package server

import (
	"context"
	"crypto/tls"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"time"

	"github.com/go-co-op/gocron/v2"
)

// Server represents an HTTP server.
type Server struct {
	srv             *http.Server
	logger          *slog.Logger
	cron            gocron.Scheduler
	cancel          context.CancelFunc
	disableTls      bool
	tlsCertFilename string
	tlsKeyFilename  string
	encryptionKey   string
}

// New creates a new server with the given logger, address and options.
func New(logger *slog.Logger, cron gocron.Scheduler, cancel context.CancelFunc, addr string, opts ...Option) *Server {

	// Set some options for TLS
	tlsConfig := &tls.Config{
		MinVersion:               tls.VersionTLS12,
		CurvePreferences:         []tls.CurveID{tls.CurveP521, tls.CurveP384, tls.CurveP256},
		PreferServerCipherSuites: true,
		InsecureSkipVerify:       true,
		CipherSuites: []uint16{
			tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
			tls.TLS_RSA_WITH_AES_256_GCM_SHA384,
			tls.TLS_RSA_WITH_AES_256_CBC_SHA,
		},
	}

	srv := &http.Server{
		Addr:         addr,
		WriteTimeout: 120 * time.Second,
		ReadTimeout:  30 * time.Second,
		TLSConfig:    tlsConfig,
		TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)),
	}

	// Set the initial server values
	server := &Server{
		srv:    srv,
		logger: logger,
		cron:   cron,
		cancel: cancel,
	}

	// Apply any options
	for _, opt := range opts {
		opt(server)
	}

	return server
}

// Option represents a server option.
type Option func(*Server)

// WithWriteTimeout sets the write timeout.
func WithWriteTimeout(timeout time.Duration) Option {
	return func(s *Server) {
		s.srv.WriteTimeout = timeout
	}
}

// WithReadTimeout sets the read timeout.
func WithReadTimeout(timeout time.Duration) Option {
	return func(s *Server) {
		s.srv.ReadTimeout = timeout
	}
}

// WithRouter sets the handler.
func WithRouter(handler http.Handler) Option {
	return func(s *Server) {
		s.srv.Handler = handler
	}
}

// SetKey sets the encryption key we use when generating secrets
func SetKey(key string) Option {
	return func(s *Server) {
		s.encryptionKey = key
	}
}

// SetTls sets the disable tls value
func SetTls(disableTls bool) Option {
	return func(s *Server) {
		s.disableTls = disableTls
	}
}

// SetCertificate sets the path to the certificate used for TLS, in PEM format
func SetCertificate(tlsCertFilename string) Option {
	return func(s *Server) {
		//fmt.Printf("Setting tlsCertFilename to '%s'\n", tlsCertFilename)
		s.tlsCertFilename = tlsCertFilename
	}
}

// SetPrivateKey sets the path to the private key used for TLS, in PEM format
func SetPrivateKey(tlsKeyFilename string) Option {
	return func(s *Server) {
		s.tlsKeyFilename = tlsKeyFilename
	}
}

// StartAndWait starts the server and waits for a signal to shut down.
func (s *Server) StartAndWait() {
	s.Start()
	s.GracefulShutdown()
}

// Start starts the server.
func (s *Server) Start() {

	go func() {
		if s.disableTls {
			s.logger.Info("starting server", "port", s.srv.Addr)
			if err := s.srv.ListenAndServe(); err != nil {
				s.logger.Error("failed to start server", "error", err)
				os.Exit(1)
			}
		} else {
			s.logger.Info("starting TLS server", "port", s.srv.Addr, "cert", s.tlsCertFilename, "key", s.tlsKeyFilename)
			if err := s.srv.ListenAndServeTLS(s.tlsCertFilename, s.tlsKeyFilename); err != nil && err != http.ErrServerClosed {
				s.logger.Error("failed to start server", "error", err)
				os.Exit(1)
			}
		}
	}()
}

// GracefulShutdown shuts down the server gracefully.
func (s *Server) GracefulShutdown() {
	c := make(chan os.Signal, 1)
	// We'll accept graceful shutdowns when quit via SIGINT (Ctrl+C)
	// SIGKILL, SIGQUIT or SIGTERM (Ctrl+/) will not be caught.
	signal.Notify(c, os.Interrupt)

	// Block until we receive our signal.
	<-c

	// Create a deadline to wait for.
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	// Doesn't block if no connections, but will otherwise wait
	// until the timeout deadline.
	_ = s.srv.Shutdown(ctx)

	s.logger.Info("runing cron shutdown")
	err := s.cron.Shutdown()
	if err != nil {
		s.logger.Error("error shutting cron", "error", err)
	}

	s.logger.Info("runing cancel")
	s.cancel()

	// Optionally, you could run srv.Shutdown in a goroutine and block on
	// <-ctx.Done() if your application should wait for other services
	// to finalize based on context cancellation.
	s.logger.Info("shutting down")
	//os.Exit(0)
}