import hashlib
import os
import re
from datetime import datetime, timedelta, timezone

from flask import Blueprint, request, jsonify
from sqlalchemy import func, text

from app.extensions import db
from app.models.page_view import PageView
from app.models.property import Property
from app.utils.auth import require_admin

analytics_bp = Blueprint("analytics", __name__)

# ─── Helpers ─────────────────────────────────────────────────────────────────

_PROPERTY_PATH_RE = re.compile(
    r"^/api/v1/properties/([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})",
    re.IGNORECASE,
)

_SKIP_PREFIXES = ("/api/v1/admin", "/api/v1/auth", "/static")


def _should_track(path: str, method: str) -> bool:
    if method != "GET":
        return False
    for prefix in _SKIP_PREFIXES:
        if path.startswith(prefix):
            return False
    return True


def _ip_hash(ip: str) -> str:
    salt = os.environ.get("IP_SALT", "default-salt")
    return hashlib.sha256(f"{ip}{salt}".encode()).hexdigest()


def record_page_view(path: str, ip: str, user_agent: str) -> None:
    """Insert a page_view row. Silently swallows errors to never break requests."""
    try:
        match = _PROPERTY_PATH_RE.match(path)
        property_id = match.group(1) if match else None

        pv = PageView(
            path=path,
            property_id=property_id,
            ip_hash=_ip_hash(ip),
            user_agent=(user_agent or "")[:512],
        )
        db.session.add(pv)
        db.session.commit()
    except Exception:
        db.session.rollback()


# ─── Admin endpoints ──────────────────────────────────────────────────────────


def _period_start(days: int) -> datetime:
    return datetime.now(timezone.utc) - timedelta(days=days)


@analytics_bp.get("/summary")
@require_admin
def analytics_summary():
    """Cards: total today / this week / this month + daily series."""
    days = int(request.args.get("days", 30))
    if days not in (7, 30, 90):
        days = 30

    now = datetime.now(timezone.utc)
    start_day = now.replace(hour=0, minute=0, second=0, microsecond=0)
    start_week = start_day - timedelta(days=now.weekday())
    start_month = start_day.replace(day=1)
    start_period = _period_start(days)

    def count_since(dt: datetime) -> int:
        return (
            db.session.query(func.count(PageView.id))
            .filter(PageView.accessed_at >= dt)
            .scalar()
            or 0
        )

    # daily series for sparkline/chart
    daily = (
        db.session.query(
            func.date_trunc("day", PageView.accessed_at).label("day"),
            func.count(PageView.id).label("views"),
        )
        .filter(PageView.accessed_at >= start_period)
        .group_by(text("day"))
        .order_by(text("day"))
        .all()
    )

    series = [
        {"date": row.day.strftime("%Y-%m-%d"), "views": row.views} for row in daily
    ]

    return jsonify(
        {
            "today": count_since(start_day),
            "this_week": count_since(start_week),
            "this_month": count_since(start_month),
            "period_days": days,
            "period_total": count_since(start_period),
            "series": series,
        }
    )


@analytics_bp.get("/top-pages")
@require_admin
def analytics_top_pages():
    """Top 10 most-viewed paths in the given period."""
    days = int(request.args.get("days", 30))
    if days not in (7, 30, 90):
        days = 30

    rows = (
        db.session.query(PageView.path, func.count(PageView.id).label("views"))
        .filter(PageView.accessed_at >= _period_start(days))
        .group_by(PageView.path)
        .order_by(func.count(PageView.id).desc())
        .limit(10)
        .all()
    )

    return jsonify([{"path": r.path, "views": r.views} for r in rows])


@analytics_bp.get("/top-properties")
@require_admin
def analytics_top_properties():
    """Top 10 most-viewed properties in the given period."""
    days = int(request.args.get("days", 30))
    if days not in (7, 30, 90):
        days = 30

    rows = (
        db.session.query(PageView.property_id, func.count(PageView.id).label("views"))
        .filter(
            PageView.accessed_at >= _period_start(days),
            PageView.property_id.isnot(None),
        )
        .group_by(PageView.property_id)
        .order_by(func.count(PageView.id).desc())
        .limit(10)
        .all()
    )

    result = []
    for row in rows:
        prop = db.session.get(Property, row.property_id)
        if prop:
            photos = prop.photos or []
            result.append(
                {
                    "property_id": row.property_id,
                    "views": row.views,
                    "title": prop.title,
                    "cover": photos[0] if photos else None,
                    "city": prop.city.name if prop.city else None,
                    "neighborhood": (
                        prop.neighborhood.name if prop.neighborhood else None
                    ),
                }
            )

    return jsonify(result)