/**
 * Fork-authoring helpers: turn a chosen set of catalog blocks into the concrete
 * files that go into a tenant's forked app repo. The AI app builder calls these
 * to produce a reviewable change (applied as a PR), so the base template stays
 * thin — only what's chosen lands in a fork.
 *
 * Today: `renderDashboardConfig` writes the home layout (foundry.dashboard.ts)
 * from built-in widgets. Per-component scaffolding of heavier blocks (calendar,
 * gantt, …) layers on next, emitting additional ScaffoldFiles.
 */
import { UI_CATALOG } from './catalog';
import type { ScaffoldFile } from './types';

/** One home widget: a catalog widget id + its per-widget params (type, title…). */
export interface DashboardWidgetConfig {
  kind: string;
  [param: string]: unknown;
}

const WIDGET_IDS = new Set(UI_CATALOG.filter((e) => e.category === 'widget').map((e) => e.id));

/** Which of the chosen widgets are NOT built into the base template (need scaffolding). */
export function widgetsNeedingScaffold(widgets: DashboardWidgetConfig[]): string[] {
  const builtIn = new Set(UI_CATALOG.filter((e) => e.builtIn).map((e) => e.id));
  return [...new Set(widgets.map((w) => w.kind))].filter((k) => WIDGET_IDS.has(k) && !builtIn.has(k));
}

export interface RenderResult {
  ok: boolean;
  /** Unknown/invalid widget kinds — the AI should fix these before applying. */
  errors: string[];
  file?: ScaffoldFile;
}

/**
 * Render `src/foundry.dashboard.ts` for the given home layout. Validates each
 * widget `kind` against the catalog's widget blocks; an unknown kind fails the
 * whole render (so we never write a config referencing a widget the app can't
 * render). Serializes params as a plain literal — valid TS the owner can hand-edit.
 */
export function renderDashboardConfig(widgets: DashboardWidgetConfig[]): RenderResult {
  const errors: string[] = [];
  if (widgets.length === 0) errors.push('layout is empty — choose at least one widget');
  for (const w of widgets) {
    if (!w.kind) errors.push('a widget is missing its "kind"');
    else if (!WIDGET_IDS.has(w.kind)) errors.push(`unknown widget kind "${w.kind}"`);
  }
  if (errors.length > 0) return { ok: false, errors };

  const body = widgets.map((w) => `  ${JSON.stringify(w)},`).join('\n');
  const content = `/**
 * Your app's home, as data. Generated by the Foundry app builder — safe to
 * hand-edit. Each entry is a widget (see components/dashboard for the registry);
 * add/remove/reorder them, or set this to 'auto' to derive a layout from your
 * schema. Widget shapes live in components/dashboard/config.
 */
import type { DashboardConfig } from '@/components/dashboard/config';

export const dashboard: DashboardConfig = [
${body}
];
`;
  return { ok: true, errors: [], file: { path: 'src/foundry.dashboard.ts', content } };
}