package main

import (
	"crypto/tls"
	"crypto/x509"
	"flag"
	"log"
	"net/http"
	"net/http/httputil"
	"net/url"

	"github.com/dstotijn/gurp/pkg/proxy"
	"github.com/gorilla/mux"
)

var (
	caCertFile = flag.String("cert", "", "CA certificate file path")
	caKeyFile  = flag.String("key", "", "CA private key file path")
	dev        = flag.Bool("dev", false, "Run in development mode")
	adminPath  = flag.String("adminPath", "", "File path to admin build")
)

func main() {
	flag.Parse()

	tlsCA, err := tls.LoadX509KeyPair(*caCertFile, *caKeyFile)
	if err != nil {
		log.Fatalf("[FATAL] Could not load CA key pair: %v", err)
	}

	caCert, err := x509.ParseCertificate(tlsCA.Certificate[0])
	if err != nil {
		log.Fatalf("[FATAL] Could not parse CA: %v", err)
	}

	p, err := proxy.NewProxy(caCert, tlsCA.PrivateKey)
	if err != nil {
		log.Fatalf("[FATAL] Could not create Proxy: %v", err)
	}

	p.UseRequestModifier(func(next proxy.RequestModifyFunc) proxy.RequestModifyFunc {
		return func(req *http.Request) {
			log.Printf("[DEBUG] Incoming request: %v", req.URL)
			next(req)
		}
	})

	p.UseResponseModifier(func(next proxy.ResponseModifyFunc) proxy.ResponseModifyFunc {
		return func(res *http.Response) error {
			log.Printf("[DEBUG] Downstream response: %v %v %v", res.Proto, res.StatusCode, http.StatusText(res.StatusCode))
			return next(res)
		}
	})

	router := mux.NewRouter().SkipClean(true)
	adminRouter := router.Host("gurp.proxy")

	if *dev {
		adminURL, err := url.Parse("http://localhost:3000")
		if err != nil {
			log.Fatalf("[FATAL] Invalid admin URL: %v", err)
		}
		adminRouter.Handler(httputil.NewSingleHostReverseProxy(adminURL))
	} else {
		if *adminPath == "" {
			log.Fatal("[FATAL] `adminPath` must be set")
		}
		adminRouter.Handler(http.FileServer(http.Dir(*adminPath)))
	}

	router.PathPrefix("").Handler(p)

	s := &http.Server{
		Addr:         ":8080",
		Handler:      router,
		TLSNextProto: map[string]func(*http.Server, *tls.Conn, http.Handler){}, // Disable HTTP/2
	}

	err = s.ListenAndServe()
	if err != nil && err != http.ErrServerClosed {
		log.Fatalf("[FATAL] HTTP server closed: %v", err)
	}
}