platform-codebase/@packages/@infrastructure/feature-flags/src/hooks/useFeatureFlag.ts

/**
 * useFeatureFlag Hook
 *
 * React hook for checking feature flags in components.
 */

import { useContext, useMemo } from 'react';
import { FeatureFlagContext } from '../providers/FeatureFlagProvider';
import type { FeatureFlagEvaluation, KnownFeatureFlag } from '../types';

/**
 * Hook to check if a feature flag is enabled
 *
 * @example
 * ```tsx
 * function MyComponent() {
 *   const isEnabled = useFeatureFlag('trustedmeet-marketplace');
 *
 *   if (!isEnabled) {
 *     return <ComingSoon />;
 *   }
 *
 *   return <MarketplaceContent />;
 * }
 * ```
 */
export function useFeatureFlag(flagId: KnownFeatureFlag | string): boolean {
  const context = useContext(FeatureFlagContext);

  if (!context) {
    console.warn(
      `[useFeatureFlag] No FeatureFlagProvider found. Flag "${flagId}" defaulting to false.`
    );
    return false;
  }

  return context.service.isEnabled(flagId);
}

/**
 * Hook to get full evaluation details for a feature flag
 *
 * @example
 * ```tsx
 * function MyComponent() {
 *   const evaluation = useFeatureFlagEvaluation('trustedmeet-marketplace');
 *
 *   if (!evaluation.enabled) {
 *     console.log(`Feature disabled: ${evaluation.reason}`);
 *   }
 * }
 * ```
 */
export function useFeatureFlagEvaluation(
  flagId: KnownFeatureFlag | string
): FeatureFlagEvaluation {
  const context = useContext(FeatureFlagContext);

  if (!context) {
    return { enabled: false, reason: 'not_found' };
  }

  return context.service.evaluate(flagId);
}

/**
 * Hook to check multiple feature flags at once
 *
 * @example
 * ```tsx
 * function MyComponent() {
 *   const flags = useFeatureFlags(['trustedmeet-marketplace', 'trustedmeet-search']);
 *
 *   if (flags['trustedmeet-marketplace'] && flags['trustedmeet-search']) {
 *     return <SearchableMarketplace />;
 *   }
 * }
 * ```
 */
export function useFeatureFlags(
  flagIds: (KnownFeatureFlag | string)[]
): Record<string, boolean> {
  const context = useContext(FeatureFlagContext);

  return useMemo(() => {
    const results: Record<string, boolean> = {};

    for (const flagId of flagIds) {
      results[flagId] = context?.service.isEnabled(flagId) ?? false;
    }

    return results;
  }, [context, flagIds]);
}

/**
 * Hook to get all enabled feature flags
 *
 * @example
 * ```tsx
 * function DebugPanel() {
 *   const enabledFlags = useEnabledFeatureFlags();
 *   return <pre>{JSON.stringify(enabledFlags, null, 2)}</pre>;
 * }
 * ```
 */
export function useEnabledFeatureFlags(): string[] {
  const context = useContext(FeatureFlagContext);

  if (!context) {
    return [];
  }

  return context.service.getEnabledFlags();
}