"""
Shared role / access helpers for DigiServer blueprints.

Import these instead of duplicating decorators in every blueprint.
"""
from functools import wraps
from flask import abort, flash, redirect, url_for
from flask_login import current_user


# ── Role-gate decorators ──────────────────────────────────────────────────────

def editor_required(f):
    """Allow admin and editor roles; redirect viewers with a flash message."""
    @wraps(f)
    def decorated(*args, **kwargs):
        if not current_user.is_authenticated:
            return redirect(url_for('auth.login'))
        if current_user.role not in ('admin', 'editor'):
            flash('You need editor or admin privileges to perform this action.', 'danger')
            return redirect(url_for('main.dashboard'))
        return f(*args, **kwargs)
    return decorated


def admin_required(f):
    """Allow admin role only."""
    @wraps(f)
    def decorated(*args, **kwargs):
        if not current_user.is_authenticated:
            return redirect(url_for('auth.login'))
        if current_user.role != 'admin':
            flash('Administrator access required.', 'danger')
            return redirect(url_for('main.dashboard'))
        return f(*args, **kwargs)
    return decorated


# ── Playlist permission check ─────────────────────────────────────────────────

def can_edit_playlist(user, playlist_id: int) -> bool:
    """
    Return True if *user* is allowed to edit the given playlist.

    - admin / editor  → always True
    - viewer          → True only when a PlaylistPermission row exists
    """
    if user.role in ('admin', 'editor'):
        return True
    from app.models.playlist_permission import PlaylistPermission
    return PlaylistPermission.query.filter_by(
        user_id=user.id, playlist_id=playlist_id
    ).first() is not None


def get_editable_playlist_ids(user) -> set:
    """Return the set of playlist IDs the user may edit (used in list views)."""
    if user.role in ('admin', 'editor'):
        # Import here to avoid circular imports at module load time
        from app.models.playlist import Playlist
        return {p.id for p in Playlist.query.with_entities(Playlist.id).all()}
    from app.models.playlist_permission import PlaylistPermission
    rows = PlaylistPermission.query.filter_by(user_id=user.id).all()
    return {r.playlist_id for r in rows}