"""Bounded optional daily Garmin imports; provider failures never disclose sessions."""

from datetime import UTC, datetime, timedelta
from zoneinfo import ZoneInfo

from .analytics import numeric
from .extensions import db
from .models import DailyHealth


def normalize(stats, hrv, sleep):
    summary = (hrv or {}).get("hrvSummary") or {}
    dto = (sleep or {}).get("dailySleepDTO") or {}
    candidates = {"resting_hr": (stats or {}).get("restingHeartRate"),
                  "hrv": summary.get("lastNightAvg"),
                  "sleep_hours": dto.get("sleepTimeSeconds"),
                  "stress": (stats or {}).get("averageStressLevel")}
    values = {}
    for key, number in candidates.items():
        if not numeric(number):
            continue
        if key == "sleep_hours":
            number /= 3600
        low, high = {"resting_hr": (25, 220), "hrv": (1, 500),
                     "sleep_hours": (0, 24), "stress": (0, 100)}[key]
        if low <= number <= high:
            values[key] = number
    return values


def sync_health(api, user, days=90, limit=5):
    today = datetime.now(UTC).astimezone(ZoneInfo(user.timezone)).date()
    first = today - timedelta(days=days - 1)
    known = {row.day: row for row in db.session.scalars(db.select(DailyHealth).where(
        DailyHealth.owner_id == user.id, DailyHealth.day >= first))}
    # Refresh today/yesterday; then walk backwards through missing history.
    dates = [today, today - timedelta(days=1)]
    dates += [today - timedelta(days=i) for i in range(2, days)
              if today - timedelta(days=i) not in known or
              not known[today - timedelta(days=i)].values.get("_complete")]
    dates = [day for day in dates if day >= first][:limit]
    imported = failures = 0
    for day in dates:
        documents = []
        day_failures = 0
        for method in ("get_stats", "get_hrv_data", "get_sleep_data"):
            try:
                document = getattr(api, method)(day.isoformat())
                documents.append(document if isinstance(document, dict) else {})
            except Exception:  # noqa: BLE001 -- never log provider responses or credentials
                documents.append({})
                failures += 1
                day_failures += 1
        values = normalize(*documents)
        if day_failures and not values:
            # Retry later; stop the batch instead of hammering a failing provider.
            break
        row = known.get(day)
        if not row:
            row = DailyHealth(owner_id=user.id, day=day, values={})
            db.session.add(row)
        row.values = {**row.values, **values, "_complete": day_failures == 0}
        row.fetched_at = datetime.now(UTC)
        db.session.commit()
        imported += 1
        if day_failures:
            break
    return {"days": imported, "failures": failures,
            "message": f"Daily recovery: {imported} dates checked." +
            (" Some observations unavailable; will retry." if failures else
             " Missing watch observations remain missing.")}