from datetime import datetime

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy.orm import Session as DBSession

from app.core.notes import next_position, rename_section, set_section
from app.db.database import get_db
from app.db.models import NotePage

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


class NotePageResponse(BaseModel):
    id: int
    title: str
    content: str
    position: int
    section: str | None
    updated_at: datetime

    class Config:
        from_attributes = True


class NotePageCreate(BaseModel):
    title: str = "新しいページ"
    content: str = ""
    section: str | None = None


class NotePageUpdate(BaseModel):
    title: str | None = None
    content: str | None = None
    section: str | None = None


class SectionRenameRequest(BaseModel):
    old_name: str
    new_name: str | None = None


@router.get("", response_model=list[NotePageResponse])
def list_pages(db: DBSession = Depends(get_db)):
    return db.query(NotePage).order_by(NotePage.position, NotePage.id).all()


@router.post("", response_model=NotePageResponse, status_code=201)
def create_page(req: NotePageCreate, db: DBSession = Depends(get_db)):
    title = req.title.strip() or "新しいページ"
    page = NotePage(title=title, content=req.content, position=next_position(db))
    db.add(page)
    db.commit()
    db.refresh(page)
    if req.section is not None and req.section.strip():
        page = set_section(db, page.id, req.section)
    return page


@router.post("/sections/rename")
def rename_section_endpoint(req: SectionRenameRequest, db: DBSession = Depends(get_db)):
    """old_name セクションに属する全ページを new_name セクションへ一括で付け替える。new_name が空ならグループ解除。"""
    count = rename_section(db, req.old_name, req.new_name)
    return {"renamed": count}


@router.patch("/{page_id}", response_model=NotePageResponse)
def update_page(page_id: int, req: NotePageUpdate, db: DBSession = Depends(get_db)):
    page = db.get(NotePage, page_id)
    if not page:
        raise HTTPException(status_code=404, detail="Note page not found")
    if req.title is not None:
        title = req.title.strip()
        if not title:
            raise HTTPException(status_code=400, detail="title is empty")
        page.title = title
    if req.content is not None:
        page.content = req.content
    db.commit()
    db.refresh(page)

    # section はページの並び順にも影響するため、変更があれば専用ロジックで反映する
    if "section" in req.model_fields_set:
        page = set_section(db, page_id, req.section)

    return page


@router.delete("/{page_id}", status_code=204)
def delete_page(page_id: int, db: DBSession = Depends(get_db)):
    page = db.get(NotePage, page_id)
    if not page:
        raise HTTPException(status_code=404, detail="Note page not found")
    db.delete(page)
    db.commit()