import asyncio
import json
import re
from collections.abc import Awaitable, Callable
from datetime import datetime, timezone
from typing import TYPE_CHECKING, Any
from zoneinfo import ZoneInfo

from apscheduler.schedulers.asyncio import AsyncIOScheduler
from apscheduler.triggers.cron import CronTrigger
from apscheduler.triggers.date import DateTrigger

from astrbot import logger
from astrbot.core.agent.tool import ToolSet
from astrbot.core.cron.events import CronMessageEvent
from astrbot.core.db import BaseDatabase
from astrbot.core.db.po import CronJob
from astrbot.core.platform.message_session import MessageSession
from astrbot.core.platform.message_type import MessageType
from astrbot.core.provider.entites import ProviderRequest
from astrbot.core.utils.history_saver import persist_agent_history

if TYPE_CHECKING:
    from astrbot.core.star.context import Context


_CRONTAB_WEEKDAY_NAMES = ("sun", "mon", "tue", "wed", "thu", "fri", "sat")
_CRONTAB_WEEKDAY_PATTERN = re.compile(r"^(?:(\*)|(\d+)(?:-(\d+))?)(?:/(\d+))?$")


def _normalize_crontab_day_of_week(day_of_week: str) -> str:
    """Normalize standard crontab weekdays for APScheduler.

    APScheduler treats numeric weekdays as Monday=0, while standard crontab and
    AstrBot's WebUI use Sunday=0/7. Numeric weekday fields are expanded to
    weekday names so the scheduled day remains unambiguous.

    Args:
        day_of_week: The day-of-week field from a five-part crontab expression.

    Returns:
        A day-of-week field compatible with APScheduler.

    Raises:
        ValueError: If a numeric weekday value or step is outside the supported
            crontab range.
    """
    normalized_parts: list[str] = []
    for raw_part in day_of_week.split(","):
        part = raw_part.strip().lower()
        match = _CRONTAB_WEEKDAY_PATTERN.fullmatch(part)
        if not match:
            normalized_parts.append(part)
            continue

        wildcard, start_text, end_text, step_text = match.groups()
        step = int(step_text or "1")
        if step < 1:
            raise ValueError("day_of_week step must be greater than 0")

        if wildcard:
            if step == 1:
                normalized_parts.append("*")
                continue
            values = range(0, 7, step)
        else:
            start = int(start_text)
            end = int(end_text) if end_text is not None else None
            if start < 0 or start > 7 or (end is not None and (end < 0 or end > 7)):
                raise ValueError("day_of_week values must be between 0 and 7")
            if end is not None and start > end:
                raise ValueError("day_of_week range start must not exceed end")
            if end is None:
                end = 7 if step_text else start
            values = range(start, end + 1, step)

        weekdays: list[int] = []
        for value in values:
            weekday = 0 if value == 7 else value
            if weekday not in weekdays:
                weekdays.append(weekday)

        if len(weekdays) == 7:
            normalized_parts.append("*")
        else:
            normalized_parts.extend(_CRONTAB_WEEKDAY_NAMES[value] for value in weekdays)

    return ",".join(normalized_parts)


class CronJobSchedulingError(Exception):
    """Raised when a cron job fails to be scheduled."""

    pass


class CronJobManager:
    """Central scheduler for BasicCronJob and ActiveAgentCronJob."""

    def __init__(self, db: BaseDatabase) -> None:
        self.db = db
        self.scheduler = AsyncIOScheduler()
        self._basic_handlers: dict[str, Callable[..., Any]] = {}
        self._lock = asyncio.Lock()
        self._started = False

    async def start(self, ctx: "Context") -> None:
        self.ctx: Context = ctx  # star context
        async with self._lock:
            if self._started:
                return
            self.scheduler.start()
            self._started = True
            await self.sync_from_db()

    async def shutdown(self) -> None:
        async with self._lock:
            if not self._started:
                return
            self.scheduler.shutdown(wait=False)
            self._started = False

    async def sync_from_db(self) -> None:
        jobs = await self.db.list_cron_jobs()
        for job in jobs:
            if not job.enabled or not job.persistent:
                continue
            if job.job_type == "basic" and job.job_id not in self._basic_handlers:
                logger.warning(
                    "Skip scheduling basic cron job %s due to missing handler.",
                    job.job_id,
                )
                continue
            try:
                self._schedule_job(job)
            except CronJobSchedulingError:
                continue  # Error already logged in _schedule_job

    async def add_basic_job(
        self,
        *,
        name: str,
        cron_expression: str,
        handler: Callable[..., Any | Awaitable[Any]],
        description: str | None = None,
        timezone: str | None = None,
        payload: dict | None = None,
        enabled: bool = True,
        persistent: bool = False,
    ) -> CronJob:
        job = await self.db.create_cron_job(
            name=name,
            job_type="basic",
            cron_expression=cron_expression,
            timezone=timezone,
            payload=payload or {},
            description=description,
            enabled=enabled,
            persistent=persistent,
        )
        self._basic_handlers[job.job_id] = handler
        if enabled:
            self._schedule_job(job)
        return job

    async def add_active_job(
        self,
        *,
        name: str,
        cron_expression: str | None,
        payload: dict,
        description: str | None = None,
        timezone: str | None = None,
        enabled: bool = True,
        persistent: bool = True,
        run_once: bool = False,
        run_at: datetime | None = None,
    ) -> CronJob:
        # If run_once with run_at, store run_at in payload for later reference.
        if run_once and run_at:
            payload = {**payload, "run_at": run_at.isoformat()}
        job = await self.db.create_cron_job(
            name=name,
            job_type="active_agent",
            cron_expression=cron_expression,
            timezone=timezone,
            payload=payload,
            description=description,
            enabled=enabled,
            persistent=persistent,
            run_once=run_once,
        )
        if enabled:
            self._schedule_job(job)
        return job

    async def update_job(self, job_id: str, **kwargs) -> CronJob | None:
        job = await self.db.update_cron_job(job_id, **kwargs)
        if not job:
            return None
        self._remove_scheduled(job_id)
        if job.enabled:
            self._schedule_job(job)
        return job

    async def delete_job(self, job_id: str) -> None:
        self._remove_scheduled(job_id)
        self._basic_handlers.pop(job_id, None)
        await self.db.delete_cron_job(job_id)

    async def list_jobs(self, job_type: str | None = None) -> list[CronJob]:
        return await self.db.list_cron_jobs(job_type)

    def _remove_scheduled(self, job_id: str) -> None:
        if self.scheduler.get_job(job_id):
            self.scheduler.remove_job(job_id)

    def _schedule_job(self, job: CronJob) -> None:
        if not self._started:
            self.scheduler.start()
            self._started = True
        try:
            tzinfo = None
            if job.timezone:
                try:
                    tzinfo = ZoneInfo(job.timezone)
                except Exception:
                    logger.warning(
                        "Invalid timezone %s for cron job %s, fallback to system.",
                        job.timezone,
                        job.job_id,
                    )
            if job.run_once:
                run_at_str = None
                if isinstance(job.payload, dict):
                    run_at_str = job.payload.get("run_at")
                run_at_str = run_at_str or job.cron_expression
                if not run_at_str:
                    raise ValueError("run_once job missing run_at timestamp")
                run_at = datetime.fromisoformat(run_at_str)
                if run_at.tzinfo is None and tzinfo is not None:
                    run_at = run_at.replace(tzinfo=tzinfo)
                trigger = DateTrigger(run_date=run_at, timezone=tzinfo)
            else:
                if not job.cron_expression:
                    raise ValueError("recurring job missing cron_expression")
                minute, hour, day, month, day_of_week = job.cron_expression.split()
                normalized_cron_expression = " ".join(
                    [
                        minute,
                        hour,
                        day,
                        month,
                        _normalize_crontab_day_of_week(day_of_week),
                    ]
                )
                trigger = CronTrigger.from_crontab(
                    normalized_cron_expression, timezone=tzinfo
                )
            self.scheduler.add_job(
                self._run_job,
                id=job.job_id,
                trigger=trigger,
                args=[job.job_id],
                replace_existing=True,
                misfire_grace_time=30,
            )
            asyncio.create_task(
                self.db.update_cron_job(
                    job.job_id, next_run_time=self._get_next_run_time(job.job_id)
                )
            )
        except (ValueError, TypeError) as e:
            logger.exception("Failed to schedule cron job %s", job.job_id)
            raise CronJobSchedulingError(str(e)) from e

    def _get_next_run_time(self, job_id: str):
        aps_job = self.scheduler.get_job(job_id)
        if not aps_job or aps_job.next_run_time is None:
            return None
        return aps_job.next_run_time.astimezone(timezone.utc)

    async def run_job_now(self, job_id: str) -> None:
        await self._run_job(job_id, ignore_enabled=True, delete_run_once=False)

    async def _run_job(
        self,
        job_id: str,
        *,
        ignore_enabled: bool = False,
        delete_run_once: bool = True,
    ) -> None:
        job = await self.db.get_cron_job(job_id)
        if not job or (not job.enabled and not ignore_enabled):
            return
        start_time = datetime.now(timezone.utc)
        await self.db.update_cron_job(
            job_id, status="running", last_run_at=start_time, last_error=None
        )
        status = "completed"
        last_error = None
        try:
            if job.job_type == "basic":
                await self._run_basic_job(job)
            elif job.job_type == "active_agent":
                await self._run_active_agent_job(job, start_time=start_time)
            else:
                raise ValueError(f"Unknown cron job type: {job.job_type}")
        except Exception as e:  # noqa: BLE001
            status = "failed"
            last_error = str(e)
            logger.error(f"Cron job {job_id} failed: {e!s}", exc_info=True)
        finally:
            next_run = self._get_next_run_time(job_id)
            await self.db.update_cron_job(
                job_id,
                status=status,
                last_run_at=start_time,
                last_error=last_error,
                next_run_time=next_run,
            )
            if job.run_once and delete_run_once:
                # one-shot: remove after execution regardless of success
                await self.delete_job(job_id)

    async def _run_basic_job(self, job: CronJob) -> None:
        handler = self._basic_handlers.get(job.job_id)
        if not handler:
            raise RuntimeError(f"Basic cron job handler not found for {job.job_id}")
        payload = job.payload or {}
        result = handler(**payload) if payload else handler()
        if asyncio.iscoroutine(result):
            await result

    async def _run_active_agent_job(self, job: CronJob, start_time: datetime) -> None:
        payload = job.payload or {}
        delivery_session_str = str(payload.get("session") or "").strip()
        session_str = delivery_session_str or str(
            MessageSession(
                platform_name="cron",
                message_type=MessageType.OTHER_MESSAGE,
                session_id=job.job_id,
            )
        )
        note = payload.get("note") or job.description or job.name

        extras = {
            "cron_job": {
                "id": job.job_id,
                "name": job.name,
                "type": job.job_type,
                "run_once": job.run_once,
                "description": job.description,
                "note": note,
                "run_started_at": start_time.isoformat(),
                "run_at": (
                    job.payload.get("run_at") if isinstance(job.payload, dict) else None
                ),
                "session": delivery_session_str,
            },
            "cron_payload": payload,
        }

        await self._woke_main_agent(
            message=note,
            session_str=session_str,
            extras=extras,
            delivery_session_str=delivery_session_str,
        )

    async def _woke_main_agent(
        self,
        *,
        message: str,
        session_str: str,
        extras: dict,
        delivery_session_str: str = "",
    ) -> None:
        """Woke the main agent to handle the cron job message."""
        from astrbot.core.astr_main_agent import (
            MainAgentBuildConfig,
            _get_session_conv,
            build_main_agent,
        )
        from astrbot.core.astr_main_agent_resources import (
            PROACTIVE_AGENT_CRON_WOKE_SYSTEM_PROMPT,
        )
        from astrbot.core.tools.message_tools import SendMessageToUserTool

        try:
            session = (
                session_str
                if isinstance(session_str, MessageSession)
                else MessageSession.from_str(session_str)
            )
        except Exception as e:  # noqa: BLE001
            logger.error(f"Invalid session for cron job: {e}")
            return

        cron_event = CronMessageEvent(
            context=self.ctx,
            session=session,
            message=message,
            extras=extras or {},
            message_type=session.message_type,
        )

        # judge user's role
        umo = cron_event.unified_msg_origin
        cfg = self.ctx.get_config(umo=umo)
        cron_payload = extras.get("cron_payload", {}) if extras else {}
        sender_id = cron_payload.get("sender_id")
        admin_ids = cfg.get("admins_id", [])
        if admin_ids:
            cron_event.role = "admin" if sender_id in admin_ids else "member"
        if cron_payload.get("origin", "tool") == "api":
            cron_event.role = "admin"

        provider_settings = cfg.get("provider_settings", {}) or {}
        tool_call_timeout = provider_settings.get("tool_call_timeout", 120)
        config = MainAgentBuildConfig(
            tool_call_timeout=tool_call_timeout,
            llm_safety_mode=False,
            streaming_response=False,
            provider_settings=provider_settings,
        )
        req = ProviderRequest()
        conv = await _get_session_conv(event=cron_event, plugin_context=self.ctx)
        req.conversation = conv
        # finetine the messages
        context = json.loads(conv.history)
        if context:
            req.contexts = context
            context_dump = req._print_friendly_context()
            req.contexts = []
            req.system_prompt += (
                "\n\nBellow is you and user previous conversation history:\n"
                f"---\n"
                f"{context_dump}\n"
                f"---\n"
            )
        cron_job_str = json.dumps(extras.get("cron_job", {}), ensure_ascii=False)
        req.system_prompt += PROACTIVE_AGENT_CRON_WOKE_SYSTEM_PROMPT.format(
            cron_job=cron_job_str
        )
        req.prompt = (
            "You are now responding to a scheduled task. "
            "Proceed according to your system instructions. "
            "Output using same language as previous conversation. "
            "After completing your task, summarize and output your actions and results."
        )
        if delivery_session_str:
            if not req.func_tool:
                req.func_tool = ToolSet()
            req.func_tool.add_tool(
                self.ctx.get_llm_tool_manager().get_builtin_tool(SendMessageToUserTool)
            )

        result = await build_main_agent(
            event=cron_event, plugin_context=self.ctx, config=config, req=req
        )
        if not result:
            logger.error("Failed to build main agent for cron job.")
            return

        runner = result.agent_runner
        async for _ in runner.step_until_done(30):
            # agent will send message to user via using tools
            pass
        llm_resp = runner.get_final_llm_resp()
        cron_meta = extras.get("cron_job", {}) if extras else {}
        summary_note = (
            f"[CronJob] {cron_meta.get('name') or cron_meta.get('id', 'unknown')}: {cron_meta.get('description', '')} "
            f" triggered at {cron_meta.get('run_started_at', 'unknown time')}, "
        )
        if llm_resp and llm_resp.role == "assistant":
            summary_note += (
                f"I finished this job, here is the result: {llm_resp.completion_text}"
            )

        await persist_agent_history(
            self.ctx.conversation_manager,
            event=cron_event,
            req=req,
            summary_note=summary_note,
        )
        if not llm_resp:
            logger.warning("Cron job agent got no response")
            return


__all__ = ["CronJobManager"]
