import { ASTRALVIEW_SCHEMA_VERSION, type Screen } from './schema';

/**
 * Placeholder for future schema migrations.
 * Keep it pure and versioned.
 */
function toNumber(v: unknown, fallback: number): number {
  return typeof v === 'number' && Number.isFinite(v) ? v : fallback;
}

function asString(v: unknown): string {
  return typeof v === 'string' ? v : '';
}

function sanitizeScreenV1(input: Screen): Screen {
  const allowedTypes = new Set(['text', 'image', 'iframe', 'video']);

  const nodes = Array.isArray(input.nodes) ? input.nodes : [];

  const sanitizedNodes = nodes
    .filter((n): n is Screen['nodes'][number] => !!n && typeof n === 'object')
    .filter((n) => allowedTypes.has((n as { type?: unknown }).type as string))
    .map((n, i) => {
      const anyNode = n as unknown as Record<string, unknown>;
      const rect = (anyNode.rect ?? {}) as Record<string, unknown>;

      const base = {
        ...n,
        id: asString(anyNode.id) || `import_${Date.now()}_${i}`,
        rect: {
          x: toNumber(rect.x, 0),
          y: toNumber(rect.y, 0),
          w: toNumber(rect.w, 100),
          h: toNumber(rect.h, 60),
        },
      };

      // Ensure required props exist for media widgets to prevent runtime crashes.
      const props = (base as unknown as { props?: unknown }).props;
      const propsObj = (props && typeof props === 'object' ? (props as Record<string, unknown>) : {}) as Record<
        string,
        unknown
      >;

      if (base.type === 'image') {
        return { ...base, props: { ...propsObj, src: asString(propsObj.src) } };
      }
      if (base.type === 'iframe') {
        return { ...base, props: { ...propsObj, src: asString(propsObj.src) } };
      }
      if (base.type === 'video') {
        return { ...base, props: { ...propsObj, src: asString(propsObj.src) } };
      }
      if (base.type === 'text') {
        return { ...base, props: { ...propsObj, text: asString(propsObj.text) || '' } };
      }

      return base;
    });

  return {
    ...input,
    id: input.id || `av_${Date.now()}`,
    name: input.name || 'Untitled Screen',
    width: toNumber(input.width, 1920),
    height: toNumber(input.height, 1080),
    nodes: sanitizedNodes,
  };
}

/**
 * Placeholder for future schema migrations.
 * Keep it pure and versioned.
 */
export function migrateScreen(input: unknown): Screen {
  const s = input as Partial<Screen>;
  if (!s || typeof s !== 'object') {
    throw new Error('Invalid screen: not an object');
  }
  const version = (s as Screen).version;
  if (version === ASTRALVIEW_SCHEMA_VERSION) {
    // Even for the current version, we defensively sanitize to avoid runtime
    // "assertNever" crashes when users import malformed JSON.
    return sanitizeScreenV1(s as Screen);
  }

  // Future: apply incremental migrations.
  throw new Error(`Unsupported screen version: ${String(version)}`);
}