package main

import (
	"bufio"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"time"
)

type terminal struct{ r *bufio.Reader }

func (t terminal) ask(label, current string) (string, error) {
	fmt.Printf("%s [%s]: ", label, current)
	s, e := t.r.ReadString('\n')
	if e != nil {
		return "", e
	}
	s = strings.TrimSpace(s)
	if s == "" {
		return current, nil
	}
	return s, nil
}
func (a *App) tui() error {
	t := terminal{bufio.NewReader(os.Stdin)}
	for {
		a.mu.Lock()
		s := a.settings
		a.mu.Unlock()
		fmt.Println("\nwswg |", a.engine.status().Line())
		for i, p := range s.Profiles {
			mark := ""
			if p.ID == a.engine.activeID() {
				mark = " [connected]"
			}
			fmt.Printf("%d. %s%s\n", i+1, p.Name, mark)
		}
		fmt.Println("n. New config\ns. Settings\nx. Disconnect\nq. Quit")
		v, err := t.ask(">", "")
		if err != nil {
			return nil
		}
		switch v {
		case "q":
			return nil
		case "x":
			a.engine.stop()
		case "s":
			fmt.Printf("On boot: %t\n", s.OnBoot)
			v, err = t.ask("Toggle on boot? y/n", "n")
			if err != nil {
				return nil
			}
			if v == "y" {
				if err = a.setOptions(s.Autorun, !s.OnBoot); err != nil {
					fmt.Println(err)
				}
			}
		case "n":
			name, err := t.ask("Name", "New config")
			if err != nil {
				return nil
			}
			p := Profile{Name: name, DNS: true, Tunnel: Tunnel{Port: 443, HTTPS: true}}
			if err = editConfig(a.dir, &p); err == nil {
				err = a.save(p)
			}
			if err != nil {
				fmt.Println(err)
			}
		default:
			p, err := s.find(v)
			if err != nil {
				fmt.Println(err)
				continue
			}
			if err = a.profileMenu(t, p); err != nil {
				fmt.Println(err)
			}
		}
	}
}
func (a *App) profileMenu(t terminal, p Profile) error {
	for {
		fmt.Printf("\n%s\n1. WireGuard (DNS: %t)\n2. wstunnel (enabled: %t, host: %s, port: %d, HTTPS: %t)\n3. Use DNS from WireGuard config: %t\n4. Rename\n5. Connect\n6. Disconnect\n7. Delete\n0. Back\n", p.Name, p.DNS, p.Tunnel.Enabled, p.Tunnel.Host, p.Tunnel.Port, p.Tunnel.HTTPS, p.DNS)
		v, err := t.ask(">", "")
		if err != nil {
			return err
		}
		next := p
		switch v {
		case "0":
			return nil
		case "1":
			err = editConfig(a.dir, &next)
		case "2":
			err = tunnelMenu(t, &next)
		case "3":
			next.DNS = !next.DNS
		case "4":
			next.Name, err = t.ask("Name", p.Name)
		case "5":
			err = a.connect(p.ID)
			if err == nil {
				return a.watch(t)
			}
		case "6":
			a.engine.stop()
			continue
		case "7":
			v, err = t.ask("Delete this profile? y/n", "n")
			if err == nil && v == "y" {
				return a.remove(p.ID)
			}
			continue
		default:
			continue
		}
		if err == nil && v != "5" {
			err = a.save(next)
			if err == nil {
				p = next
			}
		}
		if err != nil {
			fmt.Println(err)
		}
	}
}
func tunnelMenu(t terminal, p *Profile) error {
	for {
		fmt.Printf("\n1. Enabled: %t\n2. IP/host: %s (empty = WireGuard endpoint)\n3. Port: %d\n4. HTTPS: %t\n0. Back\n", p.Tunnel.Enabled, p.Tunnel.Host, p.Tunnel.Port, p.Tunnel.HTTPS)
		v, e := t.ask(">", "")
		if e != nil {
			return e
		}
		switch v {
		case "0":
			return nil
		case "1":
			p.Tunnel.Enabled = !p.Tunnel.Enabled
		case "2":
			h, e := t.ask("Host, '-' to reset", p.Tunnel.Host)
			if e != nil {
				return e
			}
			if h == "-" {
				h = ""
			}
			p.Tunnel.Host = h
		case "3":
			v, e = t.ask("Port", strconv.Itoa(p.Tunnel.Port))
			if e != nil {
				return e
			}
			n, e := strconv.Atoi(v)
			if e != nil || n < 1 || n > 65535 {
				fmt.Println("Port must be 1..65535")
			} else {
				p.Tunnel.Port = n
			}
		case "4":
			p.Tunnel.HTTPS = !p.Tunnel.HTTPS
		}
	}
}
func editConfig(dir string, p *Profile) error {
	f, err := os.CreateTemp(dir, "edit-*.conf")
	if err != nil {
		return err
	}
	path := f.Name()
	defer os.Remove(path)
	if err = f.Chmod(0600); err == nil {
		_, err = f.WriteString(p.WireGuard)
	}
	ce := f.Close()
	if err != nil {
		return err
	}
	if ce != nil {
		return ce
	}
	editor := os.Getenv("EDITOR")
	if editor == "" {
		editor = "nano"
	}
	args, err := editorArgs(editor)
	if err != nil {
		return err
	}
	c := exec.Command(args[0], append(args[1:], filepath.Clean(path))...)
	c.Stdin = os.Stdin
	c.Stdout = os.Stdout
	c.Stderr = os.Stderr
	if err = c.Run(); err != nil {
		return err
	}
	b, err := os.ReadFile(path)
	if err != nil {
		return err
	}
	p.WireGuard = string(b)
	return nil
}

// Parse quoted executable paths and arguments without executing a shell.
func editorArgs(s string) ([]string, error) {
	var args []string
	var word strings.Builder
	var quote rune
	for _, r := range s {
		if quote != 0 {
			if r == quote {
				quote = 0
			} else {
				word.WriteRune(r)
			}
			continue
		}
		if r == '\'' || r == '"' {
			quote = r
		} else if r == ' ' || r == '\t' {
			if word.Len() > 0 {
				args = append(args, word.String())
				word.Reset()
			}
		} else {
			word.WriteRune(r)
		}
	}
	if quote != 0 {
		return nil, fmt.Errorf("unclosed quote in EDITOR")
	}
	if word.Len() > 0 {
		args = append(args, word.String())
	}
	if len(args) == 0 {
		return nil, fmt.Errorf("empty EDITOR")
	}
	return args, nil
}
func (a *App) watch(t terminal) error {
	fmt.Println("Connected. Enter returns to menu, Ctrl+C quits.")
	done := make(chan struct{})
	go func() { defer close(done); _, _ = t.r.ReadString('\n') }()
	for {
		fmt.Printf("\r\033[K%s", a.engine.status().Line())
		select {
		case <-done:
			fmt.Println()
			return nil
		case <-time.After(time.Second):
		}
	}
}