package api

import (
	"context"
	"crypto/tls"
	"net"
	"net/http"
	"time"

	"git.giftfish.de/ston1th/haproxy-lb/pkg/api/types"
	serverv1 "git.giftfish.de/ston1th/haproxy-lb/pkg/api/v1/server"
	"git.giftfish.de/ston1th/haproxy-lb/pkg/config"
	"git.giftfish.de/ston1th/haproxy-lb/pkg/db"

	"git.giftfish.de/ston1th/netalloc"

	"github.com/go-logr/logr"
	"github.com/gorilla/mux"
)

// Server is the webapp and api server
type Server struct {
	srv *http.Server
	mux *mux.Router
	log logr.Logger

	Data *types.ContextData
	cidr string

	init         chan struct{}
	stop         chan struct{}
	stopKeyReset chan struct{}

	tlsConfig *tls.Config
	listen    net.Listener
}

type notFoundHandler struct {
	s *Server
}

func (nf *notFoundHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	types.NewContext(w, r, nf.s.Data, nf.s.log).NotFound()
}

// NewHTTPServer returns a new HTTPServer
func NewServer(c *config.Config, log logr.Logger) (*Server, error) {
	s := &Server{
		mux:  mux.NewRouter(),
		log:  log,
		cidr: c.VIP.Prefix,
		Data: &types.ContextData{},

		init:         make(chan struct{}),
		stop:         make(chan struct{}),
		stopKeyReset: make(chan struct{}),
	}
	s.Data.Auth = types.NewAuth(c.Server.BasicAuth)

	if c.Server.TLS != nil {
		cert, err := tls.LoadX509KeyPair(c.Server.TLS.Cert, c.Server.TLS.Key)
		if err != nil {
			return nil, err
		}
		s.tlsConfig = &tls.Config{
			MinVersion: tls.VersionTLS12,
			CipherSuites: []uint16{
				tls.TLS_AES_256_GCM_SHA384,
				tls.TLS_CHACHA20_POLY1305_SHA256,
				tls.TLS_AES_128_GCM_SHA256,
				tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
				tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
				tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
				tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
			},
			CurvePreferences: []tls.CurveID{
				tls.X25519,
				tls.CurveP384,
				tls.CurveP521,
			},
			PreferServerCipherSuites: true,
			Certificates:             []tls.Certificate{cert},
		}
		l, err := tls.Listen("tcp", c.Server.Listen, s.tlsConfig)
		if err != nil {
			return nil, err
		}
		s.listen = l
	} else {
		l, err := net.Listen("tcp", c.Server.Listen)
		if err != nil {
			return nil, err
		}
		s.listen = l
	}

	s.mux.NotFoundHandler = &notFoundHandler{s}
	for _, v := range serverv1.Routes {
		s.mux.HandleFunc(v.Path, s.contextWrapper(v.Handler)).Methods(v.Methods...)
	}
	s.start()
	return s, nil
}

func (s *Server) UpdateDB(db *db.DB) error {
	s.Data.DB = db
	if s.Data.Net == nil {
		na, err := netalloc.NewGenericAlloc(db, s.cidr)
		if err != nil {
			return err
		}
		s.Data.Net = na
		close(s.init)
	} else {
		s.Data.Net.SetStore(db)
	}
	return nil
}

func (s *Server) start() {
	s.srv = &http.Server{
		Handler:      s.mux,
		TLSConfig:    s.tlsConfig,
		ReadTimeout:  10 * time.Second,
		WriteTimeout: 10 * time.Second,
	}
	go func() {
		<-s.init
		err := s.srv.Serve(s.listen)
		if err != nil {
			s.log.Error(err, "")
		}
	}()
	return
}

func (s *Server) contextWrapper(h types.CtxHandler) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		h(types.NewContext(w, r, s.Data, s.log))
	}
}

// Stop stops listening for incoming connections and closes currently open connections
func (s *Server) Stop() {
	s.log.Info("stopping")
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
	defer cancel()
	err := s.srv.Shutdown(ctx)
	if err != nil {
		s.log.Error(err, "")
	}
	s.log.Info("stopped")
}