/**
 * Component discovery utilities.
 *
 * Extracted from the docs app component-registry so that any consumer
 * (govern presets, CLI tools, third-party integrations) can discover
 * components from a module's exports without duplicating the logic.
 */

/**
 * Check if a value is likely a React component.
 * Functions or objects with $$typeof (forwardRef, memo) qualify.
 */
export function isReactComponent(value: unknown): boolean {
  if (!value) return false;

  // Function component (most common case)
  if (typeof value === 'function') {
    return true;
  }

  // ForwardRef, memo, etc. have $$typeof
  if (typeof value === 'object') {
    const obj = value as Record<string, unknown>;
    if (obj.$$typeof) return true;
  }

  return false;
}

export interface DiscoverComponentsOptions {
  /** Set of export names to skip */
  exclude?: Set<string>;
}

/**
 * Discover all components and sub-components from a module's exports.
 * Returns a sorted array of component names including compound names (e.g. 'Card.Header').
 *
 * @param moduleExports - The exports object from a component library (e.g. `import * as UI from '@fragments-sdk/ui'`)
 * @param options - Optional configuration
 */
export function discoverComponents(
  moduleExports: Record<string, unknown>,
  options?: DiscoverComponentsOptions,
): string[] {
  const exclude = options?.exclude;
  const names: string[] = [];

  for (const [exportName, exportValue] of Object.entries(moduleExports)) {
    // Skip excluded exports
    if (exclude?.has(exportName)) continue;

    // Skip non-components (types, constants, etc.)
    if (!isReactComponent(exportValue)) continue;

    // Skip lowercase exports (likely utilities)
    if (exportName[0] !== exportName[0].toUpperCase()) continue;

    // Add the main component
    names.push(exportName);

    // Check for sub-components by looking at ALL properties of the component
    const componentObj = exportValue as Record<string, unknown>;

    for (const key of Object.keys(componentObj)) {
      // Skip internal properties and non-component properties
      if (key.startsWith('_') || key.startsWith('$')) continue;
      if (key === 'displayName' || key === 'propTypes' || key === 'defaultProps') continue;
      // Skip 'render' which is a forwardRef internal, and 'Tabbed' which is a special variant
      if (key === 'render' || key === 'Tabbed') continue;

      const subComponent = componentObj[key];
      if (isReactComponent(subComponent)) {
        names.push(`${exportName}.${key}`);
      }
    }
  }

  return names.sort();
}