from typing import List
from datetime import datetime
from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
from sqlalchemy.orm import Session
from croniter import croniter

from app.core.database import get_db
from app.models.schedule import Schedule
from app.schemas.schedule import ScheduleResponse, ScheduleUpdate, ScheduleLogResponse

router = APIRouter(prefix="/schedules", tags=["schedules"])


@router.get("", response_model=List[ScheduleResponse])
def list_schedules(db: Session = Depends(get_db)):
    return db.query(Schedule).order_by(Schedule.id).all()


@router.get("/{schedule_id}", response_model=ScheduleResponse)
def get_schedule(schedule_id: int, db: Session = Depends(get_db)):
    s = db.get(Schedule, schedule_id)
    if not s:
        raise HTTPException(status_code=404, detail="Schedule not found")
    return s


@router.put("/{schedule_id}", response_model=ScheduleResponse)
def update_schedule_cron(schedule_id: int, payload: ScheduleUpdate, db: Session = Depends(get_db)):
    s = db.get(Schedule, schedule_id)
    if not s:
        raise HTTPException(status_code=404, detail="Schedule not found")
    # Validate cron expression
    try:
        cron = croniter(payload.cron_timer, datetime.utcnow())
        next_run = cron.get_next(datetime)
    except Exception:
        raise HTTPException(status_code=422, detail="Invalid cron expression")
    s.cron_timer = payload.cron_timer
    s.next_run_at = next_run
    db.commit()
    db.refresh(s)
    return s


@router.post("/{schedule_id}/run", status_code=202)
def manual_run(schedule_id: int, background_tasks: BackgroundTasks, db: Session = Depends(get_db)):
    """手動觸發排程（非同步執行）"""
    s = db.get(Schedule, schedule_id)
    if not s:
        raise HTTPException(status_code=404, detail="Schedule not found")
    if s.status == "Going":
        raise HTTPException(status_code=409, detail="Schedule is already running")

    from app.services.scheduler.runner import dispatch_schedule
    background_tasks.add_task(dispatch_schedule, schedule_id)
    return {"message": f"Schedule '{s.name}' triggered", "schedule_id": schedule_id}


@router.get("/{schedule_id}/logs", response_model=List[ScheduleLogResponse])
def get_schedule_logs(schedule_id: int, limit: int = 20, db: Session = Depends(get_db)):
    from app.models.schedule import ScheduleLog
    logs = (
        db.query(ScheduleLog)
        .filter(ScheduleLog.schedule_id == schedule_id)
        .order_by(ScheduleLog.started_at.desc())
        .limit(limit)
        .all()
    )
    return logs