ahmet / ft_linear_regression

import csv

THETAS_PATH = "thetas.csv"


def estimate_price(theta0, theta1, mileage):
    """estimatePrice(mileage) = theta0 + (theta1 * mileage)"""
    return theta0 + (theta1 * mileage)


def load_thetas():
    """Both thetas default to 0 until the training program has run."""
    try:
        with open(THETAS_PATH, newline="") as f:
            row = next(csv.DictReader(f))
        return float(row["theta0"]), float(row["theta1"])
    except (FileNotFoundError, StopIteration, KeyError, TypeError, ValueError):
        return 0.0, 0.0


def main():
    theta0, theta1 = load_thetas()

    try:
        mileage = float(input("Mileage: "))
    except (ValueError, EOFError, KeyboardInterrupt):
        print("\nPlease enter a valid number.")
        return

    if mileage < 0:
        print("Mileage cannot be negative.")
        return

    print(f"Estimated price: {estimate_price(theta0, theta1, mileage):.2f}")


if __name__ == "__main__":
    main()