from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.cron import CronTrigger
from app.utils.config import server_config
from app.utils.logger import logger
from app.utils.playlist_merge import sync_all_playlists, SyncMode
import asyncio

scheduler = BackgroundScheduler()

def validate_cron_expression(expression: str) -> bool:
    try:
        parts = expression.split()
        if len(parts) != 5:
            return False
        # Try to create a trigger to validate
        CronTrigger(
            minute=parts[0],
            hour=parts[1],
            day=parts[2],
            month=parts[3],
            day_of_week=parts[4]
        )
        return True
    except Exception:
        return False

def job_function():
    logger.info("Executing scheduled sync job...")
    try:
        # Re-read config to ensure latest values
        server_config.load()
        
        mode_str = server_config.sync_mode
        regex_rules = server_config.path_rules
        local_path = server_config.local_path
        
        asyncio.run(sync_all_playlists(
            sync_mode=SyncMode(mode_str),
            path_rules=regex_rules,
            local_dir=local_path
        ))
        
        logger.info("Scheduled sync job completed.")
    except Exception as e:
        logger.error(f"Scheduled sync job failed: {e}")

def start_scheduler():
    if not scheduler.running:
        scheduler.start()
        logger.info("Scheduler started.")
    update_scheduler_job()

def update_scheduler_job():
    scheduler.remove_all_jobs()
    
    # Reload config to get latest schedule settings
    server_config.load()
    mode = server_config.schedule_mode
    
    if mode == "DISABLED":
        logger.info("Schedule is disabled.")
        return

    trigger = None
    
    if mode == "CRON":
        cron_exp = server_config.schedule_cron
        if cron_exp:
            try:
                # 5 parts: minute hour day month day_of_week
                parts = cron_exp.split()
                if len(parts) == 5:
                    trigger = CronTrigger(
                        minute=parts[0],
                        hour=parts[1],
                        day=parts[2],
                        month=parts[3],
                        day_of_week=parts[4]
                    )
            except Exception as e:
                logger.error(f"Invalid cron expression: {cron_exp}, error: {e}")

    elif mode == "DAILY":
        time_str = server_config.schedule_daily_time
        try:
            hour, minute = map(int, time_str.split(':'))
            trigger = CronTrigger(hour=hour, minute=minute)
        except ValueError:
            logger.error(f"Invalid daily time: {time_str}")

    elif mode == "WEEKLY":
        days = server_config.schedule_weekly_days # list of ints 0-6 (Sun-Sat)
        time_str = server_config.schedule_weekly_time
        
        # Frontend: 0(Sun), 1(Mon)... 6(Sat)
        # APScheduler: 0(Mon)... 6(Sun)
        
        aps_days = []
        for d in days:
            if d == 0: aps_days.append(6)
            else: aps_days.append(d - 1)
            
        days_str = ",".join(map(str, aps_days))
        
        try:
            hour, minute = map(int, time_str.split(':'))
            trigger = CronTrigger(day_of_week=days_str, hour=hour, minute=minute)
        except ValueError:
            logger.error(f"Invalid weekly time: {time_str}")

    if trigger:
        scheduler.add_job(job_function, trigger)
        logger.info(f"Added scheduled job with mode {mode} and trigger {trigger}")
    else:
        logger.warning(f"Failed to create trigger for mode {mode}")

def get_next_run_time():
    jobs = scheduler.get_jobs()
    if not jobs:
        return None
    # Assuming only one job
    job = jobs[0]
    return job.next_run_time