import json
from typing import Dict, Any, Tuple


class PackingError(Exception):
    pass


class GXPacker:
    MAGIC = b'XIC'
    VERSION = 1

    @staticmethod
    def pack(manifest: Dict[str, Any], compressed_payload: bytes) -> bytes:
        try:
            header = GXPacker.MAGIC
            header += bytes([GXPacker.VERSION])

            manifest_json = json.dumps(manifest, separators=(',', ':')).encode('utf-8')
            manifest_len = len(manifest_json)
            header += manifest_len.to_bytes(4, 'big')

            result = header + manifest_json + compressed_payload

            return result
        except Exception as e:
            raise PackingError(f"Packing failed: {e}")

    @staticmethod
    def unpack(data: bytes) -> Tuple[Dict[str, Any], bytes]:
        try:
            if len(data) < 8:
                raise PackingError("Data too short for GX header")

            if data[:3] != GXPacker.MAGIC:
                raise PackingError("Invalid magic number")

            version = data[3]
            if version != GXPacker.VERSION:
                raise PackingError(f"Unsupported version: {version}")

            manifest_len = int.from_bytes(data[4:8], 'big')

            if len(data) < 8 + manifest_len:
                raise PackingError("Incomplete manifest")

            manifest_json = data[8:8 + manifest_len]
            compressed_payload = data[8 + manifest_len:]

            manifest = json.loads(manifest_json.decode('utf-8'))

            return manifest, compressed_payload
        except PackingError:
            raise
        except Exception as e:
            raise PackingError(f"Unpacking failed: {e}")