package main

import (
	"bufio"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/unixvoid/glogger"
	"golang.org/x/crypto/sha3"
	"gopkg.in/gcfg.v1"
	"gopkg.in/redis.v5"
)

type Config struct {
	NethackLauncher struct {
		Loglevel       string
		ServerDisplay  string
		NethackVersion string
		HackDir        string
		NhdatLocation  string
		BootstrapDelay time.Duration
	}

	Redis struct {
		Host     string
		Password string
	}
}

var (
	config = Config{}
	wg     sync.WaitGroup
)

func main() {
	// read conf file
	readConf()
	// init config file and logger
	initLogger()
	// init redis connection
	redisClient, redisErr := initRedisConnection()
	if redisErr != nil {
		glogger.Debug.Printf("redis connection cannot be made, trying again in %s second(s)\n", config.NethackLauncher.BootstrapDelay*time.Second)
		time.Sleep(config.NethackLauncher.BootstrapDelay * time.Second)
		redisClient, redisErr = initRedisConnection()
		if redisErr != nil {
			glogger.Error.Println("redis connection cannot be made, exiting.")
			panic(redisErr)
		}
	} else {
		glogger.Debug.Println("connection to redis succeeded.")
	}

	// create initial files needed by nethack
	createInitialFiles()

	// start janitor
	go janitor(redisClient)

	// start homescreen
	screenFunction := printWelcomeScreen(redisClient)
	fmt.Printf("screen %s recieved\n", screenFunction)
}

func readConf() {
	// init config file
	err := gcfg.ReadFileInto(&config, "config.gcfg")
	if err != nil {
		panic(fmt.Sprintf("Could not load config.gcfg, error: %s\n", err))
	}
}

func initLogger() {
	// init logger
	if config.NethackLauncher.Loglevel == "debug" {
		glogger.LogInit(os.Stdout, os.Stdout, os.Stdout, os.Stderr)
	} else if config.NethackLauncher.Loglevel == "cluster" {
		glogger.LogInit(os.Stdout, os.Stdout, ioutil.Discard, os.Stderr)
	} else if config.NethackLauncher.Loglevel == "info" {
		glogger.LogInit(os.Stdout, ioutil.Discard, ioutil.Discard, os.Stderr)
	} else {
		glogger.LogInit(ioutil.Discard, ioutil.Discard, ioutil.Discard, os.Stderr)
	}
}

func initRedisConnection() (*redis.Client, error) {
	// init redis connection
	redisClient := redis.NewClient(&redis.Options{
		Addr:     config.Redis.Host,
		Password: config.Redis.Password,
		DB:       0,
	})

	_, redisErr := redisClient.Ping().Result()
	return redisClient, redisErr
}

func checkFiles() {
	// make sure record file exists
	if _, err := os.Stat(fmt.Sprintf("%s/record", config.NethackLauncher.HackDir)); os.IsNotExist(err) {
		glogger.Info.Printf("record file not found in %s/record\n", config.NethackLauncher.HackDir)
		fmt.Printf("%s\n", err)
		os.Exit(1)
	}
	// make sure initial rcfile exists
	hackRCLoc := fmt.Sprintf("%s/.nethackrc", config.NethackLauncher.HackDir)
	if _, err := os.Stat(hackRCLoc); os.IsNotExist(err) {
		glogger.Info.Printf("initial config file not found at: %s\n", hackRCLoc)
		fmt.Printf("%s\n", err)
		os.Exit(1)
	}
}

func clearScreen() {
	cmd := exec.Command("clear")
	cmd.Stdout = os.Stdout
	cmd.Run()
}

func printWelcomeScreen(redisClient *redis.Client) string {
	clearScreen()
	fmt.Printf(" %s\n", config.NethackLauncher.ServerDisplay)
	println("")
	println(" Not logged in.")
	println("")
	println(" l) Login")
	println(" r) Register new user")
	println(" w) Watch games in progress")
	println(" h) View highscores")
	println(" q) Quit")
	println("")
	fmt.Printf(">> ")

	// disable input buffering
	exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()
	// do not display entered characters on the screen
	exec.Command("stty", "-F", "/dev/tty", "-echo").Run()

	var b []byte = make([]byte, 1)
	for {
		os.Stdin.Read(b)
		switch string(b) {
		case "l":
			// restart display
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			printLoginScreen(redisClient)
		case "r":
			// restart display
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			printRegisterScreen(redisClient)
		case "w":
			clearScreen()
			printProgressScreen(redisClient, "")
		case "h":
			clearScreen()
			printHighScores(redisClient, "")
		case "q":
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			os.Exit(0)
		default:
		}
	}
}

func printUserScreen(redisClient *redis.Client, username string) string {
	clearScreen()
	fmt.Printf(" %s\n", config.NethackLauncher.ServerDisplay)
	println("")
	fmt.Printf(" Logged in as: %s\n", username)
	println("")
	println(" l) Logout")
	println(" w) Watch games in progress")
	println(" h) View highscores")
	println(" e) Edit config")
	fmt.Printf(" p) Play NetHack %s\n", config.NethackLauncher.NethackVersion)
	println(" q) Quit")
	println("")
	fmt.Printf(">> ")

	// disable input buffering
	exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()
	// do not display entered characters on the screen
	exec.Command("stty", "-F", "/dev/tty", "-echo").Run()

	var b []byte = make([]byte, 1)
	for {
		os.Stdin.Read(b)
		switch string(b) {
		case "l":
			// restart display
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			printWelcomeScreen(redisClient)
		case "e":
			hackRCLoc := fmt.Sprintf("%s/user/%s/.nethackrc", config.NethackLauncher.HackDir, username)
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			nh := exec.Command("vim", "-Z", hackRCLoc)
			nh.Stdout = os.Stdout
			nh.Stdin = os.Stdin
			nh.Stderr = os.Stderr
			nh.Run()
			clearScreen()
			printUserScreen(redisClient, username)
		case "w":
			clearScreen()
			printProgressScreen(redisClient, username)
		case "h":
			clearScreen()
			printHighScores(redisClient, username)
		case "p":
			wg.Add(1)
			currentTime := time.Now().UTC()
			fulltime := currentTime.Format("2006-01-02.03:04:05")
			go runGame(username, fulltime)
			watcher := startWatcher(username, fulltime, redisClient)
			wg.Wait()
			fmt.Println("CLOSING")
			close(watcher)
			printUserScreen(redisClient, username)
		case "q":
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			os.Exit(0)
		default:
		}
	}
}

func printLoginScreen(redisClient *redis.Client) {
	fmt.Printf(" %s\n", config.NethackLauncher.ServerDisplay)
	println("")
	println(" Please enter your username. (blank entry aborts)")
	println("")
	fmt.Printf(">> ")

	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		if scanner.Text() == "" {
			printWelcomeScreen(redisClient)
		}

		// check redis for user
		username := scanner.Text()
		storedHash, err := redisClient.Get(fmt.Sprintf("user:%s", username)).Result()
		if err != nil {
			// user does not exist
			fmt.Printf(" There was a problem with your last entry.\n>> ")
		} else {
			// get password from user and compare
			// turn off echo display
			exec.Command("stty", "-F", "/dev/tty", "-echo").Run()

			noPass := true
			for noPass {
				fmt.Printf("\n Please enter your password (blank entry aborts).\n>> ")
				reader := bufio.NewReader(os.Stdin)

				typedAuth, _ := reader.ReadString('\n')
				typedAuth = strings.Replace(typedAuth, "\n", "", -1)

				if typedAuth == "" {
					// exit to main menu
					printWelcomeScreen(redisClient)
				}

				// get hash of typedAuth
				typedHash := sha3.Sum512([]byte(typedAuth))
				if fmt.Sprintf("%x", typedHash) == storedHash {
					// user authed
					printUserScreen(redisClient, username)
					noPass = false
				} else {
					fmt.Printf("\n There was a problem with your last entry.")
				}
			}
		}
	}
	if err := scanner.Err(); err != nil {
		fmt.Printf("%s\n", err)
	}
}

func printRegisterScreen(redisClient *redis.Client) {
	// TODO : configure password restriction checking
	fmt.Printf(" %s\n", config.NethackLauncher.ServerDisplay)
	println("")
	println(" Welcome new user. Please enter a username")
	println(" Only characters and numbers are allowed, with no spaces.")
	println(" 20 characters max. (blank entry aborts)")
	println("")
	fmt.Printf(">> ")

	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		if scanner.Text() == "" {
			printWelcomeScreen(redisClient)
		}

		// check redis for user
		username := scanner.Text()
		_, err := redisClient.Get(fmt.Sprintf("user:%s", username)).Result()
		if err != redis.Nil {
			// user already exists
			fmt.Printf("There was a problem with your last entry.\n>> ")
		} else {
			// set up user

			// turn off echo display
			exec.Command("stty", "-F", "/dev/tty", "-echo").Run()
			reader := bufio.NewReader(os.Stdin)

			noPass := true
			sec := ""
			for noPass {
				// pull pass the first time
				fmt.Printf(" Please enter your password (blank entry aborts).\n>> ")
				sec0, _ := reader.ReadString('\n')
				sec0 = strings.Replace(sec0, "\n", "", -1)
				if sec0 == "" {
					printWelcomeScreen(redisClient)
				}

				// pull pass the second time
				fmt.Printf("\n Please enter your password again.\n>> ")
				sec1, _ := reader.ReadString('\n')
				sec1 = strings.Replace(sec1, "\n", "", -1)

				// make sure passwords match
				if sec0 == sec1 {
					sec = sec0
					noPass = false
				} else {
					fmt.Println("Lets try that again.")
				}
			}

			// reset display
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()

			// set user in redis
			secHash := sha3.Sum512([]byte(sec))
			redisClient.Set(fmt.Sprintf("user:%s", username), fmt.Sprintf("%x", secHash), 0).Err()

			// create user directories
			userPath := fmt.Sprintf("%s/user/%s/ttyrec/", config.NethackLauncher.HackDir, username)
			exec.Command("mkdir", "-p", userPath).Run()

			// copy in rc file
			hackRCLoc := fmt.Sprintf("%s/.nethackrc", config.NethackLauncher.HackDir)
			hackRCDest := fmt.Sprintf("%s/user/%s/.nethackrc", config.NethackLauncher.HackDir, username)
			exec.Command("cp", hackRCLoc, hackRCDest).Run()

			// back to main screen
			printUserScreen(redisClient, username)
		}
	}
	if err := scanner.Err(); err != nil {
		fmt.Printf("%s\n", err)
	}
}

func printProgressScreen(redisClient *redis.Client, username string) {
	// print header
	fmt.Printf(" %s\n", config.NethackLauncher.ServerDisplay)
	println("")

	// check directory for live players
	isNotEmpty, err := redisClient.Exists("inprogress").Result()
	if err != nil {
		panic(err)
	}
	if isNotEmpty {
		println(" Choose a player to spectate ('enter' without selection returns)")
	} else {
		println(" No live players currently (blank entry returns)")
	}
	println("")

	inProg := make(map[int]string)
	inProgTimer := 1
	inprogress, err := redisClient.SMembers("inprogress").Result()
	if err != nil {
		panic(err)
	}
	for _, i := range inprogress {
		// loop through users
		fmt.Printf(" %d) %s\n", inProgTimer, i)

		// add user to line map
		inProg[inProgTimer] = i
		inProgTimer++
	}

	println("")
	fmt.Printf(">> ")
	// start user input

	// disable input buffering
	exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()
	// do not display entered characters on the screen
	exec.Command("stty", "-F", "/dev/tty", "-echo").Run()

	var b []byte = make([]byte, 1)
	for {
		os.Stdin.Read(b)
		s, _ := strconv.Atoi(string(b))

		// check if user is trying to navigate
		if string(b) == "\n" {
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			if username == "" {
				printWelcomeScreen(redisClient)
			} else {
				printUserScreen(redisClient, username)
			}
		}

		// check if selection is in out map
		if inProg[s] != "" {
			user := strings.Split(inProg[s], ":")
			fmt.Printf("going to spectate '%s'\n", user[0])

			// set ttyrec path
			ttyName, _ := redisClient.Get(fmt.Sprintf("inprogress:%s", user[0])).Result()
			ttyrecPath := fmt.Sprintf("%s/user/%s/ttyrec/%s.ttyrec", config.NethackLauncher.HackDir, user[0], ttyName)

			// restart display
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			nh := exec.Command("ttyplay", "-p", ttyrecPath)
			nh.Stdout = os.Stdout
			nh.Stdin = os.Stdin
			nh.Stderr = os.Stderr
			nh.Run()
			if username == "" {
				printWelcomeScreen(redisClient)
			} else {
				printUserScreen(redisClient, username)
			}
			// TODO fix bug where user has to <ctrl-c> when game exists
		}
	}
}

func runGame(username, timestamp string) {
	// put together users home dir
	homeDir := fmt.Sprintf("%s/user/%s/", config.NethackLauncher.HackDir, username)
	nhCommand := fmt.Sprintf("HOME=%s nethack -d %s -u %s\n", homeDir, config.NethackLauncher.HackDir, username)
	ttyrecPath := fmt.Sprintf("%s/user/%s/ttyrec/%s.ttyrec", config.NethackLauncher.HackDir, username, timestamp)
	exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
	clearScreen()
	nh := exec.Command("ttyrec", ttyrecPath, "-e", nhCommand)
	nh.Stdout = os.Stdout
	nh.Stdin = os.Stdin
	nh.Stderr = os.Stderr
	nh.Run()
	exec.Command("exit").Run()
	wg.Done()
}

func startWatcher(username, timestamp string, redisClient *redis.Client) chan struct{} {
	// create initial keys
	redisClient.SAdd("inprogress", username)
	redisClient.Set(fmt.Sprintf("inprogress:%s", username), timestamp, 0)

	ch := make(chan struct{})
	// enter inital inprogress yet
	go func() {
		for {
			select {
			case <-ch:
				return
			default:
				redisClient.Expire(fmt.Sprintf("inprogress:%s", username), 10*time.Second)
				time.Sleep(8 * time.Second)
			}
		}
	}()
	return ch
}

func createInitialFiles() {
	// create necessary directories if they dont exist
	if _, err := os.Stat(config.NethackLauncher.HackDir); os.IsNotExist(err) {
		os.Mkdir(config.NethackLauncher.HackDir, os.ModeDir)
	}
	if _, err := os.Stat(fmt.Sprintf("%s/dumps/", config.NethackLauncher.HackDir)); os.IsNotExist(err) {
		os.Mkdir(fmt.Sprintf("%s/dumps/", config.NethackLauncher.HackDir), os.ModeDir)
	}
	if _, err := os.Stat(fmt.Sprintf("%s/save/", config.NethackLauncher.HackDir)); os.IsNotExist(err) {
		os.Mkdir(fmt.Sprintf("%s/save/", config.NethackLauncher.HackDir), os.ModeDir)
	}

	// create necessary files if they dont exist
	os.OpenFile(fmt.Sprintf("%s/logfile", config.NethackLauncher.HackDir), os.O_RDONLY|os.O_CREATE, 0666)
	os.OpenFile(fmt.Sprintf("%s/perm", config.NethackLauncher.HackDir), os.O_RDONLY|os.O_CREATE, 0666)
	os.OpenFile(fmt.Sprintf("%s/record", config.NethackLauncher.HackDir), os.O_RDONLY|os.O_CREATE, 0666)
	os.OpenFile(fmt.Sprintf("%s/xlogfile", config.NethackLauncher.HackDir), os.O_RDONLY|os.O_CREATE, 0666)

	// move in nhdat file if it does not exist
	if _, err := os.Stat(fmt.Sprintf("%s/nhdat", config.NethackLauncher.HackDir)); os.IsNotExist(err) {
		exec.Command("cp", config.NethackLauncher.NhdatLocation, config.NethackLauncher.HackDir).Run()
	}
}

func janitor(redisClient *redis.Client) {
	// loop through the set
	for {
		inprogress, err := redisClient.SMembers("inprogress").Result()
		if err != nil {
			panic(err)
		}
		for _, i := range inprogress {
			// for each user, make sure the expire key exists
			exists, err := redisClient.Exists(fmt.Sprintf("inprogress:%s", i)).Result()
			if err != nil {
				panic(err)
			}
			if !exists {
				redisClient.SRem("inprogress", i)
			}
		}

		time.Sleep(10 * time.Second)
	}
}

func printHighScores(redisClient *redis.Client, username string) {
	exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
	clearScreen()

	nh := exec.Command("nethack", "-d", config.NethackLauncher.HackDir, "-s")
	nh.Stdout = os.Stdout
	nh.Stdin = os.Stdin
	nh.Stderr = os.Stderr
	nh.Run()

	println("")
	println(" Press enter to return to menu")
	println("")
	fmt.Printf(">> ")

	// allow user back to home screen
	// disable input buffering
	exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()
	// do not display entered characters on the screen
	exec.Command("stty", "-F", "/dev/tty", "-echo").Run()

	var b []byte = make([]byte, 1)
	for {
		os.Stdin.Read(b)

		// check if user is trying to navigate
		if string(b) == "\n" {
			exec.Command("stty", "-F", "/dev/tty", "echo", "-cbreak").Run()
			clearScreen()
			if username == "" {
				printWelcomeScreen(redisClient)
			} else {
				printUserScreen(redisClient, username)
			}
		}
	}
}

func checkDir(dirName string) (bool, error) {
	f, err := os.Open(dirName)
	if err != nil {
		return false, err
	}
	defer f.Close()

	_, err = f.Readdirnames(1)
	if err == io.EOF {
		return true, nil
	}
	return false, err
}