from celery import Celery
from celery.schedules import crontab
from app.services.bot_service import BotService
import os
import json
from datetime import datetime, timedelta
from typing import List, Dict, Optional

celery = Celery(
    'tasks',
    broker=os.getenv("CELERY_BROKER_URL", "redis://localhost:6379/0"),
    backend=os.getenv("CELERY_RESULT_BACKEND", "redis://localhost:6379/0"),
)

bot_service = BotService(
    os.getenv("TELEGRAM_BOT_TOKEN", ""),
    os.getenv("TELEGRAM_CHAT_ID", "")
)

# Load schedules from JSON
def load_schedules() -> List[Dict]:
    schedules_path = "/app/schedules.json"
    if os.path.exists(schedules_path):
        with open(schedules_path, "r") as f:
            return json.load(f)
    return []

# Save schedules to JSON
def save_schedules(schedules: List[Dict]):
    with open("/app/schedules.json", "w") as f:
        json.dump(schedules, f, indent=2)

def schedule_is_due(schedule: Dict) -> bool:
    raw = str(schedule.get("time", "")).replace("Z", "+00:00")
    when = datetime.fromisoformat(raw)
    if when.tzinfo is not None:
        when = when.astimezone().replace(tzinfo=None)
    return datetime.now() >= when


@celery.task
def send_scheduled_message(schedule_id: int = None):
    """Send enabled schedules whose time has arrived and that were not sent yet."""
    schedules = load_schedules()
    due = []
    for item in schedules:
        if schedule_id is not None and item.get("id") != schedule_id:
            continue
        if not item.get("enabled", True) or item.get("sent"):
            continue
        try:
            ready = schedule_is_due(item)
        except ValueError:
            print(f"Invalid schedule time: {item.get('time')}")
            continue
        if ready:
            due.append(item)

    if not due:
        print("No schedules due")
        return

    changed = False
    for schedule in due:
        try:
            bot_service.send_scheduled_message(schedule)
            schedule["sent"] = True
            changed = True
            print(f"Sent scheduled message: {schedule['time']}")
        except Exception as e:
            print(f"Error sending scheduled message: {e}")
    if changed:
        save_schedules(schedules)

@celery.task
def generate_daily_content():
    """Generate daily content for all books."""
    try:
        bot_service.generate_daily_content()
        print("Sent daily content")
    except Exception as e:
        print(f"Error generating daily content: {e}")

# Periodic tasks
celery.conf.beat_schedule = {
    'send-scheduled-messages': {
        'task': 'app.tasks.celery_tasks.send_scheduled_message',
        'schedule': crontab(minute=0),  # Every hour
        'args': (None,),  # Process all enabled schedules
    },
    'generate-daily-content': {
        'task': 'app.tasks.celery_tasks.generate_daily_content',
        'schedule': crontab(hour=8, minute=0),  # Daily at 8 AM
    },
}