"""
文档管理 API

本模块提供文档上传、查询、删除等管理功能，包括：
- 单文件和批量上传
- 文档列表查询
- 文档切片管理

路由列表:
    POST   /documents/upload              : 上传文件（单个）
    POST   /documents/batch-upload        : 批量上传文件
    GET    /documents/list                : 文档列表
    GET    /documents/<doc_id>/status     : 文件处理状态
    PUT    /documents/<doc_id>            : 更新文件
    DELETE /documents/<doc_path>          : 删除文档
    GET    /documents/<doc_id>/chunks     : 查看文件切片
    GET    /documents/<doc_id>/preview    : 文档预览（支持按切片序号跳转）

切片管理:
    POST   /chunks                        : 新增切片
    PUT    /chunks/<chunk_id>             : 修改切片
    DELETE /chunks/<chunk_id>             : 删除切片

架构说明:
    - 权限验证由后端网关完成，RAG 服务不做权限判断
    - 文档存储在 documents/<collection>/ 目录下
    - 上传后自动触发向量化（如果同步服务可用）

Example:
    # 上传文件
    curl -X POST http://localhost:5001/documents/upload \\
         -H "Authorization: Bearer mock-token-admin" \\
         -F "file=@report.pdf" \\
         -F "collection=public_kb"
"""

import os
import re
import uuid
from datetime import datetime
from typing import Optional, Tuple, Any, List, Dict
from flask import Blueprint, request
import logging

logger = logging.getLogger(__name__)
from werkzeug.utils import secure_filename
from auth.gateway import require_gateway_auth
from config import DEV_MODE
from core.status_codes import (
    UPLOAD_SUCCESS, BATCH_UPLOAD_SUCCESS, BAD_REQUEST, SUCCESS,
    NO_FILE, NO_FILE_SELECTED, NO_COLLECTION, NOT_FOUND,
    FILE_TOO_LARGE, UNSUPPORTED_FORMAT, INTERNAL_ERROR,
    SERVICE_UNAVAILABLE, DELETE_SUCCESS, UPDATE_SUCCESS, NO_CONTENT,
    FORBIDDEN
)
from api.response_utils import success_response, error_response

document_bp = Blueprint('document', __name__)

# 文件限制
ALLOWED_EXTENSIONS = {'.pdf', '.docx', '.doc', '.xlsx', '.txt'}
MAX_FILE_SIZE = 10 * 1024 * 1024  # 10MB


def safe_filename(filename: str) -> str:
    """
    安全文件名处理 - 保留中文，仅移除危险字符

    与 werkzeug.secure_filename() 不同，此函数保留 Unicode 字符（包括中文），
    仅移除路径分隔符和其他可能导致路径遍历攻击的字符。

    Args:
        filename: 原始文件名

    Returns:
        安全的文件名；无效输入返回空字符串

    Example:
        >>> safe_filename("财务报告.pdf")
        '财务报告.pdf'
        >>> safe_filename("../../../etc/passwd")
        'etc_passwd'
    """
    if not filename:
        return ""

    # 移除路径分隔符和危险字符
    dangerous_chars = ['/', '\\', '..', '\x00', '\n', '\r', '\t']
    safe_name = filename
    for char in dangerous_chars:
        safe_name = safe_name.replace(char, '_')

    # 移除首尾空格和点
    safe_name = safe_name.strip(' .')

    # 如果文件名为空或只有扩展名，返回空
    if not safe_name or safe_name.startswith('.') and safe_name.count('.') == 1:
        return ""

    return safe_name


def _validate_doc_path(doc_path: str, documents_path: str) -> str:
    """
    校验文档路径是否在允许目录内，防止路径遍历攻击。

    Returns:
        解析后的安全绝对路径
    Raises:
        ValueError: 路径不合法
    """
    filepath = os.path.join(documents_path, doc_path)
    real_path = os.path.realpath(filepath)
    real_base = os.path.realpath(documents_path)
    if not real_path.startswith(real_base + os.sep) and real_path != real_base:
        raise ValueError("非法路径")
    return real_path


# 延迟初始化缓存
_kb_manager = None
_kb_checked = False


def _get_kb_manager() -> Optional[Any]:
    """
    获取知识库管理器（延迟加载）

    Returns:
        知识库管理器实例，导入失败返回 None
    """
    global _kb_manager, _kb_checked
    if not _kb_checked:
        try:
            from knowledge.manager import get_kb_manager
            _kb_manager = get_kb_manager()
        except ImportError as e:
            logger.warning(f"知识库管理器导入失败: {e}")
        _kb_checked = True
    return _kb_manager


def _get_sync_service() -> Optional[Any]:
    """
    获取同步服务实例

    Returns:
        同步服务实例，不可用时返回 None
    """
    try:
        from flask import current_app
        return current_app.config.get('SYNC_SERVICE')
    except Exception as e:
        logger.debug(f"获取同步服务失败: {e}")
        return None


# ==================== 文档管理 ====================

@document_bp.route('/documents/<path:doc_path>/raw', methods=['GET'])
@require_gateway_auth
def serve_document_file(doc_path: str) -> Tuple[Any, int]:
    """
    返回文档原始文件（仅开发模式）

    用于前端预览文档内容，生产环境禁用此接口。

    Args:
        doc_path: 文档相对路径（collection/filename）

    Returns:
        文件内容或错误响应

    Note:
        仅在 DEV_MODE=true 时可用（需在 .env 中显式设置）
    """
    if not DEV_MODE:
        return error_response("FORBIDDEN", FORBIDDEN, "仅开发环境可用", http_status=403)

    from config import DOCUMENTS_PATH
    from flask import send_from_directory

    filepath = os.path.join(DOCUMENTS_PATH, doc_path)
    try:
        filepath = _validate_doc_path(doc_path, DOCUMENTS_PATH)
    except ValueError:
        return error_response("FORBIDDEN", FORBIDDEN, "非法路径", http_status=403)
    if not os.path.exists(filepath):
        return error_response("NOT_FOUND", NOT_FOUND, "文件不存在", http_status=404)

    directory = os.path.dirname(filepath)
    filename = os.path.basename(filepath)
    return send_from_directory(directory, filename)


@document_bp.route('/documents/upload', methods=['POST'])
@require_gateway_auth
def upload_document() -> Tuple[Any, int]:
    """
    上传单个文件到知识库

    接收文件上传，保存到指定向量库目录，并触发向量化。

    表单参数:
        file: 文件（必需）
        collection: 目标向量库名称（必需）

    支持的文件类型:
        - PDF (.pdf)
        - Word (.docx, .doc)
        - Excel (.xlsx)
        - 文本 (.txt)

    文件大小限制:
        - 最大 10MB

    Returns:
        成功: {"success": true, "data": {"file": {...}, "sync_status": "..."}}
        失败: {"error": "...", "error_code": "..."}

    Example:
        curl -X POST http://localhost:5001/documents/upload \\
             -F "file=@report.pdf" \\
             -F "collection=public_kb"
    """
    from config import DOCUMENTS_PATH

    # 1. 检查文件
    if 'file' not in request.files:
        return error_response("NO_FILE", NO_FILE, "没有上传文件", http_status=400)

    file = request.files['file']
    if file.filename == '':
        return error_response("NO_FILE_SELECTED", NO_FILE_SELECTED, "没有选择文件", http_status=400)

    # 2. 获取目标向量库
    collection = request.form.get('collection') or request.form.get('kb_name')
    if not collection:
        return error_response("NO_COLLECTION", NO_COLLECTION, "请指定目标向量库 (collection 参数)", http_status=400)

    # 3. 文件类型验证
    ext = os.path.splitext(file.filename)[1].lower()
    if ext not in ALLOWED_EXTENSIONS:
        return error_response(
            "UNSUPPORTED_FORMAT",
            UNSUPPORTED_FORMAT,
            f"不支持的文件类型: {ext}，支持: pdf, docx, doc, xlsx, txt",
            http_status=400
        )

    # 4. 文件大小验证
    file.seek(0, os.SEEK_END)
    file_size = file.tell()
    file.seek(0)
    if file_size > MAX_FILE_SIZE:
        return error_response("FILE_TOO_LARGE", FILE_TOO_LARGE, "文件大小超过限制 (最大 10MB)", http_status=400)

    # 5. 保存文件到对应目录（目录名 = 向量库名）
    target_subdir = collection
    target_dir = os.path.join(DOCUMENTS_PATH, target_subdir)
    os.makedirs(target_dir, exist_ok=True)

    # 安全文件名 + 处理重名
    original_filename = file.filename
    ext = os.path.splitext(original_filename)[1].lower()
    filename = safe_filename(original_filename)
    if not filename:
        filename = f"upload_{datetime.now().strftime('%Y%m%d%H%M%S')}{ext}"

    filepath = os.path.join(target_dir, filename)

    # 同名文件处理：清理旧切片 + 覆盖旧文件（替代原来的时间戳重命名策略）
    replaced = False
    if os.path.exists(filepath):
        replaced = True
        # 1. 清理旧切片（ChromaDB + BM25 + DocStore）
        kb_manager = _get_kb_manager()
        if kb_manager:
            old_chunks = kb_manager.get_document_chunks(collection, filename)
            if old_chunks:
                old_ids = [c['id'] for c in old_chunks]
                coll_obj = kb_manager.get_collection(collection)
                if coll_obj:
                    coll_obj.delete(ids=old_ids)
                    logger.info(f"替换上传: 清理旧切片 {filename} -> {collection}, 共 {len(old_ids)} 个")

                    # 清理关联的 DocStore 文件
                    try:
                        from pathlib import Path as _Path
                        docstore_dir = _Path('.data/docstore')
                        if docstore_dir.exists():
                            for ds_file in docstore_dir.glob(f'{collection}_{filename}_*.json'):
                                ds_file.unlink()
                    except Exception as e:
                        logger.warning(f"清理 DocStore 失败: {e}")

                    # 重建 BM25 索引
                    kb_manager.rebuild_bm25_index(collection)

        # 2. 清理同步哈希记录（以便 sync 能正确检测为新文件）
        try:
            from knowledge.sync import SyncDatabase
            sync_db = SyncDatabase()
            sync_db.delete_document_hash(f"{collection}/{filename}")
        except Exception as e:
            logger.warning(f"清理哈希记录失败: {e}")

    # 保存文件（覆盖同名旧文件）
    file.save(filepath)

    # 版本管理：覆盖上传时标记旧版本为 superseded（新版本记录由 sync 服务统一创建）
    if replaced:
        try:
            from knowledge.document_versions import get_version_query
            from data.db import get_connection
            vq = get_version_query()
            active = vq.get_active_version(collection, filename)

            if active:
                with get_connection("knowledge") as conn:
                    conn.execute("""
                        UPDATE document_versions
                        SET status='superseded', deprecated_date=?,
                            deprecated_reason='重新上传覆盖'
                        WHERE collection=? AND document_id=? AND version=?
                    """, (datetime.now().isoformat(), collection,
                          filename, active.version))
                    conn.commit()
                vq.log_version_change(
                    collection, filename,
                    change_type="reupload",
                    old_version=active.version,
                    old_status="active", new_status="superseded",
                    reason="重新上传覆盖",
                    changed_by=request.current_user.get('user_id', '')
                )
        except Exception as e:
            logger.warning(f"标记旧版本失败: {e}")

    # 6. 触发向量化（异步任务）
    sync_status = "已保存，等待手动同步"
    sync_service = _get_sync_service()
    task_id = None

    if sync_service:
        from core.task_registry import get_registry
        registry = get_registry()

        task = registry.create_task('upload', f"向量化: {filename}")
        task_id = task.id

        def _do_vectorize(task, svc, change_obj, fname):
            """后台执行向量化"""
            registry.update_progress(task.id, stage='向量化', message=f"正在处理: {fname}")
            svc.process_change(change_obj)
            return {'filename': fname, 'sync_status': '已添加到向量库'}

        try:
            from knowledge.sync import DocumentChange, ChangeType
            change = DocumentChange(
                document_id=f"{target_subdir}/{filename}",
                document_name=filename,
                change_type=ChangeType.ADDED,
                old_hash=None,
                new_hash=sync_service.calculate_file_hash(filepath),
                change_time=datetime.now()
            )
            registry.start_task(task.id, _do_vectorize, sync_service, change, filename)
            sync_status = "已保存，向量化任务已启动"
        except Exception as e:
            logger.warning(f"创建向量化任务失败: {e}")
            registry.fail_task(task.id, str(e))
            sync_status = "已保存，向量化任务创建失败"

    return success_response(
        data={
            "file": {
                "filename": filename,
                "collection": collection,
                "path": f"{target_subdir}/{filename}",
                "size": file_size,
                "replaced": replaced
            },
            "sync_status": sync_status,
            "task_id": task_id
        },
        status_code=UPLOAD_SUCCESS,
        message=f"文件上传成功，{sync_status}"
    )


@document_bp.route('/documents/batch-upload', methods=['POST'])
@require_gateway_auth
def batch_upload_documents() -> Tuple[Any, int]:
    """
    批量上传文件到知识库

    支持同时上传多个文件到指定向量库目录。

    表单参数:
        files: 文件列表（必需）
        collection: 目标向量库名称（必需）

    Returns:
        {
            "success": true,
            "data": {
                "total": N,
                "success_count": M,
                "results": [...]
            }
        }
    """
    from config import DOCUMENTS_PATH

    # 检查文件
    if 'files' not in request.files:
        return error_response("NO_FILE", NO_FILE, "没有上传文件", http_status=400)

    files = request.files.getlist('files')
    if not files:
        return error_response("NO_FILE_SELECTED", NO_FILE_SELECTED, "没有选择文件", http_status=400)

    # 获取目标向量库
    collection = request.form.get('collection') or request.form.get('kb_name')
    if not collection:
        return error_response("NO_COLLECTION", NO_COLLECTION, "请指定目标向量库 (collection 参数)", http_status=400)

    # 确定存储目录（目录名 = 向量库名）
    target_subdir = collection
    target_dir = os.path.join(DOCUMENTS_PATH, target_subdir)
    os.makedirs(target_dir, exist_ok=True)

    # 批量处理
    results = []
    for file in files:
        if file.filename == '':
            continue

        ext = os.path.splitext(file.filename)[1].lower()
        if ext not in ALLOWED_EXTENSIONS:
            results.append({
                "filename": file.filename,
                "status": "error",
                "message": f"不支持的文件类型: {ext}"
            })
            continue

        # 文件大小校验
        file.seek(0, 2)
        file_size = file.tell()
        file.seek(0)
        if file_size > MAX_FILE_SIZE:
            results.append({
                "filename": file.filename,
                "status": "error",
                "message": f"文件过大（最大 {MAX_FILE_SIZE // 1024 // 1024}MB）"
            })
            continue

        try:
            original_filename = file.filename
            ext = os.path.splitext(original_filename)[1].lower()
            filename = safe_filename(original_filename)
            if not filename:
                filename = f"upload_{datetime.now().strftime('%Y%m%d%H%M%S')}{ext}"
            filepath = os.path.join(target_dir, filename)

            # 同名文件处理：清理旧切片 + 覆盖旧文件
            replaced = False
            if os.path.exists(filepath):
                replaced = True
                kb_mgr = _get_kb_manager()
                if kb_mgr:
                    old_chunks = kb_mgr.get_document_chunks(collection, filename)
                    if old_chunks:
                        old_ids = [c['id'] for c in old_chunks]
                        coll_obj = kb_mgr.get_collection(collection)
                        if coll_obj:
                            coll_obj.delete(ids=old_ids)
                            logger.info(f"批量替换: 清理旧切片 {filename} -> {collection}, 共 {len(old_ids)} 个")
                    kb_mgr.rebuild_bm25_index(collection)

                try:
                    from knowledge.sync import SyncDatabase
                    sync_db = SyncDatabase()
                    sync_db.delete_document_hash(f"{collection}/{filename}")
                except Exception as e:
                    logger.warning(f"清理哈希记录失败: {e}")

            file.save(filepath)

            # 版本管理：覆盖上传时标记旧版本为 superseded（新版本记录由 sync 服务统一创建）
            if replaced:
                try:
                    from knowledge.document_versions import get_version_query
                    from data.db import get_connection
                    vq = get_version_query()
                    active = vq.get_active_version(collection, filename)

                    if active:
                        with get_connection("knowledge") as conn:
                            conn.execute("""
                                UPDATE document_versions
                                SET status='superseded', deprecated_date=?,
                                    deprecated_reason='批量上传覆盖'
                                WHERE collection=? AND document_id=? AND version=?
                            """, (datetime.now().isoformat(), collection,
                                  filename, active.version))
                            conn.commit()
                except Exception as e:
                    logger.warning(f"批量上传标记旧版本失败: {e}")

            results.append({
                "filename": filename,
                "status": "success",
                "path": f"{target_subdir}/{filename}",
                "replaced": replaced
            })
        except Exception as e:
            logger.error(f"上传处理异常: {e}")
            results.append({
                "filename": file.filename,
                "status": "error",
                "message": "上传处理失败"
            })

    success_count = len([r for r in results if r["status"] == "success"])
    task_id = None

    # 批量上传完成后自动触发向量化（异步任务）
    sync_service = _get_sync_service()
    if sync_service and success_count > 0:
        from core.task_registry import get_registry
        registry = get_registry()

        running = registry.list_tasks(status='running', task_type='batch_upload', limit=1)
        if not running:
            task = registry.create_task('batch_upload', f"批量向量化: {success_count} 个文件", total=success_count)
            task_id = task.id

            def _do_batch_vectorize(task, svc, count):
                processed = [0]

                def on_change(change):
                    processed[0] += 1
                    registry.update_progress(
                        task.id, current=processed[0], total=count,
                        stage='批量向量化',
                        message=f"已处理: {change.document_name if hasattr(change, 'document_name') else change.document_id}"
                    )

                old_cb = svc.on_change_callback
                svc.on_change_callback = on_change
                try:
                    registry.update_progress(task.id, stage='扫描文档', message='正在检测变更...')
                    result = svc.sync_now()
                    return {
                        'synced': result.documents_processed,
                        'added': result.documents_added,
                        'errors': result.errors,
                    }
                finally:
                    svc.on_change_callback = old_cb

            registry.start_task(task.id, _do_batch_vectorize, sync_service, success_count)

    return success_response(
        data={
            "total": len(results),
            "success_count": success_count,
            "results": results,
            "task_id": task_id
        },
        status_code=BATCH_UPLOAD_SUCCESS,
        message=f"批量上传完成，成功 {success_count}/{len(results)} 个文件"
    )


@document_bp.route('/documents/list', methods=['GET'])
@require_gateway_auth
def list_documents() -> Tuple[Any, int]:
    """
    获取文档列表

    扫描文档目录，返回所有可用的文档信息。

    查询参数:
        collection: 过滤指定向量库（可选）

    Returns:
        {
            "documents": [
                {
                    "filename": "...",
                    "collection": "...",
                    "path": "...",
                    "size": N,
                    "last_modified": "ISO 8601"
                },
                ...
            ],
            "total": N
        }
    """
    from config import DOCUMENTS_PATH

    collection = request.args.get('collection') or request.args.get('kb_name')

    # 确定要扫描的目录（目录名 = 向量库名）
    if collection:
        subdirs = [collection]
    else:
        # 列出所有文档目录
        subdirs = []
        if os.path.exists(DOCUMENTS_PATH):
            for d in os.listdir(DOCUMENTS_PATH):
                if os.path.isdir(os.path.join(DOCUMENTS_PATH, d)):
                    subdirs.append(d)

    documents = []
    supported_extensions = {'.pdf', '.docx', '.doc', '.xlsx', '.txt'}

    for subdir in subdirs:
        level_dir = os.path.join(DOCUMENTS_PATH, subdir)
        if not os.path.exists(level_dir):
            continue

        # 目录名即向量库名
        coll_name = subdir

        for filename in os.listdir(level_dir):
            ext = os.path.splitext(filename)[1].lower()
            if ext not in supported_extensions:
                continue

            filepath = os.path.join(level_dir, filename)
            try:
                stat = os.stat(filepath)
                documents.append({
                    "filename": filename,
                    "collection": coll_name,
                    "path": f"{subdir}/{filename}",
                    "size": stat.st_size,
                    "last_modified": datetime.fromtimestamp(stat.st_mtime).isoformat()
                })
            except Exception as e:
                logger.warning(f"读取文件信息失败: {filename}, {e}")

    # 按修改时间倒序
    documents.sort(key=lambda x: x['last_modified'], reverse=True)

    return success_response(data={"documents": documents, "total": len(documents)})


@document_bp.route('/documents/<path:doc_path>/status', methods=['GET'])
@require_gateway_auth
def get_document_status(doc_path: str) -> Tuple[Any, int]:
    """
    获取文件处理状态

    查询指定文档的向量化状态和切片数量。

    Args:
        doc_path: 文档相对路径（collection/filename）

    Returns:
        {
            "success": true,
            "status": "processed|pending|error",
            "chunk_count": N,
            "last_processed": "ISO 8601"
        }
    """
    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    # 解析路径
    parts = doc_path.split('/')
    if len(parts) < 2:
        return error_response("BAD_REQUEST", BAD_REQUEST, "无效的文档路径", http_status=400)

    subdir = parts[0]
    filename = '/'.join(parts[1:])

    # 目录名即向量库名
    collection = subdir

    # 获取文档信息
    from config import DOCUMENTS_PATH
    file_on_disk = os.path.isfile(os.path.join(DOCUMENTS_PATH, subdir, filename))

    doc_info = kb_manager.get_document_info(collection, filename)

    if not doc_info:
        if file_on_disk:
            return success_response(data={
                "status": "unprocessed",
                "chunk_count": 0,
                "last_processed": None
            })
        return error_response("NOT_FOUND", NOT_FOUND, "文档不存在", http_status=404)

    return success_response(data={
        "status": doc_info.get("status", "unknown"),
        "chunk_count": doc_info.get("total_chunks", 0),
        "last_processed": doc_info.get("effective_date") or doc_info.get("version")
    })


@document_bp.route('/documents/<path:doc_path>', methods=['PUT'])
@require_gateway_auth
def update_document(doc_path: str) -> Tuple[Any, int]:
    """
    更新文件（重新上传覆盖）

    替换现有文件内容，并触发重新向量化。

    Args:
        doc_path: 文档相对路径（collection/filename）

    表单参数:
        file: 新文件（必需）

    Returns:
        {"success": true, "message": "文件已更新"}
    """
    from config import DOCUMENTS_PATH

    if 'file' not in request.files:
        return error_response("NO_FILE", NO_FILE, "没有上传文件", http_status=400)

    file = request.files['file']
    if file.filename == '':
        return error_response("NO_FILE_SELECTED", NO_FILE_SELECTED, "没有选择文件", http_status=400)

    # 文件类型校验
    ext = os.path.splitext(file.filename)[1].lower()
    if ext not in ALLOWED_EXTENSIONS:
        return error_response("UNSUPPORTED_FORMAT", UNSUPPORTED_FORMAT, f"不支持的文件类型: {ext}", http_status=400)

    # 文件大小校验
    file.seek(0, 2)  # 跳到文件末尾获取大小
    file_size = file.tell()
    file.seek(0)  # 回到文件开头
    if file_size > MAX_FILE_SIZE:
        return error_response("FILE_TOO_LARGE", FILE_TOO_LARGE, f"文件过大（最大 {MAX_FILE_SIZE // 1024 // 1024}MB）", http_status=400)

    # 解析路径
    parts = doc_path.split('/')
    if len(parts) < 2:
        return error_response("BAD_REQUEST", BAD_REQUEST, "无效的文档路径", http_status=400)

    try:
        filepath = _validate_doc_path(doc_path, DOCUMENTS_PATH)
    except ValueError:
        return error_response("FORBIDDEN", FORBIDDEN, "非法路径", http_status=403)
    if not os.path.exists(filepath):
        return error_response("NOT_FOUND", NOT_FOUND, "文件不存在", http_status=404)

    # 覆盖文件
    file.save(filepath)

    # 触发重新向量化
    sync_service = _get_sync_service()
    if sync_service:
        try:
            subdir = parts[0]
            filename = '/'.join(parts[1:])
            from knowledge.sync import DocumentChange, ChangeType
            change = DocumentChange(
                document_id=doc_path,
                document_name=filename,
                change_type=ChangeType.MODIFIED,
                old_hash=None,
                new_hash=sync_service.calculate_file_hash(filepath),
                change_time=datetime.now()
            )
            sync_service.process_change(change)
        except Exception as e:
            logger.warning(f"重新向量化失败: {e}")

    return success_response(message="文件已更新")


@document_bp.route('/documents/<path:doc_path>', methods=['DELETE'])
@require_gateway_auth
def delete_document(doc_path: str) -> Tuple[Any, int]:
    """
    删除文档

    同时删除向量库中的切片和物理文件。

    Args:
        doc_path: 文档相对路径（collection/filename）

    Returns:
        {"success": true, "message": "文档已删除"}

    Note:
        此操作不可逆，请谨慎使用
    """
    from config import DOCUMENTS_PATH

    # 解析路径
    parts = doc_path.split('/')
    if len(parts) < 2:
        return error_response("BAD_REQUEST", BAD_REQUEST, "无效的文档路径", http_status=400)

    subdir = parts[0]
    filename = '/'.join(parts[1:])

    # 目录名即向量库名
    collection = subdir

    try:
        filepath = _validate_doc_path(doc_path, DOCUMENTS_PATH)
    except ValueError:
        return error_response("FORBIDDEN", FORBIDDEN, "非法路径", http_status=403)
    if not os.path.exists(filepath):
        return error_response("NOT_FOUND", NOT_FOUND, "文件不存在", http_status=404)

    try:
        # 1. 从向量库删除（source 存的是文件名，不是完整路径）
        kb_manager = _get_kb_manager()
        if kb_manager:
            kb_manager.delete_document(collection, filename)

        # 2. 删除文件
        os.remove(filepath)

        return success_response(status_code=DELETE_SUCCESS, message="文档已删除")

    except Exception as e:
        logger.error(f"删除文档异常: {e}")
        return error_response("INTERNAL_ERROR", INTERNAL_ERROR, "删除失败，请稍后重试", http_status=500)


@document_bp.route('/documents/<path:doc_path>/chunks', methods=['GET'])
@require_gateway_auth
def list_document_chunks(doc_path: str) -> Tuple[Any, int]:
    """
    查看文件切片

    返回指定文档的所有切片内容，用于调试和验证。

    Args:
        doc_path: 文档相对路径（collection/filename）

    Returns:
        {
            "success": true,
            "document_id": "...",
            "collection": "...",
            "chunks": [...],
            "total": N
        }
    """
    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    # 解析路径
    parts = doc_path.split('/')
    if len(parts) < 2:
        return error_response("BAD_REQUEST", BAD_REQUEST, "无效的文档路径", http_status=400)

    subdir = parts[0]
    # 目录名即向量库名
    collection = subdir

    chunks = kb_manager.get_document_chunks(collection, os.path.basename(doc_path))

    return success_response(data={
        "document_id": doc_path,
        "collection": collection,
        "chunks": chunks,
        "total": len(chunks)
    })


@document_bp.route('/documents/<path:doc_path>/preview', methods=['GET'])
@require_gateway_auth
def preview_document(doc_path: str) -> Tuple[Any, int]:
    """
    文档预览接口（支持按切片序号跳转）

    用于前端引用溯源点击跳转：给定 chunk_index，返回目标切片及其上下文。
    复用现有切片查询逻辑，不新增存储。

    Query Params:
        chunk_index (int): 目标切片序号（来自 citation 的 chunk_index 字段）
        context (int): 上下文切片数，默认 2（前后各取 2 个）

    Returns:
        {
            "success": true,
            "collection": "...",
            "source": "文件名",
            "total_chunks": N,
            "target_index": M,
            "chunks": [
                {"id": "...", "content": "...", "metadata": {...}, "is_target": true/false},
                ...
            ]
        }
    """
    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    # 解析路径
    parts = doc_path.split('/')
    if len(parts) < 2:
        return error_response("BAD_REQUEST", BAD_REQUEST, "无效的文档路径，格式: collection/filename", http_status=400)

    collection = parts[0]
    filename = os.path.basename(doc_path)

    # 查询参数
    chunk_index_str = request.args.get('chunk_index')
    try:
        context_count = max(0, min(int(request.args.get('context', 2)), 10))
    except (ValueError, TypeError):
        context_count = 2

    # 获取所有切片
    all_chunks = kb_manager.get_document_chunks(collection, filename)
    if not all_chunks:
        return error_response("NOT_FOUND", NOT_FOUND, f"文档 '{filename}' 不存在或无切片", http_status=404)

    total = len(all_chunks)

    # 如果未指定 chunk_index，返回前 5 个切片作为概览
    if chunk_index_str is None:
        preview_chunks = all_chunks[:5]
        for c in preview_chunks:
            c['is_target'] = False
        return success_response(data={
            "collection": collection,
            "source": filename,
            "total_chunks": total,
            "target_index": None,
            "chunks": preview_chunks
        })

    # 定位目标切片 —— 按 meta.chunk_index 排序后查找，避免数组下标与 chunk_index 不一致
    try:
        target_chunk_index = int(chunk_index_str)
    except ValueError:
        return error_response("BAD_REQUEST", BAD_REQUEST, "chunk_index 必须为整数", http_status=400)

    # 按 chunk_index 排序（Chroma 返回顺序不保证有序）
    all_chunks.sort(key=lambda c: c.get('metadata', {}).get('chunk_index', 0))

    # 按 meta.chunk_index 查找目标切片在排序后数组中的实际位置
    target_pos = None
    for i, c in enumerate(all_chunks):
        if c.get('metadata', {}).get('chunk_index') == target_chunk_index:
            target_pos = i
            break

    # 回退：直接用数组下标（兼容旧数据无 chunk_index 字段的情况）
    if target_pos is None:
        if 0 <= target_chunk_index < total:
            target_pos = target_chunk_index
        else:
            max_idx = max(
                (c.get('metadata', {}).get('chunk_index', 0) for c in all_chunks),
                default=total - 1
            )
            return error_response("BAD_REQUEST", BAD_REQUEST, f"chunk_index={target_chunk_index} 未找到对应切片 (可用范围 0-{max_idx})", http_status=400)

    # 截取上下文窗口
    start = max(0, target_pos - context_count)
    end = min(total, target_pos + context_count + 1)
    window = all_chunks[start:end]

    # 标记目标切片
    for i, c in enumerate(window):
        c['is_target'] = (start + i == target_pos)

    return success_response(data={
        "collection": collection,
        "source": filename,
        "total_chunks": total,
        "target_index": target_chunk_index,
        "chunks": window
    })


# ==================== 切片管理 ====================

@document_bp.route('/chunks', methods=['POST'])
@require_gateway_auth
def create_chunk() -> Tuple[Any, int]:
    """
    新增切片

    手动向向量库添加一个切片，用于补充或修正内容。

    请求体:
        {
            "collection": "向量库名称",
            "content": "切片内容",
            "metadata": {}  // 可选
        }

    Returns:
        {"success": true, "chunk_id": "...", "message": "切片已添加"}
    """
    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    data = request.json or {}
    collection = data.get('collection')
    content = data.get('content')
    metadata = data.get('metadata', {})

    if not collection:
        return error_response("NO_COLLECTION", NO_COLLECTION, "请指定向量库 (collection)", http_status=400)
    if not content:
        return error_response("NO_CONTENT", NO_CONTENT, "切片内容不能为空", http_status=400)

    chunk_id = kb_manager.add_chunk(collection, content, metadata)

    return success_response(data={"chunk_id": chunk_id}, message="切片已添加")


@document_bp.route('/chunks/<chunk_id>', methods=['PUT'])
@require_gateway_auth
def update_chunk(chunk_id: str) -> Tuple[Any, int]:
    """
    修改切片

    更新指定切片的内容或元数据。

    Args:
        chunk_id: 切片 ID

    请求体:
        {
            "collection": "向量库名称",
            "content": "新内容",  // 可选
            "metadata": {}  // 可选
        }

    Returns:
        {"success": true, "message": "切片已更新"}
    """
    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    data = request.json or {}
    collection = data.get('collection')
    content = data.get('content')
    metadata = data.get('metadata')

    if not collection:
        return error_response("NO_COLLECTION", NO_COLLECTION, "请指定向量库 (collection)", http_status=400)

    success = kb_manager.update_chunk(collection, chunk_id, content=content, metadata=metadata)

    if success:
        return success_response(message="切片已更新")
    return error_response("INTERNAL_ERROR", INTERNAL_ERROR, "更新失败", http_status=500)


@document_bp.route('/chunks/<chunk_id>', methods=['DELETE'])
@require_gateway_auth
def delete_chunk(chunk_id: str) -> Tuple[Any, int]:
    """
    删除切片

    从向量库中移除指定切片。如果删除后该文件没有其他切片，
    同时清理文档哈希记录，以便同步服务能重新检测该文件。

    Args:
        chunk_id: 切片 ID

    请求体或查询参数:
        collection: 向量库名称（必需）

    Returns:
        {"success": true, "message": "切片已删除"}
    """
    data = request.get_json(silent=True) or {}
    collection = data.get('collection') if data else None

    if not collection:
        collection = request.args.get('collection')

    if not collection:
        return error_response("NO_COLLECTION", NO_COLLECTION, "请指定向量库 (collection)", http_status=400)

    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    # 删除切片，返回 (success, source_file)
    success, source_file = kb_manager.delete_chunk(collection, chunk_id)

    if success and source_file:
        # 检查该文件是否还有其他切片
        remaining_chunks = kb_manager.list_chunks(collection, limit=100000)
        has_other_chunks = any(
            c.get('metadata', {}).get('source') == source_file
            for c in remaining_chunks
        )

        # 如果没有其他切片了，删除哈希记录
        if not has_other_chunks:
            try:
                from knowledge.sync import SyncDatabase
                sync_db = SyncDatabase()
                document_id = f"{collection}/{source_file}"
                sync_db.delete_document_hash(document_id)
                logger.info(f"清理文档哈希记录: {document_id}")
            except Exception as e:
                logger.warning(f"清理哈希记录失败: {e}")

    if success:
        return success_response(status_code=DELETE_SUCCESS, message="切片已删除")
    return error_response("INTERNAL_ERROR", INTERNAL_ERROR, "删除失败", http_status=500)


@document_bp.route('/chunks/batch', methods=['DELETE'])
@require_gateway_auth
def delete_chunks_by_source() -> Tuple[Any, int]:
    """
    批量删除指定文件的所有切片

    删除指定向量库中某个文件的所有切片，并清理哈希记录。
    相比逐个删除，批量删除更高效，避免前端超时。

    请求体:
        {
            "collection": "向量库名称",
            "source": "文件名"
        }

    Returns:
        {"success": true, "deleted_count": N, "message": "..."}
    """
    data = request.get_json(silent=True) or {}
    collection = data.get('collection')
    source = data.get('source')

    if not collection:
        return error_response("NO_COLLECTION", NO_COLLECTION, "请指定向量库 (collection)", http_status=400)
    if not source:
        return error_response("BAD_REQUEST", BAD_REQUEST, "请指定文件名 (source)", http_status=400)

    kb_manager = _get_kb_manager()
    if not kb_manager:
        return error_response("SERVICE_UNAVAILABLE", SERVICE_UNAVAILABLE, "知识库管理器未初始化", http_status=503)

    # 批量删除该文件的所有切片
    try:
        deleted_count = kb_manager.delete_chunks_by_source(collection, source)

        # 清理哈希记录
        if deleted_count > 0:
            try:
                from knowledge.sync import SyncDatabase
                sync_db = SyncDatabase()
                # 统一使用正斜杠格式（与 sync.py scan_documents 一致）
                document_id = f"{collection}/{source}"
                sync_db.delete_document_hash(document_id)
                logger.info(f"清理文档哈希记录: {document_id}")
            except Exception as e:
                logger.warning(f"清理哈希记录失败: {e}")

        return success_response(data={"deleted_count": deleted_count}, message=f"已删除 {deleted_count} 个切片")
    except Exception as e:
        logger.error(f"操作异常: {e}")
        return error_response("INTERNAL_ERROR", INTERNAL_ERROR, "操作失败，请稍后重试", http_status=500)