#!/usr/bin/env python3
"""Verify cmtd+0x08 checksums: prove_checksum.py a.bin [b.bin ...]

Exit 0 iff every image's stored checksum equals compute_checksum(image).
See lofi_image.compute_checksum for the algorithm.
"""
import os
import struct
import sys

sys.path.insert(0, os.path.dirname(__file__))
from lofi_image import compute_checksum, parse_image


def main() -> int:
    ok = True
    for path in sys.argv[1:]:
        d = open(path, "rb").read()
        info = parse_image(d)  # validates container chain
        stored = info["cmtd"]["checksum"]
        calc = compute_checksum(d)
        match = stored == calc
        ok &= match
        fw = ".".join(map(str, info["mmtd"]["fw"]))
        print("%s fw=%s size=%d stored=%08X calc=%08X %s"
              % (path, fw, len(d), stored, calc,
                 "MATCH" if match else "MISMATCH"))
    return 0 if ok and len(sys.argv) > 1 else 1


if __name__ == "__main__":
    sys.exit(main())