"""UI helper functions for data formatting and display."""

import re


def prefer_language(value: str | dict | None, lang_code: str) -> str | None:
    """Return the value for the requested language with sensible fallbacks."""
    if isinstance(value, str):
        return value or None
    if not isinstance(value, dict):
        return None
    order = [lang_code, "de", "fr", "it", "rm", "en"]
    for code in order:
        text = value.get(code)
        if text:
            return text
    for text in value.values():
        if text:
            return text
    return None


def strip_html(text: str) -> str:
    """Remove HTML tags and collapse whitespace for short summaries."""
    if not text:
        return ""
    cleaned = re.sub(r"<[^>]+>", " ", text)
    cleaned = re.sub(r"\s+", " ", cleaned).strip()
    return cleaned


def pick_external_url(*candidates) -> str | None:
    """Return the first non-empty external URL."""
    for candidate in candidates:
        if not candidate:
            continue
        if isinstance(candidate, dict):
            # Prefer German, fall back to any available language
            url = prefer_language(candidate, "de") or prefer_language(candidate, "fr") or prefer_language(candidate, "it")
            if url:
                return url
        elif isinstance(candidate, str) and candidate.strip():
            return candidate.strip()
    return None