package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"net"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"golang.org/x/crypto/ssh/terminal"
)

func main() {
	addr := flag.String("addr", "127.0.0.1:8282", "DebTik CLI server address")
	username := flag.String("u", "", "Username for automatic authentication")
	password := flag.String("p", "", "Password for automatic authentication")
	cmdFlag := flag.String("c", "", "Execute a single command non-interactively and exit")
	flag.Parse()

	conn, err := net.DialTimeout("tcp", *addr, 3*time.Second)
	if err != nil {
		fmt.Fprintf(os.Stderr, "\033[31mError: Could not connect to DebTik CLI service on %s\033[0m\n", *addr)
		fmt.Fprintf(os.Stderr, "Ensure proxmox-router service is active and listening on port 8282.\n")
		os.Exit(1)
	}
	defer conn.Close()

	// If one-shot command execution is requested:
	if *cmdFlag != "" {
		runOneShot(conn, *username, *password, *cmdFlag)
		return
	}

	// Interactive Mode
	runInteractive(conn, *username, *password)
}

func runOneShot(conn net.Conn, username, password, command string) {
	reader := bufio.NewReader(conn)
	// If credentials were provided, handle initial prompt
	if username != "" && password != "" {
		_ = autoLogin(conn, reader, username, password)
	}

	// Send command followed by quit
	_, _ = fmt.Fprintf(conn, "%s\nquit\n", command)

	// Read until EOF
	_, _ = io.Copy(os.Stdout, reader)
}

func runInteractive(conn net.Conn, username, password string) {
	fd := int(os.Stdin.Fd())
	isTerm := terminal.IsTerminal(fd)

	if isTerm {
		oldState, err := terminal.MakeRaw(fd)
		if err == nil {
			defer func() {
				_ = terminal.Restore(fd, oldState)
			}()
		}
	}

	// Setup clean signal handling to restore terminal on SIGINT/SIGTERM
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
	go func() {
		<-sigChan
		if isTerm {
			_ = terminal.Restore(fd, nil)
		}
		os.Exit(0)
	}()

	errChan := make(chan error, 2)

	// Copy from Remote Server -> Local Terminal
	go func() {
		_, err := io.Copy(os.Stdout, conn)
		errChan <- err
	}()

	// Copy from Local Terminal -> Remote Server
	go func() {
		_, err := io.Copy(conn, os.Stdin)
		errChan <- err
	}()

	// Wait for connection to close
	<-errChan
}

func autoLogin(conn net.Conn, reader *bufio.Reader, username, password string) error {
	// Read until "login: "
	for {
		line, err := reader.ReadString(':')
		if err != nil {
			return err
		}
		if strings.Contains(strings.ToLower(line), "login") {
			_, _ = fmt.Fprintf(conn, "%s\n", username)
			break
		}
	}

	// Read until "Password: "
	for {
		line, err := reader.ReadString(':')
		if err != nil {
			return err
		}
		if strings.Contains(strings.ToLower(line), "password") {
			_, _ = fmt.Fprintf(conn, "%s\n", password)
			break
		}
	}
	return nil
}