"""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 fastapi.responses import FileResponse
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
    document_type: str | None
    importance: str | None
    ai_confidence: float | None
    user_note: str | None
    derived_path: str | None
    original_format: str | None
    conversion_status: str | None
    review_status: str | None
    edit_url: str | None
    preview_status: 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
    user_note: str | None = None
    edit_url: str | None = None
    source_channel: str | None = None
    data_origin: str | None = None


# ─── 스키마 (트리) ───


class TreeNode(BaseModel):
    name: str
    path: str
    count: int
    children: list["TreeNode"]


# ─── 엔드포인트 ───


@router.get("/tree")
async def get_document_tree(
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """도메인 트리 (3단계 경로 파싱, 사이드바용)"""
    from sqlalchemy import text as sql_text

    result = await session.execute(
        sql_text("""
            SELECT ai_domain, COUNT(*)
            FROM documents
            WHERE ai_domain IS NOT NULL AND ai_domain != ''
              AND deleted_at IS NULL
            GROUP BY ai_domain
            ORDER BY ai_domain
        """)
    )

    # 경로를 트리로 파싱
    root: dict = {}
    for domain_path, count in result:
        parts = domain_path.split("/")
        node = root
        for part in parts:
            if part not in node:
                node[part] = {"_count": 0, "_children": {}}
            node[part]["_count"] += count
            node = node[part]["_children"]

    def build_tree(d: dict, prefix: str = "") -> list[dict]:
        nodes = []
        for name, data in sorted(d.items()):
            path = f"{prefix}/{name}" if prefix else name
            children = build_tree(data["_children"], path)
            nodes.append({
                "name": name,
                "path": path,
                "count": data["_count"],
                "children": children,
            })
        return nodes

    return build_tree(root)


@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,
    sub_group: str | None = None,
    source: str | None = None,
    format: str | None = None,
):
    """문서 목록 조회 (페이지네이션 + 필터)"""
    query = select(Document).where(Document.deleted_at == None)

    if domain:
        # prefix 매칭: Industrial_Safety 클릭 시 하위 전부 포함
        query = query.where(Document.ai_domain.startswith(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 or doc.deleted_at is not None:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")
    return DocumentResponse.model_validate(doc)


@router.get("/{doc_id}/file")
async def get_document_file(
    doc_id: int,
    session: Annotated[AsyncSession, Depends(get_session)],
    token: str | None = Query(None, description="Bearer token (iframe용)"),
    user: User | None = Depends(lambda: None),
):
    """문서 원본 파일 서빙 (Bearer 헤더 또는 ?token= 쿼리 파라미터)"""
    from core.auth import decode_token

    # 쿼리 파라미터 토큰 검증
    if token:
        payload = decode_token(token)
        if not payload or payload.get("type") != "access":
            raise HTTPException(status_code=401, detail="유효하지 않은 토큰")
    else:
        # 일반 Bearer 헤더 인증 시도
        raise HTTPException(status_code=401, detail="토큰이 필요합니다")

    doc = await session.get(Document, doc_id)
    if not doc:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")

    file_path = Path(settings.nas_mount_path) / doc.file_path
    if not file_path.exists():
        raise HTTPException(status_code=404, detail="파일을 찾을 수 없습니다")

    # 미디어 타입 매핑
    media_types = {
        ".pdf": "application/pdf",
        ".jpg": "image/jpeg", ".jpeg": "image/jpeg",
        ".png": "image/png", ".gif": "image/gif",
        ".bmp": "image/bmp", ".tiff": "image/tiff",
        ".svg": "image/svg+xml",
        ".txt": "text/plain", ".md": "text/plain",
        ".html": "text/html", ".csv": "text/csv",
        ".json": "application/json", ".xml": "application/xml",
    }
    suffix = file_path.suffix.lower()
    media_type = media_types.get(suffix, "application/octet-stream")

    return FileResponse(
        path=str(file_path),
        media_type=media_type,
        headers={"Content-Disposition": "inline"},
    )


@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")

    # 파일명 정규화 (경로 이탈 방지)
    safe_name = Path(file.filename).name
    if not safe_name or safe_name.startswith("."):
        raise HTTPException(status_code=400, detail="유효하지 않은 파일명")

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

    # Inbox 하위 경로 검증
    if not str(target).startswith(str(inbox_dir.resolve())):
        raise HTTPException(status_code=400, detail="잘못된 파일 경로")

    # 중복 파일명 처리
    counter = 1
    stem, suffix = target.stem, target.suffix
    while target.exists():
        target = inbox_dir.resolve() / 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.put("/{doc_id}/content")
async def save_document_content(
    doc_id: int,
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
    body: dict = None,
):
    """Markdown 원본 파일 저장 + extracted_text 갱신"""
    doc = await session.get(Document, doc_id)
    if not doc:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")

    if doc.file_format not in ("md", "txt"):
        raise HTTPException(status_code=400, detail="편집 가능한 포맷이 아닙니다 (md, txt만 가능)")

    content = body.get("content", "") if body else ""
    file_path = Path(settings.nas_mount_path) / doc.file_path
    file_path.write_text(content, encoding="utf-8")

    # 메타 갱신
    doc.file_size = len(content.encode("utf-8"))
    doc.file_hash = file_hash(file_path)
    doc.extracted_text = content[:15000]
    doc.updated_at = datetime.now(timezone.utc)
    await session.commit()

    return DocumentResponse.model_validate(doc)


@router.get("/{doc_id}/preview")
async def get_document_preview(
    doc_id: int,
    session: Annotated[AsyncSession, Depends(get_session)],
    token: str | None = Query(None, description="Bearer token (iframe용)"),
):
    """PDF 미리보기 캐시 서빙"""
    from core.auth import decode_token

    if token:
        payload = decode_token(token)
        if not payload or payload.get("type") != "access":
            raise HTTPException(status_code=401, detail="유효하지 않은 토큰")
    else:
        raise HTTPException(status_code=401, detail="토큰이 필요합니다")

    doc = await session.get(Document, doc_id)
    if not doc:
        raise HTTPException(status_code=404, detail="문서를 찾을 수 없습니다")

    preview_path = Path(settings.nas_mount_path) / "PKM" / ".preview" / f"{doc_id}.pdf"
    if not preview_path.exists():
        raise HTTPException(status_code=404, detail="미리보기가 아직 생성되지 않았습니다")

    return FileResponse(
        path=str(preview_path),
        media_type="application/pdf",
        headers={"Content-Disposition": "inline"},
    )


@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")

    # soft-delete (물리 파일은 cleanup job에서 나중에 정리)
    doc.deleted_at = datetime.now(timezone.utc)
    await session.commit()

    return {"message": f"문서 {doc_id} soft-delete 완료"}