package app

import (
	"crypto/rand"
	"encoding/base64"
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

func ClientTokenPath() (string, error) {
	base := os.Getenv("XDG_DATA_HOME")
	if base == "" {
		home, err := os.UserHomeDir()
		if err != nil {
			return "", err
		}
		base = filepath.Join(home, ".local", "share")
	}
	return filepath.Join(base, "patterm", "clients", "token"), nil
}

func LoadClientToken() (string, error) {
	path, err := ClientTokenPath()
	if err != nil {
		return "", err
	}
	b, err := os.ReadFile(path)
	if err != nil {
		return "", err
	}
	return strings.TrimSpace(string(b)), nil
}

func LoadOrCreateClientToken() (string, error) {
	if token, err := LoadClientToken(); err == nil && token != "" {
		return token, nil
	}
	token, err := generateClientToken()
	if err != nil {
		return "", err
	}
	path, err := ClientTokenPath()
	if err != nil {
		return "", err
	}
	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
		return "", err
	}
	if err := os.WriteFile(path, []byte(token+"\n"), 0o600); err != nil {
		return "", err
	}
	return token, nil
}

func generateClientToken() (string, error) {
	var b [32]byte
	if _, err := rand.Read(b[:]); err != nil {
		return "", fmt.Errorf("token: random: %w", err)
	}
	return base64.RawURLEncoding.EncodeToString(b[:]), nil
}