Support group battle preparation powers

game/battle-power-question.ts

@@ -1,4 +1,5 @@
 import { voiceChoices } from './battle-cards';
+import { coalitionBattleBeneficiary, type CoalitionBattlePreparationContext } from './coalition-battle-preparation';
 
 export type NativeBattlePower = 'voice' | 'prescience';
 export type BattlePowerClaim =
@@ -15,7 +16,7 @@ export type NativeBattlePowerOpportunity = {
   event: string; territory: string; power: NativeBattlePower; owner: string;
   beneficiary: string; target: string; ready: boolean;
 };
-export type NativeBattlePowerGame = {
+export type NativeBattlePowerGame = Omit<CoalitionBattlePreparationContext, 'players' | 'status'> & {
   status: string;
   phase: number;
   players: readonly { id: string; faction: string; ally?: string | null }[];
@@ -110,9 +111,8 @@ export function nativeBattlePowerOpportunity(game: NativeBattlePowerGame, actor:
   const side = (kind: NativeBattlePower) => {
     const owners = game.players.filter(player => player.faction === (kind === 'voice' ? 'beneGesserit' : 'atreides'));
     if (owners.length !== 1) return null;
-    const owner = owners[0], combatants = [battle.attacker, battle.defender];
-    const beneficiary = combatants.includes(owner.id) ? owner.id : owner.ally && combatants.includes(owner.ally) &&
-      game.players.some(player => player.id === owner.ally && player.ally === owner.id) ? owner.ally : null;
+    const owner = owners[0];
+    const beneficiary = coalitionBattleBeneficiary(game, owner.id, battle.attacker, battle.defender, true);
     return beneficiary ? { owner: owner.id, beneficiary,
       target: battle.attacker === beneficiary ? battle.defender : battle.attacker } : null;
   };

game/coalition-battle-preparation.ts

@@ -0,0 +1,61 @@
+import { coalitionOf, CoalitionAllianceError, type CoalitionState } from './coalition-alliance';
+
+/** Only public roster and rule-profile data are required to select a side.
+ * Inspection answers and sealed plans are deliberately absent. */
+export type CoalitionBattlePreparationContext = {
+  status: string;
+  players: readonly { id: string; faction: string; ally?: string | null; allySinceTurn?: number }[];
+  coalitionState?: CoalitionState;
+  advanced?: boolean;
+  expansions?: readonly unknown[];
+  homeworlds?: unknown;
+  nexusCards?: unknown;
+  leaderSkills?: unknown;
+  techTokens?: unknown;
+  strongholdCards?: unknown;
+  ecazTreachery?: unknown;
+  discoveryEnabled?: unknown;
+};
+
+const classicFactions = new Set(['atreides', 'beneGesserit', 'emperor', 'fremen', 'guild', 'harkonnen']);
+
+/** Select the owner or a single allied combatant for native Voice or
+ * Prescience. The unexposed group extension is limited to the same bare Basic
+ * classic profile as its other faction powers. Ambiguous group battles fail
+ * closed. `requireMutualPair` preserves the stricter legacy Truthtrance quote;
+ * normal battle preparation historically accepted the owner's scalar ally. */
+export function coalitionBattleBeneficiary(
+  game: CoalitionBattlePreparationContext,
+  ownerId: string,
+  attacker: string,
+  defender: string,
+  requireMutualPair = false,
+): string | null {
+  if (!Array.isArray(game.players) || !ownerId || !attacker || !defender || attacker === defender) return null;
+  const owner = game.players.find(player => player.id === ownerId);
+  if (!owner || !game.players.some(player => player.id === attacker) ||
+      !game.players.some(player => player.id === defender)) return null;
+  const combatants = [attacker, defender];
+  if (game.coalitionState && game.status === 'playing' && game.advanced === false &&
+      Array.isArray(game.expansions) && game.expansions.length === 0 &&
+      !game.homeworlds && !game.nexusCards && !game.leaderSkills && !game.techTokens &&
+      !game.strongholdCards && !game.ecazTreachery && !game.discoveryEnabled &&
+      game.players.every(player => classicFactions.has(player.faction))) {
+    try {
+      const seats = game.players.map(player => ({id: player.id, ally: player.ally ?? null,
+        ...(player.allySinceTurn !== undefined ? {allySinceTurn: player.allySinceTurn} : {})}));
+      const group = coalitionOf(seats, game.coalitionState, ownerId);
+      if (group?.members.length === 3) {
+        const members = combatants.filter(player => group.members.includes(player));
+        return members.length === 1 ? members[0] : null;
+      }
+    } catch (error) {
+      if (error instanceof CoalitionAllianceError) return null;
+      throw error;
+    }
+  }
+  if (combatants.includes(owner.id)) return owner.id;
+  if (!owner.ally || !combatants.includes(owner.ally)) return null;
+  if (requireMutualPair && !game.players.some(player => player.id === owner.ally && player.ally === owner.id)) return null;
+  return owner.ally;
+}

game/combat-response-quote.ts

@@ -2,6 +2,7 @@ import { FACTIONS, type FactionId } from './catalog';
 import { voiceChoices } from './battle-cards';
 import { quoteEcazOccupyBattle, type EcazOccupyBattleProfile } from './ecaz-occupy-battle';
 import { validateNexusBorrowedVoice, type NexusBorrowedVoiceFrame } from './nexus-borrowed-voice';
+import { coalitionBattleBeneficiary, type CoalitionBattlePreparationContext } from './coalition-battle-preparation';
 
 export type CombatCheckKind =
   | 'kwisatz'
@@ -10,7 +11,7 @@ export type CombatCheckKind =
   | 'choamBattleAid';
 export type CombatResponseKind = CombatCheckKind | 'voice' | 'prescience';
 export type CombatCheck = { kind: CombatCheckKind; owner: string };
-export type CombatResponseInput = {
+export type CombatResponseInput = Omit<CoalitionBattlePreparationContext, 'players' | 'status' | 'advanced'> & {
   ecazOccupy?: EcazOccupyBattleProfile;
   status: string;
   phase: number;
@@ -21,6 +22,7 @@ export type CombatResponseInput = {
     id: string;
     faction: FactionId;
     ally?: string | null;
+    allySinceTurn?: number;
     specialKaramaUsed?: boolean;
   }[];
   battle: {
@@ -317,11 +319,7 @@ function calculate(
   requireCombat(owner, 'Combat preparation response has no owner.');
   // Match battlePreparation's existing provider selection, including its
   // one-way ally link. CHOAM's queue above independently requires mutual links.
-  const beneficiary = combatants.includes(owner.id)
-    ? owner.id
-    : owner.ally && combatants.includes(owner.ally)
-      ? owner.ally
-      : null;
+  const beneficiary = coalitionBattleBeneficiary(input, owner.id, b.attacker, b.defender);
   requireCombat(
     beneficiary,
     'Combat preparation owner has no combatant beneficiary.',
@@ -339,13 +337,7 @@ function calculate(
     // Voice has already advanced preparation to Prescience (or its finish).
     if (b.preparation !== undefined) {
       const atreides = input.players.find((p) => p.faction === 'atreides');
-      const recipient =
-        atreides &&
-        (combatants.includes(atreides.id)
-          ? atreides.id
-          : atreides.ally && combatants.includes(atreides.ally)
-            ? atreides.ally
-            : null);
+      const recipient = atreides && coalitionBattleBeneficiary(input, atreides.id, b.attacker, b.defender);
       requireCombat(
         record(b.preparation) &&
           b.preparation.kind === 'prescience' &&

game/engine.ts

@@ -753,6 +753,7 @@ import { isAlliedShipmentVisit, makeBasicAlliedShipment, quoteBasicAlliedShipmen
   type BasicAlliedShipment } from './allied-separation';
 import { answerCoalitionAdmission, beginCoalitionAdmission, coalitionGroups, coalitionOf,
   leaveCoalition, CoalitionAllianceError, type CoalitionState, type CoalitionTransition } from './coalition-alliance';
+import { coalitionBattleBeneficiary } from './coalition-battle-preparation';
 import { reconcileCoalitionEscrow, setCoalitionPledge, type CoalitionEscrowMembership,
   type CoalitionEscrowState } from './coalition-escrow';
 import { CoalitionFundingError, quoteCoalitionFunding, settleCoalitionFunding,
@@ -30596,6 +30597,15 @@ function currentCombatResponseQuote(
         status: g.status,
         phase: g.phase,
         advanced: g.advanced,
+        coalitionState: g.coalitionState,
+        expansions: g.expansions,
+        homeworlds: g.homeworlds,
+        nexusCards: g.nexusCards,
+        leaderSkills: g.leaderSkills,
+        techTokens: g.techTokens,
+        strongholdCards: g.strongholdCards,
+        ecazTreachery: g.ecazTreachery,
+        discoveryEnabled: g.discoveryEnabled,
         turn: g.turn,
         ...(g.battle?.ecazOccupy ? { ecazOccupy: ecazBattleProfile(g)! } : {}),
         territoryIds: combatLocations(g).map((t) => t.id),
@@ -30603,6 +30613,7 @@ function currentCombatResponseQuote(
           id: p.id,
           faction: p.faction,
           ally: p.ally,
+          allySinceTurn: p.allySinceTurn,
           specialKaramaUsed: p.specialKaramaUsed,
         })),
         battle: g.battle,
@@ -30690,13 +30701,7 @@ function battlePreparation(g: Game, kind: 'voice' | 'prescience', fresh = false)
   }
   const owner = byFaction(g, kind === 'voice' ? 'beneGesserit' : 'atreides');
   const combatants = [b.attacker, b.defender];
-  const beneficiary =
-    owner &&
-    (combatants.includes(owner.id)
-      ? owner.id
-      : owner.ally && combatants.includes(owner.ally)
-        ? owner.ally
-        : null);
+  const beneficiary = owner && coalitionBattleBeneficiary(g, owner.id, combatants[0], combatants[1]);
   if (owner && beneficiary) {
     const target = b.attacker === beneficiary ? b.defender : b.attacker;
     const occupation = kind === 'voice'

game/reference.ts

@@ -4500,11 +4500,11 @@ export const RULE_TOPICS: RuleTopic[] = [
     example:
       'At the final turn with neither Guild nor Fremen, two players each hold two qualifying strongholds and a third holds one. The two leaders of the count share the win.',
     checklist: [
-      { area: 'Implementation', status: 'Partial', detail: 'A host-selectable shorter two-member target shares victory calculation. Unexposed staged Basic groups connect Nexus, selected funding and the Emperor’s targeted aid; other group benefits remain open.', evidence: ['game/alliance-victory-option.ts', 'game/victory-progress.ts', 'game/victory-quote.ts', 'game/engine.ts', 'game/terminal-cancellation.ts'] },
+      { area: 'Implementation', status: 'Partial', detail: 'A host-selectable shorter two-member target shares victory calculation. Unexposed staged Basic groups connect Nexus, selected funding, Emperor and Fremen aid, and native Voice and Prescience; other group benefits remain open.', evidence: ['game/alliance-victory-option.ts', 'game/victory-progress.ts', 'game/victory-quote.ts', 'game/engine.ts', 'game/coalition-battle-preparation.ts', 'game/terminal-cancellation.ts'] },
       { area: 'Player controls', status: 'Partial', detail: 'The lobby offers the pair option. A staged group Emperor can choose either ally for spice and extra revival; group games cannot yet be started from the lobby.', evidence: ['components/game-table.tsx', 'components/coalition-emperor-aid.tsx', 'tests/short-alliance-victory-controls.test.tsx'] },
       { area: 'AI', status: 'Partial', detail: 'Legal alliance and victory paths use the shared target; staged group Emperor bots can offer a targeted revival. Strategic tuning remains deferred.', evidence: ['game/bots.ts', 'game/victory-progress.ts'] },
       { area: 'Documentation', status: 'Partial', detail: 'The printed option and provisional two-controller precedence are recorded.', evidence: ['docs/OPTIONAL_ALLIANCE_VICTORY.md'] },
-      { area: 'Verification', status: 'Partial', detail: 'Focused pair and staged group evidence includes real Nexus actions and Emperor aid; larger alliances and full combinations remain open.', evidence: ['tests/alliance-victory-option.test.ts', 'tests/short-alliance-victory-runtime.test.ts', 'tests/coalition-emperor-aid.test.ts'] },
+      { area: 'Verification', status: 'Partial', detail: 'Focused pair and staged group evidence includes real Nexus actions, Emperor and Fremen aid and battle preparation; larger alliances and full combinations remain open.', evidence: ['tests/alliance-victory-option.test.ts', 'tests/short-alliance-victory-runtime.test.ts', 'tests/coalition-emperor-aid.test.ts', 'tests/coalition-fremen-revival.test.ts', 'tests/coalition-battle-preparation.test.ts', 'tests/coalition-battle-power-question.test.ts'] },
     ],
     related: [
       'mentat',