managarten/apps-archived/memoro/apps/mobile/features/memos/config/realtimeConfig.ts

/**
 * Feature flags for Realtime subscription migration
 * Controls the gradual rollout from direct subscriptions to centralized service
 */

// Environment variable control for feature flags
const getEnvFlag = (key: string, defaultValue: boolean = false): boolean => {
	const envValue = process.env[key];
	if (envValue === undefined) return defaultValue;
	return envValue.toLowerCase() === 'true';
};

export const RealtimeConfig = {
	/**
	 * Use centralized MemoRealtimeService instead of direct Supabase subscriptions
	 * Can be overridden per environment
	 */
	USE_CENTRALIZED_REALTIME: getEnvFlag('EXPO_PUBLIC_USE_CENTRALIZED_REALTIME', false),

	/**
	 * Enable DirectMemoTitle migration to centralized service
	 * When false, uses original DirectMemoTitle implementation
	 * When true, uses centralized service via useDirectMemoTitle hook
	 */
	MIGRATE_DIRECT_MEMO_TITLE: getEnvFlag('EXPO_PUBLIC_MIGRATE_DIRECT_MEMO_TITLE', true),

	/**
	 * Development and debugging flags
	 */
	DEBUG_REALTIME_CONNECTIONS: getEnvFlag('EXPO_PUBLIC_DEBUG_REALTIME_CONNECTIONS', false),

	/**
	 * Gradual rollout percentages (0-100)
	 * Used for A/B testing the migration
	 */
	MIGRATION_ROLLOUT_PERCENTAGE: parseInt(
		process.env.EXPO_PUBLIC_MIGRATION_ROLLOUT_PERCENTAGE || '0',
		10
	),

	/**
	 * Check if a specific user should use the new implementation
	 * Based on rollout percentage (simple hash-based distribution)
	 */
	shouldUseCentralizedRealtime: (userId?: string): boolean => {
		// If feature flag is explicitly set, use that
		if (process.env.EXPO_PUBLIC_USE_CENTRALIZED_REALTIME !== undefined) {
			return RealtimeConfig.USE_CENTRALIZED_REALTIME;
		}

		// If no userId provided, use default
		if (!userId) {
			return RealtimeConfig.USE_CENTRALIZED_REALTIME;
		}

		// Simple hash-based rollout
		const rolloutPercentage = RealtimeConfig.MIGRATION_ROLLOUT_PERCENTAGE;
		if (rolloutPercentage === 0) return false;
		if (rolloutPercentage >= 100) return true;

		// Create a simple hash from userId
		let hash = 0;
		for (let i = 0; i < userId.length; i++) {
			const char = userId.charCodeAt(i);
			hash = (hash << 5) - hash + char;
			hash = hash & hash; // Convert to 32-bit integer
		}

		// Convert hash to percentage (0-99)
		const userPercentage = Math.abs(hash) % 100;

		return userPercentage < rolloutPercentage;
	},

	/**
	 * Log configuration for debugging
	 */
	logConfig: (): void => {
		if (RealtimeConfig.DEBUG_REALTIME_CONNECTIONS) {
			console.log('RealtimeConfig:', {
				USE_CENTRALIZED_REALTIME: RealtimeConfig.USE_CENTRALIZED_REALTIME,
				MIGRATE_DIRECT_MEMO_TITLE: RealtimeConfig.MIGRATE_DIRECT_MEMO_TITLE,
				MIGRATION_ROLLOUT_PERCENTAGE: RealtimeConfig.MIGRATION_ROLLOUT_PERCENTAGE,
				DEBUG_REALTIME_CONNECTIONS: RealtimeConfig.DEBUG_REALTIME_CONNECTIONS,
			});
		}
	},
};

export default RealtimeConfig;