"""Regression check: our SAB output must be byte-identical to sedonac.exe's.

Usage:  python verify.py [sedona_home]
"""
import os, sys, subprocess, tempfile, shutil
import sab

HERE = os.path.dirname(os.path.abspath(__file__))
HOME = sys.argv[1] if len(sys.argv) > 1 else os.path.join(os.path.dirname(HERE), "sedona")


def check(sax, reference=None):
    """Encode `sax` with sab.py; compare against `reference` or a fresh sedonac run."""
    tmp = tempfile.mkdtemp()
    try:
        if reference is None:
            work = os.path.join(tmp, os.path.basename(sax))
            shutil.copy(sax, work)
            exe = os.path.join(HOME, "bin", "sedonac.exe")
            r = subprocess.run([exe, work], capture_output=True, text=True)
            if r.returncode != 0:
                print("  sedonac failed:\n" + r.stdout + r.stderr)
                return False
            reference = os.path.splitext(work)[0] + ".sab"

        mine = os.path.join(tmp, "mine.sab")
        sab.encode(sax, HOME, mine)

        a = open(reference, "rb").read()
        b = open(mine, "rb").read()
        name = os.path.basename(sax)
        if a == b:
            print("  PASS  %-28s %d bytes identical" % (name, len(a)))
            return True

        diffs = [i for i in range(min(len(a), len(b))) if a[i] != b[i]]
        print("  FAIL  %-28s sedonac=%d ours=%d, %d byte diffs" % (name, len(a), len(b), len(diffs)))
        if diffs:
            i = diffs[0]
            lo, hi = max(0, i - 12), i + 12
            print("        first diff at offset %d" % i)
            print("        sedonac  %s" % a[lo:hi].hex())
            print("        ours     %s" % b[lo:hi].hex())
        return False
    finally:
        shutil.rmtree(tmp, ignore_errors=True)


if __name__ == "__main__":
    print("sedona home: %s" % HOME)
    ok = check(os.path.join(HERE, "test_normal.sax"),
               os.path.join(HERE, "test_normal_sedonac.sab"))
    sys.exit(0 if ok else 1)