import os
import threading
from datetime import datetime, timezone
from typing import Optional
import pytz
from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.date import DateTrigger

from bot.monitor import fetch_latest_videos
from bot.downloader import download_video
from bot.uploader import upload_to_tiktok
from bot.logger import get_logger

logger = get_logger("scheduler")
MMT = pytz.timezone("Asia/Yangon")

# Poll interval (seconds)
POLL_INTERVAL = 150  # 2.5 minutes


class BotScheduler:
    def __init__(self):
        self.scheduler = BackgroundScheduler(timezone=MMT)
        self.seen_ids: set = set()
        self.queue: list[dict] = []  # scheduled jobs metadata
        self.lock = threading.Lock()
        self.running = False
        self.log_buffer: list[str] = []

    # ──────────────────────────────────────────────
    # Public control
    # ──────────────────────────────────────────────
    def start(self):
        if self.running:
            return
        self.running = True
        self.scheduler.start()
        # Poll job: run every POLL_INTERVAL seconds
        self.scheduler.add_job(
            self._poll_channel,
            "interval",
            seconds=POLL_INTERVAL,
            id="poll_channel",
            next_run_time=datetime.now(tz=MMT),  # run immediately on start
        )
        self._log("Bot started ✅")
        logger.info("Bot started")

    def stop(self):
        if not self.running:
            return
        self.running = False
        self.scheduler.shutdown(wait=False)
        self.scheduler = BackgroundScheduler(timezone=MMT)  # reset
        self._log("Bot stopped 🛑")
        logger.info("Bot stopped")

    # ──────────────────────────────────────────────
    # Internal
    # ──────────────────────────────────────────────
    def _poll_channel(self):
        """RSS ကို စစ်ဆေးပြီး အသစ်ဝင်သော video များကို schedule လုပ်သည်"""
        self._log("🔍 Checking RSS feed...")
        new_videos = fetch_latest_videos(self.seen_ids)

        for video in new_videos:
            with self.lock:
                self.seen_ids.add(video["video_id"])

            pub_mmt: datetime = video["published_mmt"]
            now_mmt = datetime.now(tz=MMT)

            # အချိန်ကျော်သွားပြီဆိုလျှင် ချက်ချင်းတင်
            if pub_mmt <= now_mmt:
                self._log(f"⚡ Immediate upload (past time): {video['title']}")
                self.scheduler.add_job(
                    self._process_video,
                    trigger=DateTrigger(run_date=now_mmt),
                    args=[video],
                    id=f"upload_{video['video_id']}",
                    replace_existing=True,
                )
            else:
                # Original publish time အတိုင်း schedule
                self._log(
                    f"📅 Scheduled: '{video['title']}' @ "
                    f"{pub_mmt.strftime('%Y-%m-%d %H:%M:%S')} MMT"
                )
                self.scheduler.add_job(
                    self._process_video,
                    trigger=DateTrigger(run_date=pub_mmt),
                    args=[video],
                    id=f"upload_{video['video_id']}",
                    replace_existing=True,
                )

            with self.lock:
                self.queue.append({
                    "video_id": video["video_id"],
                    "title": video["title"],
                    "scheduled_time": pub_mmt,
                    "status": "pending",
                })

    def _process_video(self, video: dict):
        """Download + Upload pipeline"""
        vid_id = video["video_id"]
        self._log(f"⬇️  Downloading: {video['title']}")

        file_path = download_video(video)
        if not file_path:
            self._log(f"❌ Download failed: {video['title']}")
            self._update_status(vid_id, "download_failed")
            return

        self._log(f"⬆️  Uploading to TikTok: {video['title']}")
        success = upload_to_tiktok(video, file_path)

        if success:
            self._log(f"✅ Upload success: {video['title']}")
            self._update_status(vid_id, "uploaded")
        else:
            self._log(f"❌ Upload failed: {video['title']}")
            self._update_status(vid_id, "upload_failed")

        # Clean up downloaded file
        try:
            os.remove(file_path)
        except Exception:
            pass

    def _update_status(self, vid_id: str, status: str):
        with self.lock:
            for item in self.queue:
                if item["video_id"] == vid_id:
                    item["status"] = status
                    break

    def _log(self, msg: str):
        ts = datetime.now(tz=MMT).strftime("%H:%M:%S")
        line = f"[{ts}] {msg}"
        logger.info(msg)
        with self.lock:
            self.log_buffer.append(line)
            if len(self.log_buffer) > 200:
                self.log_buffer = self.log_buffer[-200:]

    # ──────────────────────────────────────────────
    # Status helpers (Gradio UI အတွက်)
    # ──────────────────────────────────────────────
    def get_queue_display(self) -> str:
        with self.lock:
            if not self.queue:
                return "Queue ထဲတွင် video မရှိသေး"
            lines = []
            for item in sorted(self.queue, key=lambda x: x["scheduled_time"]):
                t = item["scheduled_time"].strftime("%Y-%m-%d %H:%M:%S")
                lines.append(
                    f"[{item['status'].upper()}] {t} MMT — {item['title'][:60]}"
                )
            return "\n".join(lines)

    def get_upcoming_display(self) -> str:
        now_mmt = datetime.now(tz=MMT)
        with self.lock:
            upcoming = [
                item for item in self.queue
                if item["status"] == "pending" and item["scheduled_time"] > now_mmt
            ]
        if not upcoming:
            return "Upcoming schedule မရှိသေး"
        upcoming.sort(key=lambda x: x["scheduled_time"])
        lines = []
        for item in upcoming[:10]:
            t = item["scheduled_time"].strftime("%Y-%m-%d %H:%M:%S")
            lines.append(f"🕐 {t} MMT — {item['title'][:60]}")
        return "\n".join(lines)

    def get_logs(self) -> str:
        with self.lock:
            return "\n".join(self.log_buffer[-50:])

    def get_status_summary(self) -> str:
        with self.lock:
            total = len(self.queue)
            pending = sum(1 for i in self.queue if i["status"] == "pending")
            uploaded = sum(1 for i in self.queue if i["status"] == "uploaded")
            failed = sum(1 for i in self.queue if "failed" in i["status"])
        state = "🟢 Running" if self.running else "🔴 Stopped"
        now = datetime.now(tz=MMT).strftime("%Y-%m-%d %H:%M:%S")
        return (
            f"Bot Status: {state}\n"
            f"Current Time (MMT): {now}\n"
            f"Total Queued: {total} | Pending: {pending} | "
            f"Uploaded: {uploaded} | Failed: {failed}\n"
            f"Poll Interval: {POLL_INTERVAL}s"
        )