package adapter

import (
	"crypto/tls"
	"crypto/x509"
	"errors"
	"os"

	"github.com/apache/pulsar-client-go/pulsar"
	"github.com/apache/pulsar-client-go/pulsar/auth"

	"go.yandata.net/iod/iod/trustlog-sdk/api/logger"
)

// tlsConfigProvider defines the interface for TLS configuration.
type tlsConfigProvider interface {
	GetTLSTrustCertsFilePath() string
	GetTLSCertificateFilePath() string
	GetTLSKeyFilePath() string
	GetTLSAllowInsecureConnection() bool
}

// configureTLSForClient configures TLS/mTLS settings for the Pulsar client.
func configureTLSForClient(opts *pulsar.ClientOptions, config tlsConfigProvider, logger logger.Logger) error {
	// If no TLS configuration is provided, skip TLS setup
	if config.GetTLSTrustCertsFilePath() == "" &&
		config.GetTLSCertificateFilePath() == "" &&
		config.GetTLSKeyFilePath() == "" {
		return nil
	}

	// Configure TLS trust certificates
	if config.GetTLSTrustCertsFilePath() != "" {
		if _, err := os.ReadFile(config.GetTLSTrustCertsFilePath()); err != nil {
			return errors.Join(err, errors.New("failed to read TLS trust certificates file"))
		}
		opts.TLSTrustCertsFilePath = config.GetTLSTrustCertsFilePath()
		logger.Debug(
			"TLS trust certificates configured",
			"path", config.GetTLSTrustCertsFilePath(),
		)
	}

	// Configure TLS allow insecure connection
	opts.TLSAllowInsecureConnection = config.GetTLSAllowInsecureConnection()

	// Configure mTLS authentication if both certificate and key are provided
	if config.GetTLSCertificateFilePath() != "" && config.GetTLSKeyFilePath() != "" {
		// Load client certificate and key
		cert, err := tls.LoadX509KeyPair(
			config.GetTLSCertificateFilePath(),
			config.GetTLSKeyFilePath(),
		)
		if err != nil {
			return errors.Join(err, errors.New("failed to load client certificate and key"))
		}

		// Create TLS authentication provider
		// Pulsar Go client uses auth.NewAuthenticationTLS with certificate and key file paths
		tlsAuth := auth.NewAuthenticationTLS(
			config.GetTLSCertificateFilePath(),
			config.GetTLSKeyFilePath(),
		)

		opts.Authentication = tlsAuth
		logger.Debug(
			"mTLS authentication configured",
			"cert", config.GetTLSCertificateFilePath(),
			"key", config.GetTLSKeyFilePath(),
		)

		// Verify the certificate is valid
		if _, parseErr := x509.ParseCertificate(cert.Certificate[0]); parseErr != nil {
			return errors.Join(parseErr, errors.New("invalid client certificate"))
		}
	} else if config.GetTLSCertificateFilePath() != "" || config.GetTLSKeyFilePath() != "" {
		return errors.New(
			"both TLS certificate and key file paths must be provided for mTLS authentication",
		)
	}

	return nil
}

// GetTLSTrustCertsFilePath returns the TLS trust certificates file path for PublisherConfig.
func (c PublisherConfig) GetTLSTrustCertsFilePath() string {
	return c.TLSTrustCertsFilePath
}

// GetTLSCertificateFilePath returns the TLS certificate file path for PublisherConfig.
func (c PublisherConfig) GetTLSCertificateFilePath() string {
	return c.TLSCertificateFilePath
}

// GetTLSKeyFilePath returns the TLS key file path for PublisherConfig.
func (c PublisherConfig) GetTLSKeyFilePath() string {
	return c.TLSKeyFilePath
}

// GetTLSAllowInsecureConnection returns whether to allow insecure TLS connections for PublisherConfig.
func (c PublisherConfig) GetTLSAllowInsecureConnection() bool {
	return c.TLSAllowInsecureConnection
}

// GetTLSTrustCertsFilePath returns the TLS trust certificates file path for SubscriberConfig.
func (c SubscriberConfig) GetTLSTrustCertsFilePath() string {
	return c.TLSTrustCertsFilePath
}

// GetTLSCertificateFilePath returns the TLS certificate file path for SubscriberConfig.
func (c SubscriberConfig) GetTLSCertificateFilePath() string {
	return c.TLSCertificateFilePath
}

// GetTLSKeyFilePath returns the TLS key file path for SubscriberConfig.
func (c SubscriberConfig) GetTLSKeyFilePath() string {
	return c.TLSKeyFilePath
}

// GetTLSAllowInsecureConnection returns whether to allow insecure TLS connections for SubscriberConfig.
func (c SubscriberConfig) GetTLSAllowInsecureConnection() bool {
	return c.TLSAllowInsecureConnection
}