"""Disclosure request service — create, review, check active grants."""

from datetime import datetime, timedelta, timezone
from typing import Optional

from sqlalchemy.orm import Session

from app.models.audit import DisclosureRequest, Notification
from app.models.case import Case
from app.models.user import User


def has_active_disclosure(db: Session, case_id: int, user_id: int) -> tuple[bool, Optional[datetime]]:
    """Check if user has an active (approved, non-expired) disclosure for a case.

    Returns (granted: bool, expires_at: datetime | None).
    """
    dr = (
        db.query(DisclosureRequest)
        .filter(
            DisclosureRequest.case_id == case_id,
            DisclosureRequest.requester_id == user_id,
            DisclosureRequest.status == "approved",
            DisclosureRequest.expires_at > datetime.now(timezone.utc),
        )
        .first()
    )
    if dr:
        return True, dr.expires_at
    return False, None


def has_pending_request(db: Session, case_id: int, user_id: int) -> bool:
    """Check if user already has a pending disclosure request for a case."""
    return (
        db.query(DisclosureRequest)
        .filter(
            DisclosureRequest.case_id == case_id,
            DisclosureRequest.requester_id == user_id,
            DisclosureRequest.status == "pending",
        )
        .first()
    ) is not None


def create_disclosure_request(
    db: Session, case_id: int, user_id: int, reason: str
) -> DisclosureRequest:
    """Create a new disclosure request and notify admins."""
    dr = DisclosureRequest(
        case_id=case_id,
        requester_id=user_id,
        reason=reason,
    )
    db.add(dr)
    db.flush()

    # Notify all active admins
    case = db.query(Case).filter(Case.id == case_id).first()
    fall_id = case.fall_id if case else str(case_id)
    requester = db.query(User).filter(User.id == user_id).first()
    requester_name = requester.username if requester else str(user_id)

    admins = db.query(User).filter(User.role == "admin", User.is_active == True).all()  # noqa: E712
    for admin in admins:
        db.add(Notification(
            recipient_id=admin.id,
            notification_type="disclosure_request",
            title=f"Freigabe-Anfrage für Fall {fall_id}",
            message=f"{requester_name} bittet um Einsicht in Personendaten. Begründung: {reason}",
            related_entity_type="disclosure_request",
            related_entity_id=dr.id,
        ))

    db.commit()
    db.refresh(dr)
    return dr


def review_disclosure_request(
    db: Session, request_id: int, admin_id: int, new_status: str
) -> DisclosureRequest:
    """Approve or reject a disclosure request."""
    dr = db.query(DisclosureRequest).filter(DisclosureRequest.id == request_id).first()
    if not dr:
        raise ValueError("Disclosure request not found")
    if dr.status != "pending":
        raise ValueError("Request already reviewed")

    dr.status = new_status
    dr.reviewed_by = admin_id
    dr.reviewed_at = datetime.now(timezone.utc)

    if new_status == "approved":
        dr.expires_at = datetime.now(timezone.utc) + timedelta(hours=24)

    # Notify requester
    case = db.query(Case).filter(Case.id == dr.case_id).first()
    fall_id = case.fall_id if case else str(dr.case_id)

    status_text = "genehmigt" if new_status == "approved" else "abgelehnt"
    db.add(Notification(
        recipient_id=dr.requester_id,
        notification_type="disclosure_resolved",
        title=f"Freigabe-Anfrage {status_text}",
        message=f"Ihre Anfrage für Fall {fall_id} wurde {status_text}.",
        related_entity_type="disclosure_request",
        related_entity_id=dr.id,
    ))

    db.commit()
    db.refresh(dr)
    return dr


def _utcnow_naive() -> datetime:
    """Return current UTC time as a naive datetime, matching MySQL DATETIME columns."""
    return datetime.now(timezone.utc).replace(tzinfo=None)


def revoke_disclosure(db: Session, request_id: int, user_id: int, *, admin: bool = False) -> DisclosureRequest:
    """Revoke an active disclosure by setting expires_at to now.

    If admin=False, only the original requester can revoke their own disclosure.
    If admin=True, any admin can revoke any disclosure.
    """
    dr = db.query(DisclosureRequest).filter(DisclosureRequest.id == request_id).first()
    if not dr:
        raise ValueError("Disclosure request not found")
    if dr.status != "approved":
        raise ValueError("Only approved disclosures can be revoked")
    if dr.expires_at and dr.expires_at <= _utcnow_naive():
        raise ValueError("Disclosure already expired")
    if not admin and dr.requester_id != user_id:
        raise ValueError("Not authorized to revoke this disclosure")

    dr.expires_at = _utcnow_naive()
    db.commit()
    db.refresh(dr)
    return dr


def delete_disclosure_request(db: Session, request_id: int, user_id: int) -> None:
    """Permanently delete a non-active disclosure request owned by the user."""
    dr = db.query(DisclosureRequest).filter(DisclosureRequest.id == request_id).first()
    if not dr:
        raise ValueError("Disclosure request not found")
    if dr.requester_id != user_id:
        raise ValueError("Not authorized to delete this disclosure")
    # Only allow deletion of inactive requests (rejected, expired, revoked)
    if dr.status == "pending":
        raise ValueError("Pending requests cannot be deleted")
    if dr.status == "approved" and dr.expires_at and dr.expires_at > _utcnow_naive():
        raise ValueError("Active disclosures cannot be deleted")
    db.delete(dr)
    db.commit()


def get_my_disclosure_requests(db: Session, user_id: int) -> list[DisclosureRequest]:
    """Return all disclosure requests made by a specific user."""
    return (
        db.query(DisclosureRequest)
        .filter(DisclosureRequest.requester_id == user_id)
        .order_by(DisclosureRequest.created_at.desc())
        .all()
    )


def get_pending_requests(db: Session) -> list[DisclosureRequest]:
    """Return all pending disclosure requests."""
    return (
        db.query(DisclosureRequest)
        .filter(DisclosureRequest.status == "pending")
        .order_by(DisclosureRequest.created_at.desc())
        .all()
    )


def get_pending_count(db: Session) -> int:
    """Return count of pending disclosure requests."""
    return (
        db.query(DisclosureRequest)
        .filter(DisclosureRequest.status == "pending")
        .count()
    )