주소 후보의 해석 오류와 항목 실패를 나누는 모듈

"""Ordered syntax selection; this module never fetches a resource."""
from urllib.parse import urljoin, urlsplit

MAX_CANDIDATES = 32
MAX_CHARACTERS = 4096

def select_candidate(base, candidates):
    """Return an index and bounded diagnostics, never the input addresses."""
    if type(base) is not str or not base or len(base) > MAX_CHARACTERS:
        raise ValueError("invalid base contract")
    parsed_base = urlsplit(base)
    if parsed_base.scheme not in ("http", "https") or not parsed_base.hostname:
        raise ValueError("base must be an absolute HTTP(S) address")
    if type(candidates) is not list or len(candidates) > MAX_CANDIDATES:
        raise ValueError("expected at most 32 ordered candidates")
    if any(type(value) is not str or len(value) > MAX_CHARACTERS
           for value in candidates):
        raise ValueError("candidate must be a string of at most 4096 characters")
    errors, skipped = [], []
    chosen = None
    attempted = 0
    for index, raw in enumerate(candidates):
        attempted += 1
        value = raw.strip()
        if not value:
            skipped.append({"index": index, "reason": "empty"})
            continue
        try:
            parsed = urlsplit(urljoin(base, value))
        except ValueError:
            errors.append({"index": index, "reason": "parse_error"})
            continue
        if parsed.scheme not in ("http", "https"):
            skipped.append({"index": index, "reason": "unsupported_scheme"})
            continue
        chosen = index
        break
    return {
        "selected_index": chosen,
        "attempted": attempted,
        "parse_errors": errors,
        "skipped": skipped,
        "unresolved_parse_failure": chosen is None and bool(errors),
        "performs_fetch": False,
        "security_approval": False,
    }