import random
import string
from typing import Optional
import redis
import json
from app.core.config import settings


# Mock Redis client for development
class MockRedisClient:
    def __init__(self):
        self.data = {}

    def setex(self, key: str, time: int, value: str):
        self.data[key] = value
        return True

    def get(self, key: str) -> Optional[str]:
        return self.data.get(key)

    def delete(self, key: str):
        if key in self.data:
            del self.data[key]
        return True


try:
    redis_client = redis.from_url(settings.REDIS_URL)
    redis_client.ping()
except Exception:
    redis_client = MockRedisClient()


def generate_otp() -> str:
    return "".join(random.choices(string.digits, k=6))


def store_otp(phone_number: str, otp: str) -> bool:
    try:
        otp_data = {"otp": otp, "attempts": 0}
        redis_client.setex(
            f"otp:{phone_number}",
            settings.OTP_EXPIRE_MINUTES * 60,
            json.dumps(otp_data),
        )
        return True
    except Exception:
        return False


def verify_otp(phone_number: str, otp: str) -> bool:
    try:
        stored_data = redis_client.get(f"otp:{phone_number}")
        if not stored_data:
            return False

        otp_data = json.loads(stored_data)

        if otp_data["attempts"] >= settings.OTP_MAX_ATTEMPTS:
            redis_client.delete(f"otp:{phone_number}")
            return False

        if otp_data["otp"] == otp:
            redis_client.delete(f"otp:{phone_number}")
            return True
        else:
            otp_data["attempts"] += 1
            redis_client.setex(
                f"otp:{phone_number}",
                settings.OTP_EXPIRE_MINUTES * 60,
                json.dumps(otp_data),
            )
            return False
    except Exception:
        return False


def send_otp(phone_number: str, otp: str) -> bool:
    # Mock SMS sending for development
    print(f"Sending OTP {otp} to {phone_number}")
    return True