"""문서 CRUD API"""

import shutil
from datetime import datetime, timezone
from pathlib import Path
from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException, Query, UploadFile, status
from pydantic import BaseModel
from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from core.auth import get_current_user
from core.config import settings
from core.database import get_session
from core.utils import file_hash
from models.document import Document
from models.queue import ProcessingQueue
from models.user import User

router = APIRouter()


# ─── 스키마 ───


class DocumentResponse(BaseModel):
    id: int
    file_path: str
    file_format: str
    file_size: int | None
    file_type: str
    title: str | None
    ai_domain: str | None
    ai_sub_group: str | None
    ai_tags: list | None
    ai_summary: str | None
    source_channel: str | None
    data_origin: str | None
    extracted_at: datetime | None
    ai_processed_at: datetime | None
    embedded_at: datetime | None
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class DocumentListResponse(BaseModel):
    items: list[DocumentResponse]
    total: int
    page: int
    page_size: int


class DocumentUpdate(BaseModel):
    title: str | None = None
    ai_domain: str | None = None
    ai_sub_group: str | None = None
    ai_tags: list | None = None
    source_channel: str | None = None
    data_origin: str | None = None


# ─── 엔드포인트 ───


@router.get("/", response_model=DocumentListResponse)
async def list_documents(
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    domain: str | None = None,
    source: str | None = None,
    format: str | None = None,
):
    """문서 목록 조회 (페이지네이션 + 필터)"""
    query = select(Document)

    if domain:
        query = query.where(Document.ai_domain == domain)
    if source:
        query = query.where(Document.source_channel == source)
    if format:
        query = query.where(Document.file_format == format)

    # 전체 건수
    count_query = select(func.count()).select_from(query.subquery())
    total = (await session.execute(count_query)).scalar()

    # 페이지네이션
    query = query.order_by(Document.created_at.desc())
    query = query.offset((page - 1) * page_size).limit(page_size)
    result = await session.execute(query)
    items = result.scalars().all()

    return DocumentListResponse(
        items=[DocumentResponse.model_validate(doc) for doc in items],
        total=total,
        page=page,
        page_size=page_size,
    )


@router.get("/{doc_id}", response_model=DocumentResponse)
async def get_document(
    doc_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """문서 단건 조회"""
    doc = await session.get(Document, doc_id)
    if not doc:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")
    return DocumentResponse.model_validate(doc)


@router.post("/", response_model=DocumentResponse, status_code=201)
async def upload_document(
    file: UploadFile,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """파일 업로드 → Inbox 저장 + DB 등록 + 처리 큐 등록"""
    if not file.filename:
        raise HTTPException(status_code=400, detail="파일명이 필요합니다")

    # Inbox에 파일 저장
    inbox_dir = Path(settings.nas_mount_path) / "PKM" / "Inbox"
    inbox_dir.mkdir(parents=True, exist_ok=True)
    target = inbox_dir / file.filename

    # 중복 파일명 처리
    counter = 1
    stem, suffix = target.stem, target.suffix
    while target.exists():
        target = inbox_dir / f"{stem}_{counter}{suffix}"
        counter += 1

    content = await file.read()
    target.write_bytes(content)

    # 상대 경로 (NAS 루트 기준)
    rel_path = str(target.relative_to(Path(settings.nas_mount_path)))
    fhash = file_hash(target)
    ext = target.suffix.lstrip(".").lower() or "unknown"

    # DB 등록
    doc = Document(
        file_path=rel_path,
        file_hash=fhash,
        file_format=ext,
        file_size=len(content),
        file_type="immutable",
        title=target.stem,
        source_channel="manual",
    )
    session.add(doc)
    await session.flush()

    # 처리 큐 등록
    session.add(ProcessingQueue(
        document_id=doc.id,
        stage="extract",
        status="pending",
    ))
    await session.commit()

    return DocumentResponse.model_validate(doc)


@router.patch("/{doc_id}", response_model=DocumentResponse)
async def update_document(
    doc_id: int,
    body: DocumentUpdate,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """문서 메타데이터 수정 (수동 오버라이드)"""
    doc = await session.get(Document, doc_id)
    if not doc:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")

    update_data = body.model_dump(exclude_unset=True)
    for field, value in update_data.items():
        setattr(doc, field, value)
    doc.updated_at = datetime.now(timezone.utc)
    await session.commit()

    return DocumentResponse.model_validate(doc)


@router.delete("/{doc_id}")
async def delete_document(
    doc_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
    delete_file: bool = Query(False, description="NAS 파일도 함께 삭제"),
):
    """문서 삭제 (기본: DB만 삭제, 파일 유지)"""
    doc = await session.get(Document, doc_id)
    if not doc:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")

    if delete_file:
        file_path = Path(settings.nas_mount_path) / doc.file_path
        if file_path.exists():
            file_path.unlink()

    await session.delete(doc)
    await session.commit()

    return {"message": f"문서 {doc_id} 삭제됨", "file_deleted": delete_file}