import secrets
import hashlib
from datetime import datetime, timedelta
from sqlalchemy.orm import Session
from database import get_db
from models import APIKey, User, Quota, Usage

def get_user_by_username(db: Session, username: str):
    return db.query(User).filter(User.username == username).first()

def get_user_by_email(db: Session, email: str):
    return db.query(User).filter(User.email == email).first()

def generate_api_key():
    return "sk-" + secrets.token_urlsafe(32)

def hash_password(password: str):
    return hashlib.sha256(password.encode()).hexdigest()

def create_user(db: Session, username: str, email: str, password: str):
    db_user = User(
        username=username,
        email=email,
        hashed_password=hash_password(password)
    )
    db.add(db_user)
    db.commit()
    db.refresh(db_user)
    
    default_quota = Quota(
        user_id=db_user.id,
        daily_tokens=1000000,
        monthly_tokens=10000000,
        daily_requests=1000,
        monthly_requests=10000
    )
    db.add(default_quota)
    db.commit()
    
    return db_user

def create_api_key(db: Session, user_id: int, name: str):
    key = generate_api_key()
    db_key = APIKey(
        name=name,
        key=key,
        user_id=user_id
    )
    db.add(db_key)
    db.commit()
    db.refresh(db_key)
    return db_key

def verify_api_key(db: Session, api_key: str):
    return db.query(APIKey).filter(APIKey.key == api_key, APIKey.is_active == True).first()

def get_quota(db: Session, user_id: int):
    return db.query(Quota).filter(Quota.user_id == user_id).first()

def check_quota(db: Session, user_id: int, tokens: int = 0, requests: int = 1):
    quota = get_quota(db, user_id)
    usage = get_usage(db, user_id)
    
    if quota.daily_tokens and (usage.tokens_used + tokens) > quota.daily_tokens:
        return False
    if quota.monthly_tokens and (usage.tokens_used + tokens) > quota.monthly_tokens:
        return False
    if quota.daily_requests and (usage.requests_count + requests) > quota.daily_requests:
        return False
    if quota.monthly_requests and (usage.requests_count + requests) > quota.monthly_requests:
        return False
    
    return True

def increment_usage(db: Session, user_id: int, tokens: int = 0, requests: int = 1):
    usage = get_or_create_usage(db, user_id)
    usage.tokens_used += tokens
    usage.requests_count += requests
    db.commit()
    db.refresh(usage)

def get_usage(db: Session, user_id: int):
    return db.query(Usage).filter(Usage.user_id == user_id).first()

def get_quota_by_user_id(db: Session, user_id: int):
    return db.query(Quota).filter(Quota.user_id == user_id).first()

def get_or_create_usage(db: Session, user_id: int):
    usage = get_usage(db, user_id)
    if not usage:
        usage = Usage(user_id=user_id)
        db.add(usage)
        db.commit()
        db.refresh(usage)
    return usage