# core/commands/check.py
from core.connection import BuzzerError

def _split_parent_and_name(path: str) -> tuple[str, str]:
    normalized = path.rstrip("/")
    if not normalized or normalized == "/":
        raise BuzzerError("Für CHECK wird ein Dateipfad benötigt.")

    idx = normalized.rfind("/")
    if idx <= 0:
        return "/", normalized

    parent = normalized[:idx]
    name = normalized[idx + 1:]
    if not name:
        raise BuzzerError("Ungültiger Dateipfad für CHECK.")
    return parent, name


def _lookup_file_size_bytes(conn, path: str) -> int | None:
    parent, filename = _split_parent_and_name(path)
    lines = conn.list_directory(parent)

    for line in lines:
        parts = line.split(",", 2)
        if len(parts) != 3:
            continue

        entry_type, entry_size, entry_name = parts
        if entry_type == "F" and entry_name == filename:
            try:
                return int(entry_size)
            except ValueError:
                return None

    return None


def _estimate_crc_timeout_seconds(conn, size_bytes: int | None) -> float:
    min_timeout = float(getattr(conn, "crc_timeout_min_seconds", 2.0))
    ms_per_100kb = float(getattr(conn, "crc_timeout_ms_per_100kb", 1.5))

    base = max(float(conn.timeout), min_timeout)
    if size_bytes is None or size_bytes <= 0:
        return base

    blocks_100kb = size_bytes / (100.0 * 1024.0)
    extra = blocks_100kb * (ms_per_100kb / 1000.0)
    return base + extra

def execute(conn, path: str) -> dict:
    """Holt die CRC32 nur über Audiodaten und passt Timeout für große Dateien an."""
    size_bytes = _lookup_file_size_bytes(conn, path)
    timeout = _estimate_crc_timeout_seconds(conn, size_bytes)
    crc32 = conn.check_file_crc(path, timeout=timeout)

    return {
        "crc32": crc32,
        "size_bytes": size_bytes,
    }