"""메모 CRUD API — 파일 없는 문서(file_type='note')"""

import hashlib
import re
from datetime import datetime, timezone
from typing import Annotated

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

from core.auth import get_current_user
from core.database import get_session
from models.document import Document
from models.queue import ProcessingQueue
from models.user import User

router = APIRouter()

# #태그 파싱 패턴: 한글/영문/숫자/밑줄, 2자 이상
TAG_PATTERN = re.compile(r"(?:^|(?<=\s))#([가-힣a-zA-Z0-9_]{2,})")


def _parse_hashtags(content: str) -> list[str]:
    """본문에서 #태그 추출, 중복 제거, 순서 유지"""
    seen: set[str] = set()
    tags: list[str] = []
    for m in TAG_PATTERN.finditer(content):
        tag = m.group(1)
        if tag not in seen:
            seen.add(tag)
            tags.append(tag)
    return tags


def _content_hash(content: str) -> str:
    """메모 본문의 SHA-256 해시 (note의 file_hash = content hash)"""
    return hashlib.sha256(content.encode("utf-8")).hexdigest()


def _auto_title(content: str) -> str:
    """첫 줄에서 제목 자동 생성 (80자 절단, 마크다운 헤딩 제거)"""
    first_line = content.split("\n", 1)[0].strip()
    title = re.sub(r"^#+\s*", "", first_line)[:80] or "메모"
    return title


async def _enqueue_ai_stages(session: AsyncSession, document_id: int):
    """classify + embed + chunk 큐 등록. 기존 pending 건 정리 (중복 방지)."""
    stages = ["classify", "embed", "chunk"]
    await session.execute(
        delete(ProcessingQueue).where(
            ProcessingQueue.document_id == document_id,
            ProcessingQueue.stage.in_(stages),
            ProcessingQueue.status == "pending",
        )
    )
    for stage in stages:
        session.add(ProcessingQueue(
            document_id=document_id,
            stage=stage,
            status="pending",
        ))


# ─── 스키마 ───


class MemoCreate(BaseModel):
    content: str
    ask_includable: bool = True


class MemoUpdate(BaseModel):
    content: str


class ArchiveSet(BaseModel):
    archived: bool


class MemoResponse(BaseModel):
    id: int
    title: str | None
    content: str | None  # extracted_text
    file_format: str
    user_tags: list | None
    ai_tags: list | None
    ai_domain: str | None
    ai_sub_group: str | None
    ai_summary: str | None
    pinned: bool
    archived: bool
    ask_includable: bool
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class MemoListResponse(BaseModel):
    items: list[MemoResponse]
    total: int
    page: int
    page_size: int


def _to_memo_response(doc: Document) -> MemoResponse:
    return MemoResponse(
        id=doc.id,
        title=doc.title,
        content=doc.extracted_text,
        file_format=doc.file_format,
        user_tags=doc.user_tags,
        ai_tags=doc.ai_tags,
        ai_domain=doc.ai_domain,
        ai_sub_group=doc.ai_sub_group,
        ai_summary=doc.ai_summary,
        pinned=doc.pinned,
        archived=doc.archived,
        ask_includable=doc.ask_includable,
        created_at=doc.created_at,
        updated_at=doc.updated_at,
    )


# ─── 엔드포인트 ───


@router.post("/", response_model=MemoResponse, status_code=201)
async def create_memo(
    body: MemoCreate,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """메모 생성 — file_type='note', 파일 없는 문서"""
    content = body.content.strip()
    if not content:
        raise HTTPException(status_code=400, detail="메모 내용이 비어있습니다")

    doc = Document(
        file_path=None,
        file_hash=_content_hash(content),
        file_format="md",
        file_size=len(content.encode("utf-8")),
        file_type="note",
        title=_auto_title(content),
        extracted_text=content,
        review_status="approved",
        source_channel="memo",
        user_tags=_parse_hashtags(content),
        pinned=False,
        archived=False,
        ask_includable=body.ask_includable,
    )
    session.add(doc)
    await session.flush()

    await _enqueue_ai_stages(session, doc.id)
    await session.commit()
    await session.refresh(doc)

    return _to_memo_response(doc)


@router.get("/", response_model=MemoListResponse)
async def list_memos(
    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),
    tag: str | None = Query(None, description="user_tags 또는 ai_tags 필터"),
    archived: bool = Query(False, description="true면 아카이브 목록"),
):
    """메모 목록 — 활성: 핀 우선 + 최신순 / 아카이브: 최신순 (핀 무시)"""
    base = select(Document).where(
        Document.file_type == "note",
        Document.deleted_at == None,  # noqa: E711
        Document.archived == archived,
    )

    if tag:
        base = base.where(
            Document.user_tags.op("@>")(f'["{tag}"]')
            | Document.ai_tags.op("@>")(f'["{tag}"]')
        )

    count_query = select(func.count()).select_from(base.subquery())
    total = (await session.execute(count_query)).scalar() or 0

    # 활성: pinned DESC + created_at DESC / 아카이브: created_at DESC (핀 무시)
    if archived:
        query = base.order_by(Document.created_at.desc())
    else:
        query = base.order_by(Document.pinned.desc(), Document.created_at.desc())

    query = query.offset((page - 1) * page_size).limit(page_size)
    result = await session.execute(query)
    items = result.scalars().all()

    return MemoListResponse(
        items=[_to_memo_response(doc) for doc in items],
        total=total,
        page=page,
        page_size=page_size,
    )


@router.get("/{memo_id}", response_model=MemoResponse)
async def get_memo(
    memo_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """메모 단건 조회"""
    doc = await session.get(Document, memo_id)
    if not doc or doc.file_type != "note" or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="메모를 찾을 수 없습니다")
    return _to_memo_response(doc)


@router.patch("/{memo_id}", response_model=MemoResponse)
async def update_memo(
    memo_id: int,
    body: MemoUpdate,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """메모 수정 — content 변경 시 AI 데이터 초기화 + 재처리 큐 등록"""
    doc = await session.get(Document, memo_id)
    if not doc or doc.file_type != "note" or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="메모를 찾을 수 없습니다")

    content = body.content.strip()
    if not content:
        raise HTTPException(status_code=400, detail="메모 내용이 비어있습니다")

    doc.extracted_text = content
    doc.file_hash = _content_hash(content)
    doc.file_size = len(content.encode("utf-8"))
    doc.title = _auto_title(content)
    doc.user_tags = _parse_hashtags(content)

    # stale AI 데이터 즉시 초기화
    doc.ai_summary = None
    doc.ai_domain = None
    doc.ai_sub_group = None
    doc.ai_tags = None
    doc.ai_confidence = None
    doc.ai_processed_at = None
    doc.embedding = None
    doc.embedded_at = None

    # 기존 chunks 삭제
    from models.chunk import DocumentChunk
    await session.execute(
        delete(DocumentChunk).where(DocumentChunk.document_id == memo_id)
    )

    # 재처리 큐 등록
    await _enqueue_ai_stages(session, memo_id)

    doc.updated_at = datetime.now(timezone.utc)
    await session.commit()
    await session.refresh(doc)

    return _to_memo_response(doc)


@router.delete("/{memo_id}", status_code=204)
async def delete_memo(
    memo_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """메모 soft delete"""
    doc = await session.get(Document, memo_id)
    if not doc or doc.file_type != "note" or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="메모를 찾을 수 없습니다")

    doc.deleted_at = datetime.now(timezone.utc)
    await session.commit()


@router.patch("/{memo_id}/pin", response_model=MemoResponse)
async def toggle_pin(
    memo_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """메모 핀 토글"""
    doc = await session.get(Document, memo_id)
    if not doc or doc.file_type != "note" or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="메모를 찾을 수 없습니다")

    doc.pinned = not doc.pinned
    doc.updated_at = datetime.now(timezone.utc)
    await session.commit()
    await session.refresh(doc)

    return _to_memo_response(doc)


@router.patch("/{memo_id}/archive", response_model=MemoResponse)
async def set_archive(
    memo_id: int,
    body: ArchiveSet,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """메모 아카이브 설정 (멱등, 토글 아님)"""
    doc = await session.get(Document, memo_id)
    if not doc or doc.file_type != "note" or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="메모를 찾을 수 없습니다")

    doc.archived = body.archived
    doc.updated_at = datetime.now(timezone.utc)
    await session.commit()
    await session.refresh(doc)

    return _to_memo_response(doc)


@router.patch("/{memo_id}/ask-includable", response_model=MemoResponse)
async def toggle_ask_includable(
    memo_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """/ask 합성 포함 여부 토글"""
    doc = await session.get(Document, memo_id)
    if not doc or doc.file_type != "note" or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="메모를 찾을 수 없습니다")

    doc.ask_includable = not doc.ask_includable
    doc.updated_at = datetime.now(timezone.utc)
    await session.commit()
    await session.refresh(doc)

    return _to_memo_response(doc)