"""Walk the body assuming chunks delimited by 0x10 NN tags. Print each chunk's structure."""
import sys
sys.path.insert(0, ".")
from analysis.load_bundle import load_bundle


def walk(body: bytes, start_offset: int = 7, max_chunks: int = 30):
    """Find all positions where byte = 0x10 followed by a multiple-of-4 byte. Print chunks."""
    chunks = []
    i = start_offset
    while i < len(body) - 1:
        # Find next `10 NN` where NN is multiple of 4 (and not preceded by another 0x10 immediately, which would be data).
        if body[i] == 0x10 and (body[i+1] % 4 == 0):
            chunks.append(i)
        i += 1
    return chunks


def main():
    for name in ("event-c", "event-d"):
        b = load_bundle(name)
        body = b.body
        positions = []
        i = 7  # skip 7-byte preamble
        while i < len(body) - 1:
            if body[i] == 0x10 and body[i+1] % 4 == 0 and body[i+1] > 0:
                positions.append(i)
                i += 2  # skip past tag
            else:
                i += 1
        print(f"\n=== {name} ===  body={len(body)}, total `10 NN` (NN%4==0, NN>0) tags: {len(positions)}")
        # Print first 20 chunks: show position, NN, gap to next tag
        for k in range(min(30, len(positions))):
            pos = positions[k]
            NN = body[pos + 1]
            next_pos = positions[k+1] if k+1 < len(positions) else len(body)
            gap = next_pos - pos
            data_bytes = body[pos+2 : next_pos]
            print(f"  chunk[{k:>3}] @ {pos:>5}  NN=0x{NN:02x} ({NN:>3}, NN/2={NN//2})  gap={gap:>3}  "
                  f"data={data_bytes[:24].hex(' ')}{'...' if len(data_bytes) > 24 else ''}")


if __name__ == "__main__":
    main()