from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy.orm import Session
from typing import List, Optional
from datetime import datetime, date
from calendar import monthrange

from ..database import get_db
from ..models import ContentCalendar, Topic
from ..schemas import (
    ContentCalendarCreate, ContentCalendarUpdate, ContentCalendarResponse,
    ContentCalendarBase
)
from .auth import get_current_user

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


@router.get("", response_model=List[ContentCalendarResponse])
def get_calendar(
    year: Optional[int] = Query(None),
    month: Optional[int] = Query(None),
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    today = date.today()
    year = year or today.year
    month = month or today.month
    start = date(year, month, 1)
    last_day = monthrange(year, month)[1]
    end = date(year, month, last_day)
    return db.query(ContentCalendar).filter(
        ContentCalendar.planned_date >= start,
        ContentCalendar.planned_date <= end
    ).order_by(ContentCalendar.planned_date).all()


@router.get("/entries", response_model=List[ContentCalendarResponse])
def list_entries(
    start_date: Optional[date] = None,
    end_date: Optional[date] = None,
    status: Optional[str] = None,
    platform: Optional[str] = None,
    limit: int = Query(50, le=200),
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    query = db.query(ContentCalendar)
    if start_date:
        query = query.filter(ContentCalendar.planned_date >= start_date)
    if end_date:
        query = query.filter(ContentCalendar.planned_date <= end_date)
    if status:
        query = query.filter(ContentCalendar.status == status)
    if platform:
        query = query.filter(ContentCalendar.platform == platform)
    return query.order_by(ContentCalendar.planned_date.desc()).limit(limit).all()


@router.post("/entries", response_model=ContentCalendarResponse)
def create_entry(
    data: ContentCalendarCreate,
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    if data.topic_id:
        topic = db.query(Topic).filter(Topic.id == data.topic_id).first()
        if not topic:
            raise HTTPException(status_code=404, detail="选题不存在")

    entry = ContentCalendar(**data.model_dump())
    db.add(entry)
    db.commit()
    db.refresh(entry)

    if data.topic_id and data.title:
        if not topic.title or topic.title != data.title:
            topic.title = data.title
            db.commit()
    return entry


@router.put("/entries/{entry_id}", response_model=ContentCalendarResponse)
def update_entry(
    entry_id: int,
    data: ContentCalendarUpdate,
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    entry = db.query(ContentCalendar).filter(ContentCalendar.id == entry_id).first()
    if not entry:
        raise HTTPException(status_code=404, detail="日历条目不存在")

    for k, v in data.model_dump(exclude_unset=True).items():
        setattr(entry, k, v)
    db.commit()
    db.refresh(entry)

    if entry.topic_id:
        topic = db.query(Topic).filter(Topic.id == entry.topic_id).first()
        if topic and entry.status == "published" and not entry.published_date:
            entry.published_date = date.today()
            if topic.status == "pending" or topic.status == "ready":
                topic.status = "published"
                topic.published_at = date.today()
                topic.updated_at = datetime.now()
            db.commit()

    return entry


@router.delete("/entries/{entry_id}")
def delete_entry(
    entry_id: int,
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    entry = db.query(ContentCalendar).filter(ContentCalendar.id == entry_id).first()
    if not entry:
        raise HTTPException(status_code=404, detail="日历条目不存在")
    db.delete(entry)
    db.commit()
    return {"ok": True}


@router.post("/entries/bind-topic")
def bind_topic_to_entry(
    entry_id: int,
    topic_id: str,
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    entry = db.query(ContentCalendar).filter(ContentCalendar.id == entry_id).first()
    if not entry:
        raise HTTPException(status_code=404, detail="日历条目不存在")
    topic = db.query(Topic).filter(Topic.id == topic_id).first()
    if not topic:
        raise HTTPException(status_code=404, detail="选题不存在")
    entry.topic_id = topic_id
    entry.title = topic.title
    if topic.field_name:
        entry.field_id = topic.field_id
    db.commit()
    db.refresh(entry)
    return entry


@router.get("/stats")
def calendar_stats(
    year: int = Query(...),
    month: int = Query(...),
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    start = date(year, month, 1)
    last_day = monthrange(year, month)[1]
    end = date(year, month, last_day)
    entries = db.query(ContentCalendar).filter(
        ContentCalendar.planned_date >= start,
        ContentCalendar.planned_date <= end
    ).all()

    stats = {"total": len(entries), "planned": 0, "published": 0, "delayed": 0, "cancelled": 0}
    for e in entries:
        if e.status in stats:
            stats[e.status] += 1
    return stats


@router.post("/entries/from-topic")
def create_from_topic(
    topic_id: str,
    planned_date: date,
    platform: str = Query(...),
    db: Session = Depends(get_db),
    current_user=Depends(get_current_user)
):
    topic = db.query(Topic).filter(Topic.id == topic_id).first()
    if not topic:
        raise HTTPException(status_code=404, detail="选题不存在")
    entry = ContentCalendar(
        topic_id=topic_id,
        field_id=topic.field_id,
        title=topic.title,
        planned_date=planned_date,
        platform=platform,
        created_by=current_user.username
    )
    db.add(entry)
    db.commit()
    db.refresh(entry)
    return entry