feat(state): view model action availability and story passage

src/state/viewModel.ts

@@ -1,5 +1,11 @@
-import type { Content } from '../content/schema';
-import type { GameState } from '../engine/game';
+import type { GameContent } from '../content/index';
+import {
+  canAffordAction,
+  canUnlockAction,
+  isActionAvailable,
+  type GameState,
+} from '../engine/game';
+import { getAvailableChoices, getCurrentNode } from '../engine/story';
 
 /**
  * Pure mapping from engine state to the view model the React shell renders.
@@ -12,6 +18,29 @@ export interface ResourceView {
   amount: number;
 }
 
+export interface ActionView {
+  id: string;
+  name: string;
+  available: boolean;
+  disabledReason: string | null;
+  storyHint?: string;
+  storyTooltip?: string;
+  costsSummary: string | null;
+  yieldsSummary: string | null;
+}
+
+export interface StoryChoiceView {
+  id: string;
+  label: string;
+  disabled: boolean;
+  disabledReason: string | null;
+}
+
+export interface StoryView {
+  currentProse: string | null;
+  choices: StoryChoiceView[];
+}
+
 export interface GameView {
   resources: ResourceView[];
   activeActionId: string | null;
@@ -20,9 +49,30 @@ export interface GameView {
   actionProgress: number;
   queuedActionIds: string[];
   queuedActionNames: string[];
+  actions: ActionView[];
+  story: StoryView;
 }
 
-export function toView(state: GameState, content: Content): GameView {
+function actionDisabledReason(
+  state: GameState,
+  content: GameContent,
+  actionId: string,
+): string | null {
+  if (!canUnlockAction(state, content, actionId)) return 'Locked';
+  if (!canAffordAction(state, content, actionId)) return 'Not enough resources';
+  return null;
+}
+
+function formatResourceList(
+  items: { resourceId: string; amount: number }[],
+  content: GameContent,
+): string {
+  return items
+    .map((i) => `${i.amount} ${content.resourcesById[i.resourceId]?.name ?? i.resourceId}`)
+    .join(', ');
+}
+
+export function toView(state: GameState, content: GameContent): GameView {
   const resources: ResourceView[] = content.resources.map((resource) => ({
     id: resource.id,
     name: resource.name,
@@ -34,6 +84,34 @@ export function toView(state: GameState, content: Content): GameView {
   const queuedActionIds = [...state.actionQueue];
   const queuedActionNames = queuedActionIds.map((id) => content.actionsById[id]?.name ?? id);
 
+  const actions: ActionView[] = content.actions.map((a) => ({
+    id: a.id,
+    name: a.name,
+    available: isActionAvailable(state, content, a.id),
+    disabledReason: actionDisabledReason(state, content, a.id),
+    storyHint: a.storyHint,
+    storyTooltip: a.storyTooltip,
+    costsSummary: a.costs.length ? formatResourceList(a.costs, content) : null,
+    yieldsSummary: formatResourceList(a.yields, content),
+  }));
+
+  const node = getCurrentNode(state, content);
+  const availableChoices = getAvailableChoices(state, content);
+  const allChoices = node?.choices ?? [];
+
+  const story: StoryView = {
+    currentProse: node?.prose ?? null,
+    choices: allChoices.map((choice) => {
+      const available = availableChoices.some((c) => c.id === choice.id);
+      return {
+        id: choice.id,
+        label: choice.label,
+        disabled: !available,
+        disabledReason: available ? null : 'Requirements not met',
+      };
+    }),
+  };
+
   return {
     resources,
     activeActionId: state.activeActionId,
@@ -41,6 +119,8 @@ export function toView(state: GameState, content: Content): GameView {
     actionProgress,
     queuedActionIds,
     queuedActionNames,
+    actions,
+    story,
   };
 }