swallowed", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+    const before = JSON.stringify(state);
+
+    assert.equal(HoldemState.swapSeats(state, 0, 99), false);
+    assert.equal(HoldemState.swapSeats(state, -1, 0), false);
+    assert.equal(JSON.stringify(state), before);
+});
+
+test("swapping twice puts everything back", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1, 2, 3], stack: 100 });
+    Betting.beginHand(state);
+    const before = JSON.stringify(state);
+
+    HoldemState.swapSeats(state, 1, 3);
+    HoldemState.swapSeats(state, 1, 3);
+
+    assert.equal(JSON.stringify(state), before);
+});
+
+test("moving into an empty chair leaves an empty chair behind", () => {
+    const state = makeTable({ seatCount: 6, seated: [0, 1], stack: 100 });
+    state.seats[1].name = "Ben";
+
+    HoldemState.swapSeats(state, 1, 5);
+
+    assert.equal(state.seats[5].name, "Ben");
+    assert.equal(state.seats[5].inHand, true);
+    assert.equal(state.seats[1].inHand, false);
+});

tests/holdem/uiAudit.js

@@ -180,6 +180,12 @@ const LayoutAudit = {
     collapsedColumns() {
         const offenders = [];
         [...document.querySelectorAll("[class*='Row'], [class*='row']")].forEach(row => {
+            // Nothing inside something the page has hidden. A hidden element's children
+            // all measure zero wide, so the standings header — which is hidden along
+            // with its table until somebody has bought in — was reported as three
+            // collapsed columns on every empty table. A column nobody can see hasn't
+            // collapsed; it isn't there.
+            if (row.closest("[hidden]")) return;
             if (getComputedStyle(row).display !== "grid") return;
             [...row.children].forEach(cell => {
                 if (getComputedStyle(cell).display === "none") return;
@@ -522,8 +528,15 @@ const LayoutAudit = {
         const chips = [...document.querySelectorAll(".dealerChip")];
         const shown = chips.filter(chip => {
             const style = getComputedStyle(chip);
-            return style.display !== "none" && style.visibility !== "hidden" &&
-                parseFloat(style.opacity) > 0.05;
+            if (style.display === "none" || style.visibility === "hidden") return false;
+            if (parseFloat(style.opacity) <= 0.05) return false;
+            // A hovered seat deliberately fades its empty slot in — that's the "put the
+            // button here" preview, and it is on screen because a pointer is sitting on
+            // that seat. Counting it reports two buttons whenever the mouse happens to
+            // rest on the table, which is most of the time a mouse exists.
+            const seat = chip.closest(".seat");
+            if (seat && seat.matches(":hover") && !chip.classList.contains("active")) return false;
+            return true;
         });
         const offenders = [];