"""Shared firmware release catalog contract from ``update.json``."""

from __future__ import annotations

import json
import re
from dataclasses import dataclass
from pathlib import Path
from urllib.parse import urljoin, urlparse

MAX_MANIFEST_BYTES = 128 * 1024
SUPPORTED_TRANSPORTS = frozenset({"rs485", "can", "stm32", "tms"})


@dataclass(frozen=True)
class FirmwareRelease:
    product: str
    version: str
    version_code: int
    image_url: str
    sha256: str
    file_name: str
    notes: str = ""
    transport: str = "rs485"
    base_address: int | None = None


def parse_firmware_catalog(data: bytes, manifest_url: str) -> list[FirmwareRelease]:
    """Parse and validate the optional ``firmware.releases`` section."""
    if len(data) > MAX_MANIFEST_BYTES:
        raise ValueError("Файл каталога прошивок слишком большой")
    try:
        root = json.loads(data.decode("utf-8"))
    except (UnicodeDecodeError, json.JSONDecodeError) as error:
        raise ValueError("Некорректный JSON каталога прошивок") from error
    firmware = root.get("firmware") if isinstance(root, dict) else None
    rows = firmware.get("releases") if isinstance(firmware, dict) else firmware
    if not isinstance(rows, list):
        raise ValueError("В update.json не опубликован каталог прошивок")
    releases: list[FirmwareRelease] = []
    for index, row in enumerate(rows, 1):
        if not isinstance(row, dict):
            raise ValueError(f"Некорректная запись прошивки №{index}")
        product = str(row.get("product", row.get("device", ""))).strip()
        version = str(row.get("versionName", row.get("version", ""))).strip()
        raw_url = str(row.get("imageUrl", row.get("url", ""))).strip()
        sha256 = str(row.get("sha256", "")).strip().lower()
        try:
            version_code = int(row.get("versionCode", 0))
        except (TypeError, ValueError) as error:
            raise ValueError(f"Некорректная версия прошивки №{index}") from error
        if not product or not version or version_code < 0 or not raw_url:
            raise ValueError(f"Не заполнены обязательные поля прошивки №{index}")
        if len(sha256) != 64 or any(char not in "0123456789abcdef" for char in sha256):
            raise ValueError(f"Некорректный SHA-256 прошивки №{index}")
        image_url = urljoin(manifest_url, raw_url)
        parsed = urlparse(image_url)
        if parsed.scheme.lower() != "https" or not parsed.hostname:
            raise ValueError("Обновления разрешены только по HTTPS")
        file_name = str(row.get("fileName", Path(parsed.path).name)).strip()
        if not re.fullmatch(r"[A-Za-zА-Яа-яЁё0-9._ -]+\.(?:bin|hex)", file_name, re.I):
            raise ValueError(f"Некорректное имя файла прошивки №{index}")
        base_raw = row.get("baseAddress")
        try:
            base_address = int(str(base_raw), 0) if base_raw is not None else None
        except ValueError as error:
            raise ValueError(f"Некорректный адрес прошивки №{index}") from error
        transport = str(row.get("transport", "rs485")).strip().lower()
        if transport not in SUPPORTED_TRANSPORTS:
            raise ValueError(f"Некорректный канал прошивки №{index}")
        releases.append(FirmwareRelease(
            product, version, version_code, image_url, sha256, file_name,
            str(row.get("notes", "")).strip(), transport, base_address,
        ))
    return sorted(releases, key=lambda item: (item.product.casefold(), -item.version_code))