import json
from typing import Any

from core.domain.errors import (
    CDRProcessingError,
    FailureReason,
)
from core.domain.models import NormalizedCDR
from core.domain.normalization import normalize_cdr
from core.domain.validation import parse_raw_cdr


def decode_payload(value: bytes) -> dict[str, Any]:
    try:
        text = value.decode("utf-8")
        payload = json.loads(text)

    except (UnicodeDecodeError, json.JSONDecodeError) as exc:
        raise CDRProcessingError(
            reason=FailureReason.MALFORMED_JSON,
            detail=f"Unable to decode Kafka message as JSON: {exc}",
        ) from exc

    if not isinstance(payload, dict):
        raise CDRProcessingError(
            reason=FailureReason.NORMALIZATION_ERROR,
            detail="Kafka JSON payload must be an object.",
        )

    return payload


def process_payload(
    payload: dict[str, Any],
) -> NormalizedCDR:
    raw_cdr = parse_raw_cdr(payload)

    return normalize_cdr(raw_cdr)