"""
app/api/notifications.py
------------------------
Mobile API endpoint for polling in-app notifications.

GET  /api/v1/notifications
     Returns unread notifications for the authenticated user.
     Accepts ?since=<ISO 8601> to fetch only notifications created after
     that datetime — used by the iPad poller to avoid re-delivering already-
     seen alerts.  Returns a maximum of 50 notifications per call.

PATCH /api/v1/notifications/mark-read
     Marks a list of notification IDs as read.
     Request JSON: { "ids": [1, 2, 3] }
"""

import logging
from datetime import datetime

from flask import Blueprint, request, g
from app import db
from app.models.notification import Notification
from app.api.errors import api_ok, api_error
from app.api.decorators import jwt_required

logger = logging.getLogger(__name__)

bp = Blueprint('api_notifications', __name__)

_INSPECTOR_RELEVANT = {
    'issue_assigned',
    'issue_reassigned',
    'issue_unassigned',
    'issue_status',
    'issue_comment',
    'issue_follow_update',
    'verification_requested',
    'sla_alert',
}


def _parse_since(value):
    """Parse ?since= ISO 8601 string; return None on failure."""
    if not value:
        return None
    for fmt in ('%Y-%m-%dT%H:%M:%S', '%Y-%m-%dT%H:%M:%S.%f', '%Y-%m-%d'):
        try:
            return datetime.strptime(value, fmt)
        except (ValueError, TypeError):
            pass
    return None


@bp.route('/notifications', methods=['GET'])
@jwt_required
def list_notifications():
    """
    Return unread notifications for the authenticated user.

    Query parameters
    ----------------
    since   ISO 8601 datetime  Only return notifications created after this time.
                               Omit for the initial fetch (returns last 50).
    limit   int (default 50, max 50)

    Response 200
    ------------
    {
        "ok": true,
        "data": {
            "notifications": [
                {
                    "id":         12,
                    "title":      "Issue #7 Assigned to You",
                    "body":       "...",
                    "event_type": "issue_assigned",
                    "issue_id":   7,
                    "created_at": "2026-05-15T09:30:00"
                },
                ...
            ],
            "count": 2
        }
    }
    """
    user  = g.api_user
    since = _parse_since(request.args.get('since'))
    limit = min(int(request.args.get('limit', 50)), 50)

    query = Notification.query.filter_by(
        user_id=user.id,
        is_read=False,
    )

    if since:
        query = query.filter(Notification.created_at > since)

    notifications = (
        query
        .order_by(Notification.created_at.asc())
        .limit(limit)
        .all()
    )

    payload = [
        {
            'id':         n.id,
            'title':      n.title,
            'body':       n.body,
            'event_type': n.event_type,
            'issue_id':   n.issue_id,
            'created_at': n.created_at.strftime('%Y-%m-%dT%H:%M:%S'),
        }
        for n in notifications
    ]

    logger.info('API NOTIFICATIONS | list | user=%s | since=%s | count=%d',
                user.username, since, len(payload))

    return api_ok({'notifications': payload, 'count': len(payload)})


@bp.route('/notifications/mark-read', methods=['PATCH'])
@jwt_required
def mark_read():
    """
    Mark a list of notification IDs as read.

    Request JSON: { "ids": [1, 2, 3] }

    Response 200
    ------------
    { "ok": true, "data": { "marked": 3 } }
    """
    user = g.api_user
    data = request.get_json(silent=True) or {}
    ids  = data.get('ids') or []

    if not isinstance(ids, list):
        return api_error('ids must be a list', 400)

    if ids:
        updated = (
            Notification.query
            .filter(
                Notification.id.in_(ids),
                Notification.user_id == user.id,   # never touch another user's records
            )
            .all()
        )
        for n in updated:
            n.is_read = True
        db.session.commit()
        count = len(updated)
    else:
        count = 0

    logger.info('API NOTIFICATIONS | mark_read | user=%s | count=%d', user.username, count)
    return api_ok({'marked': count})