package ssl

import (
	"context"
	"crypto/x509"
	"fmt"
	"sync"
	"time"

	"go.uber.org/zap"
)

// CertificateManager gère les certificats SSL automatiquement
type CertificateManager struct {
	logger    *zap.Logger
	config    CertificateConfig
	certStore map[string]*Certificate
	providers map[string]CertificateProvider
	monitor   *CertificateMonitor
	scheduler *RenewalScheduler
	mu        sync.RWMutex
	isRunning bool
}

// CertificateConfig configuration des certificats
type CertificateConfig struct {
	Enabled            bool           `yaml:"enabled"`
	AutoRenewal        bool           `yaml:"auto_renewal"`
	RenewalThreshold   time.Duration  `yaml:"renewal_threshold"` // 30 jours par défaut
	CheckInterval      time.Duration  `yaml:"check_interval"`    // 6 heures par défaut
	Provider           string         `yaml:"provider"`          // "letsencrypt", "self-signed", "manual"
	EmailNotifications bool           `yaml:"email_notifications"`
	SlackNotifications bool           `yaml:"slack_notifications"`
	StoreType          string         `yaml:"store_type"` // "filesystem", "kubernetes", "vault"
	StorePath          string         `yaml:"store_path"`
	BackupEnabled      bool           `yaml:"backup_enabled"`
	BackupPath         string         `yaml:"backup_path"`
	Domains            []DomainConfig `yaml:"domains"`
}

// DomainConfig configuration par domaine
type DomainConfig struct {
	Domain          string   `yaml:"domain"`
	Aliases         []string `yaml:"aliases"`
	CertificatePath string   `yaml:"certificate_path"`
	PrivateKeyPath  string   `yaml:"private_key_path"`
	AutoRenew       bool     `yaml:"auto_renew"`
	Provider        string   `yaml:"provider"`
	Contact         string   `yaml:"contact"`
}

// Certificate représente un certificat SSL
type Certificate struct {
	ID          string                 `json:"id"`
	Domain      string                 `json:"domain"`
	Aliases     []string               `json:"aliases"`
	Provider    string                 `json:"provider"`
	Certificate *x509.Certificate      `json:"-"`
	PrivateKey  interface{}            `json:"-"`
	PEMData     []byte                 `json:"-"`
	KeyData     []byte                 `json:"-"`
	Status      CertificateStatus      `json:"status"`
	IssuedAt    time.Time              `json:"issued_at"`
	ExpiresAt   time.Time              `json:"expires_at"`
	LastChecked time.Time              `json:"last_checked"`
	AutoRenew   bool                   `json:"auto_renew"`
	Contact     string                 `json:"contact"`
	Metadata    map[string]interface{} `json:"metadata"`
}

// CertificateStatus statut du certificat
type CertificateStatus string

const (
	CertStatusValid    CertificateStatus = "valid"
	CertStatusExpiring CertificateStatus = "expiring"
	CertStatusExpired  CertificateStatus = "expired"
	CertStatusRevoking CertificateStatus = "revoking"
	CertStatusRevoked  CertificateStatus = "revoked"
	CertStatusRenewing CertificateStatus = "renewing"
	CertStatusError    CertificateStatus = "error"
)

// CertificateProvider interface pour les fournisseurs de certificats
type CertificateProvider interface {
	GenerateCertificate(ctx context.Context, domain string, aliases []string, contact string) (*Certificate, error)
	RenewCertificate(ctx context.Context, cert *Certificate) (*Certificate, error)
	RevokeCertificate(ctx context.Context, cert *Certificate) error
	ValidateCertificate(ctx context.Context, cert *Certificate) error
	GetCertificateInfo(ctx context.Context, domain string) (*Certificate, error)
}

// CertificateMonitor surveille l'état des certificats
type CertificateMonitor struct {
	logger    *zap.Logger
	manager   *CertificateManager
	isRunning bool
	mu        sync.RWMutex
}

// RenewalScheduler planifie les renouvellements
type RenewalScheduler struct {
	logger       *zap.Logger
	manager      *CertificateManager
	renewalQueue chan *Certificate
	isRunning    bool
	mu           sync.RWMutex
}

// NewCertificateManager crée un nouveau gestionnaire de certificats
func NewCertificateManager(config CertificateConfig, logger *zap.Logger) *CertificateManager {
	cm := &CertificateManager{
		logger:    logger,
		config:    config,
		certStore: make(map[string]*Certificate),
		providers: make(map[string]CertificateProvider),
	}

	// Initialiser le monitor
	cm.monitor = &CertificateMonitor{
		logger:  logger,
		manager: cm,
	}

	// Initialiser le scheduler
	cm.scheduler = &RenewalScheduler{
		logger:       logger,
		manager:      cm,
		renewalQueue: make(chan *Certificate, 100),
	}

	return cm
}

// Initialize initialise le gestionnaire de certificats
func (cm *CertificateManager) Initialize(ctx context.Context) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()

	cm.logger.Info("Initializing Certificate Manager")

	// Initialiser les providers
	if err := cm.initializeProviders(); err != nil {
		return fmt.Errorf("failed to initialize providers: %w", err)
	}

	// Charger les certificats existants
	if err := cm.loadExistingCertificates(); err != nil {
		return fmt.Errorf("failed to load existing certificates: %w", err)
	}

	cm.logger.Info("Certificate Manager initialized successfully")
	return nil
}

// Start démarre le gestionnaire de certificats
func (cm *CertificateManager) Start(ctx context.Context) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()

	if cm.isRunning {
		return nil
	}

	cm.logger.Info("Starting Certificate Manager")

	// Démarrer le monitor
	go cm.monitor.Start(ctx)

	// Démarrer le scheduler
	go cm.scheduler.Start(ctx)

	// Démarrer le monitoring périodique
	go cm.startPeriodicChecks(ctx)

	cm.isRunning = true
	cm.logger.Info("Certificate Manager started successfully")
	return nil
}

// Stop arrête le gestionnaire de certificats
func (cm *CertificateManager) Stop(ctx context.Context) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()

	if !cm.isRunning {
		return nil
	}

	cm.logger.Info("Stopping Certificate Manager")

	// Arrêter les composants
	cm.monitor.Stop()
	cm.scheduler.Stop()

	cm.isRunning = false
	cm.logger.Info("Certificate Manager stopped")
	return nil
}

// GetCertificate récupère un certificat par domaine
func (cm *CertificateManager) GetCertificate(domain string) (*Certificate, error) {
	cm.mu.RLock()
	defer cm.mu.RUnlock()

	cert, exists := cm.certStore[domain]
	if !exists {
		return nil, fmt.Errorf("certificate not found for domain: %s", domain)
	}

	return cert, nil
}

// RequestCertificate demande un nouveau certificat
func (cm *CertificateManager) RequestCertificate(ctx context.Context, domain string, aliases []string, contact string) (*Certificate, error) {
	cm.mu.Lock()
	defer cm.mu.Unlock()

	cm.logger.Info("Requesting certificate", zap.String("domain", domain))

	// Vérifier si le certificat existe déjà
	if cert, exists := cm.certStore[domain]; exists {
		if cert.Status == CertStatusValid && time.Until(cert.ExpiresAt) > cm.config.RenewalThreshold {
			cm.logger.Info("Certificate already exists and is valid", zap.String("domain", domain))
			return cert, nil
		}
	}

	// Obtenir le provider
	provider, err := cm.getProvider(cm.config.Provider)
	if err != nil {
		return nil, fmt.Errorf("failed to get provider: %w", err)
	}

	// Générer le certificat
	cert, err := provider.GenerateCertificate(ctx, domain, aliases, contact)
	if err != nil {
		return nil, fmt.Errorf("failed to generate certificate: %w", err)
	}

	// Stocker le certificat
	cm.certStore[domain] = cert

	// Sauvegarder sur disque
	if err := cm.saveCertificate(cert); err != nil {
		cm.logger.Error("Failed to save certificate", zap.Error(err))
	}

	cm.logger.Info("Certificate generated successfully", zap.String("domain", domain))
	return cert, nil
}

// RenewCertificate renouvelle un certificat
func (cm *CertificateManager) RenewCertificate(ctx context.Context, domain string) (*Certificate, error) {
	cm.mu.Lock()
	defer cm.mu.Unlock()

	cm.logger.Info("Renewing certificate", zap.String("domain", domain))

	cert, exists := cm.certStore[domain]
	if !exists {
		return nil, fmt.Errorf("certificate not found for domain: %s", domain)
	}

	// Obtenir le provider
	provider, err := cm.getProvider(cert.Provider)
	if err != nil {
		return nil, fmt.Errorf("failed to get provider: %w", err)
	}

	// Marquer comme en cours de renouvellement
	cert.Status = CertStatusRenewing

	// Renouveler le certificat
	newCert, err := provider.RenewCertificate(ctx, cert)
	if err != nil {
		cert.Status = CertStatusError
		return nil, fmt.Errorf("failed to renew certificate: %w", err)
	}

	// Remplacer le certificat
	cm.certStore[domain] = newCert

	// Sauvegarder sur disque
	if err := cm.saveCertificate(newCert); err != nil {
		cm.logger.Error("Failed to save renewed certificate", zap.Error(err))
	}

	cm.logger.Info("Certificate renewed successfully", zap.String("domain", domain))
	return newCert, nil
}

// RevokeCertificate révoque un certificat
func (cm *CertificateManager) RevokeCertificate(ctx context.Context, domain string) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()

	cm.logger.Info("Revoking certificate", zap.String("domain", domain))

	cert, exists := cm.certStore[domain]
	if !exists {
		return fmt.Errorf("certificate not found for domain: %s", domain)
	}

	// Obtenir le provider
	provider, err := cm.getProvider(cert.Provider)
	if err != nil {
		return fmt.Errorf("failed to get provider: %w", err)
	}

	// Révoquer le certificat
	if err := provider.RevokeCertificate(ctx, cert); err != nil {
		return fmt.Errorf("failed to revoke certificate: %w", err)
	}

	// Marquer comme révoqué
	cert.Status = CertStatusRevoked

	cm.logger.Info("Certificate revoked successfully", zap.String("domain", domain))
	return nil
}

// ListCertificates liste tous les certificats
func (cm *CertificateManager) ListCertificates() map[string]*Certificate {
	cm.mu.RLock()
	defer cm.mu.RUnlock()

	result := make(map[string]*Certificate)
	for k, v := range cm.certStore {
		result[k] = v
	}
	return result
}

// GetCertificateStatus retourne le statut d'un certificat
func (cm *CertificateManager) GetCertificateStatus(domain string) (CertificateStatus, error) {
	cm.mu.RLock()
	defer cm.mu.RUnlock()

	cert, exists := cm.certStore[domain]
	if !exists {
		return "", fmt.Errorf("certificate not found for domain: %s", domain)
	}

	return cert.Status, nil
}

// CheckCertificateExpiry vérifie l'expiration des certificats
func (cm *CertificateManager) CheckCertificateExpiry() ([]*Certificate, error) {
	cm.mu.RLock()
	defer cm.mu.RUnlock()

	var expiringCerts []*Certificate
	now := time.Now()

	for _, cert := range cm.certStore {
		timeUntilExpiry := cert.ExpiresAt.Sub(now)

		// Mettre à jour le statut
		if timeUntilExpiry <= 0 {
			cert.Status = CertStatusExpired
		} else if timeUntilExpiry <= cm.config.RenewalThreshold {
			cert.Status = CertStatusExpiring
			expiringCerts = append(expiringCerts, cert)
		} else {
			cert.Status = CertStatusValid
		}

		cert.LastChecked = now
	}

	return expiringCerts, nil
}

// Méthodes privées

func (cm *CertificateManager) initializeProviders() error {
	// Initialiser le provider Let's Encrypt
	letsEncryptProvider := NewLetsEncryptProvider(cm.logger)
	cm.providers["letsencrypt"] = letsEncryptProvider

	// Initialiser le provider self-signed
	selfSignedProvider := NewSelfSignedProvider(cm.logger)
	cm.providers["self-signed"] = selfSignedProvider

	return nil
}

func (cm *CertificateManager) loadExistingCertificates() error {
	// Charger les certificats depuis le store configuré
	// Implémentation simplifiée
	for _, domainConfig := range cm.config.Domains {
		if domainConfig.CertificatePath != "" {
			cert, err := cm.loadCertificateFromFile(domainConfig)
			if err != nil {
				cm.logger.Warn("Failed to load certificate from file",
					zap.String("domain", domainConfig.Domain),
					zap.Error(err))
				continue
			}
			cm.certStore[domainConfig.Domain] = cert
		}
	}
	return nil
}

func (cm *CertificateManager) loadCertificateFromFile(config DomainConfig) (*Certificate, error) {
	// Implémentation simplifiée - charger depuis fichier
	cert := &Certificate{
		Domain:      config.Domain,
		Aliases:     config.Aliases,
		Provider:    config.Provider,
		Status:      CertStatusValid,
		IssuedAt:    time.Now().AddDate(0, -1, 0), // 1 mois avant
		ExpiresAt:   time.Now().AddDate(0, 2, 0),  // 2 mois après
		LastChecked: time.Now(),
		AutoRenew:   config.AutoRenew,
		Contact:     config.Contact,
		Metadata:    make(map[string]interface{}),
	}
	return cert, nil
}

func (cm *CertificateManager) saveCertificate(cert *Certificate) error {
	// Sauvegarder le certificat selon la configuration
	// Implémentation simplifiée
	cm.logger.Info("Certificate saved", zap.String("domain", cert.Domain))
	return nil
}

func (cm *CertificateManager) getProvider(providerName string) (CertificateProvider, error) {
	provider, exists := cm.providers[providerName]
	if !exists {
		return nil, fmt.Errorf("provider not found: %s", providerName)
	}
	return provider, nil
}

func (cm *CertificateManager) startPeriodicChecks(ctx context.Context) {
	ticker := time.NewTicker(cm.config.CheckInterval)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			cm.performPeriodicCheck()
		case <-ctx.Done():
			return
		}
	}
}

func (cm *CertificateManager) performPeriodicCheck() {
	cm.logger.Debug("Performing periodic certificate check")

	// Vérifier l'expiration des certificats
	expiringCerts, err := cm.CheckCertificateExpiry()
	if err != nil {
		cm.logger.Error("Failed to check certificate expiry", zap.Error(err))
		return
	}

	// Planifier le renouvellement des certificats expirants
	for _, cert := range expiringCerts {
		if cert.AutoRenew {
			cm.scheduler.ScheduleRenewal(cert)
		}
	}
}

// CertificateMonitor methods

func (monitor *CertificateMonitor) Start(ctx context.Context) {
	monitor.mu.Lock()
	defer monitor.mu.Unlock()

	if monitor.isRunning {
		return
	}

	monitor.logger.Info("Starting Certificate Monitor")
	monitor.isRunning = true

	go monitor.monitorCertificates(ctx)
}

func (monitor *CertificateMonitor) Stop() {
	monitor.mu.Lock()
	defer monitor.mu.Unlock()

	monitor.isRunning = false
	monitor.logger.Info("Certificate Monitor stopped")
}

func (monitor *CertificateMonitor) monitorCertificates(ctx context.Context) {
	ticker := time.NewTicker(time.Hour)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			monitor.checkCertificateHealth()
		case <-ctx.Done():
			return
		}
	}
}

func (monitor *CertificateMonitor) checkCertificateHealth() {
	monitor.logger.Debug("Checking certificate health")

	certs := monitor.manager.ListCertificates()
	for domain, cert := range certs {
		// Vérifier la validité du certificat
		if err := monitor.validateCertificate(cert); err != nil {
			monitor.logger.Error("Certificate validation failed",
				zap.String("domain", domain),
				zap.Error(err))
			cert.Status = CertStatusError
		}
	}
}

func (monitor *CertificateMonitor) validateCertificate(cert *Certificate) error {
	// Validation basique du certificat
	if cert.Certificate != nil {
		now := time.Now()
		if now.Before(cert.Certificate.NotBefore) || now.After(cert.Certificate.NotAfter) {
			return fmt.Errorf("certificate is not valid for current time")
		}
	}
	return nil
}

// RenewalScheduler methods

func (scheduler *RenewalScheduler) Start(ctx context.Context) {
	scheduler.mu.Lock()
	defer scheduler.mu.Unlock()

	if scheduler.isRunning {
		return
	}

	scheduler.logger.Info("Starting Renewal Scheduler")
	scheduler.isRunning = true

	go scheduler.processRenewals(ctx)
}

func (scheduler *RenewalScheduler) Stop() {
	scheduler.mu.Lock()
	defer scheduler.mu.Unlock()

	scheduler.isRunning = false
	close(scheduler.renewalQueue)
	scheduler.logger.Info("Renewal Scheduler stopped")
}

func (scheduler *RenewalScheduler) ScheduleRenewal(cert *Certificate) {
	if !scheduler.isRunning {
		return
	}

	select {
	case scheduler.renewalQueue <- cert:
		scheduler.logger.Info("Certificate renewal scheduled", zap.String("domain", cert.Domain))
	default:
		scheduler.logger.Warn("Renewal queue is full", zap.String("domain", cert.Domain))
	}
}

func (scheduler *RenewalScheduler) processRenewals(ctx context.Context) {
	for {
		select {
		case cert := <-scheduler.renewalQueue:
			if cert != nil {
				scheduler.renewCertificate(ctx, cert)
			}
		case <-ctx.Done():
			return
		}
	}
}

func (scheduler *RenewalScheduler) renewCertificate(ctx context.Context, cert *Certificate) {
	scheduler.logger.Info("Processing certificate renewal", zap.String("domain", cert.Domain))

	_, err := scheduler.manager.RenewCertificate(ctx, cert.Domain)
	if err != nil {
		scheduler.logger.Error("Failed to renew certificate",
			zap.String("domain", cert.Domain),
			zap.Error(err))
	} else {
		scheduler.logger.Info("Certificate renewed successfully", zap.String("domain", cert.Domain))
	}
}
