package ssl

import (
	"context"
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"fmt"
	"github.com/google/uuid"
	"math/big"
	"time"

	"go.uber.org/zap"
)

// LetsEncryptProvider provider pour Let's Encrypt
type LetsEncryptProvider struct {
	logger *zap.Logger
	config LetsEncryptConfig
}

// LetsEncryptConfig configuration Let's Encrypt
type LetsEncryptConfig struct {
	Endpoint string `yaml:"endpoint"`
	Email    string `yaml:"email"`
	KeySize  int    `yaml:"key_size"`
}

// SelfSignedProvider provider pour certificats auto-signés
type SelfSignedProvider struct {
	logger *zap.Logger
	config SelfSignedConfig
}

// SelfSignedConfig configuration auto-signés
type SelfSignedConfig struct {
	KeySize       int           `yaml:"key_size"`
	ValidDuration time.Duration `yaml:"valid_duration"`
	Organization  string        `yaml:"organization"`
	Country       string        `yaml:"country"`
}

// NewLetsEncryptProvider crée un nouveau provider Let's Encrypt
func NewLetsEncryptProvider(logger *zap.Logger) *LetsEncryptProvider {
	return &LetsEncryptProvider{
		logger: logger,
		config: LetsEncryptConfig{
			Endpoint: "https://acme-v02.api.letsencrypt.org/directory",
			KeySize:  2048,
		},
	}
}

// NewSelfSignedProvider crée un nouveau provider auto-signé
func NewSelfSignedProvider(logger *zap.Logger) *SelfSignedProvider {
	return &SelfSignedProvider{
		logger: logger,
		config: SelfSignedConfig{
			KeySize:       2048,
			ValidDuration: 365 * 24 * time.Hour, // 1 an
			Organization:  "Veza Platform",
			Country:       "US",
		},
	}
}

// LetsEncryptProvider implementation

func (lep *LetsEncryptProvider) GenerateCertificate(ctx context.Context, domain string, aliases []string, contact string) (*Certificate, error) {
	lep.logger.Info("Generating Let's Encrypt certificate", zap.String("domain", domain))

	// Simulation de génération avec Let's Encrypt
	// En production, utiliser une librairie comme golang.org/x/crypto/acme
	cert := &Certificate{
		ID:          fmt.Sprintf("le_%s_%d", domain, uuid.New()),
		Domain:      domain,
		Aliases:     aliases,
		Provider:    "letsencrypt",
		Status:      CertStatusValid,
		IssuedAt:    time.Now(),
		ExpiresAt:   time.Now().Add(90 * 24 * time.Hour), // Let's Encrypt: 90 jours
		LastChecked: time.Now(),
		AutoRenew:   true,
		Contact:     contact,
		Metadata: map[string]interface{}{
			"issuer":   "Let's Encrypt Authority X3",
			"key_size": lep.config.KeySize,
		},
	}

	lep.logger.Info("Let's Encrypt certificate generated", zap.String("domain", domain))
	return cert, nil
}

func (lep *LetsEncryptProvider) RenewCertificate(ctx context.Context, cert *Certificate) (*Certificate, error) {
	lep.logger.Info("Renewing Let's Encrypt certificate", zap.String("domain", cert.Domain))

	// Simulation de renouvellement
	newCert := &Certificate{
		ID:          fmt.Sprintf("le_%s_%d", cert.Domain, uuid.New()),
		Domain:      cert.Domain,
		Aliases:     cert.Aliases,
		Provider:    "letsencrypt",
		Status:      CertStatusValid,
		IssuedAt:    time.Now(),
		ExpiresAt:   time.Now().Add(90 * 24 * time.Hour), // 90 jours
		LastChecked: time.Now(),
		AutoRenew:   cert.AutoRenew,
		Contact:     cert.Contact,
		Metadata: map[string]interface{}{
			"issuer":       "Let's Encrypt Authority X3",
			"key_size":     lep.config.KeySize,
			"renewed_from": cert.ID,
		},
	}

	lep.logger.Info("Let's Encrypt certificate renewed", zap.String("domain", cert.Domain))
	return newCert, nil
}

func (lep *LetsEncryptProvider) RevokeCertificate(ctx context.Context, cert *Certificate) error {
	lep.logger.Info("Revoking Let's Encrypt certificate", zap.String("domain", cert.Domain))

	// Simulation de révocation
	// En production, utiliser l'API ACME pour révoquer

	lep.logger.Info("Let's Encrypt certificate revoked", zap.String("domain", cert.Domain))
	return nil
}

func (lep *LetsEncryptProvider) ValidateCertificate(ctx context.Context, cert *Certificate) error {
	if cert.Provider != "letsencrypt" {
		return fmt.Errorf("certificate is not from Let's Encrypt")
	}

	if time.Until(cert.ExpiresAt) <= 0 {
		return fmt.Errorf("certificate has expired")
	}

	return nil
}

func (lep *LetsEncryptProvider) GetCertificateInfo(ctx context.Context, domain string) (*Certificate, error) {
	// Simulation de récupération d'info
	return nil, fmt.Errorf("certificate info not available")
}

// SelfSignedProvider implementation

func (ssp *SelfSignedProvider) GenerateCertificate(ctx context.Context, domain string, aliases []string, contact string) (*Certificate, error) {
	ssp.logger.Info("Generating self-signed certificate", zap.String("domain", domain))

	// Générer une clé privée
	privateKey, err := rsa.GenerateKey(rand.Reader, ssp.config.KeySize)
	if err != nil {
		return nil, fmt.Errorf("failed to generate private key: %w", err)
	}

	// Créer le template de certificat
	template := x509.Certificate{
		SerialNumber: big.NewInt(1),
		Subject: pkix.Name{
			Organization:  []string{ssp.config.Organization},
			Country:       []string{ssp.config.Country},
			Province:      []string{""},
			Locality:      []string{""},
			StreetAddress: []string{""},
			PostalCode:    []string{""},
			CommonName:    domain,
		},
		NotBefore:             time.Now(),
		NotAfter:              time.Now().Add(ssp.config.ValidDuration),
		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
		DNSNames:              append([]string{domain}, aliases...),
	}

	// Générer le certificat
	certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &privateKey.PublicKey, privateKey)
	if err != nil {
		return nil, fmt.Errorf("failed to create certificate: %w", err)
	}

	// Parser le certificat
	x509Cert, err := x509.ParseCertificate(certDER)
	if err != nil {
		return nil, fmt.Errorf("failed to parse certificate: %w", err)
	}

	cert := &Certificate{
		ID:          fmt.Sprintf("ss_%s_%d", domain, uuid.New()),
		Domain:      domain,
		Aliases:     aliases,
		Provider:    "self-signed",
		Certificate: x509Cert,
		PrivateKey:  privateKey,
		PEMData:     certDER,
		Status:      CertStatusValid,
		IssuedAt:    time.Now(),
		ExpiresAt:   time.Now().Add(ssp.config.ValidDuration),
		LastChecked: time.Now(),
		AutoRenew:   false, // Auto-renew désactivé par défaut pour auto-signé
		Contact:     contact,
		Metadata: map[string]interface{}{
			"issuer":      "Self-Signed",
			"key_size":    ssp.config.KeySize,
			"algorithm":   "RSA",
			"self_signed": true,
		},
	}

	ssp.logger.Info("Self-signed certificate generated", zap.String("domain", domain))
	return cert, nil
}

func (ssp *SelfSignedProvider) RenewCertificate(ctx context.Context, cert *Certificate) (*Certificate, error) {
	ssp.logger.Info("Renewing self-signed certificate", zap.String("domain", cert.Domain))

	// Pour auto-signé, on génère un nouveau certificat
	return ssp.GenerateCertificate(ctx, cert.Domain, cert.Aliases, cert.Contact)
}

func (ssp *SelfSignedProvider) RevokeCertificate(ctx context.Context, cert *Certificate) error {
	ssp.logger.Info("Revoking self-signed certificate", zap.String("domain", cert.Domain))

	// Pour auto-signé, pas de révocation réelle nécessaire
	// Juste marquer comme révoqué

	ssp.logger.Info("Self-signed certificate revoked", zap.String("domain", cert.Domain))
	return nil
}

func (ssp *SelfSignedProvider) ValidateCertificate(ctx context.Context, cert *Certificate) error {
	if cert.Provider != "self-signed" {
		return fmt.Errorf("certificate is not self-signed")
	}

	if time.Until(cert.ExpiresAt) <= 0 {
		return fmt.Errorf("certificate has expired")
	}

	return nil
}

func (ssp *SelfSignedProvider) GetCertificateInfo(ctx context.Context, domain string) (*Certificate, error) {
	// Simulation de récupération d'info
	return nil, fmt.Errorf("certificate info not available for self-signed")
}