"""Read the archived IR schema examples without a Python numerical engine."""
from dataclasses import is_dataclass
from enum import Enum
from functools import lru_cache
import gzip
import json
from pathlib import Path

from app.simulation.ir import schema


def _decode(value):
    if isinstance(value, list):
        return tuple(_decode(item) for item in value)
    if isinstance(value, dict):
        if 'enum' in value:
            cls = getattr(schema, value['enum'])
            if not isinstance(cls, type) or not issubclass(cls, Enum):
                raise ValueError('Invalid IR enum in fixture')
            return cls(value['value'])
        cls = getattr(schema, value['type'])
        if not isinstance(cls, type) or not is_dataclass(cls):
            raise ValueError('Invalid IR record in fixture')
        return cls(**{key: _decode(item) for key, item in value['fields'].items()})
    return value


@lru_cache(maxsize=1)
def _references():
    path = Path(__file__).parent / 'data/system-ir-v2-reference.json.gz'
    return json.loads(gzip.decompress(path.read_bytes()))['programs']


def reference_ir(name):
    return _decode(_references()[name])