import hashlib
import secrets
from datetime import datetime, timedelta, timezone
from typing import Any

import bcrypt
from jose import JWTError, jwt

from app.core.config import get_settings

settings = get_settings()

API_KEY_PREFIX = "jz_live_"


def hash_password(password: str) -> str:
    return bcrypt.hashpw(password.encode("utf-8"), bcrypt.gensalt()).decode("utf-8")


def verify_password(plain_password: str, hashed_password: str) -> bool:
    return bcrypt.checkpw(plain_password.encode("utf-8"), hashed_password.encode("utf-8"))


def create_access_token(subject: str, extra_claims: dict[str, Any] | None = None) -> str:
    expire = datetime.now(timezone.utc) + timedelta(minutes=settings.access_token_expire_minutes)
    to_encode: dict[str, Any] = {"sub": subject, "exp": expire}
    if extra_claims:
        to_encode.update(extra_claims)
    return jwt.encode(to_encode, settings.jwt_secret, algorithm=settings.jwt_algorithm)


def decode_access_token(token: str) -> dict[str, Any] | None:
    try:
        return jwt.decode(token, settings.jwt_secret, algorithms=[settings.jwt_algorithm])
    except JWTError:
        return None


def generate_api_key() -> tuple[str, str, str]:
    """Returns (full_key, prefix, hashed_key). The full key is shown once and never
    stored; API keys are high-entropy (32 random bytes) so a fast SHA-256 hash is
    appropriate here, unlike user passwords."""
    full_key = f"{API_KEY_PREFIX}{secrets.token_hex(32)}"
    prefix = full_key[:16]
    hashed = hashlib.sha256(full_key.encode("utf-8")).hexdigest()
    return full_key, prefix, hashed


def verify_api_key(candidate: str, hashed_key: str) -> bool:
    return secrets.compare_digest(hashlib.sha256(candidate.encode("utf-8")).hexdigest(), hashed_key)