from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from passlib.context import CryptContext
from sqlalchemy.orm import Session
import os

from database.models import User, UserRole
from database.schemas import TokenData

# 환경 변수
SECRET_KEY = os.getenv("SECRET_KEY", "your-secret-key-here")
ALGORITHM = os.getenv("ALGORITHM", "HS256")
ACCESS_TOKEN_EXPIRE_MINUTES = int(os.getenv("ACCESS_TOKEN_EXPIRE_MINUTES", "10080"))  # 7 days

# 비밀번호 암호화 (pbkdf2_sha256 사용 - bcrypt 문제 회피)
pwd_context = CryptContext(
    schemes=["pbkdf2_sha256"], 
    deprecated="auto"
)

def verify_password(plain_password: str, hashed_password: str) -> bool:
    """비밀번호 검증 (pbkdf2_sha256 - 길이 제한 없음)"""
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password: str) -> str:
    """비밀번호 해시 생성 (pbkdf2_sha256 - 길이 제한 없음)"""
    return pwd_context.hash(password)

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

def verify_token(token: str, credentials_exception):
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
        return token_data
    except JWTError:
        raise credentials_exception

def authenticate_user(db: Session, username: str, password: str):
    user = db.query(User).filter(User.username == username).first()
    if not user:
        return False
    if not verify_password(password, user.hashed_password):
        return False
    return user

def create_admin_user(db: Session):
    """초기 관리자 계정 생성"""
    admin_username = os.getenv("ADMIN_USERNAME", "hyungi")
    admin_password = os.getenv("ADMIN_PASSWORD", "djg3-jj34-X3Q3")
    
    # 이미 존재하는지 확인
    existing_admin = db.query(User).filter(User.username == admin_username).first()
    if not existing_admin:
        admin_user = User(
            username=admin_username,
            hashed_password=get_password_hash(admin_password),
            full_name="관리자",
            role=UserRole.admin,
            is_active=True
        )
        db.add(admin_user)
        db.commit()
        print(f"관리자 계정 생성됨: {admin_username}")
    else:
        print(f"관리자 계정이 이미 존재함: {admin_username}")