"""Server-to-server client for url_shortening_service (piha.lc).

Call SHORTENER_BASE_URL (https://piha.lc / https://beta.piha.li).
Auth: Authorization: Bearer <SHORTENER_API_TOKEN> (name:secret).
"""

from __future__ import annotations

import logging

import requests
from django.conf import settings

logger = logging.getLogger(__name__)


def is_configured() -> bool:
    base = (getattr(settings, "SHORTENER_BASE_URL", None) or "").strip()
    token = (getattr(settings, "SHORTENER_API_TOKEN", None) or "").strip()
    return bool(base and token)


def mint_short_url(
    target_url: str,
    *,
    title: str = "",
    external_ref: str = "",
) -> str | None:
    """POST /api/links/. Return short_url, or None if unconfigured / failed.

    Does not raise. Compose must still work when the shortener is down or unset.
    """
    if not is_configured():
        return None
    target = (target_url or "").strip()
    if not target.lower().startswith("https://"):
        logger.info("shortener skip: target is not https")
        return None

    base = str(settings.SHORTENER_BASE_URL).rstrip("/")
    token = str(settings.SHORTENER_API_TOKEN).strip()
    timeout = int(getattr(settings, "SHORTENER_TIMEOUT_SECONDS", 10) or 10)
    try:
        response = requests.post(
            f"{base}/api/links/",
            headers={
                "Authorization": f"Bearer {token}",
                "Content-Type": "application/json",
            },
            json={
                "target_url": target,
                "title": (title or "")[:200],
                "external_ref": (external_ref or "")[:64],
            },
            timeout=timeout,
        )
    except requests.RequestException:
        logger.exception("shortener request failed")
        return None

    if response.status_code not in (200, 201):
        logger.warning(
            "shortener mint failed status=%s",
            response.status_code,
        )
        return None
    try:
        data = response.json()
    except ValueError:
        logger.warning("shortener mint returned non-json")
        return None
    if not isinstance(data, dict):
        return None
    short = (data.get("short_url") or "").strip()
    return short or None


def resolve_display_url(
    target_url: str,
    *,
    title: str = "",
    external_ref: str = "",
) -> str:
    """Short URL when mint succeeds, otherwise the original target."""
    return mint_short_url(
        target_url, title=title, external_ref=external_ref
    ) or target_url