Flip ownership to region keys: shared contract + server (v0.19 P1 of #16)

The single source of truth now keys ownership by region key (one per owned
sub-region) instead of a parent-country ISO_A3:

- shared/types.ts, shared/protocol.ts: TerritoryChange / RegionMap / regionOwner
  doc flips; mapFeatureOwner now reads the feature's stamped properties.regionKey
  (never the repacked numeric feature.id, nor the sub-region id — the #6 guard).
- server/regions.ts (new, turf-free): loads region-keys.json + regions.geo.json
  once at boot; expands a nation's ISO_A3 list to its sub-regions' keys, builds
  the LLM 'regions' reference table (key -> "name (parent)"), and exposes the
  set of valid keys. Degrades gracefully when the files are missing.
- server/engine.ts: buildSystemPrompt instructs the model to use region keys;
  buildUserPrompt gains an optional regionReference table; applyTurnResult gains
  an optional validKeys set so hallucinated keys are ignored.
- server/index.ts: loads region data at boot; expands each nation's country list
  to region keys at game creation; the jump route passes the reference + valid
  keys through runTurn.

The stub is unchanged (it emits an empty, region-key-conformant territoryChanges).

server/engine.ts

@@ -53,11 +53,12 @@ export function buildSystemPrompt(preset: Preset): string {
     '  ],',
     '  "stateChanges": [{"nation":"<nationId>","stat":"<military|economy|stability|population>","op":"<set|add>","value":<0-100>}],',
     '  "relations": [{"a":"<nationId>","b":"<nationId>","set":"<ally|neutral|rival|hostile|war>"}],',
-    '  "territoryChanges": [{"nation":"<nationId>","gain":["<ISO_A3>"],"lose":["<ISO_A3>"]}]',
+    '  "territoryChanges": [{"nation":"<nationId>","gain":["<region key>"],"lose":["<region key>"]}]',
     '}',
     '',
     'HARD CONSTRAINTS',
-    '- Use only nation ids and ISO_A3 codes that exist in the provided state.',
+    '- Use only nation ids and region keys that exist in the provided state.',
+    '- A region key identifies one sub-region; the "regions" table in the user message maps each key to "<region name> (<parent country ISO_A3>)". Use those keys in territoryChanges.',
     '- Prefer 1-4 events per turn; keep each text 1-3 sentences.',
     '- Keep your internal reasoning brief (a few sentences) and go straight to the JSON result; do not over-deliberate or re-derive facts already present in the state.',
     '- Keep every stat value between 0 and 100.',
@@ -75,7 +76,11 @@ export function buildSystemPrompt(preset: Preset): string {
  * model to simulate the combined consequences of the whole batch (or to let the
  * world advance on its own when the batch is empty) and return one TurnResult.
  */
-export function buildUserPrompt(state: GameState, items: RoundItem[]): string {
+export function buildUserPrompt(
+  state: GameState,
+  items: RoundItem[],
+  regionReference?: Record<string, string>,
+): string {
   const player = state.nations[state.playerNationId];
   const playerName = player?.name ?? state.playerNationId;
   const playerActions = items.map((i) =>
@@ -88,7 +93,7 @@ export function buildUserPrompt(state: GameState, items: RoundItem[]): string {
         )}. Simulate the combined consequences across all nations and advance the world by one period. Return a single TurnResult.`
       : 'The player takes no action this period; let the world advance on its own momentum. Return a single TurnResult.';
 
-  const payload = {
+  const payload: Record<string, unknown> = {
     state: {
       turn: state.turn,
       date: state.date,
@@ -110,6 +115,7 @@ export function buildUserPrompt(state: GameState, items: RoundItem[]): string {
     pending: items,
     roundInstruction,
   };
+  if (regionReference) payload.regions = regionReference;
   return JSON.stringify(payload, null, 2);
 }
 
@@ -283,7 +289,7 @@ function genericUnclearEvent(state: GameState): TurnEventSpec {
  * Apply a TurnResult to a GameState immutably: advance the date/turn, append
  * events, apply stat changes (clamped), symmetric relations, and territory moves.
  */
-export function applyTurnResult(state: GameState, result: TurnResult): GameState {
+export function applyTurnResult(state: GameState, result: TurnResult, validKeys?: ReadonlySet<string>): GameState {
   const next: GameState = JSON.parse(JSON.stringify(state));
   next.version = (state.version ?? 0) + 1; // every mutation is a new revision
   const actingTurn = state.turn; // this action resolves the current turn
@@ -309,15 +315,18 @@ export function applyTurnResult(state: GameState, result: TurnResult): GameState
   for (const t of result.territoryChanges) {
     const n = next.nations[t.nation];
     if (!n) continue;
-    for (const code of t.gain) {
+    const valid = (k: string) => !validKeys || validKeys.has(k);
+    for (const key of t.gain) {
+      if (!valid(key)) continue; // ignore a key that is not a real region
       for (const other of Object.values(next.nations)) {
-        const i = other.territory.indexOf(code);
+        const i = other.territory.indexOf(key);
         if (i !== -1) other.territory.splice(i, 1);
       }
-      if (!n.territory.includes(code)) n.territory.push(code);
+      if (!n.territory.includes(key)) n.territory.push(key);
     }
-    for (const code of t.lose) {
-      const i = n.territory.indexOf(code);
+    for (const key of t.lose) {
+      if (!valid(key)) continue;
+      const i = n.territory.indexOf(key);
       if (i !== -1) n.territory.splice(i, 1);
     }
   }
@@ -367,10 +376,14 @@ export async function runTurn(opts: {
   preset: Preset;
   state: GameState;
   items: RoundItem[];
+  /** Region reference table (key -> "name (parent)") to include in the user prompt. */
+  regionReference?: Record<string, string>;
+  /** Set of valid region keys; territory changes with other keys are ignored. */
+  validRegionKeys?: ReadonlySet<string>;
 }): Promise<{ state: GameState; result: TurnResult }> {
-  const { llm, preset, state, items } = opts;
+  const { llm, preset, state, items, regionReference, validRegionKeys } = opts;
   const system = buildSystemPrompt(preset);
-  const user = buildUserPrompt(state, items);
+  const user = buildUserPrompt(state, items, regionReference);
   const nudge =
     'Your previous output was invalid. Respond with ONLY the JSON object described above for this batch — no prose, no fences.';
 
@@ -398,7 +411,7 @@ export async function runTurn(opts: {
     };
   }
 
-  return { state: applyTurnResult(state, result), result };
+  return { state: applyTurnResult(state, result, validRegionKeys), result };
 }
 
 // --- Advisor (brainstorm) -----------------------------------------------------

server/index.ts

@@ -20,6 +20,7 @@ import { createLlmClient } from './llm';
 import { makeStubLlmClient } from './stub';
 import { askAdvisor, queueRoundItem, removeRoundItem, runTurn } from './engine';
 import { buildRegionMap } from './map';
+import { allTerritoryKeys, expandCountriesToKeys, loadRegions, referenceForKeys, validKeys } from './regions';
 import { createPresetStore } from './presets';
 import { openDb, type Db } from './db';
 
@@ -49,6 +50,9 @@ const dataDir = process.env.DATA_DIR ?? path.join(root, 'data');
 // the e2e config, so honor it as a fallback to keep all three in agreement.
 const PORT = parseInt(process.env.PORT ?? process.env.HISTORY_API_PORT ?? '4321', 10);
 const presetStore = createPresetStore(presetsDir);
+// Load the region-key manifest + geo once at boot (v0.19 #16 P1). A missing file
+// just means region expansion/reference degrade to the raw keys (server still boots).
+loadRegions(root);
 const db: Db = openDb(path.join(dataDir, 'history.db'));
 // LLM_STUB=1 → deterministic stub (tests/e2e/dev without a live model).
 const useStub = process.env.LLM_STUB === '1';
@@ -121,6 +125,10 @@ app.post('/api/games', (req: Request, res) => {
     pending: [],
     version: 1, // the first saved revision; every later mutation bumps it
   };
+  // v0.19 (#16 P1): expand each nation's ISO_A3 country list to the region keys
+  // of all its sub-regions, so ownership (and the choropleth) is at region
+  // granularity from the very first turn. Preset JSONs stay country-level.
+  for (const n of Object.values(state.nations)) n.territory = expandCountriesToKeys(n.territory);
   db.save(state);
   res.json({ game: state });
 });
@@ -227,6 +235,8 @@ app.post('/api/games/:id/jump', async (req, res) => {
       preset,
       state: game,
       items: game.pending,
+      regionReference: referenceForKeys(allTerritoryKeys(game)),
+      validRegionKeys: validKeys(),
     });
     db.save(state);
     broadcast(id, 'turn', { state, result });

server/map.ts

@@ -1,6 +1,8 @@
-// Build the choropleth payload from a GameState: every ISO_A3 region maps to its
-// owning nation plus that nation's stable color (see shared.nationColor). The
-// client merges this onto public/countries.geo.json and calls source.setData().
+// Build the choropleth payload from a GameState: every region key (see
+// public/region-keys.json) maps to its owning nation plus that nation's stable
+// color (see shared.nationColor). The client merges this onto the sub-national
+// regions.geo.json (resolving each feature by its own region key) and calls
+// source.setData(). Format-agnostic: it maps whatever keys sit in territory.
 import { nationColor, type RegionMap } from '../shared/protocol';
 import type { GameState } from '../shared/types';
 
@@ -8,8 +10,8 @@ export function buildRegionMap(state: GameState): RegionMap {
   const map: RegionMap = {};
   for (const [id, nation] of Object.entries(state.nations)) {
     const color = nationColor(id);
-    for (const code of nation.territory) {
-      map[code] = { color, owner: nation.name, ownerId: id };
+    for (const key of nation.territory) {
+      map[key] = { color, owner: nation.name, ownerId: id };
     }
   }
   return map;

server/regions.ts

@@ -0,0 +1,140 @@
+// Region-key data access (server). Loads the deterministic region-key manifest
+// (public/region-keys.json: stable feature id -> region key) and the sub-national
+// geo (public/regions.geo.json: feature id -> { name, parent }), then joins them
+// into the lookups the region-level ownership model (v0.19, #16 P1) needs:
+//
+//   - expand a nation's ISO_A3 country list -> the region keys of all its sub-regions
+//   - build the LLM "regions" reference table (key -> "name (parent ISO_A3)")
+//   - the set of all valid region keys (to ignore hallucinated keys in applyTurnResult)
+//
+// Deliberately turf-free: it reads the two JSON files with plain JSON.parse and
+// never imports @turf/@types/geojson (importing one pulls @types/geojson into the
+// tsc program and breaks WorldMap.tsx; see the v0.17 changelog note). Loaded once
+// at boot; the accessors below are pure data reads thereafter.
+import { existsSync, readFileSync } from 'node:fs';
+import path from 'node:path';
+import type { GameState } from '../shared/types';
+
+/** { name, parent } for one sub-region, where parent is the ISO_A3 country. */
+interface RegionInfo {
+  name: string;
+  parent: string;
+}
+
+interface RegionData {
+  /** stable feature id -> region key (from public/region-keys.json). */
+  idToKey: Record<string, string>;
+  /** region key -> { name, parent }. */
+  keyToInfo: Record<string, RegionInfo>;
+  /** ISO_A3 parent -> region keys of its sub-regions (file order, stable). */
+  keysByCountry: Record<string, string[]>;
+  /** the set of all region keys. */
+  validKeys: Set<string>;
+}
+
+let data: RegionData | null = null;
+
+/**
+ * Load (or reload) the region-key manifest + geo from `root`. Idempotent.
+ * Returns true when both files loaded cleanly. A missing/broken file clears the
+ * data and returns false, so the server still boots and degrades gracefully
+ * (expansion becomes a no-op, ownership falls back to the raw input keys).
+ */
+export function loadRegions(root: string): boolean {
+  const keyPath = path.join(root, 'public', 'region-keys.json');
+  const geoPath = path.join(root, 'public', 'regions.geo.json');
+  if (!existsSync(keyPath) || !existsSync(geoPath)) {
+    data = null;
+    return false;
+  }
+  try {
+    const idToKey = JSON.parse(readFileSync(keyPath, 'utf8')) as Record<string, string>;
+    const geo = JSON.parse(readFileSync(geoPath, 'utf8')) as {
+      features?: Array<{ id?: string | number; properties?: { name?: string; parent?: string } }>;
+    };
+    const keyToInfo: Record<string, RegionInfo> = {};
+    const keysByCountry: Record<string, string[]> = {};
+    const validKeys = new Set<string>();
+    for (const f of geo.features ?? []) {
+      const id = f.id == null ? '' : String(f.id);
+      const key = idToKey[id];
+      if (!key) continue; // a geo feature with no manifest entry is skipped
+      const name = typeof f.properties?.name === 'string' ? f.properties.name : '';
+      const parent = typeof f.properties?.parent === 'string' ? f.properties.parent : '';
+      keyToInfo[key] = { name, parent };
+      validKeys.add(key);
+      if (parent) (keysByCountry[parent] ??= []).push(key);
+    }
+    data = { idToKey, keyToInfo, keysByCountry, validKeys };
+    return validKeys.size > 0;
+  } catch (err) {
+    console.error('[regions] failed to load region data', err);
+    data = null;
+    return false;
+  }
+}
+
+/** Test/dev seam: drop the loaded data (the next accessors behave as "no data"). */
+export function resetRegions(): void {
+  data = null;
+}
+
+/** True when the manifest + geo loaded cleanly. */
+export function hasRegionData(): boolean {
+  return data !== null;
+}
+
+/**
+ * Expand a nation's ISO_A3 country list to the region keys of all its sub-regions
+ * (file order, deduped). This is what turns a preset's country-level territory
+ * into region-level ownership at game creation. Returns the input unchanged when
+ * no region data is loaded (graceful degradation — behaves like the old model).
+ */
+export function expandCountriesToKeys(countries: string[]): string[] {
+  if (!data) return countries;
+  const out: string[] = [];
+  const seen = new Set<string>();
+  for (const c of countries) {
+    for (const key of data.keysByCountry[c] ?? []) {
+      if (!seen.has(key)) {
+        seen.add(key);
+        out.push(key);
+      }
+    }
+  }
+  return out;
+}
+
+/**
+ * Build the LLM reference table: region key -> "<name> (<parent ISO_A3>)", e.g.
+ * `moselle-rygy -> "Moselle (FRA)"`. Only the given keys are included (the caller
+ * passes the game's owned-region universe) so the prompt stays bounded.
+ */
+export function referenceForKeys(keys: Iterable<string>): Record<string, string> {
+  const out: Record<string, string> = {};
+  if (!data) return out;
+  for (const key of keys) {
+    const info = data.keyToInfo[key];
+    if (info) out[key] = info.parent ? `${info.name} (${info.parent})` : info.name;
+  }
+  return out;
+}
+
+/** The region key's human name (for the dossier), or undefined if unknown. */
+export function regionName(key: string): string | undefined {
+  return data?.keyToInfo[key]?.name;
+}
+
+/** The union of every nation's territory region keys (the game's region universe). */
+export function allTerritoryKeys(state: GameState): Set<string> {
+  const out = new Set<string>();
+  for (const n of Object.values(state.nations)) {
+    for (const key of n.territory) out.add(key);
+  }
+  return out;
+}
+
+/** The set of all valid region keys (to ignore hallucinated keys in applyTurnResult). */
+export function validKeys(): ReadonlySet<string> {
+  return data ? data.validKeys : new Set<string>();
+}

shared/protocol.ts

@@ -23,7 +23,7 @@ export interface RelationChange {
   set: RelationStatus;
 }
 
-/** A nation gains/loses ISO_A3 regions this turn. */
+/** A nation gains/loses region keys (see `public/region-keys.json`) this turn. */
 export interface TerritoryChange {
   nation: string;
   gain: string[];
@@ -48,26 +48,32 @@ export interface TurnResult {
   territoryChanges: TerritoryChange[];
 }
 
-/** Per-region map payload: ISO_A3 -> owning nation + its stable color. */
+/** Per-region map payload: region key -> owning nation + its stable color. */
 export interface RegionOwner {
   color: string;
   owner: string;
   ownerId: string;
 }
+/**
+ * The authoritative ownership map: a **region key** (see `public/region-keys.json`)
+ * -> the owning nation + its stable color. Owned at sub-region granularity (v0.19,
+ * #16 P1); a key absent from this map is unowned (rendered grey).
+ */
 export type RegionMap = Record<string, RegionOwner>;
 
 /**
  * Look up the owner record from the authoritative RegionMap by a RegionMap key.
- * The RegionMap is keyed by the **parent country's** ISO_A3 code (ownership and
- * the LLM stay at country granularity — see #16), so `key` is a country code such
- * as `DEU`, never a sub-region id such as `DEU-03`. Returns `undefined` for an
- * empty/missing key or an unowned country.
+ * The RegionMap is keyed by **region key** (see `public/region-keys.json`) — one
+ * per owned sub-region (v0.19, #16 P1) — so `key` is a region key such as
+ * `moselle-rygy`, never a raw feature id such as `FR-57` and never a
+ * parent-country ISO_A3. Returns `undefined` for an empty/missing key or an
+ * unowned region.
  *
  * Pure + shared: the primitive "key → owner" lookup. The *map feature → owner*
  * resolution (deciding which key to pass) lives in {@link mapFeatureOwner} below,
- * which reads the feature's `properties.parent` — never the repacked top-level
- * `id` (MapLibre turns it into a numeric index, the "no owner" bug #6) and never
- * the sub-region id.
+ * which reads the feature's stamped `properties.regionKey` — never the repacked
+ * top-level `id` (MapLibre turns it into a numeric index, the "no owner" bug #6)
+ * and never the sub-region id.
  */
 export function regionOwner(regions: RegionMap, key: string | null | undefined): RegionOwner | undefined {
   if (!key) return undefined;
@@ -76,22 +82,23 @@ export function regionOwner(regions: RegionMap, key: string | null | undefined):
 
 /**
  * Resolve the owning-nation record for a **rendered map feature** from the
- * authoritative RegionMap. The choropleth renders sub-national regions, but the
- * RegionMap is keyed by the *parent country's* ISO_A3 (not the sub-region's own
- * id), so a feature's owner is found via its `properties.parent` (the ISO_A3 the
- * client stamps from the GeoJSON `parent` property — see WorldMap) and then
- * `regionOwner`. This is the single shared source of truth for that resolution,
- * so the "use `parent`, never the sub-region `id`/repacked `feature.id`" rule
- * lives in one tested place rather than in the React component.
+ * authoritative RegionMap. The choropleth renders sub-national regions, and the
+ * RegionMap is now keyed by **region key** (one per sub-region, v0.19 #16 P1),
+ * so a feature's owner is found via its `properties.regionKey` — the region key
+ * the client stamps from `public/region-keys.json` by the feature's stable id
+ * (see WorldMap) — and then `regionOwner`. This is the single shared source of
+ * truth for that resolution, so the "use `regionKey`, never the sub-region `id`
+ * / repacked `feature.id`" rule lives in one tested place rather than in the
+ * React component.
  *
- * Returns `undefined` for a missing feature/parent or an unowned country.
+ * Returns `undefined` for a missing feature/regionKey or an unowned region.
  */
 export function mapFeatureOwner(
   regions: RegionMap,
-  feature: { properties?: { parent?: unknown } } | null | undefined,
+  feature: { properties?: { regionKey?: unknown } } | null | undefined,
 ): RegionOwner | undefined {
-  const parent = feature?.properties?.parent;
-  return regionOwner(regions, typeof parent === 'string' ? parent : '');
+  const regionKey = feature?.properties?.regionKey;
+  return regionOwner(regions, typeof regionKey === 'string' ? regionKey : '');
 }
 
 /** Server -> client Server-Sent Events payload (see server/index.ts /sse). */

shared/types.ts

@@ -26,8 +26,10 @@ export const RELATION_STATUSES: RelationStatus[] = [
 ];
 
 /**
- * A single nation in the world. `territory` holds ISO_A3 codes; the map colors
- * each of those regions with this nation's stable color (see protocol.nationColor).
+ * A single nation in the world. `territory` holds **region keys** (see
+ * `public/region-keys.json`) — one per owned sub-region, so the choropleth can
+ * color individual sub-regions, not whole countries (v0.19, #16 P1). The map
+ * resolves each sub-region's owner by its region key (see protocol.mapFeatureOwner).
  */
 export interface Nation {
   id: string;