"""Message encoding/decoding utilities for hbd protocol."""
from typing import Dict, Any
import zlib


def dicttos(ID: str, d: Dict[str, Any], compress: bool = False):
    """Serialize a dict to protocol message bytes.

    If compress is True, the payload is zlib-compressed and the message is
    prefixed with `!ID:` as the original script did. Otherwise the format is
    `ID:key=value;...` (bytes).
    """
    s = []
    for k in d:
        v = d[k]
        if isinstance(v, float):
            s.append(f"{k}={v:0.5f}")
        else:
            s.append(f"{k}={v}")
    pk = ";".join(s)
    if compress:
        zpk = zlib.compress(pk.encode(), 6)
        hdr = ("!" + ID + ":").encode()
        return hdr + zpk
    else:
        return (ID + ":" + pk).encode()


def stodict(msg: bytes):
    """Deserialize a protocol message into a dict.

    Mirrors original behaviour: detects compressed messages starting with
    '!' and decodes accordingly. Returns a dict with key 'ID' set to the
    message ID and the parsed key/value pairs.
    """
    d = {}
    if len(msg) > 0 and chr(msg[0]) == "!":
        # message is: b'!ID:' + compressed_payload
        # original code used msg[1:4].decode() for ID (3 bytes including colon)
        try:
            pk = zlib.decompress(msg[5:]).decode()
        except Exception:
            # malformed compressed payload
            return {}
        d["ID"] = msg[1:4].decode()
    else:
        try:
            r0 = msg.split(b":", 1)
            pk = r0[1].decode()
            d["ID"] = r0[0].decode()
        except Exception:
            return {}
    if not pk:
        return d
    parts = pk.split(";")
    for v in parts:
        if not v:
            continue
        vr = v.split("=", 1)
        k = vr[0].strip()
        if len(vr) == 1:
            d[k] = None
        else:
            val = vr[1].strip()
            if val and val[0].isdigit():
                try:
                    val_e = eval(val)
                except Exception:
                    val_e = val
                d[k] = val_e
            else:
                d[k] = val
    return d


def oldmtodict(msg: bytes):
    """Compatibility wrapper for old-style messages (no ID prefix).

    The original implementation prefixed with 'HTB:' and called stodict.
    """
    return stodict(b"HTB:" + msg)