"""
User Activity model for real-time presence tracking.
Tracks who is currently on the site and what page they're viewing.
"""
from datetime import datetime, timezone, timedelta
from pymongo import DESCENDING
from ..core.db_connector import db

ACTIVITY_COLLECTION = "user_activity"
activity_collection = db[ACTIVITY_COLLECTION]


def _ensure_indexes():
    try:
        activity_collection.create_index([("last_seen", DESCENDING)])
        activity_collection.create_index([("user_id", DESCENDING)])
        activity_collection.create_index("last_seen", expireAfterSeconds=300)
    except Exception:
        pass


_ensure_indexes()


def ping_user(user_id, username, avatar, page_url, page_title="", anonymous_id=None, ip_address=None):
    """Record or update a user's presence on the site.

    For authenticated users:
      - keyed by user_id (MongoDB ObjectId str)
      - shows their username & avatar

    For anonymous visitors:
      - keyed by anonymous_id (client-generated UUID stored in localStorage)
      - deduplicated by ip_address if anonymous_id not provided
      - shows "Guest" in the activity feed
    """
    now = datetime.now(timezone.utc)

    if user_id and username:
        # Authenticated user
        filter_key = {"user_id": str(user_id)}
        display_name = username
    elif anonymous_id:
        # Anonymous user with client ID
        filter_key = {"anonymous_id": anonymous_id}
        display_name = "Guest"
    elif ip_address:
        # Anonymous user identified by IP (fallback)
        filter_key = {"ip_address": ip_address, "user_id": {"$exists": False}}
        display_name = "Guest"
    else:
        return False

    doc = {
        "last_seen": now,
        "page_url": page_url,
        "page_title": page_title,
    }

    if user_id and username:
        doc["user_id"] = str(user_id)
        doc["username"] = username
        doc["avatar"] = avatar or ""
        # Remove any anonymous fields if user later logs in
        activity_collection.update_many(
            {"ip_address": ip_address, "user_id": {"$exists": False}},
            {"$set": {"user_id": str(user_id), "username": username, "avatar": avatar or ""}}
        )
    else:
        doc["is_anonymous"] = True
        doc["username"] = "Guest"
        doc["avatar"] = ""
        if anonymous_id:
            doc["anonymous_id"] = anonymous_id
        if ip_address:
            doc["ip_address"] = ip_address

    activity_collection.update_one(
        filter_key,
        {"$set": doc, "$setOnInsert": {"first_seen": now}},
        upsert=True
    )
    return True


def get_active_users(minutes=5):
    """Get users active within the last N minutes.
    Returns: list of dicts with user info including is_anonymous flag.
    """
    cutoff = datetime.now(timezone.utc) - timedelta(minutes=minutes)
    cursor = activity_collection.find(
        {"last_seen": {"$gte": cutoff}}
    ).sort("last_seen", DESCENDING)

    seen_ids = set()
    users = []
    for doc in cursor:
        # Deduplicate: prefer authenticated version over anonymous
        uid = doc.get("user_id") or doc.get("anonymous_id") or doc.get("ip_address") or ""
        if uid in seen_ids:
            continue
        seen_ids.add(uid)

        is_anon = doc.get("is_anonymous", False) or not doc.get("user_id")
        display_name = doc.get("username", "Guest")
        # Differentiate anonymous guests with a short ID suffix
        if is_anon and doc.get("anonymous_id"):
            short_id = str(doc["anonymous_id"])[-5:]
            display_name = f"Guest_{short_id}"

        users.append({
            "user_id": doc.get("user_id", ""),
            "username": display_name,
            "avatar": doc.get("avatar", ""),
            "page_url": doc.get("page_url", ""),
            "page_title": doc.get("page_title", ""),
            "last_seen": doc["last_seen"].isoformat() if doc.get("last_seen") else None,
            "first_seen": doc["first_seen"].isoformat() if doc.get("first_seen") else None,
            "is_anonymous": is_anon,
        })
    return users


def get_active_user_count(minutes=5):
    """Count users active within the last N minutes."""
    cutoff = datetime.now(timezone.utc) - timedelta(minutes=minutes)
    return activity_collection.count_documents({"last_seen": {"$gte": cutoff}})