package main

import (
	"bytes"
	"fmt"
	"github.com/gliderlabs/ssh"
	"github.com/kr/pty"
	"io"
	"log"
	"net/http"
	"os/exec"
)

var (
	metrics_num_passwords int
)

func main() {
	log.Println("Starting SSH listener")

	//// start the ssh server
	//go func() {
	//	listenErr := ssh.ListenAndServe(":2222", nil, ssh.PasswordAuth(handlePass))
	//	if listenErr != nil {
	//		log.Fatalln(listenErr.Error())
	//	}
	//}()

	go func() {
		// star the metrics listener
		log.Println("Starting HTTP metrics listener")
		http.HandleFunc("/metrics", metricsHandler)
		listenErr := http.ListenAndServe(":8080", nil)
		if listenErr != nil {
			log.Fatalln(listenErr.Error())
		}
	}()

	ssh.Handle(handleConnection)
	log.Fatal(ssh.ListenAndServe(":2222", nil, ssh.PasswordAuth(handlePass)))
}

func handleConnection(s ssh.Session) {
	cmd := exec.Command("bash")
	p, _ := pty.Start(cmd)

	go func() {
		var readErr error
		for readErr == nil {
			// create two buffers, one for storing the char input (buf)
			// and the other for storing complete commands (commandBuffer)
			buf := make([]byte, 1024)
			commandBuffer := make([]byte, 0)

			// the current char
			var char string

			// read until ENTER is pressed
			for char != "\x0d"{

				// read the char inserted by the user into the buffer
				_, readErr = s.Read(buf)

				// trim the char and append it to the commandBuffer
				char1 := bytes.Trim(buf, "\x00")[0]
				if char1 == []byte("\x03")[0] {
					s.Close()
					return
				}
				commandBuffer = append(commandBuffer, char1)

				// write the char to stdout
				char = string(bytes.Trim(buf, "\x00"))
				input := string(bytes.Trim(buf, "\x00"))
				io.WriteString(s, input)
			}

			// prepare the command for execution
			input := string(bytes.Trim(commandBuffer, "\x00"))

			// filter out unwanted commands
			filteredInput := filter(input)

			// write the string to the commandHandler
			io.WriteString(p, filteredInput)
			s.Close()
			return
		}
	}()

	io.Copy(s, p)
	s.Close()
}

func filter(buffer string) string {
	//if strings.Contains(buffer, "wget") == false {
	//	return "\n"
	//}
	//return buffer

	// all ways return a newline -> track what is input
	log.Printf("%s", buffer)
	return "\n"
}

func handlePass(ctx ssh.Context, pass string) bool {
	metrics_num_passwords++
	log.Printf("%s@%s: '%s'", ctx.User(), ctx.RemoteAddr().String(), pass)
	return true
}

// Handle HTTP /metrics requests
func metricsHandler(w http.ResponseWriter, req *http.Request) {
	fmt.Fprintf(w, "num_passwords %d\n", metrics_num_passwords)
}