"""
安全相关功能：密码加密、JWT、Refresh Token
"""
import json
import uuid
from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
import bcrypt
from app.core.config import settings

# Redis client (lazy init)
_redis = None

def _get_redis():
    global _redis
    if _redis is None:
        try:
            from app.core.redis_client import get_redis_client
            _redis = get_redis_client()
        except Exception:
            _redis = False
    return _redis

# Refresh token TTL: 30 days
REFRESH_TOKEN_TTL_SEC = 30 * 24 * 3600  # 30 days


def verify_password(plain_password: str, hashed_password: str) -> bool:
    """验证密码"""
    try:
        # bcrypt限制密码长度最多72字节
        password_bytes = plain_password.encode('utf-8')
        if len(password_bytes) > 72:
            password_bytes = password_bytes[:72]
        return bcrypt.checkpw(password_bytes, hashed_password.encode('utf-8'))
    except Exception:
        return False


def get_password_hash(password: str) -> str:
    """获取密码哈希"""
    # bcrypt限制密码长度最多72字节
    password_bytes = password.encode('utf-8')
    if len(password_bytes) > 72:
        password_bytes = password_bytes[:72]

    # 生成盐并哈希密码
    salt = bcrypt.gensalt()
    hashed = bcrypt.hashpw(password_bytes, salt)
    return hashed.decode('utf-8')


def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    """创建访问令牌"""
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=settings.JWT_ACCESS_TOKEN_EXPIRE_MINUTES)

    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, settings.JWT_SECRET_KEY or settings.SECRET_KEY, algorithm=settings.JWT_ALGORITHM)
    return encoded_jwt


def decode_access_token(token: str) -> Optional[dict]:
    """解码访问令牌"""
    try:
        payload = jwt.decode(token, settings.JWT_SECRET_KEY or settings.SECRET_KEY, algorithms=[settings.JWT_ALGORITHM])
        return payload
    except JWTError:
        return None


# ─── Refresh Token ──────────────────────────────────────────

def create_refresh_token(user_id: str, username: str, workspace_id: str = "") -> str:
    """创建 refresh token，存储到 Redis，返回 token 字符串。"""
    token = str(uuid.uuid4())
    data = {
        "user_id": user_id,
        "username": username,
        "ws": workspace_id,
        "created_at": datetime.utcnow().isoformat(),
    }
    r = _get_redis()
    if r:
        r.setex(f"refresh_token:{token}", REFRESH_TOKEN_TTL_SEC, json.dumps(data))
    return token


def verify_refresh_token(token: str) -> Optional[dict]:
    """验证 refresh token，返回存储的数据或 None。"""
    r = _get_redis()
    if not r:
        return None
    raw = r.get(f"refresh_token:{token}")
    if not raw:
        return None
    try:
        return json.loads(raw)
    except Exception:
        return None


def revoke_refresh_token(token: str):
    """撤销 refresh token。"""
    r = _get_redis()
    if r:
        r.delete(f"refresh_token:{token}")