"""문서 CRUD API"""

import shutil
from datetime import datetime, timezone
from pathlib import Path
from typing import Annotated
from urllib.parse import quote

from fastapi import APIRouter, Depends, Form, 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, enqueue_stage
from models.user import User

router = APIRouter()


# ─── 스키마 ───


class DocumentResponse(BaseModel):
    id: int
    file_path: str | None
    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
    user_tags: list | None
    pinned: bool | None
    ask_includable: bool | None
    derived_path: str | None
    original_format: str | None
    conversion_status: str | None
    is_read: bool | None
    review_status: str | None
    edit_url: str | None
    preview_status: str | None
    source_channel: str | None
    data_origin: str | None
    doc_purpose: 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_tags: list | None = None
    user_note: str | None = None
    is_read: bool | None = None
    edit_url: str | None = None
    source_channel: str | None = None
    data_origin: str | None = None
    doc_purpose: str | None = None
    pinned: bool | 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 ai_domain != 'News'
              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("/library-tree")
async def get_library_tree(
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
):
    """자료실 트리 (user_tags @library/ 경로 기반, unique doc count)"""
    from core.library import LIBRARY_PREFIX

    result = await session.execute(
        select(Document.id, Document.user_tags).where(
            Document.deleted_at == None,  # noqa: E711
            Document.user_tags != None,  # noqa: E711
        )
    )

    root: dict = {}
    for doc_id, tags in result:
        if not tags:
            continue
        seen_ancestors: set[str] = set()
        for tag in tags:
            if not isinstance(tag, str) or not tag.startswith(LIBRARY_PREFIX):
                continue
            path = tag[len(LIBRARY_PREFIX):]
            parts = path.split("/")
            node = root
            for i, part in enumerate(parts):
                if part not in node:
                    node[part] = {"_docs": set(), "_children": {}}
                ancestor_key = "/".join(parts[: i + 1])
                if ancestor_key not in seen_ancestors:
                    node[part]["_docs"].add(doc_id)
                    seen_ancestors.add(ancestor_key)
                node = node[part]["_children"]

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

    return build_library_tree(root)


@router.get("/library", response_model=DocumentListResponse)
async def list_library_documents(
    user: Annotated[User, Depends(get_current_user)],
    session: Annotated[AsyncSession, Depends(get_session)],
    path: str | None = None,
    q: str | None = None,
    sort: str = Query("updated_desc"),
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
):
    """자료실 문서 목록 (prefix match, title 검색, 정렬)"""
    from sqlalchemy import text as sql_text

    from core.library import LIBRARY_PREFIX, normalize_library_path

    # path 쿼리 정규화 (PATCH와 동일 semantics)
    if path:
        try:
            path = normalize_library_path(path)
        except ValueError as e:
            raise HTTPException(status_code=400, detail=str(e))

    query = select(Document).where(
        Document.deleted_at == None,  # noqa: E711
    )

    if path:
        exact = f"{LIBRARY_PREFIX}{path}"
        prefix = f"{LIBRARY_PREFIX}{path}/%"
        query = query.where(
            sql_text("""
                EXISTS (
                    SELECT 1 FROM jsonb_array_elements_text(documents.user_tags) AS t
                    WHERE t = :exact OR t LIKE :prefix
                )
            """).bindparams(exact=exact, prefix=prefix)
        )
    else:
        query = query.where(
            sql_text("""
                EXISTS (
                    SELECT 1 FROM jsonb_array_elements_text(documents.user_tags) AS t
                    WHERE t LIKE '@library/%'
                )
            """)
        )

    if q:
        query = query.where(Document.title.ilike(f"%{q}%"))

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

    # 정렬
    sort_map = {
        "updated_desc": Document.updated_at.desc(),
        "title_asc": Document.title.asc(),
        "created_desc": Document.created_at.desc(),
    }
    query = query.order_by(sort_map.get(sort, Document.updated_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("/", 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=500),
    domain: str | None = None,
    sub_group: str | None = None,
    source: str | None = None,
    format: str | None = None,
    review_status: str | None = Query(None, description="pending | approved | rejected"),
):
    """문서 목록 조회 (페이지네이션 + 필터, 뉴스/메모 제외)"""
    query = select(Document).where(
        Document.deleted_at == None,  # noqa: E711
        Document.source_channel != "news",
        Document.file_type != "note",
    )

    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)
    if review_status:
        query = query.where(Document.review_status == review_status)

    # 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)"),
    download: bool = Query(False, description="true면 attachment (브라우저 다운로드)"),
    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")

    # note(메모)는 물리 파일이 없음
    if not doc.file_path:
        raise HTTPException(status_code=404, detail="파일이 없는 문서입니다 (메모)")

    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")

    # Content-Disposition: download=true면 attachment (한글 filename* 호환)
    if download:
        raw_title = doc.title or f"document-{doc_id}"
        ascii_fallback = raw_title.encode("ascii", "replace").decode()
        utf8_encoded = quote(f"{raw_title}{suffix}")
        disposition = f'attachment; filename="{ascii_fallback}{suffix}"; filename*=UTF-8\'\'{utf8_encoded}'
    else:
        disposition = "inline"

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


@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)],
    doc_purpose: str | None = Form(None, description="business | knowledge"),
    library_path: str | None = Form(None, description="자료실 경로 (자동 @library/ 태깅)"),
):
    """파일 업로드 → Inbox 저장 + DB 등록 + 처리 큐 등록"""
    from core.library import DEFAULT_LIBRARY_PATH, LIBRARY_PREFIX, normalize_library_path

    # doc_purpose 검증
    if doc_purpose is not None:
        doc_purpose = doc_purpose.strip().lower()
        if doc_purpose == "":
            doc_purpose = None
        elif doc_purpose not in ("business", "knowledge"):
            raise HTTPException(status_code=400, detail="doc_purpose는 business 또는 knowledge만 가능")

    # library_path 검증 + 정규화
    library_tag = None
    if library_path:
        try:
            normalized = normalize_library_path(library_path)
            library_tag = f"{LIBRARY_PREFIX}{normalized}"
        except ValueError as e:
            raise HTTPException(status_code=400, detail=f"잘못된 자료실 경로: {e}")

    # 자료실 업로드인데 경로 미지정 → 미분류 자동 태깅
    if doc_purpose == "business" and not library_tag:
        library_tag = f"{LIBRARY_PREFIX}{DEFAULT_LIBRARY_PATH}"

    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",
        doc_purpose=doc_purpose,
        user_tags=[library_tag] if library_tag else [],
    )
    session.add(doc)
    await session.flush()

    # 처리 큐 등록
    await enqueue_stage(session, doc.id, "extract")
    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)"""
    from core.library import validate_user_tags

    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)

    # user_tags 검증: @library/ 경로 정규화 + 타입/중복 체크
    if "user_tags" in update_data and update_data["user_tags"] is not None:
        try:
            update_data["user_tags"] = validate_user_tags(update_data["user_tags"])
        except (TypeError, ValueError) as e:
            raise HTTPException(status_code=400, detail=str(e))

    # doc_purpose 검증
    if "doc_purpose" in update_data:
        val = update_data["doc_purpose"]
        if val is not None and val not in ("business", "knowledge"):
            raise HTTPException(status_code=400, detail="doc_purpose는 business 또는 knowledge만 가능")

    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)")

    # note(메모)는 /api/memos/{id} PATCH로 수정
    if not doc.file_path:
        raise HTTPException(status_code=400, detail="파일이 없는 문서입니다. 메모는 /api/memos 사용")

    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)"),
    download: bool = Query(False, description="true면 attachment (PDF 다운로드)"),
):
    """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")

    if download:
        raw_title = doc.title or f"document-{doc_id}"
        ascii_fallback = raw_title.encode("ascii", "replace").decode()
        utf8_encoded = quote(f"{raw_title}.pdf")
        disposition = f'attachment; filename="{ascii_fallback}.pdf"; filename*=UTF-8\'\'{utf8_encoded}'
    else:
        disposition = "inline"

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


@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"}