"""
Background scheduler for the Saxo connection — mirrors services/var_scheduler.py.

Two independent loops:
- Token refresh: proactively renews the access/refresh token well before the 40-min
  refresh-token expiry (SIM), so the user never has to re-login as long as the
  server keeps running.
- Snapshot poller: periodically captures an options-chain snapshot for each symbol
  in the configured watchlist and appends it to saxo_option_snapshots.
"""
from __future__ import annotations

import json
import logging
import threading

logger = logging.getLogger(__name__)

_refresh_thread: threading.Thread | None = None
_snapshot_thread: threading.Thread | None = None
_refresh_stop = threading.Event()
_snapshot_stop = threading.Event()

DEFAULT_WATCHLIST = ["SPY", "QQQ", "GLD", "SLV", "USO"]
REFRESH_INTERVAL_SECONDS = 10 * 60  # well under the 40-min refresh-token lifetime


def get_watchlist() -> list[str]:
    from .database import get_config
    raw = get_config("saxo_watchlist")
    if not raw:
        return DEFAULT_WATCHLIST
    try:
        return json.loads(raw)
    except Exception:
        return DEFAULT_WATCHLIST


def set_watchlist(symbols: list[str]):
    from .database import set_config
    set_config("saxo_watchlist", json.dumps([s.upper() for s in symbols]))


def _refresh_loop(stop: threading.Event):
    while not stop.wait(0):
        try:
            from .saxo_auth import get_status, refresh_tokens, disconnect
            if get_status().get("connected"):
                try:
                    refresh_tokens()
                    logger.info("[Saxo Scheduler] Token refreshed proactively")
                except Exception as e:
                    # Refresh token rejected (expired/rotated/invalid) — the stored access
                    # token is now dead even though its expires_at hasn't passed yet. Clear
                    # it so /api/saxo/status stops reporting a stale "connected" state, and
                    # the user gets a clear "reconnect" signal instead of silent 401s later.
                    logger.error(f"[Saxo Scheduler] Refresh failed, clearing dead session: {e}")
                    disconnect()
        except Exception as e:
            logger.error(f"[Saxo Scheduler] Refresh loop error: {e}")
        stop.wait(timeout=REFRESH_INTERVAL_SECONDS)


def get_snapshot_minutes() -> float:
    from .database import get_config
    return float(get_config("saxo_snapshot_minutes") or "5")


def set_snapshot_minutes(minutes: float):
    from .database import set_config
    set_config("saxo_snapshot_minutes", str(minutes))


def run_snapshot_pass() -> dict[str, int]:
    """Snapshot every watchlist symbol once — shared by the periodic loop, the
    'connect now' trigger (saxo_oauth.py callback), and the manual refresh button."""
    from .saxo_client import snapshot_options_chain
    from .database import save_saxo_snapshot_rows
    results: dict[str, int] = {}
    for symbol in get_watchlist():
        try:
            rows = snapshot_options_chain(symbol)
            save_saxo_snapshot_rows(rows)
            results[symbol] = len(rows)
            logger.info(f"[Saxo Scheduler] Snapshot saved: {symbol} ({len(rows)} rows)")
        except Exception as e:
            results[symbol] = 0
            logger.warning(f"[Saxo Scheduler] Snapshot failed for {symbol}: {e}")
    return results


def _snapshot_loop(stop: threading.Event):
    while not stop.wait(0):
        try:
            from .saxo_auth import get_status
            minutes = get_snapshot_minutes()

            if get_status().get("connected"):
                run_snapshot_pass()
            else:
                minutes = max(minutes, 5)  # don't busy-loop while disconnected
        except Exception as e:
            logger.error(f"[Saxo Scheduler] Snapshot loop error: {e}")
            minutes = 5

        stop.wait(timeout=minutes * 60)


def start_saxo_scheduler():
    global _refresh_thread, _snapshot_thread
    _refresh_stop.clear()
    _snapshot_stop.clear()
    if not (_refresh_thread and _refresh_thread.is_alive()):
        _refresh_thread = threading.Thread(target=_refresh_loop, args=(_refresh_stop,), name="saxo-refresh", daemon=True)
        _refresh_thread.start()
    if not (_snapshot_thread and _snapshot_thread.is_alive()):
        _snapshot_thread = threading.Thread(target=_snapshot_loop, args=(_snapshot_stop,), name="saxo-snapshot", daemon=True)
        _snapshot_thread.start()
    logger.info("[Saxo Scheduler] Started")


def stop_saxo_scheduler():
    _refresh_stop.set()
    _snapshot_stop.set()