from __future__ import annotations

import os
import threading
from datetime import datetime, time, timedelta
from zoneinfo import ZoneInfo

from sqlalchemy import select

from app.core.agent_enums import AgentRunSource, AgentRunStatus
from app.core.logging import get_logger
from app.db.session import get_session_factory
from app.models.agent_run import AgentRun
from app.services.digital_employee_finance_report_task import (
    FINANCE_REPORT_TASK_TYPE,
    DigitalEmployeeFinanceReportTaskService,
)

logger = get_logger("app.services.finance_report_scheduler")


class FinanceReportScheduler:
    def __init__(self) -> None:
        timezone_name = str(os.environ.get("X_FINANCIAL_SCHEDULER_TZ") or "Asia/Shanghai").strip()
        report_time = str(os.environ.get("X_FINANCIAL_FINANCE_REPORT_TIME") or "08:30").strip()
        initial_delay = int(
            os.environ.get("X_FINANCIAL_FINANCE_REPORT_INITIAL_DELAY_SECONDS") or "36"
        )
        self._timezone = ZoneInfo(timezone_name or "Asia/Shanghai")
        self._report_time = self._parse_time(report_time)
        self._initial_delay_seconds = max(1, initial_delay)
        self._stop_event = threading.Event()
        self._thread: threading.Thread | None = None
        self._lock = threading.Lock()

    def start(self) -> None:
        with self._lock:
            if self._thread is not None and self._thread.is_alive():
                return
            self._stop_event.clear()
            self._thread = threading.Thread(
                target=self._run_loop,
                name="finance-report-scheduler",
                daemon=True,
            )
            self._thread.start()
            logger.info(
                "Finance report scheduler started timezone=%s report_time=%s",
                self._timezone.key,
                self._report_time.strftime("%H:%M"),
            )

    def shutdown(self) -> None:
        with self._lock:
            thread = self._thread
            self._thread = None
        self._stop_event.set()
        if thread is not None and thread.is_alive():
            thread.join(timeout=3)
        logger.info("Finance report scheduler stopped")

    def _run_loop(self) -> None:
        if self._stop_event.wait(self._initial_delay_seconds):
            return
        while not self._stop_event.is_set():
            wait_seconds = self._seconds_until_next_report_time()
            if self._stop_event.wait(wait_seconds):
                break
            self._run_due_reports()

    def _run_due_reports(self) -> None:
        now = datetime.now(self._timezone)
        due_types = ["weekly"]
        if now.day <= 7 and now.month in {1, 4, 7, 10}:
            due_types.append("quarterly")
        if now.day <= 7 and now.month == 1:
            due_types.append("annual")
        for report_type in due_types:
            self._run_report_once(report_type=report_type, now=now)

    def _run_report_once(self, *, report_type: str, now: datetime) -> None:
        db = get_session_factory()()
        try:
            if self._already_generated(db, report_type=report_type, now=now):
                return
            result = DigitalEmployeeFinanceReportTaskService(db).generate_report(
                report_type=report_type,  # type: ignore[arg-type]
                source=AgentRunSource.SCHEDULE.value,
            )
            db.commit()
            logger.info(
                "Finance report generated type=%s status=%s",
                report_type,
                (result.get("delivery") or {}).get("status"),
            )
        except Exception:
            db.rollback()
            logger.exception("Scheduled finance report failed type=%s", report_type)
        finally:
            db.close()

    def _already_generated(self, db, *, report_type: str, now: datetime) -> bool:
        day_start = datetime.combine(
            now.date(),
            time.min,
            tzinfo=self._timezone,
        ).astimezone(ZoneInfo("UTC"))
        day_end = day_start + timedelta(days=1)
        stmt = (
            select(AgentRun)
            .where(AgentRun.started_at >= day_start)
            .where(AgentRun.started_at < day_end)
            .where(AgentRun.status == AgentRunStatus.SUCCEEDED.value)
        )
        for run in db.scalars(stmt).all():
            route_json = run.route_json or {}
            if (
                str(route_json.get("task_type") or "") == FINANCE_REPORT_TASK_TYPE
                and str(route_json.get("report_type") or "") == report_type
            ):
                return True
        return False

    def _seconds_until_next_report_time(self) -> float:
        now = datetime.now(self._timezone)
        target = datetime.combine(now.date(), self._report_time, tzinfo=self._timezone)
        if target <= now:
            target += timedelta(days=1)
        return max(1.0, (target - now).total_seconds())

    @staticmethod
    def _parse_time(raw_value: str) -> time:
        try:
            hour_text, minute_text = str(raw_value or "").split(":", 1)
            return time(
                hour=max(0, min(int(hour_text), 23)),
                minute=max(0, min(int(minute_text), 59)),
            )
        except Exception:
            return time(hour=8, minute=30)


finance_report_scheduler = FinanceReportScheduler()