import sys, csv
import matplotlib.pyplot as plt

def main(csv_path, out_prefix="curves"):
    thr = []
    prec = []
    rec = []
    with open(csv_path, newline="") as f:
        r = csv.DictReader(f)
        for row in r:
            thr.append(float(row["threshold"]))
            prec.append(float(row["precision"]))
            rec.append(float(row["recall"]))

    # Precision-Recall
    plt.figure()
    plt.plot(rec, prec, marker='o')
    plt.xlabel('Recall')
    plt.ylabel('Precision')
    plt.title('Precision-Recall Curve')
    plt.grid(True)
    plt.tight_layout()
    plt.savefig(f"{out_prefix}_pr.png", dpi=160)

    # Precision & Recall vs Threshold
    plt.figure()
    plt.plot(thr, prec, marker='o', label="Precision")
    plt.plot(thr, rec, marker='o', label="Recall")
    plt.xlabel('Confidence threshold')
    plt.ylabel('Score')
    plt.title('Precision/Recall vs Threshold')
    plt.legend()
    plt.grid(True)
    plt.tight_layout()
    plt.savefig(f"{out_prefix}_thr.png", dpi=160)

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python scripts/plot_eval.py metrics.csv [out_prefix]")
        sys.exit(1)
    csv_path = sys.argv[1]
    out_prefix = sys.argv[2] if len(sys.argv) > 2 else "curves"
    main(csv_path, out_prefix)