from sqlalchemy.orm import Session
from fastapi import HTTPException, Depends
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from app.models.user import User
from app.utils.security import (
    hash_password,
    verify_password,
    create_access_token,
    create_refresh_token,
    decode_token,
)
from app.database import get_db

security = HTTPBearer()

def register_user(db: Session, email: str, password: str, name: str) -> User:
    existing = db.query(User).filter(User.email == email).first()
    if existing:
        raise HTTPException(status_code=400, detail="Email already registered")
    user = User(email=email, password_hash=hash_password(password), name=name, roles=[])
    db.add(user)
    db.commit()
    db.refresh(user)
    return user

def login_user(db: Session, email: str, password: str) -> dict:
    user = db.query(User).filter(User.email == email).first()
    if not user or not verify_password(password, user.password_hash):
        raise HTTPException(status_code=401, detail="Invalid email or password")
    access_token = create_access_token(str(user.id))
    refresh_token = create_refresh_token(str(user.id))
    return {"access_token": access_token, "refresh_token": refresh_token, "token_type": "bearer"}

def refresh_tokens(refresh_token: str) -> dict:
    payload = decode_token(refresh_token)
    if not payload or payload.get("type") != "refresh":
        raise HTTPException(status_code=401, detail="Invalid or expired refresh token")
    user_id = payload.get("sub")
    access_token = create_access_token(user_id)
    new_refresh = create_refresh_token(user_id)
    return {"access_token": access_token, "refresh_token": new_refresh, "token_type": "bearer"}

def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: Session = Depends(get_db),
) -> User:
    token = credentials.credentials
    payload = decode_token(token)
    if not payload or payload.get("type") != "access":
        raise HTTPException(status_code=401, detail="Invalid or expired access token")
    user_id = payload.get("sub")
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=401, detail="User not found")
    return user

def is_admin(user: User) -> bool:
    """Check if user has maia.admin role."""
    return "maia.admin" in (user.roles or [])

def get_or_create_sso_user(db: Session, user_info: dict, roles: list = None) -> User:
    """Look up user by email (SSO login). Create or update if found."""
    import uuid as _uuid
    email = user_info.get("email", "")
    name = user_info.get("name", "") or email or "SSO User"
    roles = roles or []

    user = db.query(User).filter(User.email == email).first()
    if user:
        user.name = name
        # Merge KC roles with existing DB roles (don't downgrade if KC lacks a role)
        existing = set(user.roles or [])
        incoming = set(roles or [])
        user.roles = sorted(existing | incoming)
        db.commit()
        db.refresh(user)
        return user

    placeholder_hash = hash_password(str(_uuid.uuid4()))
    user = User(email=email, password_hash=placeholder_hash, name=name, roles=roles)
    db.add(user)
    db.commit()
    db.refresh(user)
    return user