package ws

import (
	"crypto/ed25519"
	"crypto/rand"
	"encoding/hex"
	"os"
	"path/filepath"
)

// LoadOrCreateServerKey 加载/生成服务器 Ed25519 密钥（hex 文件）
func LoadOrCreateServerKey(path string) (ed25519.PrivateKey, error) {
	if raw, err := os.ReadFile(path); err == nil {
		seed, err := hex.DecodeString(string(raw))
		if err == nil && len(seed) == ed25519.SeedSize {
			return ed25519.NewKeyFromSeed(seed), nil
		}
	}
	_, priv, err := ed25519.GenerateKey(rand.Reader)
	if err != nil {
		return nil, err
	}
	if err = os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		return nil, err
	}
	if err = os.WriteFile(path, []byte(hex.EncodeToString(priv.Seed())), 0o600); err != nil {
		return nil, err
	}
	return priv, nil
}