/*
Volt Platform — License Enforcement

Runtime enforcement of tier-based feature gating. Commands call RequireFeature()
at the top of their RunE functions to gate access. If the current license tier
doesn't include the requested feature, the user sees a clear upgrade message.

No license on disk = Community tier (free).
Trial licenses are checked for expiration.
*/
package license

import "fmt"

// RequireFeature checks if the current license tier includes the named feature.
// If no license file exists, defaults to Community tier.
// Returns nil if allowed, error with upgrade message if not.
func RequireFeature(feature string) error {
	store := NewStore()
	lic, err := store.Load()
	if err != nil {
		// No license = Community tier — check Community features
		if TierIncludes(TierCommunity, feature) {
			return nil
		}
		return fmt.Errorf("feature %q requires a Pro or Enterprise license\n  Register at: https://armoredgate.com/pricing\n  Or run: volt system register --license VOLT-PRO-XXXX-...", feature)
	}

	// Check trial expiration
	if lic.IsTrialExpired() {
		// Expired trial — fall back to Community tier
		if TierIncludes(TierCommunity, feature) {
			return nil
		}
		return fmt.Errorf("trial license expired on %s — feature %q requires an active Pro or Enterprise license\n  Upgrade at: https://armoredgate.com/pricing\n  Or run: volt system register --license VOLT-PRO-XXXX-...",
			lic.TrialEndsAt.Format("2006-01-02"), feature)
	}

	// Check license expiration (non-trial)
	if !lic.ExpiresAt.IsZero() {
		expired, _ := store.IsExpired()
		if expired {
			if TierIncludes(TierCommunity, feature) {
				return nil
			}
			return fmt.Errorf("license expired on %s — feature %q requires an active Pro or Enterprise license\n  Renew at: https://armoredgate.com/pricing",
				lic.ExpiresAt.Format("2006-01-02"), feature)
		}
	}

	if TierIncludes(lic.Tier, feature) {
		return nil
	}

	return fmt.Errorf("feature %q requires %s tier (current: %s)\n  Upgrade at: https://armoredgate.com/pricing",
		feature, requiredTier(feature), TierName(lic.Tier))
}

// RequireFeatureWithStore checks feature access using a caller-provided Store.
// Useful for testing with a custom license directory.
func RequireFeatureWithStore(store *Store, feature string) error {
	lic, err := store.Load()
	if err != nil {
		if TierIncludes(TierCommunity, feature) {
			return nil
		}
		return fmt.Errorf("feature %q requires a Pro or Enterprise license\n  Register at: https://armoredgate.com/pricing\n  Or run: volt system register --license VOLT-PRO-XXXX-...", feature)
	}

	if lic.IsTrialExpired() {
		if TierIncludes(TierCommunity, feature) {
			return nil
		}
		return fmt.Errorf("trial license expired on %s — feature %q requires an active Pro or Enterprise license\n  Upgrade at: https://armoredgate.com/pricing\n  Or run: volt system register --license VOLT-PRO-XXXX-...",
			lic.TrialEndsAt.Format("2006-01-02"), feature)
	}

	if !lic.ExpiresAt.IsZero() {
		expired, _ := store.IsExpired()
		if expired {
			if TierIncludes(TierCommunity, feature) {
				return nil
			}
			return fmt.Errorf("license expired on %s — feature %q requires an active Pro or Enterprise license\n  Renew at: https://armoredgate.com/pricing",
				lic.ExpiresAt.Format("2006-01-02"), feature)
		}
	}

	if TierIncludes(lic.Tier, feature) {
		return nil
	}

	return fmt.Errorf("feature %q requires %s tier (current: %s)\n  Upgrade at: https://armoredgate.com/pricing",
		feature, requiredTier(feature), TierName(lic.Tier))
}

// RequireContainerLimit checks if adding one more container would exceed
// the tier's per-node container limit.
func RequireContainerLimit(currentCount int) error {
	store := NewStore()
	tier := TierCommunity

	lic, err := store.Load()
	if err == nil {
		if lic.IsTrialExpired() {
			tier = TierCommunity
		} else {
			tier = lic.Tier
		}
	}

	limit := MaxContainersPerNode(tier)
	if limit == 0 {
		// 0 = unlimited (Enterprise)
		return nil
	}

	if currentCount >= limit {
		return fmt.Errorf("container limit reached: %d/%d (%s tier)\n  Upgrade at: https://armoredgate.com/pricing",
			currentCount, limit, TierName(tier))
	}

	return nil
}

// RequireContainerLimitWithStore checks container limits using a caller-provided Store.
func RequireContainerLimitWithStore(store *Store, currentCount int) error {
	tier := TierCommunity

	lic, err := store.Load()
	if err == nil {
		if lic.IsTrialExpired() {
			tier = TierCommunity
		} else {
			tier = lic.Tier
		}
	}

	limit := MaxContainersPerNode(tier)
	if limit == 0 {
		return nil
	}

	if currentCount >= limit {
		return fmt.Errorf("container limit reached: %d/%d (%s tier)\n  Upgrade at: https://armoredgate.com/pricing",
			currentCount, limit, TierName(tier))
	}

	return nil
}

// requiredTier returns the human-readable name of the minimum tier that
// includes the given feature. Checks from lowest to highest.
func requiredTier(feature string) string {
	if TierIncludes(TierCommunity, feature) {
		return TierName(TierCommunity)
	}
	if TierIncludes(TierPro, feature) {
		return TierName(TierPro)
	}
	if TierIncludes(TierEnterprise, feature) {
		return TierName(TierEnterprise)
	}
	return "Unknown"
}