package main

import (
	"converge/pkg/comms"
	"converge/pkg/models"
	"converge/pkg/server/converge"
	"converge/pkg/support/websocketutil"
	"fmt"
	"log"
	"math/rand"
	"net"
	"net/http"
	_ "net/http/pprof"
	"os"
	"regexp"
	"strconv"
	"strings"
	_ "time/tzdata"
)

func parsePublicId(path string) (publicId string, _ error) {
	pattern := regexp.MustCompile("^/[^/]+/([^/]+)$")
	matches := pattern.FindStringSubmatch(path)
	if len(matches) != 2 {
		return "", fmt.Errorf("Invalid URL path '%s'", path)
	}
	return matches[1], nil
}

func catchAllHandler(w http.ResponseWriter, r *http.Request) {
	http.Redirect(w, r, "/docs", http.StatusFound)
	return
}

func printHelp(msg string) {
	if msg != "" {
		fmt.Fprintf(os.Stderr, "ERROR: %s\n\n", msg)
	}
	helpText := "Usage: converge [options]\n" +
		"\n" +
		"Converge server is a rendez-vous server for debugging continuous integration\n" +
		"jobs be providing the capability to log into the agents where jobs are running.\n" +
		"This is achieve by starting an agent in the continuous integration job\n" +
		"which connects to Converge using a websocket connection. The end user also connects\n" +
		"to Converge using ssh over websockets. The server then matches the end-user with\n" +
		"the agent running in the continous integration job (the rendez-vous) and sets up\n" +
		"an end-to-end SSH connection between end-user and agent, with the agent providing\n" +
		"an embedded SSH server to provide interactive access to the end-user. This works\n" +
		"both on linux and on windows.\n" +
		"\n" +
		"-d <contentdir>: directory where static content of converge is placed"
	fmt.Fprintln(os.Stderr, helpText)
	os.Exit(1)
}

func main() {

	downloadDir := "../static"

	args := os.Args[1:]
	for len(args) > 0 && strings.HasPrefix(args[0], "-") {
		switch args[0] {
		case "-d":
			if len(args) <= 1 {
				printHelp("The -d option expects an argument")
			}
			downloadDir = args[1]
			args = args[1:]
		default:
			printHelp("Unknown option " + args[0])
		}
		args = args[1:]
	}
	log.Println("Content directory", downloadDir)

	if len(args) != 0 {
		printHelp("")
	}

	userPassword := comms.UserPassword{
		Username: strconv.Itoa(rand.Int()),
		Password: strconv.Itoa(rand.Int()),
	}

	username, ok := os.LookupEnv("CONVERGE_USERNAME")
	if ok {
		userPassword.Username = username
	} else {
		os.Setenv("CONVERGE_USERNAME", userPassword.Username)
	}

	password, ok := os.LookupEnv("CONVERGE_PASSWORD")
	if ok {
		userPassword.Password = password
	} else {
		os.Setenv("CONVERGE_PASSWORD", userPassword.Password)
	}

	log.Printf("Using username '%s' and password '%s'", userPassword.Username, userPassword.Password)

	notifications := make(chan *models.State, 10)
	admin := converge.NewAdmin(notifications)
	websessions := converge.NewWebSessions(notifications)

	// For agents connecting
	registrationService := websocketutil.WebSocketService{
		Handler: func(w http.ResponseWriter, r *http.Request, conn net.Conn) {
			publicId, err := parsePublicId(r.URL.Path)
			if err != nil {
				log.Printf("Cannot parse public id from url: '%v'\n", err)
				return
			}
			log.Printf("Got registration connection: '%s'\n", publicId)
			err = admin.Register(publicId, conn,
				userPassword)
			if err != nil {
				log.Printf("Error %v\n", err)
			}
		},
	}

	// For users connecting with ssh
	clientService := websocketutil.WebSocketService{
		Handler: func(w http.ResponseWriter, r *http.Request, conn net.Conn) {
			publicId, err := parsePublicId(r.URL.Path)
			if err != nil {
				log.Printf("Cannot parse public id from url: '%v'\n", err)
				return
			}
			log.Printf("Got client connection: '%s'\n", publicId)
			err = admin.Connect(publicId, conn)
			if err != nil {
				log.Printf("Error %v\n", err)
			}
		},
	}

	// for the web browser getting live status updates.
	sessionService := websocketutil.WebSocketService{
		Handler: func(w http.ResponseWriter, r *http.Request, conn net.Conn) {
			websession := websessions.NewSession(conn)
			defer websessions.SessionClosed(websession)
			location, err := converge.GetUserLocation(r)
			if err != nil {
				panic(err)
			}
			websession.WriteNotifications(location)
		},
		Text: true,
	}

	// websocket endpoints
	http.HandleFunc("/agent/", registrationService.Handle)
	http.HandleFunc("/client/", clientService.Handle)
	http.HandleFunc("/ws/sessions", sessionService.Handle)

	// create filehandler with templating for html files.
	http.Handle("/docs/", http.StripPrefix("/docs/", http.HandlerFunc(pageHandler)))
	http.Handle("/static/", http.StripPrefix("/static/",
		http.FileServer(http.Dir(downloadDir))))
	http.HandleFunc("/", catchAllHandler)

	// Start HTTP server
	fmt.Println("Rendez-vous server listening on :8000")
	log.Fatal(http.ListenAndServe(":8000", nil))
}