#!/usr/bin/env python3
"""Decode a captured Blaze Fire2 frame: 16-byte header + Heat2 TDF payload.
Clean-room: parses the wire bytes of our own client's traffic."""
import sys, struct

def decode_tag(b):
    # Heat2 tag: 3 bytes -> 4 chars, each 6-bit; 0 -> ' ' (trimmed). char = v ? v+0x20 : ' '
    a,b1,c = b[0],b[1],b[2]
    v=[ (a>>2)&0x3f, ((a&0x3)<<4)|((b1>>4)&0xf), ((b1&0xf)<<2)|((c>>6)&0x3), c&0x3f ]
    return ''.join(chr(x+0x20) if x else ' ' for x in v).rstrip()

TYPES={0x00:'int',0x01:'string',0x02:'blob',0x03:'struct',0x04:'list',
       0x05:'map',0x06:'union',0x07:'intlist',0x08:'objtype',0x09:'objid',0x0a:'float'}

def read_varint(buf,i):
    # Heat2 varint: 7 bits/byte, high bit = continue; first byte only 6 data bits (bit6=continue)
    b=buf[i]; i+=1
    val=b&0x3f
    if b&0x80:
        shift=6
        while True:
            b=buf[i]; i+=1
            val|=(b&0x7f)<<shift; shift+=7
            if not (b&0x80): break
    return val,i

def walk(buf, depth=0, i=0, end=None):
    if end is None: end=len(buf)
    pad='  '*depth
    while i < end:
        if i+4>end:
            print(f"{pad}[trailing {buf[i:end].hex()}]"); break
        tag=decode_tag(buf[i:i+3]); typ=buf[i+3]; i+=4
        tn=TYPES.get(typ,f'0x{typ:02x}')
        if typ==0x00: # int varint
            v,i=read_varint(buf,i); print(f"{pad}{tag} (int) = {v}")
        elif typ==0x01: # string: varint len + bytes (incl null)
            ln,i=read_varint(buf,i); s=buf[i:i+ln]; i+=ln
            print(f"{pad}{tag} (str) = {s.rstrip(bytes([0])).decode(errors='replace')!r}")
        elif typ==0x02: # blob
            ln,i=read_varint(buf,i); print(f"{pad}{tag} (blob[{ln}]) = {buf[i:i+ln].hex()}"); i+=ln
        elif typ==0x03: # struct: nested until 0x00 terminator
            print(f"{pad}{tag} (struct) {{")
            i=walk(buf,depth+1,i,end)  # walk handles 0x00 term
            print(f"{pad}}}")
        else:
            # unknown/complex: dump remainder briefly and stop this level
            print(f"{pad}{tag} ({tn}) <complex; raw from here> {buf[i:min(i+24,end)].hex()}")
            # best-effort: skip nothing, bail to avoid misparse
            return end
        if i<end and buf[i]==0x00:  # struct terminator
            i+=1; return i
    return i

def main():
    data=open(sys.argv[1],'rb').read()
    ln=struct.unpack('>I',data[0:4])[0]
    comp=struct.unpack('>H',data[6:8])[0]
    cmd=struct.unpack('>H',data[8:10])[0]
    err=struct.unpack('>H',data[10:12])[0]
    mtyp=data[12]
    print(f"== {sys.argv[1]} ==")
    print(f"Fire2 header: len={ln} component=0x{comp:04x} command=0x{cmd:04x} error=0x{err:04x} msgtype=0x{mtyp:02x}")
    print(f"payload ({len(data)-16} bytes):")
    walk(data[16:])

main()