/*
Volt Platform — License Management
Core license types and validation logic
*/
package license

import (
	"fmt"
	"regexp"
	"time"
)

// License represents a Volt platform license
type License struct {
	Key          string    `yaml:"key"`
	Tier         string    `yaml:"tier"` // community, pro, enterprise
	NodeID       string    `yaml:"node_id"`
	Organization string    `yaml:"organization"`
	ActivatedAt  time.Time `yaml:"activated_at"`
	ExpiresAt    time.Time `yaml:"expires_at"`
	Token        string    `yaml:"token"` // signed activation token from server
	Features     []string  `yaml:"features"`
	Fingerprint  string    `yaml:"fingerprint"`
	CouponCode   string    `yaml:"coupon_code,omitempty"`   // Promotional code used
	TrialEndsAt  time.Time `yaml:"trial_ends_at,omitempty"` // Trial expiration
	IsTrial      bool      `yaml:"is_trial,omitempty"`      // Whether this is a trial license
}

// IsTrialExpired checks if a trial license has expired.
// Returns false for non-trial licenses.
func (l *License) IsTrialExpired() bool {
	if !l.IsTrial {
		return false
	}
	if l.TrialEndsAt.IsZero() {
		return false
	}
	return time.Now().After(l.TrialEndsAt)
}

// licenseKeyPattern validates VOLT-{TIER}-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX format
// Tier prefix: COM (Community), PRO (Professional), ENT (Enterprise)
// Followed by 6 groups of 4 uppercase hex characters
var licenseKeyPattern = regexp.MustCompile(`^VOLT-(COM|PRO|ENT)-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{4}-[A-F0-9]{4}$`)

// ValidateKeyFormat checks if a license key matches the expected format
func ValidateKeyFormat(key string) error {
	if !licenseKeyPattern.MatchString(key) {
		return fmt.Errorf("invalid license key format: expected VOLT-{COM|PRO|ENT}-XXXX-XXXX-XXXX-XXXX-XXXX-XXXX")
	}
	return nil
}

// TierName returns a human-readable tier name
func TierName(tier string) string {
	switch tier {
	case TierCommunity:
		return "Community"
	case TierPro:
		return "Professional"
	case TierEnterprise:
		return "Enterprise"
	default:
		return "Unknown"
	}
}

// DetermineTier determines the tier from a license key prefix
func DetermineTier(key string) string {
	if len(key) < 8 {
		return TierCommunity
	}
	switch key[5:8] {
	case "PRO":
		return TierPro
	case "ENT":
		return TierEnterprise
	default:
		return TierCommunity
	}
}