feat(game): official first-move tile draw + admin step-by-step replay

Decide who moves first by the official rule: each seated player draws one
tile, the one closest to "A" leads (a blank beats every letter), ties
re-drawing until a single leader remains. Each draw uses honest per-draw
crypto/rand entropy (not the deterministic bag seed), so the recorded draw —
not a seed — is the only account of the outcome. The leader takes seat 0, so
the engine and journal replay are unchanged.

The draw is recorded with the game (game_setup_draws, migration 00013) for
future tournaments, designed as a discrete "player N draws a tile" step.
Friend/AI games draw at creation. Auto-match draws when the game opens,
against a synthetic uuid.Nil opponent whose draw rows (NULL account_id) are
back-filled to the real opponent on join — so the opener's seat is fixed up
front and the existing open-game pre-move is preserved with no reseating.

Admin /_gm/games/:id gains the recorded draw list and a simple step-by-step
board replay (game.ReplayTimeline + a vanilla-JS stepper): a board with
A-O/1-15 headers and highlighted premium squares, placed letters with their
tile value as a subscript, rack panels around the board (seat 0 top, 1
bottom, 2 left, 3 right) with the current player highlighted, and a per-move
log with the tiles drawn and the bag remainder.

Docs: ARCHITECTURE §6/§9, FUNCTIONAL (+_ru), PRERELEASE (FM row), design spec.

backend/internal/adminconsole/assets/console.css

@@ -137,3 +137,59 @@ code { background: var(--bg); padding: 0.05rem 0.3rem; border-radius: 4px; }
    an image attachment is previewed inline, bounded so it cannot dominate the page. */
 .msgbody { white-space: pre-wrap; word-break: break-word; background: var(--bg); padding: 0.6rem 0.8rem; border-radius: 6px; margin: 0.6rem 0; }
 .attach { max-width: 100%; max-height: 480px; height: auto; border: 1px solid var(--line); border-radius: 6px; }
+
+/* Game replay (admin): a script-stepped board with rack panels around it, a move log and the
+   first-move draw. A placed tile shows its value as a subscript; a 0 value (a blank) shows none. */
+.replay-stage {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr) auto;
+  grid-template-areas: ".    top    ." "left board  right" ".    bottom .";
+  gap: 0.5rem;
+  align-items: center;
+  justify-items: center;
+  margin-bottom: 0.6rem;
+}
+.rack-top { grid-area: top; }
+.rack-bottom { grid-area: bottom; }
+.rack-left { grid-area: left; }
+.rack-right { grid-area: right; }
+.replay-board { grid-area: board; overflow: auto; }
+.board-grid {
+  display: grid;
+  grid-template-columns: 1.4rem repeat(15, 1.7rem);
+  grid-auto-rows: 1.7rem;
+  gap: 1px;
+  background: var(--line);
+  border: 1px solid var(--line);
+  width: max-content;
+}
+.board-grid .bh { display: flex; align-items: center; justify-content: center; font-size: 0.6rem; color: var(--ink-dim); background: var(--panel); }
+.board-grid .cell { position: relative; display: flex; align-items: center; justify-content: center; background: var(--panel-hi); }
+.cell .prem { font-size: 0.55rem; color: var(--ink); opacity: 0.8; }
+.cell.tw { background: #7a2230; }
+.cell.dw { background: #a8506a; }
+.cell.tl { background: #235a7a; }
+.cell.dl { background: #3f87a8; }
+.cell.centre .prem { font-size: 0.95rem; color: var(--warn); opacity: 1; }
+.tile {
+  display: inline-flex; align-items: baseline; justify-content: center;
+  min-width: 1.35rem; height: 1.35rem; padding: 0 0.12rem;
+  background: #e8d9a0; color: #1b1408; border-radius: 3px;
+  font-weight: 700; font-size: 0.8rem; line-height: 1.35rem;
+}
+.tile sub { font-size: 0.5rem; font-weight: 600; line-height: 1; align-self: flex-end; margin-left: 1px; }
+.tile.blank { background: #cdbfe0; }
+.cell.filled { background: var(--panel-hi); }
+.cell.filled .tile { width: 100%; height: 100%; border-radius: 2px; }
+.rack-slot { padding: 0.25rem; border-radius: 6px; }
+.rack-slot.active { outline: 2px solid var(--accent); background: var(--panel-hi); }
+.rack-name { font-size: 0.72rem; color: var(--ink-dim); margin-bottom: 0.2rem; text-align: center; }
+.rack-tiles { display: flex; gap: 2px; flex-wrap: wrap; justify-content: center; }
+.rack-left .rack-tiles, .rack-right .rack-tiles { flex-direction: column; }
+.replay-controls { display: flex; align-items: center; gap: 0.8rem; justify-content: center; margin: 0.6rem 0; }
+.replay-controls button { background: var(--panel-hi); color: var(--ink); border: 1px solid var(--line); font-weight: 600; }
+.replay-controls button:disabled { opacity: 0.4; cursor: default; }
+.replay-pos { color: var(--ink-dim); font-variant-numeric: tabular-nums; }
+.replay-log { margin: 0.4rem 0 0; padding-left: 1.4rem; max-height: 14rem; overflow: auto; font-size: 0.85rem; }
+.replay-log li { color: var(--ink-dim); padding: 0.1rem 0; }
+.replay-log li.cur { color: var(--ink); font-weight: 600; }

backend/internal/adminconsole/templates/pages/game_detail.gohtml

@@ -27,5 +27,87 @@
 </table>
 {{if .HasRobot}}<p><small>Play-to-win is decided once per game from the bag seed; robots play to win in ~{{.RobotTargetPct}}% of games.</small></p>{{end}}
 </section>
+{{if .SetupDraws}}
+<section class="panel"><h2>First-move draw</h2>
+<p class="note">Each player draws a tile; the one closest to &ldquo;A&rdquo; moves first (a blank beats every letter), ties re-drawing until a single leader remains.{{if .FirstMover}} <b>{{.FirstMover}}</b> leads.{{end}}</p>
+<table class="list">
+<thead><tr><th>Round</th><th>Player</th><th>Tile</th><th>Rank</th></tr></thead>
+<tbody>
+{{range .SetupDraws}}
+<tr><td>{{.Round}}</td><td>{{if .AccountID}}<a href="/_gm/users/{{.AccountID}}">{{.Name}}</a>{{else}}{{.Name}}{{end}}</td><td>{{.Letter}}{{if .Blank}} <small>(blank)</small>{{end}}</td><td>{{.Rank}}</td></tr>
+{{end}}
+</tbody>
+</table>
+</section>
+{{end}}
+{{if .HasReplay}}
+<section class="panel"><h2>Replay</h2>
+<div class="replay-stage">
+  <div class="rack-slot rack-top" data-seat="0"></div>
+  <div class="rack-slot rack-left" data-seat="2"></div>
+  <div class="replay-board" id="replay-board"></div>
+  <div class="rack-slot rack-right" data-seat="3"></div>
+  <div class="rack-slot rack-bottom" data-seat="1"></div>
+</div>
+<div class="replay-controls">
+  <button type="button" id="replay-prev">&#9664; prev</button>
+  <span class="replay-pos" id="replay-pos"></span>
+  <button type="button" id="replay-next">next &#9654;</button>
+</div>
+<ol class="replay-log" id="replay-log"></ol>
+<script>
+const REPLAY = {{.ReplayJSON}};
+(function(){
+  if(!REPLAY||!REPLAY.steps){return;}
+  const N=15, COLS="ABCDEFGHIJKLMNO", PREM={tw:"3W",dw:"2W",tl:"3L",dl:"2L"};
+  const boardEl=document.getElementById("replay-board"), logEl=document.getElementById("replay-log");
+  const posEl=document.getElementById("replay-pos"), prevBtn=document.getElementById("replay-prev"), nextBtn=document.getElementById("replay-next");
+  let step=0;
+  function esc(s){const d=document.createElement("div");d.textContent=s==null?"":s;return d.innerHTML;}
+  function tileHTML(t){const sub=(t.v&&t.v>0)?"<sub>"+t.v+"<\/sub>":"";return "<span class=\"tile"+(t.b?" blank":"")+"\">"+esc(t.l)+sub+"<\/span>";}
+  function placedAt(k){const m={};for(let s=1;s<=k;s++){const mv=REPLAY.steps[s]&&REPLAY.steps[s].move;if(mv&&mv.placements){for(const p of mv.placements){m[p.r+","+p.c]=p;}}}return m;}
+  function renderBoard(){
+    const placed=placedAt(step);let h="<div class=\"board-grid\"><div class=\"bh corner\"><\/div>";
+    for(let c=0;c<N;c++){h+="<div class=\"bh\">"+COLS[c]+"<\/div>";}
+    for(let r=0;r<N;r++){h+="<div class=\"bh\">"+(r+1)+"<\/div>";
+      for(let c=0;c<N;c++){const p=placed[r+","+c];
+        if(p){h+="<div class=\"cell filled\">"+tileHTML(p)+"<\/div>";continue;}
+        const prem=REPLAY.premium[r][c], centre=(r===REPLAY.centre[0]&&c===REPLAY.centre[1]);
+        const label=centre?"&#9733;":(prem?PREM[prem]:"");
+        h+="<div class=\"cell "+(prem||"")+(centre?" centre":"")+"\">"+(label?"<span class=\"prem\">"+label+"<\/span>":"")+"<\/div>";}}
+    h+="<\/div>";boardEl.innerHTML=h;
+  }
+  function renderRacks(){
+    const st=REPLAY.steps[step];
+    document.querySelectorAll(".rack-slot").forEach(function(slot){
+      const seat=parseInt(slot.dataset.seat,10), info=REPLAY.seats.find(function(s){return s.seat===seat;}), rack=st.racks[seat];
+      if(!info||!rack){slot.style.display="none";slot.innerHTML="";return;}
+      slot.style.display="";slot.classList.toggle("active",st.toMove===seat);
+      const nm=info.accountId?"<a href=\"/_gm/users/"+info.accountId+"\">"+esc(info.name)+"<\/a>":esc(info.name||("seat "+seat));
+      slot.innerHTML="<div class=\"rack-name\">"+nm+" &middot; "+(st.scores[seat]||0)+"<\/div><div class=\"rack-tiles\">"+rack.map(tileHTML).join("")+"<\/div>";
+    });
+  }
+  function renderLog(){
+    let h="";
+    for(let s=1;s<=step;s++){const st=REPLAY.steps[s], m=st.move;if(!m){continue;}
+      const who=((REPLAY.seats.find(function(x){return x.seat===m.seat;})||{}).name)||("seat "+m.seat);
+      let desc;
+      if(m.action==="play"){desc="played "+((m.words&&m.words.length)?m.words.join(", "):"")+" for "+m.score;}
+      else if(m.action==="exchange"){desc="exchanged "+((m.exchanged&&m.exchanged.length)||0)+" tiles";}
+      else if(m.action==="pass"){desc="passed";}
+      else{desc=m.action;}
+      const drew=(st.drawn&&st.drawn.length)?" &middot; drew "+st.drawn.map(function(t){return t.l;}).join(""):"";
+      h+="<li class=\""+(s===step?"cur":"")+"\">"+esc(who)+" "+esc(desc)+drew+" &middot; bag "+st.bagLen+"<\/li>";}
+    logEl.innerHTML=h||"<li class=\"note\">opening position<\/li>";
+  }
+  function render(){renderBoard();renderRacks();renderLog();posEl.textContent=step+" / "+(REPLAY.steps.length-1);prevBtn.disabled=step<=0;nextBtn.disabled=step>=REPLAY.steps.length-1;}
+  prevBtn.onclick=function(){if(step>0){step--;render();}};
+  nextBtn.onclick=function(){if(step<REPLAY.steps.length-1){step++;render();}};
+  document.addEventListener("keydown",function(e){if(e.key==="ArrowLeft"){prevBtn.click();}else if(e.key==="ArrowRight"){nextBtn.click();}});
+  render();
+})();
+</script>
+</section>
+{{end}}
 {{end}}
 {{- end}}

backend/internal/adminconsole/views.go

@@ -268,6 +268,27 @@ type GameDetailView struct {
 	// RobotTargetPct is the configured global play-to-win rate, in percent.
 	HasRobot       bool
 	RobotTargetPct int
+	// ReplayJSON is the game-replay payload (board, seats, per-step racks/scores/bag) the
+	// game_detail page feeds to its vanilla-JS stepper; HasReplay gates the replay section.
+	ReplayJSON template.JS
+	HasReplay  bool
+	// SetupDraws is the first-move draw — one row per tile drawn (docs/ARCHITECTURE.md §6) —
+	// and FirstMover is the resolved name of the seat-0 player the draw elected.
+	SetupDraws []SetupDrawRow
+	FirstMover string
+}
+
+// SetupDrawRow is one tile drawn in the first-move seeding (docs/ARCHITECTURE.md §6): the
+// round, the player (Name/AccountID, or "(opponent)" with an empty AccountID for an
+// auto-match synthetic draw not yet back-filled), the drawn letter (upper-cased; "?" for a
+// blank) and its draw rank.
+type SetupDrawRow struct {
+	Round     int
+	Name      string
+	AccountID string
+	Letter    string
+	Blank     bool
+	Rank      int
 }
 
 // SeatRow is one seat of a game. For a robot seat (IsRobot) RobotIntent is the game's

backend/internal/engine/setup.go

@@ -0,0 +1,52 @@
+package engine
+
+import "fmt"
+
+// SetupTile is one tile of a variant's full bag, decoded for the first-move draw
+// (docs/ARCHITECTURE.md §6): its concrete letter (or the blank marker), a blank
+// flag, and its draw rank. Lower rank wins the draw — a blank ranks above every
+// letter, and letters rank by alphabet index, so the tile closest to the start of
+// the alphabet ("A") wins. It is dictionary-independent, built from the variant's
+// solver ruleset alone.
+type SetupTile struct {
+	// Letter is the concrete character (the case the solver ruleset emits), or
+	// the blank marker "?" for a blank.
+	Letter string
+	// Blank reports whether the tile is a blank.
+	Blank bool
+	// Rank orders the draw: BlankRank for a blank (best), else the letter's
+	// alphabet index (0 = closest to "A").
+	Rank int
+}
+
+// BlankRank is the first-move draw rank of a blank: below every letter index, so a
+// blank always beats a lettered tile, matching the official rule that a blank
+// supersedes all letters.
+const BlankRank = -1
+
+// SetupBag returns variant's full tile bag — every lettered tile expanded by its
+// count, plus one entry per blank — decoded for the first-move seeding draw. The
+// order is deterministic (alphabet order, blanks last); callers shuffle it with
+// their own entropy. It needs no dictionary, so it is built from the variant's
+// ruleset alone and reports ErrUnknownVariant for an unrecognised variant.
+func SetupBag(v Variant) ([]SetupTile, error) {
+	rs, ok := v.ruleset()
+	if !ok {
+		return nil, fmt.Errorf("%w: %d", ErrUnknownVariant, v)
+	}
+	bag := make([]SetupTile, 0, 128)
+	for i, n := range rs.Counts {
+		ch, err := rs.Alphabet.Character(byte(i))
+		if err != nil {
+			// An offered variant's alphabet never yields a bad index; skip defensively.
+			continue
+		}
+		for range n {
+			bag = append(bag, SetupTile{Letter: ch, Rank: i})
+		}
+	}
+	for range rs.Blanks {
+		bag = append(bag, SetupTile{Letter: blankLetter, Blank: true, Rank: BlankRank})
+	}
+	return bag, nil
+}

backend/internal/engine/setup_test.go

@@ -0,0 +1,47 @@
+package engine
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestSetupBagEnglish(t *testing.T) {
+	bag, err := SetupBag(VariantEnglish)
+	if err != nil {
+		t.Fatalf("SetupBag: %v", err)
+	}
+	// English Scrabble: 98 lettered tiles + 2 blanks = 100.
+	if len(bag) != 100 {
+		t.Fatalf("bag size = %d, want 100", len(bag))
+	}
+	blanks, aCount := 0, 0
+	for _, tl := range bag {
+		switch {
+		case tl.Blank:
+			blanks++
+			if tl.Rank != BlankRank {
+				t.Errorf("blank rank = %d, want %d", tl.Rank, BlankRank)
+			}
+			if tl.Letter != blankLetter {
+				t.Errorf("blank letter = %q, want %q", tl.Letter, blankLetter)
+			}
+		case tl.Letter == "a":
+			aCount++
+			if tl.Rank != 0 {
+				t.Errorf("'a' rank = %d, want 0 (closest to A)", tl.Rank)
+			}
+		}
+	}
+	if blanks != 2 {
+		t.Errorf("blanks = %d, want 2", blanks)
+	}
+	if aCount != 9 {
+		t.Errorf("'a' count = %d, want 9", aCount)
+	}
+}
+
+func TestSetupBagUnknownVariant(t *testing.T) {
+	if _, err := SetupBag(Variant(99)); !errors.Is(err, ErrUnknownVariant) {
+		t.Fatalf("err = %v, want ErrUnknownVariant", err)
+	}
+}

backend/internal/game/replay_timeline.go

@@ -0,0 +1,144 @@
+package game
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/engine"
+)
+
+// ReplayStep is one step of an admin game replay: the move that produced it (nil for the
+// initial dealt state, step 0) and the resulting position — every seat's rack, the running
+// scores, whose turn it is and the bag remainder. Step k's board is the union of every
+// play's placements through step k, which the renderer accumulates onto an empty grid
+// (docs/ARCHITECTURE.md §9.1 visual replay).
+type ReplayStep struct {
+	// Move is the journalled move that produced this state, or nil for the initial deal.
+	Move *HistoryMove
+	// Drawn lists the tiles the mover drew from the bag after this move ("?" for a blank);
+	// empty for the initial deal, a pass or a resignation.
+	Drawn []string
+	// Racks holds every seat's rack at this step, indexed by seat ("?" for a blank).
+	Racks [][]string
+	// Scores holds every seat's running score, indexed by seat.
+	Scores []int
+	// ToMove is the seat to move at this step.
+	ToMove int
+	// BagLen is the number of tiles left in the bag at this step.
+	BagLen int
+}
+
+// ReplayTimelineView is the admin replay of a game: the persisted game plus the ordered
+// replay steps (the initial deal followed by one step per journalled move).
+type ReplayTimelineView struct {
+	Game  Game
+	Steps []ReplayStep
+}
+
+// ReplayTimeline rebuilds a game from its pinned seed and journal and returns the ordered
+// replay steps for the admin console: the initial deal (step 0) then one step per
+// journalled move, each carrying the resulting racks, scores, turn cursor, bag size and the
+// tiles the mover drew. The deterministic bag makes the reconstruction exact. It needs no
+// dictionary beyond the engine the seed deals, and — like the live replay — stops early if a
+// committed move became illegal under tightened rules rather than failing.
+func (svc *Service) ReplayTimeline(ctx context.Context, gameID uuid.UUID) (ReplayTimelineView, error) {
+	pre, err := svc.store.GetGame(ctx, gameID)
+	if err != nil {
+		return ReplayTimelineView{}, err
+	}
+	seed, err := svc.store.GameSeed(ctx, gameID)
+	if err != nil {
+		return ReplayTimelineView{}, err
+	}
+	g, err := engine.New(svc.registry, engine.Options{
+		Variant:              pre.Variant,
+		Version:              pre.DictVersion,
+		Players:              pre.Players,
+		Seed:                 seed,
+		DropoutTiles:         pre.DropoutTiles,
+		MultipleWordsPerTurn: pre.MultipleWordsPerTurn,
+	})
+	if err != nil {
+		return ReplayTimelineView{}, err
+	}
+	moves, err := svc.store.GetJournal(ctx, gameID)
+	if err != nil {
+		return ReplayTimelineView{}, err
+	}
+	steps := make([]ReplayStep, 0, len(moves)+1)
+	steps = append(steps, snapshotStep(g, nil, nil))
+	for i := range moves {
+		mv := moves[i]
+		before := g.Hand(mv.Seat)
+		if err := replayMove(g, mv); err != nil {
+			if errors.Is(err, engine.ErrIllegalPlay) {
+				g.Abort()
+				break
+			}
+			return ReplayTimelineView{}, fmt.Errorf("game: replay-timeline %s move %d: %w", gameID, mv.Seq, err)
+		}
+		moveCopy := mv
+		steps = append(steps, snapshotStep(g, &moveCopy, drawnTiles(before, g.Hand(mv.Seat), usedTiles(mv))))
+	}
+	return ReplayTimelineView{Game: pre, Steps: steps}, nil
+}
+
+// snapshotStep captures the position after applying move (nil for the initial deal): every
+// seat's rack and score, the turn cursor and the bag size, with the supplied drawn tiles.
+func snapshotStep(g *engine.Game, move *HistoryMove, drawn []string) ReplayStep {
+	n := g.Players()
+	racks := make([][]string, n)
+	scores := make([]int, n)
+	for i := 0; i < n; i++ {
+		racks[i] = g.Hand(i)
+		scores[i] = g.Score(i)
+	}
+	return ReplayStep{Move: move, Drawn: drawn, Racks: racks, Scores: scores, ToMove: g.ToMove(), BagLen: g.BagLen()}
+}
+
+// usedTiles returns the rack tiles a move consumed ("?" for a blank): the placed tiles of a
+// play or the swapped tiles of an exchange; a pass or resignation consumes none.
+func usedTiles(mv HistoryMove) []string {
+	switch mv.Action {
+	case "play":
+		used := make([]string, len(mv.Tiles))
+		for i, t := range mv.Tiles {
+			if t.Blank {
+				used[i] = "?" // a placed blank leaves the rack as the blank marker
+			} else {
+				used[i] = t.Letter
+			}
+		}
+		return used
+	case "exchange":
+		return mv.Exchanged
+	}
+	return nil
+}
+
+// drawnTiles returns the tiles the mover drew from the bag: the post-move rack (after) minus
+// the tiles kept (before minus used). It compares the racks as multisets, so duplicate
+// letters are counted correctly.
+func drawnTiles(before, after, used []string) []string {
+	kept := make(map[string]int, len(before))
+	for _, t := range before {
+		kept[t]++
+	}
+	for _, t := range used {
+		if kept[t] > 0 {
+			kept[t]--
+		}
+	}
+	var drawn []string
+	for _, t := range after {
+		if kept[t] > 0 {
+			kept[t]--
+			continue
+		}
+		drawn = append(drawn, t)
+	}
+	return drawn
+}

backend/internal/game/replay_timeline_test.go

@@ -0,0 +1,50 @@
+package game
+
+import (
+	"reflect"
+	"testing"
+
+	"scrabble/backend/internal/engine"
+)
+
+func TestUsedTiles(t *testing.T) {
+	tests := []struct {
+		name string
+		mv   HistoryMove
+		want []string
+	}{
+		{"pass", HistoryMove{Action: "pass"}, nil},
+		{"resign", HistoryMove{Action: "resign"}, nil},
+		{"play with blank", HistoryMove{Action: "play", Tiles: []engine.TileRecord{{Letter: "a"}, {Letter: "b", Blank: true}}}, []string{"a", "?"}},
+		{"exchange", HistoryMove{Action: "exchange", Exchanged: []string{"a", "?"}}, []string{"a", "?"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := usedTiles(tt.mv); !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("usedTiles = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestDrawnTiles(t *testing.T) {
+	tests := []struct {
+		name         string
+		before, used []string
+		after        []string
+		want         []string
+	}{
+		{"play refill", []string{"a", "b", "c", "d"}, []string{"a", "b"}, []string{"c", "d", "e", "f"}, []string{"e", "f"}},
+		{"blank played", []string{"?", "a"}, []string{"?"}, []string{"a", "x"}, []string{"x"}},
+		{"pass keeps rack", []string{"a", "b"}, nil, []string{"a", "b"}, nil},
+		{"duplicate letters", []string{"e", "e", "e"}, []string{"e"}, []string{"e", "e", "q"}, []string{"q"}},
+		{"empty bag no refill", []string{"a", "b"}, []string{"a"}, []string{"b"}, nil},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := drawnTiles(tt.before, tt.after, tt.used); !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("drawnTiles = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

backend/internal/game/seating.go

@@ -0,0 +1,156 @@
+package game
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/engine"
+)
+
+// maxSeedingRounds caps the first-move draw's tie re-draws. With a real bag a tie
+// breaks with positive probability each round, so this is reached only by a
+// degenerate (e.g. test) entropy source that ties forever; the cap turns that into
+// an error instead of an infinite loop.
+const maxSeedingRounds = 1000
+
+// SetupDraw is one recorded tile draw of the first-move seeding — one row of
+// game_setup_draws (docs/ARCHITECTURE.md §6, §9): the round, the draw order within
+// it, the seated account that drew, and the decoded tile with its rank. It is
+// dictionary-independent: the letter, the blank flag and the numeric rank describe
+// the draw without any alphabet table.
+type SetupDraw struct {
+	Round   int
+	PickNo  int
+	Account uuid.UUID
+	Letter  string
+	Blank   bool
+	Rank    int
+}
+
+// seedingResult is the outcome of the first-move seeding: the winning account, the
+// seated accounts rotated so the winner leads (seat 0), and the full draw log to
+// persist.
+type seedingResult struct {
+	winner uuid.UUID
+	order  []uuid.UUID
+	draws  []SetupDraw
+}
+
+// drawIntn returns a uniformly random integer in [0, n) for n > 0. It is the
+// entropy seam of the first-move seeding: production uses crypto/rand (cryptoIntn),
+// so every draw is honestly random with no single seed; tests inject a
+// deterministic source.
+type drawIntn func(n int) (int, error)
+
+// cryptoIntn draws a uniform integer in [0, n) from crypto/rand — the honest,
+// seedless entropy the first-move draw requires.
+func cryptoIntn(n int) (int, error) {
+	v, err := rand.Int(rand.Reader, big.NewInt(int64(n)))
+	if err != nil {
+		return 0, fmt.Errorf("game: first-move draw entropy: %w", err)
+	}
+	return int(v.Int64()), nil
+}
+
+// seedFirstMove runs the official first-move draw over accounts for variant v,
+// drawing tiles with the entropy source intn. Each round every contender draws one
+// tile (without replacement) from a fresh full bag; the tile closest to "A" wins, a
+// blank beating every letter; contenders tied for the best tile re-draw in the next
+// round until a single leader remains. It returns the leader, the rotation that
+// seats the leader first (preserving the others' seating order), and every draw for
+// the record. It performs no I/O beyond calling intn.
+func seedFirstMove(v engine.Variant, accounts []uuid.UUID, intn drawIntn) (seedingResult, error) {
+	if len(accounts) < 2 {
+		return seedingResult{}, fmt.Errorf("game: first-move seeding needs at least 2 accounts, got %d", len(accounts))
+	}
+	full, err := engine.SetupBag(v)
+	if err != nil {
+		return seedingResult{}, err
+	}
+	contenders := append([]uuid.UUID(nil), accounts...)
+	var draws []SetupDraw
+	for round := 1; ; round++ {
+		if round > maxSeedingRounds {
+			return seedingResult{}, fmt.Errorf("game: first-move seeding unresolved after %d rounds", maxSeedingRounds)
+		}
+		bag := append([]engine.SetupTile(nil), full...)
+		picks := make([]engine.SetupTile, len(contenders))
+		for i, acc := range contenders {
+			tile, rest, err := drawSetupTile(bag, intn)
+			if err != nil {
+				return seedingResult{}, err
+			}
+			bag = rest
+			picks[i] = tile
+			draws = append(draws, SetupDraw{
+				Round: round, PickNo: i, Account: acc,
+				Letter: tile.Letter, Blank: tile.Blank, Rank: tile.Rank,
+			})
+		}
+		winners := bestContenders(contenders, picks)
+		if len(winners) == 1 {
+			return seedingResult{winner: winners[0], order: rotateToFirst(accounts, winners[0]), draws: draws}, nil
+		}
+		contenders = winners
+	}
+}
+
+// drawSetupTile removes one uniformly random tile from bag using the entropy source
+// intn and returns it with the shrunk bag (a fresh slice, leaving bag untouched).
+// It is the per-tile draw primitive — the seam a future manual "player N draws a
+// tile" tournament API will drive, one call per external request.
+func drawSetupTile(bag []engine.SetupTile, intn drawIntn) (engine.SetupTile, []engine.SetupTile, error) {
+	if len(bag) == 0 {
+		return engine.SetupTile{}, nil, fmt.Errorf("game: first-move draw from an empty bag")
+	}
+	i, err := intn(len(bag))
+	if err != nil {
+		return engine.SetupTile{}, nil, err
+	}
+	if i < 0 || i >= len(bag) {
+		return engine.SetupTile{}, nil, fmt.Errorf("game: first-move draw index %d out of range %d", i, len(bag))
+	}
+	tile := bag[i]
+	rest := make([]engine.SetupTile, 0, len(bag)-1)
+	rest = append(rest, bag[:i]...)
+	rest = append(rest, bag[i+1:]...)
+	return tile, rest, nil
+}
+
+// bestContenders returns the contenders whose drawn tile has the lowest (best)
+// rank — the sole winner if one, else the tied set that re-draws. picks is aligned
+// with contenders by index.
+func bestContenders(contenders []uuid.UUID, picks []engine.SetupTile) []uuid.UUID {
+	best := picks[0].Rank
+	for _, p := range picks[1:] {
+		if p.Rank < best {
+			best = p.Rank
+		}
+	}
+	var winners []uuid.UUID
+	for i, p := range picks {
+		if p.Rank == best {
+			winners = append(winners, contenders[i])
+		}
+	}
+	return winners
+}
+
+// rotateToFirst returns accounts rotated cyclically so winner sits first (seat 0),
+// preserving the seating order of the rest (docs/ARCHITECTURE.md §6). winner must be
+// present in accounts.
+func rotateToFirst(accounts []uuid.UUID, winner uuid.UUID) []uuid.UUID {
+	i := 0
+	for ; i < len(accounts); i++ {
+		if accounts[i] == winner {
+			break
+		}
+	}
+	out := make([]uuid.UUID, 0, len(accounts))
+	out = append(out, accounts[i:]...)
+	out = append(out, accounts[:i]...)
+	return out
+}

backend/internal/game/seating_test.go

@@ -0,0 +1,130 @@
+package game
+
+import (
+	"testing"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/engine"
+)
+
+// scriptIntn returns a drawIntn that yields the scripted indices in order, failing
+// the test if the script is exhausted or an index is out of range. It lets a test
+// drive the first-move draw deterministically (English SetupBag order: 9 'a' at
+// 0..8, then 'b' …, blanks last).
+func scriptIntn(t *testing.T, seq ...int) drawIntn {
+	t.Helper()
+	i := 0
+	return func(n int) (int, error) {
+		if i >= len(seq) {
+			t.Fatalf("intn script exhausted (asked for [0,%d))", n)
+		}
+		v := seq[i]
+		i++
+		if v < 0 || v >= n {
+			t.Fatalf("intn script value %d out of range [0,%d)", v, n)
+		}
+		return v, nil
+	}
+}
+
+func TestSeedFirstMoveDirectWinner(t *testing.T) {
+	a, b := uuid.New(), uuid.New()
+	// a draws bag[0]='a' (rank 0); b draws bag[8]='b' (rank 1) → a wins, no tie.
+	res, err := seedFirstMove(engine.VariantEnglish, []uuid.UUID{a, b}, scriptIntn(t, 0, 8))
+	if err != nil {
+		t.Fatalf("seedFirstMove: %v", err)
+	}
+	if res.winner != a {
+		t.Fatalf("winner = %v, want %v", res.winner, a)
+	}
+	if got := res.order; len(got) != 2 || got[0] != a || got[1] != b {
+		t.Fatalf("order = %v, want [a b]", got)
+	}
+	if len(res.draws) != 2 {
+		t.Fatalf("draws = %d, want 2", len(res.draws))
+	}
+}
+
+func TestSeedFirstMoveBlankSupersedes(t *testing.T) {
+	a, b := uuid.New(), uuid.New()
+	// a draws 'a' (rank 0); after the draw the two blanks sit at 97,98 — b draws
+	// bag[97], a blank, which beats every letter.
+	res, err := seedFirstMove(engine.VariantEnglish, []uuid.UUID{a, b}, scriptIntn(t, 0, 97))
+	if err != nil {
+		t.Fatalf("seedFirstMove: %v", err)
+	}
+	if res.winner != b {
+		t.Fatalf("winner = %v, want %v (blank supersedes)", res.winner, b)
+	}
+	last := res.draws[len(res.draws)-1]
+	if !last.Blank || last.Rank != engine.BlankRank || last.Letter != "?" {
+		t.Fatalf("winning draw = %+v, want a blank (rank %d, '?')", last, engine.BlankRank)
+	}
+}
+
+func TestSeedFirstMoveTieRedraw(t *testing.T) {
+	a, b, c := uuid.New(), uuid.New(), uuid.New()
+	// Round 1: a→bag[0]='a'(0), b→bag[0]='a'(0), c→bag[7]='b'(1) → a,b tie best.
+	// Round 2 (a,b only): a→bag[0]='a'(0), b→bag[8]='b'(1) → a wins.
+	res, err := seedFirstMove(engine.VariantEnglish, []uuid.UUID{a, b, c}, scriptIntn(t, 0, 0, 7, 0, 8))
+	if err != nil {
+		t.Fatalf("seedFirstMove: %v", err)
+	}
+	if res.winner != a {
+		t.Fatalf("winner = %v, want %v", res.winner, a)
+	}
+	if len(res.draws) != 5 {
+		t.Fatalf("draws = %d, want 5 (3 in round 1, 2 in round 2)", len(res.draws))
+	}
+	if res.draws[2].Round != 1 || res.draws[3].Round != 2 {
+		t.Fatalf("round boundaries wrong: %+v", res.draws)
+	}
+	// The full table keeps every account's seating order, winner first.
+	if got := res.order; got[0] != a || got[1] != b || got[2] != c {
+		t.Fatalf("order = %v, want [a b c]", got)
+	}
+}
+
+func TestSeedFirstMoveTooFewAccounts(t *testing.T) {
+	if _, err := seedFirstMove(engine.VariantEnglish, []uuid.UUID{uuid.New()}, scriptIntn(t)); err == nil {
+		t.Fatal("want error for a single account")
+	}
+}
+
+func TestSeedFirstMovePerpetualTieCapped(t *testing.T) {
+	a, b := uuid.New(), uuid.New()
+	// Always drawing bag[0] gives both players an 'a' every round — a tie that never
+	// resolves; the round cap must turn it into an error, not an infinite loop.
+	alwaysZero := drawIntn(func(int) (int, error) { return 0, nil })
+	if _, err := seedFirstMove(engine.VariantEnglish, []uuid.UUID{a, b}, alwaysZero); err == nil {
+		t.Fatal("want error when ties never resolve")
+	}
+}
+
+func TestRotateToFirst(t *testing.T) {
+	a, b, c, d := uuid.New(), uuid.New(), uuid.New(), uuid.New()
+	tests := []struct {
+		name     string
+		accounts []uuid.UUID
+		winner   uuid.UUID
+		want     []uuid.UUID
+	}{
+		{"two winner second", []uuid.UUID{a, b}, b, []uuid.UUID{b, a}},
+		{"three winner first", []uuid.UUID{a, b, c}, a, []uuid.UUID{a, b, c}},
+		{"four winner third", []uuid.UUID{a, b, c, d}, c, []uuid.UUID{c, d, a, b}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := rotateToFirst(tt.accounts, tt.winner)
+			if len(got) != len(tt.want) {
+				t.Fatalf("len = %d, want %d", len(got), len(tt.want))
+			}
+			for i := range got {
+				if got[i] != tt.want[i] {
+					t.Fatalf("rotate = %v, want %v", got, tt.want)
+				}
+			}
+		})
+	}
+}

backend/internal/game/service.go

@@ -38,7 +38,12 @@ type Service struct {
 	version string
 	clock   func() time.Time
 	rng     func() int64
-	pub     notify.Publisher
+	// firstMoveEntropy returns the entropy source for one game's first-move draw
+	// (docs/ARCHITECTURE.md §6). The default is crypto/rand — an honest, seedless draw;
+	// tests override it via SetFirstMoveEntropy for a deterministic turn order. It is a
+	// factory so a stateful test source restarts cleanly per game.
+	firstMoveEntropy func() drawIntn
+	pub              notify.Publisher
 	// aiTrigger, when set, is called after an honest-AI game is created or advanced and
 	// is still on a robot's potential turn, so the robot replies at once instead of
 	// waiting for the next driver scan. It is fire-and-forget (the robot package wires
@@ -59,17 +64,18 @@ type Service struct {
 func NewService(store *Store, accounts *account.Store, registry *engine.Registry, cfg Config, log *zap.Logger) *Service {
 	clock := func() time.Time { return time.Now().UTC() }
 	return &Service{
-		store:    store,
-		accounts: accounts,
-		registry: registry,
-		cache:    newGameCache(cfg.CacheTTL, clock),
-		locks:    newKeyedMutex(),
-		version:  cfg.DictVersion,
-		clock:    clock,
-		rng:      randomSeed,
-		pub:      notify.Nop{},
-		metrics:  defaultGameMetrics(),
-		log:      log,
+		store:            store,
+		accounts:         accounts,
+		registry:         registry,
+		cache:            newGameCache(cfg.CacheTTL, clock),
+		locks:            newKeyedMutex(),
+		version:          cfg.DictVersion,
+		clock:            clock,
+		rng:              randomSeed,
+		firstMoveEntropy: func() drawIntn { return cryptoIntn },
+		pub:              notify.Nop{},
+		metrics:          defaultGameMetrics(),
+		log:              log,
 	}
 }
 
@@ -101,6 +107,18 @@ func (svc *Service) SetNudgeClearer(fn func(ctx context.Context, gameID, account
 	svc.clearNudges = fn
 }
 
+// SetFirstMoveEntropy overrides the entropy source for the first-move draw
+// (docs/ARCHITECTURE.md §6). It must be called during wiring or test setup before any
+// game is created; the production default is crypto/rand and is never overridden.
+// factory returns a fresh draw function per game, so a stateful deterministic test
+// source restarts cleanly for each game. It exists for deterministic tests.
+func (svc *Service) SetFirstMoveEntropy(factory func() func(n int) (int, error)) {
+	if factory == nil {
+		return
+	}
+	svc.firstMoveEntropy = func() drawIntn { return drawIntn(factory()) }
+}
+
 // triggerAI fires the honest-AI fast-move hook for an active vs_ai game (best-effort,
 // fire-and-forget). It is a no-op for non-AI games, finished games and when no hook is
 // installed, so callers can invoke it unconditionally after a create or commit.
@@ -191,15 +209,32 @@ func (svc *Service) Create(ctx context.Context, params CreateParams) (Game, erro
 		}
 	}
 	seen := make(map[uuid.UUID]bool, len(params.Seats))
-	seats := make([]seatInsert, len(params.Seats))
-	for i, id := range params.Seats {
+	for _, id := range params.Seats {
 		if seen[id] {
 			return Game{}, fmt.Errorf("%w: account %s seated twice", ErrInvalidConfig, id)
 		}
 		seen[id] = true
-		// Snapshot each seat's display name at creation. For a vs-AI game this stamps the
-		// robot's seeded account name (unchanged behaviour); a disguised auto-match robot
-		// instead gets a fresh per-game name when the reaper attaches it (AttachRobot).
+	}
+
+	// Decide who moves first by the official draw (docs/ARCHITECTURE.md §6): each seated
+	// account draws a tile, the one closest to "A" leads (a blank supersedes all letters),
+	// ties re-drawing until a single leader remains. Each draw uses fresh entropy, not the
+	// game seed, so the recorded draws — persisted with the game — are the only account of
+	// the outcome. The winner takes seat 0; the rest keep their order.
+	seeding, err := seedFirstMove(params.Variant, params.Seats, svc.firstMoveEntropy())
+	if err != nil {
+		if errors.Is(err, engine.ErrUnknownVariant) {
+			return Game{}, fmt.Errorf("%w: %v", ErrInvalidConfig, err)
+		}
+		return Game{}, err
+	}
+
+	// Build the seats in the drawn turn order, snapshotting each seat's display name. For a
+	// vs-AI game this stamps the robot's seeded account name (unchanged behaviour); a
+	// disguised auto-match robot instead gets a fresh per-game name when the reaper attaches
+	// it (AttachRobot).
+	seats := make([]seatInsert, len(seeding.order))
+	for i, id := range seeding.order {
 		acc, err := svc.accounts.GetByID(ctx, id)
 		if err != nil {
 			if errors.Is(err, account.ErrNotFound) {
@@ -249,7 +284,7 @@ func (svc *Service) Create(ctx context.Context, params CreateParams) (Game, erro
 		multipleWordsPerTurn: params.MultipleWordsPerTurn,
 		vsAI:                 params.VsAI,
 	}
-	if err := svc.store.CreateGame(ctx, ins, seats); err != nil {
+	if err := svc.store.CreateGame(ctx, ins, seats, seeding.draws); err != nil {
 		return Game{}, err
 	}
 	svc.cache.put(id, g, params.Variant.String())
@@ -312,14 +347,27 @@ func (svc *Service) OpenOrJoin(ctx context.Context, accountID uuid.UUID, params
 		status:               StatusOpen,
 		openDeadline:         &deadline,
 	}
-	// Seat the caller at seat 0 or seat 1 (seat 0 always moves first), snapshotting their
-	// display name; the other seat is left empty (a zero seatInsert) for the opponent.
-	caller := seatInsert{accountID: accountID, displayName: acc.DisplayName}
-	seats := []seatInsert{caller, {}}
-	if seed&1 == 1 {
-		seats = []seatInsert{{}, caller}
+	// Decide the first move now by the official draw, with the not-yet-arrived opponent as a
+	// synthetic placeholder (uuid.Nil): the draw fixes who sits at seat 0 — and so moves
+	// first — before either player acts (docs/ARCHITECTURE.md §6). The caller takes their
+	// drawn seat; the opponent seat is left empty. The opponent's draw rows are recorded with
+	// a NULL account and back-filled when a real opponent joins. Each draw uses fresh entropy,
+	// not the game seed. seats/draws are used only when a fresh game is opened.
+	seeding, err := seedFirstMove(params.Variant, []uuid.UUID{accountID, uuid.Nil}, svc.firstMoveEntropy())
+	if err != nil {
+		if errors.Is(err, engine.ErrUnknownVariant) {
+			return Game{}, false, fmt.Errorf("%w: %v", ErrInvalidConfig, err)
+		}
+		return Game{}, false, err
 	}
-	gameID, joined, created, err := svc.store.OpenOrJoin(ctx, accountID, acc.DisplayName, ins, seats, exclude)
+	caller := seatInsert{accountID: accountID, displayName: acc.DisplayName}
+	seats := make([]seatInsert, len(seeding.order))
+	for seat, who := range seeding.order {
+		if who == accountID {
+			seats[seat] = caller // the empty opponent seat stays a zero seatInsert
+		}
+	}
+	gameID, joined, created, err := svc.store.OpenOrJoin(ctx, accountID, acc.DisplayName, ins, seats, exclude, seeding.draws)
 	if err != nil {
 		return Game{}, false, err
 	}
@@ -547,8 +595,9 @@ func (svc *Service) transition(ctx context.Context, gameID, accountID uuid.UUID,
 		return MoveResult{}, ErrNotAPlayer
 	}
 	// A move is allowed while the game is active or still open (the starter may move on
-	// their turn before an opponent joins); only a finished game rejects it. The turn
-	// check below keeps the starter off the still-empty opponent seat.
+	// their turn before an opponent joins; the first-move draw ran when the game opened, so
+	// the seats are already fixed); only a finished game rejects it. The turn check below
+	// keeps the starter off the still-empty opponent seat.
 	if pre.Status == StatusFinished {
 		return MoveResult{}, ErrFinished
 	}
@@ -1287,6 +1336,14 @@ func (svc *Service) History(ctx context.Context, gameID uuid.UUID) (HistoryView,
 	return HistoryView{Game: g, Moves: moves}, nil
 }
 
+// SetupDraws returns a game's recorded first-move draws (docs/ARCHITECTURE.md §6), ordered by
+// round then pick. It backs the admin console's first-move section. An auto-match opponent's
+// draws carry uuid.Nil until a real opponent joins and back-fills them; an empty slice means
+// the game predates the draw record.
+func (svc *Service) SetupDraws(ctx context.Context, gameID uuid.UUID) ([]SetupDraw, error) {
+	return svc.store.SetupDraws(ctx, gameID)
+}
+
 // ExportGCG renders a game as GCG text from the journal alone (no dictionary). It
 // is allowed only on a finished game: exporting an in-progress game would leak the
 // full move journal mid-play, so an active game yields ErrGameActive.

backend/internal/game/store.go

@@ -127,11 +127,14 @@ type seatInsert struct {
 	displayName string
 }
 
-// CreateGame inserts the games row and one game_players row per seat (seat 0
-// first) inside a single transaction.
-func (s *Store) CreateGame(ctx context.Context, ins gameInsert, seats []seatInsert) error {
+// CreateGame inserts the games row, one game_players row per seat (seat 0 first) and
+// the first-move seeding draws inside a single transaction.
+func (s *Store) CreateGame(ctx context.Context, ins gameInsert, seats []seatInsert, draws []SetupDraw) error {
 	return withTx(ctx, s.db, func(tx *sql.Tx) error {
-		return insertGameTx(ctx, tx, ins, seats)
+		if err := insertGameTx(ctx, tx, ins, seats); err != nil {
+			return err
+		}
+		return insertSetupDrawsTx(ctx, tx, ins.id, draws)
 	})
 }
 
@@ -173,6 +176,30 @@ func insertGameTx(ctx context.Context, tx *sql.Tx, ins gameInsert, seats []seatI
 	return nil
 }
 
+// insertSetupDrawsTx appends the first-move seeding draws for game gameID on tx —
+// the dictionary-independent record of how the first player was chosen
+// (docs/ARCHITECTURE.md §6). The games row must already exist on tx (the foreign
+// key), so it runs after insertGameTx. An empty draws slice is a no-op.
+func insertSetupDrawsTx(ctx context.Context, tx *sql.Tx, gameID uuid.UUID, draws []SetupDraw) error {
+	for _, d := range draws {
+		// A uuid.Nil account marks the synthetic opponent of an auto-match draw, persisted as
+		// a NULL account_id and back-filled when a real opponent joins.
+		var acc any = d.Account
+		if d.Account == uuid.Nil {
+			acc = postgres.NULL
+		}
+		di := table.GameSetupDraws.INSERT(
+			table.GameSetupDraws.GameID, table.GameSetupDraws.Round, table.GameSetupDraws.PickNo,
+			table.GameSetupDraws.AccountID, table.GameSetupDraws.Letter, table.GameSetupDraws.IsBlank,
+			table.GameSetupDraws.DrawRank,
+		).VALUES(gameID, d.Round, d.PickNo, acc, d.Letter, d.Blank, d.Rank)
+		if _, err := di.ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("insert setup draw round %d pick %d: %w", d.Round, d.PickNo, err)
+		}
+	}
+	return nil
+}
+
 // openMatchKey hashes an auto-match bucket (variant + per-turn word rule) into the
 // advisory-lock key that serialises concurrent enqueues for that bucket, so two
 // players never both open a game instead of pairing.
@@ -199,8 +226,9 @@ func openMatchKey(variant string, multipleWords bool) int64 {
 // arrangement (the caller and uuid.Nil for the still-empty opponent, in the chosen
 // order) used only when a game is created; callerName is the caller's display-name
 // snapshot, stamped on their seat whether they open a fresh game or fill another
-// player's open one.
-func (s *Store) OpenOrJoin(ctx context.Context, accountID uuid.UUID, callerName string, ins gameInsert, seats []seatInsert, exclude []uuid.UUID) (gameID uuid.UUID, joined, created bool, err error) {
+// player's open one. seats and draws (the first-move draw recorded against the synthetic
+// opponent, docs/ARCHITECTURE.md §6) are used only when a game is created.
+func (s *Store) OpenOrJoin(ctx context.Context, accountID uuid.UUID, callerName string, ins gameInsert, seats []seatInsert, exclude []uuid.UUID, draws []SetupDraw) (gameID uuid.UUID, joined, created bool, err error) {
 	err = withTx(ctx, s.db, func(tx *sql.Tx) error {
 		if _, e := tx.ExecContext(ctx, `SELECT pg_advisory_xact_lock($1)`,
 			openMatchKey(ins.variant, ins.multipleWordsPerTurn)); e != nil {
@@ -222,7 +250,7 @@ func (s *Store) OpenOrJoin(ctx context.Context, accountID uuid.UUID, callerName
 			  LIMIT 1 FOR UPDATE SKIP LOCKED`,
 			ins.variant, ins.multipleWordsPerTurn, accountID, uuidArrayLiteral(exclude)).Scan(&other); {
 		case e == nil:
-			if er := fillOpenSeat(ctx, tx, other, accountID, callerName); er != nil {
+			if er := fillAndActivate(ctx, tx, other, accountID, callerName); er != nil {
 				return er
 			}
 			gameID, joined = other, true
@@ -230,10 +258,15 @@ func (s *Store) OpenOrJoin(ctx context.Context, accountID uuid.UUID, callerName
 		case !errors.Is(e, sql.ErrNoRows):
 			return fmt.Errorf("find open game: %w", e)
 		}
-		// 2. None waiting — open a fresh game seating the caller (the other seat empty).
+		// 2. None waiting — open a fresh game seating the caller (the other seat empty) and
+		// recording the first-move draw; the synthetic opponent's rows carry a NULL account
+		// until a real opponent joins and back-fills them.
 		if e := insertGameTx(ctx, tx, ins, seats); e != nil {
 			return e
 		}
+		if e := insertSetupDrawsTx(ctx, tx, ins.id, draws); e != nil {
+			return e
+		}
 		gameID, created = ins.id, true
 		return nil
 	})
@@ -258,7 +291,7 @@ func (s *Store) AttachRobot(ctx context.Context, gameID, robotID uuid.UUID, disp
 		if status != StatusOpen {
 			return nil
 		}
-		if e := fillOpenSeat(ctx, tx, gameID, robotID, displayName); e != nil {
+		if e := fillAndActivate(ctx, tx, gameID, robotID, displayName); e != nil {
 			return e
 		}
 		attached = true
@@ -267,15 +300,23 @@ func (s *Store) AttachRobot(ctx context.Context, gameID, robotID uuid.UUID, disp
 	return attached, err
 }
 
-// fillOpenSeat seats accountID in an open game's empty opponent seat — stamping
-// displayName as the seat's display-name snapshot — and flips the game to active with a
-// fresh turn clock. The caller holds the game row.
-func fillOpenSeat(ctx context.Context, tx *sql.Tx, gameID, accountID uuid.UUID, displayName string) error {
+// fillAndActivate seats accountID in an open game's empty opponent seat — stamping
+// displayName as the seat's snapshot — back-fills the first-move draw rows the open game
+// recorded for the then-unknown opponent (docs/ARCHITECTURE.md §6), and flips the game to
+// active with a fresh turn clock. The seat the joiner takes was already fixed by the draw at
+// open time, so the journal (any opening move the starter made while waiting) is never
+// disturbed. The caller holds the game row.
+func fillAndActivate(ctx context.Context, tx *sql.Tx, gameID, accountID uuid.UUID, displayName string) error {
 	if _, err := tx.ExecContext(ctx,
 		`UPDATE backend.game_players SET account_id = $2, display_name = $3 WHERE game_id = $1 AND account_id IS NULL`,
 		gameID, accountID, displayName); err != nil {
 		return fmt.Errorf("fill opponent seat: %w", err)
 	}
+	if _, err := tx.ExecContext(ctx,
+		`UPDATE backend.game_setup_draws SET account_id = $2 WHERE game_id = $1 AND account_id IS NULL`,
+		gameID, accountID); err != nil {
+		return fmt.Errorf("back-fill opponent draws: %w", err)
+	}
 	if _, err := tx.ExecContext(ctx,
 		`UPDATE backend.games SET status = 'active', open_deadline_at = NULL, turn_started_at = now(), updated_at = now()
 		  WHERE game_id = $1`, gameID); err != nil {
@@ -587,6 +628,37 @@ func (s *Store) GetJournal(ctx context.Context, id uuid.UUID) ([]HistoryMove, er
 	return out, nil
 }
 
+// SetupDraws loads the ordered first-move seeding draws for a game (round then pick
+// order), or an empty slice for a game created before the draw was recorded. It
+// backs the admin console's first-move section.
+func (s *Store) SetupDraws(ctx context.Context, id uuid.UUID) ([]SetupDraw, error) {
+	stmt := postgres.SELECT(table.GameSetupDraws.AllColumns).
+		FROM(table.GameSetupDraws).
+		WHERE(table.GameSetupDraws.GameID.EQ(postgres.UUID(id))).
+		ORDER_BY(table.GameSetupDraws.Round.ASC(), table.GameSetupDraws.PickNo.ASC())
+	var rows []model.GameSetupDraws
+	if err := stmt.QueryContext(ctx, s.db, &rows); err != nil {
+		return nil, fmt.Errorf("game: get setup draws %s: %w", id, err)
+	}
+	out := make([]SetupDraw, len(rows))
+	for i, r := range rows {
+		// A NULL account is the synthetic opponent of an auto-match draw not yet back-filled.
+		acc := uuid.Nil
+		if r.AccountID != nil {
+			acc = *r.AccountID
+		}
+		out[i] = SetupDraw{
+			Round:   int(r.Round),
+			PickNo:  int(r.PickNo),
+			Account: acc,
+			Letter:  r.Letter,
+			Blank:   r.IsBlank,
+			Rank:    int(r.DrawRank),
+		}
+	}
+	return out, nil
+}
+
 // CommitMove appends the move and applies the post-move game state — the turn
 // cursor and per-seat scores, plus the finish stamp and statistics when the move
 // ended the game — in one transaction.

backend/internal/inttest/admin_test.go

@@ -206,6 +206,12 @@ func TestConsoleGameDetailRobotSchedule(t *testing.T) {
 	if !strings.Contains(body, "~40%") {
 		t.Error("robot play-to-win target caption missing")
 	}
+	if !strings.Contains(body, "First-move draw") {
+		t.Error("first-move draw section missing from the game detail")
+	}
+	if !strings.Contains(body, `id="replay-board"`) {
+		t.Error("replay board container missing from the game detail")
+	}
 }
 
 // TestConsoleThrottledViewAndFlagClear drives the rate-limit surface end to

backend/internal/inttest/dictionary_update_test.go

@@ -134,11 +134,13 @@ func TestDictionaryUpdateFlow(t *testing.T) {
 // newGameServiceOn builds a game service over the shared pool but a caller-supplied
 // dictionary directory, version and registry, for the isolated dictionary tests.
 func newGameServiceOn(dir, version string, reg *engine.Registry) *game.Service {
-	return game.NewService(
+	svc := game.NewService(
 		game.NewStore(testDB), account.NewStore(testDB), reg,
 		game.Config{DictDir: dir, DictVersion: version, TimeoutSweepInterval: time.Minute, CacheTTL: time.Hour},
 		zap.NewNop(),
 	)
+	svc.SetFirstMoveEntropy(seatZeroFirstMove)
+	return svc
 }
 
 // seedDawgs copies the committed DAWG of every variant from src into dst (flat).

backend/internal/inttest/first_move_draw_test.go

@@ -0,0 +1,154 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
+)
+
+// The first-move-draw suite covers the official seeding (docs/ARCHITECTURE.md §6): the draw is
+// recorded with the game, decides seat 0 (the first mover), and — in auto-match — runs against
+// a synthetic opponent at open time whose draw rows are back-filled when a real opponent joins.
+
+// TestCreateRecordsFirstMoveDraws checks a directly-seated game records the draw against the
+// real seated accounts and seats the drawn leader (the suite's deterministic draw elects the
+// first-listed account) at seat 0.
+func TestCreateRecordsFirstMoveDraws(t *testing.T) {
+	ctx := context.Background()
+	svc := newGameService()
+	a := provisionAccount(t)
+	b := provisionAccount(t)
+	g, err := svc.Create(ctx, game.CreateParams{Variant: engine.VariantEnglish, Seats: []uuid.UUID{a, b}, TurnTimeout: 24 * time.Hour, Seed: 1})
+	if err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	if g.Seats[0].AccountID != a || g.Seats[1].AccountID != b {
+		t.Fatalf("seats = [%s %s], want [a b]", g.Seats[0].AccountID, g.Seats[1].AccountID)
+	}
+	draws, err := svc.SetupDraws(ctx, g.ID)
+	if err != nil {
+		t.Fatalf("setup draws: %v", err)
+	}
+	// seatZeroFirstMove resolves in one round: the first contender (a) draws a blank and wins.
+	if len(draws) != 2 {
+		t.Fatalf("draws = %d, want 2 (one round, two players)", len(draws))
+	}
+	if draws[0].Account != a || !draws[0].Blank {
+		t.Fatalf("draw[0] = %+v, want a having drawn a blank", draws[0])
+	}
+	if draws[1].Account != b {
+		t.Fatalf("draw[1] account = %s, want b", draws[1].Account)
+	}
+}
+
+// TestAutoMatchDrawBackfilledOnJoin checks an open auto-match game records the draw at open
+// time against the synthetic opponent (a NULL account) and back-fills those rows to the real
+// opponent when they join.
+func TestAutoMatchDrawBackfilledOnJoin(t *testing.T) {
+	ctx := context.Background()
+	clearOpenGames(t)
+	svc := newGameService()
+	starter := provisionAccount(t)
+	g := openGame(t, svc, starter, evenOpeningSeed(t))
+
+	draws, err := svc.SetupDraws(ctx, g.ID)
+	if err != nil {
+		t.Fatalf("setup draws: %v", err)
+	}
+	if len(draws) != 2 {
+		t.Fatalf("open draws = %d, want 2", len(draws))
+	}
+	var nullSeen, starterSeen bool
+	for _, d := range draws {
+		switch d.Account {
+		case uuid.Nil:
+			nullSeen = true
+		case starter:
+			starterSeen = true
+		}
+	}
+	if !nullSeen || !starterSeen {
+		t.Fatalf("open draws = %+v, want the starter and a NULL synthetic opponent", draws)
+	}
+
+	joiner := provisionAccount(t)
+	if _, joined, err := svc.OpenOrJoin(ctx, joiner, openParams(0), time.Now().Add(time.Minute), nil); err != nil || !joined {
+		t.Fatalf("join = (joined %v, err %v), want joined", joined, err)
+	}
+	after, err := svc.SetupDraws(ctx, g.ID)
+	if err != nil {
+		t.Fatalf("setup draws after join: %v", err)
+	}
+	for _, d := range after {
+		if d.Account == uuid.Nil {
+			t.Fatalf("draw still NULL after join: %+v", d)
+		}
+		if d.Account != starter && d.Account != joiner {
+			t.Fatalf("draw account %s is neither player", d.Account)
+		}
+	}
+}
+
+// TestReplayTimeline checks the admin replay timeline reconstructs the dealt racks and one
+// played move: the step count, the drawn tiles, the bag remainder, the running score and the
+// turn cursor.
+func TestReplayTimeline(t *testing.T) {
+	ctx := context.Background()
+	svc := newGameService()
+	a := provisionAccount(t)
+	b := provisionAccount(t)
+	seed := evenOpeningSeed(t)
+	g, err := svc.Create(ctx, game.CreateParams{Variant: engine.VariantEnglish, Seats: []uuid.UUID{a, b}, TurnTimeout: 24 * time.Hour, Seed: seed})
+	if err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	hint, ok := newMirror(t, seed, 2).HintView()
+	if !ok || len(hint.Tiles) == 0 {
+		t.Fatal("no opening move for the seed")
+	}
+	if _, err := svc.SubmitPlay(ctx, g.ID, a, hint.Tiles); err != nil {
+		t.Fatalf("play: %v", err)
+	}
+
+	tl, err := svc.ReplayTimeline(ctx, g.ID)
+	if err != nil {
+		t.Fatalf("replay timeline: %v", err)
+	}
+	if len(tl.Steps) != 2 {
+		t.Fatalf("steps = %d, want 2 (deal + one move)", len(tl.Steps))
+	}
+	deal := tl.Steps[0]
+	if deal.Move != nil {
+		t.Fatalf("step 0 must be the deal, got move %+v", deal.Move)
+	}
+	rackSize := len(deal.Racks[0])
+	if rackSize == 0 || len(deal.Racks) != 2 || len(deal.Racks[1]) != rackSize {
+		t.Fatalf("deal racks = %v, want two equal full racks", deal.Racks)
+	}
+	move := tl.Steps[1]
+	if move.Move == nil || move.Move.Action != "play" {
+		t.Fatalf("step 1 move = %+v, want a play", move.Move)
+	}
+	if len(move.Drawn) != len(hint.Tiles) {
+		t.Fatalf("drawn = %v, want %d refilled tiles", move.Drawn, len(hint.Tiles))
+	}
+	if move.BagLen != deal.BagLen-len(hint.Tiles) {
+		t.Fatalf("bag after play = %d, want %d", move.BagLen, deal.BagLen-len(hint.Tiles))
+	}
+	if len(move.Racks[0]) != rackSize {
+		t.Fatalf("mover rack after refill = %d, want %d", len(move.Racks[0]), rackSize)
+	}
+	if move.Scores[0] <= 0 {
+		t.Fatalf("seat 0 score after play = %d, want > 0", move.Scores[0])
+	}
+	if move.ToMove != 1 {
+		t.Fatalf("to_move after seat 0 play = %d, want 1", move.ToMove)
+	}
+}

backend/internal/inttest/helpers.go

@@ -26,9 +26,10 @@ import (
 // assembly, and the stats reader. Helpers used by a single test file stay in
 // that file; everything reused across files lives here.
 
-// newGameService builds a game service over the shared pool and registry.
+// newGameService builds a game service over the shared pool and registry, with a
+// deterministic first-move draw so the suite keeps a stable turn order.
 func newGameService() *game.Service {
-	return game.NewService(
+	svc := game.NewService(
 		game.NewStore(testDB),
 		account.NewStore(testDB),
 		testRegistry,
@@ -40,6 +41,39 @@ func newGameService() *game.Service {
 		},
 		zap.NewNop(),
 	)
+	svc.SetFirstMoveEntropy(seatZeroFirstMove)
+	return svc
+}
+
+// seatZeroFirstMove is a first-move-draw entropy factory that always elects the first
+// listed account as the leader, keeping the integration suite's turn order stable
+// despite the real draw's randomness: the first contender draws a blank — the best
+// possible tile — and wins outright, the rest draw the first remaining tile. It is a
+// factory so each game restarts the one-shot "blank" pick.
+func seatZeroFirstMove() func(n int) (int, error) {
+	first := true
+	return func(n int) (int, error) {
+		if first {
+			first = false
+			return n - 1, nil // a blank sits last in the bag → best rank
+		}
+		return 0, nil
+	}
+}
+
+// seatOneFirstMove is a first-move-draw entropy factory that elects the second contender (in
+// auto-match, the synthetic opponent) as the leader, so the caller is seated at seat 1: the
+// first contender draws the first remaining tile and the second draws a blank, winning.
+func seatOneFirstMove() func(n int) (int, error) {
+	pick := 0
+	return func(n int) (int, error) {
+		i := 0
+		if pick == 1 {
+			i = n - 1 // the second contender draws a blank → best rank
+		}
+		pick++
+		return i, nil
+	}
 }
 
 // newSocialService builds a social service over the shared pool, reading game

backend/internal/inttest/open_match_test.go

@@ -18,8 +18,9 @@ import (
 // The open-game suite covers an auto-match game that a player enters immediately and
 // waits inside (status 'open', the opponent seat empty) until a human or a robot joins.
 
-// evenOpeningSeed returns an even seed (so OpenOrJoin seats the starter at seat 0, which
-// moves first) whose fresh two-player English opening rack has a legal move.
+// evenOpeningSeed returns a seed whose fresh two-player English opening rack (seat 0) has a
+// legal move, for tests that drive or attempt an opening play. It scans even seeds; seat
+// order no longer depends on the seed — the first-move draw decides it (docs/ARCHITECTURE.md §6).
 func evenOpeningSeed(t *testing.T) int64 {
 	t.Helper()
 	for seed := int64(2); seed <= 400; seed += 2 {
@@ -59,9 +60,9 @@ func openGame(t *testing.T, svc *game.Service, starter uuid.UUID, seed int64) ga
 	return g
 }
 
-// TestOpenGameStarterMovesThenWaits checks the starter (seat 0) may move on their turn
-// while the game is open, after which it is the empty opponent seat's turn and the
-// starter just waits.
+// TestOpenGameStarterMovesThenWaits checks the starter may move on their turn while the game
+// is open (the first-move draw, run when the game opened, put them at seat 0), after which it
+// is the empty opponent seat's turn and the starter just waits.
 func TestOpenGameStarterMovesThenWaits(t *testing.T) {
 	ctx := context.Background()
 	clearOpenGames(t)
@@ -89,28 +90,30 @@ func TestOpenGameStarterMovesThenWaits(t *testing.T) {
 	}
 }
 
-// TestOpenGameStarterWaitsWhenOpponentMovesFirst checks that when the starter is seated
-// at seat 1 (odd seed), the still-empty seat 0 is to move, so the starter cannot act.
+// TestOpenGameStarterWaitsWhenOpponentMovesFirst checks that when the first-move draw seats
+// the starter at seat 1 (the synthetic opponent won the open draw), the still-empty seat 0 is
+// to move, so the starter cannot act until an opponent fills it.
 func TestOpenGameStarterWaitsWhenOpponentMovesFirst(t *testing.T) {
 	ctx := context.Background()
 	clearOpenGames(t)
 	svc := newGameService()
+	svc.SetFirstMoveEntropy(seatOneFirstMove) // the synthetic opponent wins → the caller sits at seat 1
 	starter := provisionAccount(t)
 	g, _, err := svc.OpenOrJoin(ctx, starter, openParams(1), time.Now().Add(time.Minute), nil)
 	if err != nil {
 		t.Fatalf("open: %v", err)
 	}
 	if g.ToMove != 0 || g.Seats[0].AccountID != uuid.Nil {
-		t.Fatalf("odd-seed open game: to_move %d seat0 %s, want the empty seat 0 to move", g.ToMove, g.Seats[0].AccountID)
+		t.Fatalf("opponent-won open draw: to_move %d seat0 %s, want the empty seat 0 to move", g.ToMove, g.Seats[0].AccountID)
 	}
 	if _, err := svc.Pass(ctx, g.ID, starter); !errors.Is(err, game.ErrNotYourTurn) {
 		t.Fatalf("starter acting on the empty seat's turn = %v, want ErrNotYourTurn", err)
 	}
 }
 
-// TestOpenGameJoinAfterStarterMoved checks a second human joins an open game even after
-// the starter has already made their first move, landing on the board mid-opening and
-// able to act on their turn.
+// TestOpenGameJoinAfterStarterMoved checks a second human joins an open game even after the
+// starter has already made their first move: the seats were fixed by the draw at open, so the
+// joiner takes the empty seat without disturbing the journal, and can act on their turn.
 func TestOpenGameJoinAfterStarterMoved(t *testing.T) {
 	ctx := context.Background()
 	clearOpenGames(t)

backend/internal/postgres/jet/backend/model/game_setup_draws.go

@@ -0,0 +1,24 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package model
+
+import (
+	"github.com/google/uuid"
+	"time"
+)
+
+type GameSetupDraws struct {
+	GameID    uuid.UUID `sql:"primary_key"`
+	Round     int16     `sql:"primary_key"`
+	PickNo    int16     `sql:"primary_key"`
+	AccountID *uuid.UUID
+	Letter    string
+	IsBlank   bool
+	DrawRank  int16
+	CreatedAt time.Time
+}

backend/internal/postgres/jet/backend/table/game_setup_draws.go

@@ -0,0 +1,99 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package table
+
+import (
+	"github.com/go-jet/jet/v2/postgres"
+)
+
+var GameSetupDraws = newGameSetupDrawsTable("backend", "game_setup_draws", "")
+
+type gameSetupDrawsTable struct {
+	postgres.Table
+
+	// Columns
+	GameID    postgres.ColumnString
+	Round     postgres.ColumnInteger
+	PickNo    postgres.ColumnInteger
+	AccountID postgres.ColumnString
+	Letter    postgres.ColumnString
+	IsBlank   postgres.ColumnBool
+	DrawRank  postgres.ColumnInteger
+	CreatedAt postgres.ColumnTimestampz
+
+	AllColumns     postgres.ColumnList
+	MutableColumns postgres.ColumnList
+	DefaultColumns postgres.ColumnList
+}
+
+type GameSetupDrawsTable struct {
+	gameSetupDrawsTable
+
+	EXCLUDED gameSetupDrawsTable
+}
+
+// AS creates new GameSetupDrawsTable with assigned alias
+func (a GameSetupDrawsTable) AS(alias string) *GameSetupDrawsTable {
+	return newGameSetupDrawsTable(a.SchemaName(), a.TableName(), alias)
+}
+
+// Schema creates new GameSetupDrawsTable with assigned schema name
+func (a GameSetupDrawsTable) FromSchema(schemaName string) *GameSetupDrawsTable {
+	return newGameSetupDrawsTable(schemaName, a.TableName(), a.Alias())
+}
+
+// WithPrefix creates new GameSetupDrawsTable with assigned table prefix
+func (a GameSetupDrawsTable) WithPrefix(prefix string) *GameSetupDrawsTable {
+	return newGameSetupDrawsTable(a.SchemaName(), prefix+a.TableName(), a.TableName())
+}
+
+// WithSuffix creates new GameSetupDrawsTable with assigned table suffix
+func (a GameSetupDrawsTable) WithSuffix(suffix string) *GameSetupDrawsTable {
+	return newGameSetupDrawsTable(a.SchemaName(), a.TableName()+suffix, a.TableName())
+}
+
+func newGameSetupDrawsTable(schemaName, tableName, alias string) *GameSetupDrawsTable {
+	return &GameSetupDrawsTable{
+		gameSetupDrawsTable: newGameSetupDrawsTableImpl(schemaName, tableName, alias),
+		EXCLUDED:            newGameSetupDrawsTableImpl("", "excluded", ""),
+	}
+}
+
+func newGameSetupDrawsTableImpl(schemaName, tableName, alias string) gameSetupDrawsTable {
+	var (
+		GameIDColumn    = postgres.StringColumn("game_id")
+		RoundColumn     = postgres.IntegerColumn("round")
+		PickNoColumn    = postgres.IntegerColumn("pick_no")
+		AccountIDColumn = postgres.StringColumn("account_id")
+		LetterColumn    = postgres.StringColumn("letter")
+		IsBlankColumn   = postgres.BoolColumn("is_blank")
+		DrawRankColumn  = postgres.IntegerColumn("draw_rank")
+		CreatedAtColumn = postgres.TimestampzColumn("created_at")
+		allColumns      = postgres.ColumnList{GameIDColumn, RoundColumn, PickNoColumn, AccountIDColumn, LetterColumn, IsBlankColumn, DrawRankColumn, CreatedAtColumn}
+		mutableColumns  = postgres.ColumnList{AccountIDColumn, LetterColumn, IsBlankColumn, DrawRankColumn, CreatedAtColumn}
+		defaultColumns  = postgres.ColumnList{IsBlankColumn, CreatedAtColumn}
+	)
+
+	return gameSetupDrawsTable{
+		Table: postgres.NewTable(schemaName, tableName, alias, allColumns...),
+
+		//Columns
+		GameID:    GameIDColumn,
+		Round:     RoundColumn,
+		PickNo:    PickNoColumn,
+		AccountID: AccountIDColumn,
+		Letter:    LetterColumn,
+		IsBlank:   IsBlankColumn,
+		DrawRank:  DrawRankColumn,
+		CreatedAt: CreatedAtColumn,
+
+		AllColumns:     allColumns,
+		MutableColumns: mutableColumns,
+		DefaultColumns: defaultColumns,
+	}
+}

backend/internal/postgres/jet/backend/table/table_use_schema.go

@@ -31,6 +31,7 @@ func UseSchema(schema string) {
 	GameInvitations = GameInvitations.FromSchema(schema)
 	GameMoves = GameMoves.FromSchema(schema)
 	GamePlayers = GamePlayers.FromSchema(schema)
+	GameSetupDraws = GameSetupDraws.FromSchema(schema)
 	Games = Games.FromSchema(schema)
 	Identities = Identities.FromSchema(schema)
 	Sessions = Sessions.FromSchema(schema)

backend/internal/postgres/migrations/00013_game_setup_draws.sql

@@ -0,0 +1,31 @@
+-- +goose Up
+-- The first-move draw (docs/ARCHITECTURE.md §6): before a game starts, each seated
+-- player draws one tile from the bag and the tile closest to "A" decides who moves
+-- first (a blank supersedes all letters); players tied for the best tile re-draw
+-- until a single leader remains. Each draw uses fresh entropy (not the game's
+-- deterministic bag seed), so this record — not a seed — is the only account of how
+-- the order was chosen. It is kept for tournaments, where the draw becomes a manual
+-- per-tile call. The record is dictionary-independent: the decoded letter, the blank
+-- flag and the numeric draw rank describe each draw without any alphabet table. The
+-- winner is reflected as seat 0 in game_players, so no order column is duplicated
+-- here. In auto-match the opponent is unknown at draw time (the draw runs against a
+-- synthetic placeholder when the game opens), so their draw rows carry a NULL account_id,
+-- back-filled when a real opponent joins. Hidden from players for now; surfaced only in the
+-- admin console.
+SET search_path = backend, pg_catalog;
+
+CREATE TABLE game_setup_draws (
+    game_id    uuid        NOT NULL REFERENCES games (game_id) ON DELETE CASCADE,
+    round      smallint    NOT NULL,
+    pick_no    smallint    NOT NULL,
+    account_id uuid        REFERENCES accounts (account_id) ON DELETE CASCADE,
+    letter     text        NOT NULL,
+    is_blank   boolean     NOT NULL DEFAULT false,
+    draw_rank  smallint    NOT NULL,
+    created_at timestamptz NOT NULL DEFAULT now(),
+    PRIMARY KEY (game_id, round, pick_no)
+);
+
+-- +goose Down
+SET search_path = backend, pg_catalog;
+DROP TABLE game_setup_draws;

backend/internal/server/handlers_admin_console.go

@@ -523,6 +523,34 @@ func (s *Server) consoleGameDetail(c *gin.Context) {
 			}
 		}
 	}
+	// First-move draw (docs/ARCHITECTURE.md §6) and the step-by-step replay timeline. Both are
+	// best-effort: a game that predates the draw or cannot be replayed still renders its
+	// summary and seats.
+	names := make(map[string]string, len(view.Seats))
+	for _, st := range view.Seats {
+		names[st.AccountID] = st.DisplayName
+	}
+	if draws, derr := s.games.SetupDraws(ctx, g.ID); derr == nil {
+		for _, d := range draws {
+			row := adminconsole.SetupDrawRow{Round: d.Round, Letter: strings.ToUpper(d.Letter), Blank: d.Blank, Rank: d.Rank}
+			if d.Account == uuid.Nil {
+				row.Name = "(opponent)"
+			} else {
+				row.Name = names[d.Account.String()]
+				row.AccountID = d.Account.String()
+			}
+			view.SetupDraws = append(view.SetupDraws, row)
+		}
+	}
+	if len(view.Seats) > 0 {
+		view.FirstMover = view.Seats[0].DisplayName
+	}
+	if tl, terr := s.games.ReplayTimeline(ctx, g.ID); terr == nil {
+		if rj, jerr := buildReplayJSON(g.Variant, tl, view.Seats); jerr == nil {
+			view.ReplayJSON = rj
+			view.HasReplay = len(tl.Steps) > 0
+		}
+	}
 	s.renderConsole(c, "game_detail", "games", "Game", view)
 }
 

backend/internal/server/handlers_admin_replay.go

@@ -0,0 +1,168 @@
+package server
+
+import (
+	"encoding/json"
+	"html/template"
+	"strings"
+
+	"scrabble/backend/internal/adminconsole"
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
+)
+
+// The admin game-replay payload embedded in the game_detail page for its vanilla-JS stepper:
+// the premium board layout, the seats and one step per replay frame (the dealt racks, then
+// one per move) carrying the resulting racks, scores, turn cursor and bag size. Letters are
+// upper-cased for display and carry their tile value (0 renders without a subscript).
+
+type replayTileJSON struct {
+	L string `json:"l"`
+	V int    `json:"v"`
+	B bool   `json:"b,omitempty"`
+}
+
+type replayPlaceJSON struct {
+	R int    `json:"r"`
+	C int    `json:"c"`
+	L string `json:"l"`
+	V int    `json:"v"`
+	B bool   `json:"b,omitempty"`
+}
+
+type replayMoveJSON struct {
+	Seat       int               `json:"seat"`
+	Action     string            `json:"action"`
+	Words      []string          `json:"words,omitempty"`
+	Score      int               `json:"score"`
+	Placements []replayPlaceJSON `json:"placements,omitempty"`
+	Exchanged  []replayTileJSON  `json:"exchanged,omitempty"`
+}
+
+type replayStepJSON struct {
+	Move   *replayMoveJSON    `json:"move"`
+	Drawn  []replayTileJSON   `json:"drawn,omitempty"`
+	Racks  [][]replayTileJSON `json:"racks"`
+	Scores []int              `json:"scores"`
+	ToMove int                `json:"toMove"`
+	BagLen int                `json:"bagLen"`
+}
+
+type replaySeatJSON struct {
+	Seat      int    `json:"seat"`
+	Name      string `json:"name"`
+	AccountID string `json:"accountId"`
+}
+
+type replayDataJSON struct {
+	Centre  [2]int           `json:"centre"`
+	Premium [][]string       `json:"premium"`
+	Seats   []replaySeatJSON `json:"seats"`
+	Steps   []replayStepJSON `json:"steps"`
+}
+
+// buildReplayJSON renders a game's replay timeline as the JSON the stepper consumes, resolving
+// each tile's value from the variant's alphabet. The result is safe to embed in a <script>:
+// encoding/json escapes <, > and & to \u00xx, so a user-chosen seat name cannot break out.
+func buildReplayJSON(variant engine.Variant, tl game.ReplayTimelineView, seats []adminconsole.SeatRow) (template.JS, error) {
+	values := map[string]int{}
+	if table, err := engine.AlphabetTable(variant); err == nil {
+		for _, e := range table {
+			values[e.Letter] = e.Value
+		}
+	}
+	tile := func(letter string, blank bool) replayTileJSON {
+		v := 0
+		if !blank {
+			v = values[strings.ToLower(letter)]
+		}
+		return replayTileJSON{L: strings.ToUpper(letter), V: v, B: blank}
+	}
+	tiles := func(letters []string) []replayTileJSON {
+		out := make([]replayTileJSON, len(letters))
+		for i, l := range letters {
+			out[i] = tile(l, l == "?")
+		}
+		return out
+	}
+
+	data := replayDataJSON{Centre: [2]int{7, 7}, Premium: premiumGrid(variant)}
+	for _, s := range seats {
+		data.Seats = append(data.Seats, replaySeatJSON{Seat: s.Seat, Name: s.DisplayName, AccountID: s.AccountID})
+	}
+	for _, st := range tl.Steps {
+		js := replayStepJSON{
+			Racks:  make([][]replayTileJSON, len(st.Racks)),
+			Scores: st.Scores,
+			ToMove: st.ToMove,
+			BagLen: st.BagLen,
+			Drawn:  tiles(st.Drawn),
+		}
+		for i, r := range st.Racks {
+			js.Racks[i] = tiles(r)
+		}
+		if st.Move != nil {
+			m := &replayMoveJSON{Seat: st.Move.Seat, Action: st.Move.Action, Words: st.Move.Words, Score: st.Move.Score}
+			for _, p := range st.Move.Tiles {
+				t := tile(p.Letter, p.Blank)
+				m.Placements = append(m.Placements, replayPlaceJSON{R: p.Row, C: p.Col, L: t.L, V: t.V, B: t.B})
+			}
+			m.Exchanged = tiles(st.Move.Exchanged)
+			js.Move = m
+		}
+		data.Steps = append(data.Steps, js)
+	}
+	b, err := json.Marshal(data)
+	if err != nil {
+		return "", err
+	}
+	return template.JS(b), nil
+}
+
+// premiumRows is the standard Scrabble premium-square layout: T triple-word, D double-word,
+// t triple-letter, d double-letter, * the centre double-word, '.' a plain square.
+var premiumRows = []string{
+	"T..d...T...d..T",
+	".D...t...t...D.",
+	"..D...d.d...D..",
+	"d..D...d...D..d",
+	"....D.....D....",
+	".t...t...t...t.",
+	"..d...d.d...d..",
+	"T..d...*...d..T",
+	"..d...d.d...d..",
+	".t...t...t...t.",
+	"....D.....D....",
+	"d..D...d...D..d",
+	"..D...d.d...D..",
+	".D...t...t...D.",
+	"T..d...T...d..T",
+}
+
+// premiumGrid returns the 15×15 premium-square codes ("tw"/"dw"/"tl"/"dl"/"") for variant.
+// Erudite carries no double-word premium on the centre square (only the start star).
+func premiumGrid(variant engine.Variant) [][]string {
+	code := func(ch byte) string {
+		switch ch {
+		case 'T':
+			return "tw"
+		case 'D', '*':
+			return "dw"
+		case 't':
+			return "tl"
+		case 'd':
+			return "dl"
+		}
+		return ""
+	}
+	grid := make([][]string, len(premiumRows))
+	for r, row := range premiumRows {
+		grid[r] = make([]string, len(row))
+		for c := 0; c < len(row); c++ {
+			grid[r][c] = code(row[c])
+		}
+	}
+	if variant == engine.VariantErudit {
+		grid[7][7] = ""
+	}
+	return grid
+}