# test_local.py
#!/usr/bin/env python3
import argparse
import numpy as np
from encoder import make_codebook, encode_message
from decoder import decode_blocks, count_errors
from channel import channel


def main():
    parser = argparse.ArgumentParser(description="Local test using channel.py")
    parser.add_argument("--message", required=True, help="40-character message")
    args = parser.parse_args()

    msg = args.message
    if len(msg) != 40:
        raise ValueError("Message must be exactly 40 characters.")
    C = make_codebook(r=5, num_blocks=len(msg))
    x = encode_message(msg, C)
    print(f"→ Total samples = {x.size}, total energy = {np.sum(x*x):.1f}")

    Y = channel(x)

    msg_hat = decode_blocks(Y, C)
    print(f"↓ Decoded message: {msg_hat}")

    errors = count_errors(msg, msg_hat)
    print(f"Errors: {len(errors)} / {len(msg)} characters differ")
    if errors:
        for i, o, e in errors:
            print(f"  Pos {i}: sent '{o}' but got '{e}'")
    else:
        print("✔️  No decoding errors!")

if __name__ == "__main__":
    main()