/**
 * @ai-summary Feature tier configuration and utilities
 * @ai-context Defines feature-to-tier mapping for gating premium features
 */

import { SubscriptionTier } from '../../features/user-profile/domain/user-profile.types';

// Tier hierarchy: higher number = higher access level
export const TIER_LEVELS: Record<SubscriptionTier, number> = {
  free: 0,
  pro: 1,
  enterprise: 2,
} as const;

// Feature configuration interface
export interface FeatureConfig {
  minTier: SubscriptionTier;
  name: string;
  upgradePrompt: string;
}

// Feature registry - add new gated features here
export const FEATURE_TIERS: Record<string, FeatureConfig> = {
  'document.scanMaintenanceSchedule': {
    minTier: 'pro',
    name: 'Scan for Maintenance Schedule',
    upgradePrompt: 'Upgrade to Pro to automatically extract maintenance schedules from your vehicle manuals.',
  },
  'vehicle.vinDecode': {
    minTier: 'pro',
    name: 'VIN Decode',
    upgradePrompt: 'Upgrade to Pro to automatically decode VIN and populate vehicle details from the NHTSA database.',
  },
} as const;

/**
 * Get numeric level for a subscription tier
 */
export function getTierLevel(tier: SubscriptionTier): number {
  return TIER_LEVELS[tier] ?? 0;
}

/**
 * Check if a user tier can access a feature
 * Higher tiers inherit access to all lower tier features
 */
export function canAccessFeature(userTier: SubscriptionTier, featureKey: string): boolean {
  const feature = FEATURE_TIERS[featureKey];
  if (!feature) {
    // Unknown features are accessible by all (fail open for unlisted features)
    return true;
  }
  return getTierLevel(userTier) >= getTierLevel(feature.minTier);
}

/**
 * Get the minimum required tier for a feature
 * Returns null if feature is not gated
 */
export function getRequiredTier(featureKey: string): SubscriptionTier | null {
  const feature = FEATURE_TIERS[featureKey];
  return feature?.minTier ?? null;
}

/**
 * Get full feature configuration
 * Returns undefined if feature is not registered
 */
export function getFeatureConfig(featureKey: string): FeatureConfig | undefined {
  return FEATURE_TIERS[featureKey];
}

/**
 * Get all feature configurations (for API endpoint)
 */
export function getAllFeatureConfigs(): Record<string, FeatureConfig> {
  return { ...FEATURE_TIERS };
}