package main

import (
	"context"
	"crypto/tls"
	"crypto/x509"
	"encoding/base64"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"os/signal"
	"sync/atomic"
	"time"

	"github.com/go-openapi/runtime/client"
	"github.com/gorilla/csrf"
	hydra "github.com/ory/hydra-client-go/client"
	log "github.com/sirupsen/logrus"

	commonHandlers "git.cacert.org/oidc_login/common/handlers"
	commonServices "git.cacert.org/oidc_login/common/services"
	"git.cacert.org/oidc_login/idp/handlers"
	"git.cacert.org/oidc_login/idp/services"
)

func main() {
	logger := log.New()
	config, err := commonServices.ConfigureApplication(
		logger,
		"IDP",
		map[string]interface{}{
			"server.port":             3000,
			"server.name":             "login.cacert.localhost",
			"server.key":              "certs/idp.cacert.localhost.key",
			"server.certificate":      "certs/idp.cacert.localhost.crt.pem",
			"security.client.ca-file": "certs/client_ca.pem",
			"admin.url":               "https://hydra.cacert.localhost:4445/",
			"i18n.languages":          []string{"en", "de"},
		})
	if err != nil {
		log.Fatalf("error loading configuration: %v", err)
	}

	logger.Infoln("Server is starting")
	ctx := context.Background()

	ctx = commonServices.InitI18n(ctx, logger, config.Strings("i18n.languages"))
	services.AddMessages(ctx)

	adminURL, err := url.Parse(config.MustString("admin.url"))
	if err != nil {
		logger.Fatalf("error parsing admin URL: %v", err)
	}
	clientTransport := client.New(adminURL.Host, adminURL.Path, []string{adminURL.Scheme})
	adminClient := hydra.New(clientTransport, nil)

	ctx, err = services.InitDatabase(ctx, services.NewDatabaseParams(config.MustString("db.dsn")))
	if err != nil {
		logger.Fatalf("error initializing the database connection: %v", err)
	}

	handlerContext := context.WithValue(ctx, handlers.CtxAdminClient, adminClient.Admin)
	loginHandler, err := handlers.NewLoginHandler(handlerContext, logger)
	if err != nil {
		logger.Fatalf("error initializing login handler: %v", err)
	}
	consentHandler, err := handlers.NewConsentHandler(handlerContext, logger)
	if err != nil {
		logger.Fatalf("error initializing consent handler: %v", err)
	}
	logoutHandler := handlers.NewLogoutHandler(handlerContext, logger)
	logoutSuccessHandler := handlers.NewLogoutSuccessHandler()
	errorHandler := handlers.NewErrorHandler()
	staticFiles := http.FileServer(http.Dir("static"))

	router := http.NewServeMux()
	router.Handle("/login", loginHandler)
	router.Handle("/consent", consentHandler)
	router.Handle("/logout", logoutHandler)
	router.Handle("/error", errorHandler)
	router.Handle("/logout-successful", logoutSuccessHandler)
	router.Handle("/health", commonHandlers.NewHealthHandler())
	router.Handle("/images/", staticFiles)
	router.Handle("/css/", staticFiles)
	router.Handle("/js/", staticFiles)

	if err != nil {
		logger.Fatal(err)
	}

	csrfKey, err := base64.StdEncoding.DecodeString(config.MustString("security.csrf.key"))
	if err != nil {
		logger.Fatalf("could not parse CSRF key bytes: %v", err)
	}

	nextRequestId := func() string {
		return fmt.Sprintf("%d", time.Now().UnixNano())
	}

	tracing := commonHandlers.Tracing(nextRequestId)
	logging := commonHandlers.Logging(logger)
	hsts := commonHandlers.EnableHSTS()
	csrfProtect := csrf.Protect(
		csrfKey,
		csrf.Secure(true),
		csrf.SameSite(csrf.SameSiteStrictMode),
		csrf.MaxAge(600))
	errorMiddleware, err := commonHandlers.ErrorHandling(
		ctx,
		logger,
		"templates/idp",
	)
	if err != nil {
		logger.Fatalf("could not initialize request error handling: %v", err)
	}

	clientCertPool := x509.NewCertPool()
	pemBytes, err := ioutil.ReadFile(config.MustString("security.client.ca-file"))
	if err != nil {
		logger.Fatalf("could not load client CA certificates: %v", err)
	}
	clientCertPool.AppendCertsFromPEM(pemBytes)

	tlsConfig := &tls.Config{
		ServerName: config.String("server.name"),
		MinVersion: tls.VersionTLS12,
		ClientAuth: tls.VerifyClientCertIfGiven,
		ClientCAs:  clientCertPool,
	}
	server := &http.Server{
		Addr:         fmt.Sprintf("%s:%d", config.String("server.name"), config.Int("server.port")),
		Handler:      tracing(logging(hsts(errorMiddleware(csrfProtect(router))))),
		ReadTimeout:  20 * time.Second,
		WriteTimeout: 20 * time.Second,
		IdleTimeout:  30 * time.Second,
		TLSConfig:    tlsConfig,
	}

	done := make(chan bool)
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, os.Interrupt)

	go func() {
		<-quit
		logger.Infoln("Server is shutting down...")
		atomic.StoreInt32(&commonHandlers.Healthy, 0)

		ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
		defer cancel()

		server.SetKeepAlivesEnabled(false)
		if err := server.Shutdown(ctx); err != nil {
			logger.Fatalf("Could not gracefully shutdown the server: %v\n", err)
		}
		close(done)
	}()

	logger.Infof("Server is ready to handle requests at https://%s/", server.Addr)
	atomic.StoreInt32(&commonHandlers.Healthy, 1)
	if err := server.ListenAndServeTLS(
		config.String("server.certificate"), config.String("server.key"),
	); err != nil && err != http.ErrServerClosed {
		logger.Fatalf("Could not listen on %s: %v\n", server.Addr, err)
	}

	<-done
	logger.Infoln("Server stopped")
}