"""
Shared notification utilities — used by llm_processor, congress_poller, etc.
Centralised here to avoid circular imports.
"""
from datetime import datetime, timedelta, timezone

_VOTE_KW       = ["passed", "failed", "agreed to", "roll call"]
_PRES_KW       = ["signed", "vetoed", "enacted", "presented to the president"]
_COMMITTEE_KW  = ["markup", "ordered to be reported", "ordered reported", "reported by", "discharged"]
_CALENDAR_KW   = ["placed on"]
_PROCEDURAL_KW = ["cloture", "conference"]
_REFERRAL_KW   = ["referred to"]

# Events created within this window for the same (user, bill, event_type) are suppressed
_DEDUP_MINUTES = 30


def categorize_action(action_text: str) -> str | None:
    """Return the action category string, or None if not notification-worthy."""
    t = (action_text or "").lower()
    if any(kw in t for kw in _VOTE_KW):       return "vote"
    if any(kw in t for kw in _PRES_KW):       return "presidential"
    if any(kw in t for kw in _COMMITTEE_KW):  return "committee_report"
    if any(kw in t for kw in _CALENDAR_KW):   return "calendar"
    if any(kw in t for kw in _PROCEDURAL_KW): return "procedural"
    if any(kw in t for kw in _REFERRAL_KW):   return "referral"
    return None


def _build_payload(
    bill, action_summary: str, action_category: str, source: str = "bill_follow"
) -> dict:
    from app.config import settings
    base_url = (settings.PUBLIC_URL or settings.LOCAL_URL).rstrip("/")
    return {
        "bill_title": bill.short_title or bill.title or "",
        "bill_label": f"{bill.bill_type.upper()} {bill.bill_number}",
        "brief_summary": (action_summary or "")[:300],
        "bill_url": f"{base_url}/bills/{bill.bill_id}",
        "action_category": action_category,
        # kept for RSS/history backwards compat
        "milestone_tier": "referral" if action_category == "referral" else "progress",
        "source": source,
    }


def _is_duplicate(db, user_id: int, bill_id: str, event_type: str) -> bool:
    """True if an identical event was already created within the dedup window."""
    from app.models.notification import NotificationEvent
    cutoff = datetime.now(timezone.utc) - timedelta(minutes=_DEDUP_MINUTES)
    return db.query(NotificationEvent).filter_by(
        user_id=user_id,
        bill_id=bill_id,
        event_type=event_type,
    ).filter(NotificationEvent.created_at > cutoff).first() is not None


def emit_bill_notification(
    db, bill, event_type: str, action_summary: str, action_category: str = "vote"
) -> int:
    """Create NotificationEvent rows for every user following this bill. Returns count."""
    from app.models.follow import Follow
    from app.models.notification import NotificationEvent

    followers = db.query(Follow).filter_by(follow_type="bill", follow_value=bill.bill_id).all()
    if not followers:
        return 0

    payload = _build_payload(bill, action_summary, action_category, source="bill_follow")
    count = 0
    for follow in followers:
        if _is_duplicate(db, follow.user_id, bill.bill_id, event_type):
            continue
        db.add(NotificationEvent(
            user_id=follow.user_id,
            bill_id=bill.bill_id,
            event_type=event_type,
            payload=payload,
        ))
        count += 1
    if count:
        db.commit()
    return count


def emit_member_follow_notifications(
    db, bill, event_type: str, action_summary: str, action_category: str = "vote"
) -> int:
    """Notify users following the bill's sponsor (dedup prevents double-alerts for bill+member followers)."""
    if not bill.sponsor_id:
        return 0

    from app.models.follow import Follow
    from app.models.notification import NotificationEvent

    followers = db.query(Follow).filter_by(follow_type="member", follow_value=bill.sponsor_id).all()
    if not followers:
        return 0

    payload = _build_payload(bill, action_summary, action_category, source="member_follow")
    count = 0
    for follow in followers:
        if _is_duplicate(db, follow.user_id, bill.bill_id, event_type):
            continue
        db.add(NotificationEvent(
            user_id=follow.user_id,
            bill_id=bill.bill_id,
            event_type=event_type,
            payload=payload,
        ))
        count += 1
    if count:
        db.commit()
    return count


def emit_topic_follow_notifications(
    db, bill, event_type: str, action_summary: str, topic_tags: list,
    action_category: str = "vote",
) -> int:
    """Notify users following any of the bill's topic tags."""
    if not topic_tags:
        return 0

    from app.models.follow import Follow
    from app.models.notification import NotificationEvent

    # Collect unique followers across all matching tags
    seen_user_ids: set[int] = set()
    followers = []
    for tag in topic_tags:
        for follow in db.query(Follow).filter_by(follow_type="topic", follow_value=tag).all():
            if follow.user_id not in seen_user_ids:
                seen_user_ids.add(follow.user_id)
                followers.append(follow)

    if not followers:
        return 0

    payload = _build_payload(bill, action_summary, action_category, source="topic_follow")
    count = 0
    for follow in followers:
        if _is_duplicate(db, follow.user_id, bill.bill_id, event_type):
            continue
        db.add(NotificationEvent(
            user_id=follow.user_id,
            bill_id=bill.bill_id,
            event_type=event_type,
            payload=payload,
        ))
        count += 1
    if count:
        db.commit()
    return count