from __future__ import annotations

from typing import Annotated

from fastapi import APIRouter, Body, Depends, HTTPException, Query, status
from fastapi.responses import FileResponse

from app.api.deps import CurrentUserContext, get_current_user, require_admin_user
from app.schemas.common import ErrorResponse
from app.schemas.knowledge import (
    KnowledgeActionResponse,
    KnowledgeDocumentDetailRead,
    KnowledgeLibraryRead,
    KnowledgeOnlyOfficeCallbackRead,
    KnowledgeOnlyOfficeCallbackWrite,
    KnowledgeOnlyOfficeConfigRead,
)
from app.services.knowledge import KnowledgeService

router = APIRouter(prefix="/knowledge")


@router.get(
    "/library",
    response_model=KnowledgeLibraryRead,
    summary="查询知识库目录",
    description="返回固定知识库目录与当前已上传文档列表。",
    responses={
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "未提供知识库访问用户头。",
        }
    },
)
def get_knowledge_library(
    _: Annotated[CurrentUserContext, Depends(get_current_user)],
) -> KnowledgeLibraryRead:
    return KnowledgeService().list_library()


@router.get(
    "/documents/{document_id}",
    response_model=KnowledgeDocumentDetailRead,
    summary="读取知识库文档详情",
    description="返回单个知识库文档的元信息、预览类型和预览内容。",
    responses={
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "未提供知识库访问用户头。",
        },
        status.HTTP_404_NOT_FOUND: {
            "model": ErrorResponse,
            "description": "知识库文件不存在。",
        },
    },
)
def get_knowledge_document(
    document_id: str,
    _: Annotated[CurrentUserContext, Depends(get_current_user)],
) -> KnowledgeDocumentDetailRead:
    try:
        return KnowledgeService().get_document_detail(document_id)
    except FileNotFoundError as exc:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="知识库文件不存在。",
        ) from exc


@router.get(
    "/documents/{document_id}/onlyoffice-config",
    response_model=KnowledgeOnlyOfficeConfigRead,
    summary="读取 ONLYOFFICE 预览配置",
    description="为支持的 Office 文档生成 ONLYOFFICE 前端配置和临时访问令牌。",
    responses={
        status.HTTP_400_BAD_REQUEST: {
            "model": ErrorResponse,
            "description": "ONLYOFFICE 未启用、配置不完整或文件格式不支持。",
        },
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "未提供知识库访问用户头。",
        },
        status.HTTP_404_NOT_FOUND: {
            "model": ErrorResponse,
            "description": "知识库文件不存在。",
        },
    },
)
def get_knowledge_document_onlyoffice_config(
    document_id: str,
    current_user: Annotated[CurrentUserContext, Depends(get_current_user)],
) -> KnowledgeOnlyOfficeConfigRead:
    try:
        return KnowledgeService().build_onlyoffice_config(document_id, current_user)
    except FileNotFoundError as exc:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="知识库文件不存在。",
        ) from exc
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc


@router.post(
    "/documents",
    response_model=KnowledgeDocumentDetailRead,
    status_code=status.HTTP_201_CREATED,
    summary="上传知识库文档",
    description="上传原始文件二进制内容到指定知识库目录。已有同名文件会覆盖并提升版本号。",
    responses={
        status.HTTP_400_BAD_REQUEST: {
            "model": ErrorResponse,
            "description": "目录、文件名或文件内容不合法。",
        },
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "未提供知识库访问用户头。",
        },
        status.HTTP_403_FORBIDDEN: {
            "model": ErrorResponse,
            "description": "只有管理员可以上传知识库文件。",
        },
    },
)
def upload_knowledge_document(
    content: Annotated[
        bytes,
        Body(
            media_type="application/octet-stream",
            description="待上传的文件二进制内容。",
        ),
    ],
    folder: Annotated[str, Query(min_length=1, description="目标知识库目录名称。")],
    filename: Annotated[str, Query(min_length=1, description="原始文件名。")],
    current_user: Annotated[CurrentUserContext, Depends(require_admin_user)],
) -> KnowledgeDocumentDetailRead:
    try:
        return KnowledgeService().upload_document(folder, filename, content, current_user)
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc


@router.delete(
    "/documents/{document_id}",
    response_model=KnowledgeActionResponse,
    summary="删除知识库文档",
    description="删除知识库文档及其索引记录。",
    responses={
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "未提供知识库访问用户头。",
        },
        status.HTTP_403_FORBIDDEN: {
            "model": ErrorResponse,
            "description": "只有管理员可以删除知识库文件。",
        },
        status.HTTP_404_NOT_FOUND: {
            "model": ErrorResponse,
            "description": "知识库文件不存在。",
        },
    },
)
def delete_knowledge_document(
    document_id: str,
    _: Annotated[CurrentUserContext, Depends(require_admin_user)],
) -> KnowledgeActionResponse:
    try:
        KnowledgeService().delete_document(document_id)
    except FileNotFoundError as exc:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="知识库文件不存在。",
        ) from exc

    return KnowledgeActionResponse(detail="知识库文件已删除。")


@router.get(
    "/documents/{document_id}/content",
    response_class=FileResponse,
    summary="下载或预览知识库原文",
    description="根据文档 ID 返回原始文件内容，可用于浏览器内联预览或下载。",
    responses={
        status.HTTP_200_OK: {
            "description": "文件内容。",
            "content": {"application/octet-stream": {}},
        },
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "未提供知识库访问用户头。",
        },
        status.HTTP_404_NOT_FOUND: {
            "model": ErrorResponse,
            "description": "知识库文件不存在。",
        },
    },
)
def get_knowledge_document_content(
    document_id: str,
    disposition: Annotated[
        str,
        Query(
            pattern="^(inline|attachment)$",
            description="内容展示方式，支持 `inline` 或 `attachment`。",
        ),
    ] = "inline",
    _: Annotated[CurrentUserContext, Depends(get_current_user)] = None,
) -> FileResponse:
    try:
        file_path, media_type, filename = KnowledgeService().get_document_content(document_id)
    except FileNotFoundError as exc:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="知识库文件不存在。",
        ) from exc

    _ = disposition
    return FileResponse(file_path, media_type=media_type, filename=filename)


@router.get(
    "/documents/{document_id}/onlyoffice/content",
    response_class=FileResponse,
    summary="读取 ONLYOFFICE 文档源文件",
    description="供 ONLYOFFICE 服务通过短时访问令牌拉取原始文件内容。",
    responses={
        status.HTTP_200_OK: {
            "description": "文件内容。",
            "content": {"application/octet-stream": {}},
        },
        status.HTTP_401_UNAUTHORIZED: {
            "model": ErrorResponse,
            "description": "ONLYOFFICE 访问令牌无效。",
        },
        status.HTTP_404_NOT_FOUND: {
            "model": ErrorResponse,
            "description": "知识库文件不存在。",
        },
    },
)
def get_knowledge_document_onlyoffice_content(
    document_id: str,
    access_token: Annotated[
        str,
        Query(min_length=1, description="ONLYOFFICE 临时访问令牌。"),
    ],
) -> FileResponse:
    try:
        service = KnowledgeService()
        service.validate_onlyoffice_access_token(document_id, access_token)
        file_path, media_type, filename = service.get_document_content(document_id)
    except FileNotFoundError as exc:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="知识库文件不存在。",
        ) from exc
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail=str(exc)) from exc

    return FileResponse(file_path, media_type=media_type, filename=filename)


@router.post(
    "/documents/{document_id}/onlyoffice/callback",
    response_model=KnowledgeOnlyOfficeCallbackRead,
    summary="接收 ONLYOFFICE 回调",
    description="接收 ONLYOFFICE 文档回写回调，在状态满足要求时更新知识库文件内容。",
    responses={
        status.HTTP_400_BAD_REQUEST: {
            "model": ErrorResponse,
            "description": "回调载荷不合法。",
        },
        status.HTTP_404_NOT_FOUND: {
            "model": ErrorResponse,
            "description": "知识库文件不存在。",
        },
    },
)
def handle_knowledge_document_onlyoffice_callback(
    document_id: str,
    payload: KnowledgeOnlyOfficeCallbackWrite,
) -> KnowledgeOnlyOfficeCallbackRead:
    try:
        KnowledgeService().handle_onlyoffice_callback(document_id, payload.model_dump())
    except FileNotFoundError as exc:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="知识库文件不存在。",
        ) from exc
    except ValueError as exc:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc

    return KnowledgeOnlyOfficeCallbackRead()