# routes/classify.py
import os
import time
import uuid
import zipfile
import rarfile
import shutil
from flask import Blueprint, request, jsonify, current_app, send_file, g, session
from werkzeug.utils import secure_filename
import mysql.connector
from utils.model_service import text_classifier # Assuming text_classifier is initialized correctly elsewhere
from utils.db import get_db, close_db
import logging

# 创建蓝图
classify_bp = Blueprint('classify', __name__, url_prefix='/api/classify')

# 设置日志
logger = logging.getLogger(__name__)

# 允许的文件扩展名
ALLOWED_TEXT_EXTENSIONS = {'txt'}
ALLOWED_ARCHIVE_EXTENSIONS = {'zip', 'rar'}


def allowed_text_file(filename):
    """检查文本文件扩展名是否允许"""
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_TEXT_EXTENSIONS


def allowed_archive_file(filename):
    """检查压缩文件扩展名是否允许"""
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_ARCHIVE_EXTENSIONS


def get_next_document_number(category):
    """获取给定类别的下一个文档编号

    Args:
        category (str): 文档类别

    Returns:
        int: 下一个编号
    """
    db = get_db()
    cursor = db.cursor(dictionary=True)

    try:
        # 查询该类别的最大编号
        query = """
        SELECT MAX(CAST(SUBSTRING_INDEX(SUBSTRING_INDEX(stored_filename, '-', 2), '-', -1) AS UNSIGNED)) as max_num
        FROM documents
        WHERE stored_filename LIKE %s
        """
        cursor.execute(query, (f"{category}-%",))
        result = cursor.fetchone()

        # 如果没有记录，或者最大编号为None，返回1，否则返回最大编号+1
        if not result or result['max_num'] is None:
            return 1
        else:
            # Ensure it's an int before adding
            return int(result['max_num']) + 1
    except Exception as e:
        logger.error(f"获取下一个文档编号时出错: {str(e)}")
        return 1
    finally:
        cursor.close()


def save_classified_document(user_id, original_filename, category, content, file_size=None):
    """保存分类后的文档

    Args:
        user_id (int): 用户ID
        original_filename (str): 原始文件名
        category (str): 分类类别
        content (str): 文档内容
        file_size (int, optional): 文件大小，如果为None则自动计算

    Returns:
        tuple: (成功标志, 存储的文件名或错误信息)
    """
    db = None # Initialize db to None
    cursor = None # Initialize cursor to None
    try:
        # 获取下一个文档编号
        next_num = get_next_document_number(category)

        # 安全处理文件名 - ensure it doesn't become empty
        safe_original_name_base = os.path.splitext(secure_filename(original_filename))[0]
        if not safe_original_name_base:
             safe_original_name_base = "untitled" # Default if name becomes empty
        safe_original_name = f"{safe_original_name_base}.txt" # Ensure .txt extension

        # 生成新文件名 (类别-编号-原文件名)
        formatted_num = f"{next_num:04d}"  # 确保编号格式为4位数
        new_filename = f"{category}-{formatted_num}-{safe_original_name}"

        # 确保uploads目录存在
        uploads_dir = os.path.join(current_app.root_path, current_app.config['UPLOAD_FOLDER'])
        category_dir = os.path.join(uploads_dir, category)
        os.makedirs(category_dir, exist_ok=True)

        # 文件完整路径
        file_path = os.path.join(category_dir, new_filename)

        # 保存文件
        with open(file_path, 'w', encoding='utf-8') as f:
            f.write(content)

        # 如果文件大小未提供，则计算
        if file_size is None:
            file_size = os.path.getsize(file_path)

        # 获取db连接
        db = get_db()
        cursor = db.cursor()

        # 获取分类类别ID
        category_query = "SELECT id FROM categories WHERE name = %s"
        cursor.execute(category_query, (category,))
        category_result = cursor.fetchone()

        if not category_result:
            logger.error(f"类别 '{category}' 在数据库中未找到。")
            # Optionally create the category if needed, or return error
            return False, f"类别 '{category}' 不存在"

        category_id = category_result[0]

        # 插入数据库记录
        insert_query = """
        INSERT INTO documents
        (user_id, original_filename, stored_filename, file_path, file_size, category_id, status, classified_time, upload_time)
        VALUES (%s, %s, %s, %s, %s, %s, %s, NOW(), NOW())
        """ # Added upload_time=NOW() assuming it's desired

        cursor.execute(
            insert_query,
            (user_id, original_filename, new_filename, file_path, file_size, category_id, '已分类')
        )

        # 提交事务
        db.commit()
        logger.info(f"成功保存文档: {new_filename} (ID: {cursor.lastrowid})")
        return True, new_filename

    except Exception as e:
        # Rollback transaction if error occurs
        if db:
            db.rollback()
        logger.exception(f"保存分类文档 '{original_filename}' 时出错: {str(e)}") # Use logger.exception for traceback
        return False, str(e)
    finally:
        if cursor:
            cursor.close()
        # Note: db connection is usually closed via @app.teardown_appcontext


@classify_bp.route('/single', methods=['POST'])
def classify_single_file():
    """单文件上传和分类API"""
    # 检查用户是否登录
    if 'user_id' not in session:
        return jsonify({"success": False, "error": "请先登录"}), 401

    user_id = session['user_id']

    # 检查是否上传了文件
    if 'file' not in request.files:
        return jsonify({"success": False, "error": "没有文件"}), 400

    file = request.files['file']
    original_filename = file.filename # Store original name early

    # 检查文件名
    if original_filename == '':
        return jsonify({"success": False, "error": "未选择文件"}), 400

    # 检查文件类型
    if not allowed_text_file(original_filename):
        return jsonify({"success": False, "error": "不支持的文件类型，仅支持txt文件"}), 400

    temp_path = None # Initialize to ensure it's defined for cleanup
    try:
        # 创建临时文件以供处理
        temp_dir = os.path.join(current_app.root_path, 'temp')
        os.makedirs(temp_dir, exist_ok=True)

        # Use secure_filename for the temp file name part as well
        temp_filename = f"{uuid.uuid4().hex}-{secure_filename(original_filename)}"
        temp_path = os.path.join(temp_dir, temp_filename)

        # 保存上传文件到临时位置
        file.save(temp_path)
        file_size = os.path.getsize(temp_path) # Get size after saving

        # 读取文件内容 - Try multiple encodings
        file_content = None
        encodings_to_try = ['utf-8', 'gbk', 'gb18030']
        for enc in encodings_to_try:
            try:
                with open(temp_path, 'r', encoding=enc) as f:
                    file_content = f.read()
                logger.info(f"成功以 {enc} 读取临时文件: {temp_path}")
                break
            except UnicodeDecodeError:
                logger.warning(f"使用 {enc} 解码临时文件失败: {temp_path}")
                continue
            except Exception as read_err: # Catch other potential read errors
                 logger.error(f"读取临时文件时出错 ({enc}): {read_err}")
                 # Decide if you want to stop or try next encoding
                 continue

        if file_content is None:
             raise ValueError(f"无法使用支持的编码 {encodings_to_try} 读取文件内容。")


        # 调用模型进行分类
        result = text_classifier.classify_text(file_content)

        if not result.get('success', False): # Check if key exists and is True
            error_msg = result.get('error', '未知的分类错误')
            logger.error(f"文本分类失败 for {original_filename}: {error_msg}")
            return jsonify({"success": False, "error": error_msg}), 500

        category = result['category']

        # 保存分类后的文档
        save_success, message = save_classified_document(
            user_id,
            original_filename, # Use the original filename here
            category,
            file_content,
            file_size
        )

        if not save_success:
            return jsonify({"success": False, "error": f"保存文档失败: {message}"}), 500

        # 返回分类结果
        return jsonify({
            "success": True,
            "filename": original_filename,
            "category": category,
            "confidence": result.get('confidence'), # Use .get for safety
            "stored_filename": message
        })

    except Exception as e:
        logger.exception(f"处理单文件 '{original_filename}' 过程中发生错误: {str(e)}") # Log exception with traceback
        return jsonify({"success": False, "error": f"文件处理错误: {str(e)}"}), 500
    finally:
        # 清理临时文件
        if temp_path and os.path.exists(temp_path):
            try:
                os.remove(temp_path)
                logger.info(f"已删除临时文件: {temp_path}")
            except OSError as rm_err:
                logger.error(f"删除临时文件失败 {temp_path}: {rm_err}")


@classify_bp.route('/batch', methods=['POST'])
def classify_batch_files():
    """批量文件上传和分类API（压缩包处理）"""
    if 'user_id' not in session:
        return jsonify({"success": False, "error": "请先登录"}), 401

    user_id = session['user_id']

    if 'file' not in request.files:
        return jsonify({"success": False, "error": "没有文件"}), 400

    file = request.files['file']
    original_archive_name = file.filename

    if original_archive_name == '':
        return jsonify({"success": False, "error": "未选择文件"}), 400

    if not allowed_archive_file(original_archive_name):
        return jsonify({"success": False, "error": "不支持的文件类型，仅支持zip和rar压缩文件"}), 400

    # Consider adding file size check here if needed (e.g., request.content_length)
    # if request.content_length > current_app.config['MAX_CONTENT_LENGTH']: # Example
    #     return jsonify({"success": False, "error": "文件过大"}), 413

    temp_dir = os.path.join(current_app.root_path, 'temp')
    extract_dir = os.path.join(temp_dir, f"extract_{uuid.uuid4().hex}")
    archive_path = None
    # --- 修改点 1: 将 total_attempted 改回 total ---
    results = {
        "total": 0, # <--- 使用 'total'
        "success": 0,
        "failed": 0,
        "categories": {},
        "failed_files": []
    }

    try:
        os.makedirs(extract_dir, exist_ok=True)
        archive_path = os.path.join(temp_dir, secure_filename(original_archive_name))
        file.save(archive_path)
        logger.info(f"已保存上传的压缩文件: {archive_path}")

        # 解压文件
        file_extension = original_archive_name.rsplit('.', 1)[1].lower()
        if file_extension == 'zip':
            with zipfile.ZipFile(archive_path, 'r') as zip_ref:
                zip_ref.extractall(extract_dir)
            logger.info(f"已解压ZIP文件到: {extract_dir}")
        elif file_extension == 'rar':
             # Ensure rarfile is installed and unrar executable is available
             try:
                with rarfile.RarFile(archive_path, 'r') as rar_ref:
                    rar_ref.extractall(extract_dir)
                logger.info(f"已解压RAR文件到: {extract_dir}")
             except rarfile.NeedFirstVolume:
                 logger.error(f"RAR文件是分卷压缩的一部分，需要第一个分卷: {original_archive_name}")
                 raise ValueError("不支持分卷压缩的RAR文件")
             except rarfile.BadRarFile:
                 logger.error(f"RAR文件损坏或格式错误: {original_archive_name}")
                 raise ValueError("RAR文件损坏或格式错误")
             except Exception as rar_err: # Catch other rar errors (like missing unrar)
                 logger.error(f"解压RAR文件时出错: {rar_err}")
                 raise ValueError(f"解压RAR文件失败: {rar_err}")


        # 递归处理所有txt文件
        for root, dirs, files in os.walk(extract_dir):
            # --- 开始过滤 macOS 文件夹 ---
            if '__MACOSX' in root.split(os.path.sep):
                logger.info(f"Skipping macOS metadata directory: {root}")
                dirs[:] = []
                files[:] = []
                continue
            # --- 结束过滤 macOS 文件夹 ---

            for filename in files:
                # --- 开始过滤 macOS 文件 ---
                if filename.startswith('._') or filename == '.DS_Store':
                    logger.info(f"Skipping macOS metadata file: {filename} in {root}")
                    continue
                # --- 结束过滤 macOS 文件 ---

                # Process only allowed text files
                if allowed_text_file(filename):
                    file_path = os.path.join(root, filename)
                    # --- 修改点 2: 将 total_attempted 改回 total ---
                    results["total"] += 1 # <--- 使用 'total'

                    try:
                        # 读取文件内容 - Try multiple encodings
                        file_content = None
                        encodings_to_try = ['utf-8', 'gbk', 'gb18030']
                        for enc in encodings_to_try:
                            try:
                                with open(file_path, 'r', encoding=enc) as f:
                                    file_content = f.read()
                                logger.info(f"成功以 {enc} 读取文件: {file_path}")
                                break
                            except UnicodeDecodeError:
                                logger.warning(f"使用 {enc} 解码文件失败: {file_path}")
                                continue
                            except Exception as read_err:
                                 logger.error(f"读取文件时发生其他错误 ({enc}) {file_path}: {read_err}")
                                 continue

                        if file_content is None:
                            raise ValueError(f"无法使用支持的编码 {encodings_to_try} 读取文件内容。")

                        # 调用模型进行分类
                        result = text_classifier.classify_text(file_content)

                        if not result.get('success', False):
                            error_msg = result.get('error', '未知的分类错误')
                            raise Exception(f"分类失败: {error_msg}")

                        category = result['category']

                        results["categories"][category] = results["categories"].get(category, 0) + 1

                        file_size = os.path.getsize(file_path)
                        save_success, message = save_classified_document(
                            user_id,
                            filename,
                            category,
                            file_content,
                            file_size
                        )

                        if save_success:
                            results["success"] += 1
                        else:
                            raise Exception(f"保存失败: {message}")

                    except Exception as e:
                        logger.error(f"处理文件 '{filename}' 失败: {str(e)}")
                        results["failed"] += 1
                        results["failed_files"].append({
                            "filename": filename,
                            "error": str(e)
                        })

        # 返回处理结果
        return jsonify({
            "success": True,
            "archive_name": original_archive_name,
            "results": results # <--- 确保返回的 results 包含 'total' 键
        })

    except Exception as e:
        logger.exception(f"处理压缩包 '{original_archive_name}' 过程中发生严重错误: {str(e)}")
        return jsonify({"success": False, "error": f"压缩包处理错误: {str(e)}"}), 500

    finally:
        # 清理临时文件和目录 (保持不变)
        if archive_path and os.path.exists(archive_path):
            try:
                os.remove(archive_path)
                logger.info(f"已删除临时压缩文件: {archive_path}")
            except OSError as rm_err:
                 logger.error(f"删除临时压缩文件失败 {archive_path}: {rm_err}")
        if os.path.exists(extract_dir):
            try:
                shutil.rmtree(extract_dir)
                logger.info(f"已删除临时解压目录: {extract_dir}")
            except OSError as rmtree_err:
                 logger.error(f"删除临时解压目录失败 {extract_dir}: {rmtree_err}")


@classify_bp.route('/documents', methods=['GET'])
def get_classified_documents():
    """获取已分类的文档列表"""
    if 'user_id' not in session:
        return jsonify({"success": False, "error": "请先登录"}), 401

    user_id = session['user_id']

    try:
        category = request.args.get('category', 'all')
        page = int(request.args.get('page', 1))
        per_page = int(request.args.get('per_page', 10))

        if per_page not in [10, 25, 50, 100]:
            per_page = 10
        if page < 1:
            page = 1

        offset = (page - 1) * per_page

        db = get_db()
        cursor = db.cursor(dictionary=True) # Use dictionary cursor

        # Get available categories first
        cursor.execute("SELECT name FROM categories ORDER BY name")
        available_categories = [row['name'] for row in cursor.fetchall()]

        # Build query
        params = [user_id]
        base_query = """
        FROM documents d
        JOIN categories c ON d.category_id = c.id
        WHERE d.user_id = %s AND d.status = '已分类'
        """
        if category != 'all' and category in available_categories:
            base_query += " AND c.name = %s"
            params.append(category)

        # Count query
        count_query = f"SELECT COUNT(*) as total {base_query}"
        cursor.execute(count_query, params)
        total_count_result = cursor.fetchone()
        total_count = total_count_result['total'] if total_count_result else 0

        total_pages = (total_count + per_page - 1) // per_page if per_page > 0 else 0

        # Data query
        data_query = f"""
        SELECT d.id, d.original_filename, d.stored_filename, d.file_size,
               c.name as category, d.upload_time, d.classified_time
        {base_query}
        ORDER BY d.classified_time DESC
        LIMIT %s OFFSET %s
        """
        params.extend([per_page, offset])
        cursor.execute(data_query, params)
        documents = cursor.fetchall()

        # Format dates if they are datetime objects (optional, depends on driver)
        for doc in documents:
            if hasattr(doc.get('upload_time'), 'isoformat'):
                 doc['upload_time'] = doc['upload_time'].isoformat()
            if hasattr(doc.get('classified_time'), 'isoformat'):
                 doc['classified_time'] = doc['classified_time'].isoformat()


        return jsonify({
            "success": True,
            "documents": documents,
            "pagination": {
                "total": total_count,
                "per_page": per_page,
                "current_page": page,
                "total_pages": total_pages
            },
            "categories": available_categories, # Send the fetched list
            "current_category": category
        })

    except Exception as e:
        logger.exception(f"获取文档列表时出错: {str(e)}") # Log traceback
        return jsonify({"success": False, "error": f"获取文档列表失败: {str(e)}"}), 500
    finally:
        # Cursor closing handled by context usually, but explicit close is safe
         if 'cursor' in locals() and cursor:
              cursor.close()


@classify_bp.route('/download/<int:document_id>', methods=['GET'])
def download_document(document_id):
    """下载已分类的文档"""
    if 'user_id' not in session:
        return jsonify({"success": False, "error": "请先登录"}), 401

    user_id = session['user_id']
    cursor = None
    try:
        db = get_db()
        cursor = db.cursor(dictionary=True)

        query = """
        SELECT file_path, original_filename
        FROM documents
        WHERE id = %s AND user_id = %s AND status = '已分类'
        """
        cursor.execute(query, (document_id, user_id))
        document = cursor.fetchone()

        if not document:
            return jsonify({"success": False, "error": "文档不存在或无权访问"}), 404

        file_path = document['file_path']
        download_name = document['original_filename']

        if not os.path.exists(file_path):
             logger.error(f"请求下载的文件在服务器上不存在: {file_path} (Doc ID: {document_id})")
             # Update status in DB?
             # update_status_query = "UPDATE documents SET status = '文件丢失' WHERE id = %s"
             # cursor.execute(update_status_query, (document_id,))
             # db.commit()
             return jsonify({"success": False, "error": "文件在服务器上丢失"}), 404

        logger.info(f"用户 {user_id} 请求下载文档 ID: {document_id}, 文件: {download_name}")
        return send_file(
            file_path,
            as_attachment=True,
            download_name=download_name, # Use original filename for download
            mimetype='text/plain' # Assuming text, adjust if other types allowed
        )

    except Exception as e:
        logger.exception(f"下载文档 ID {document_id} 时出错: {str(e)}")
        return jsonify({"success": False, "error": f"下载文档失败: {str(e)}"}), 500
    finally:
        if cursor:
            cursor.close()


@classify_bp.route('/download-multiple', methods=['POST'])
def download_multiple_documents():
    """下载多个文档（打包为zip）"""
    if 'user_id' not in session:
        return jsonify({"success": False, "error": "请先登录"}), 401

    user_id = session['user_id']
    cursor = None
    zip_path = None # Initialize for finally block

    try:
        data = request.get_json()
        if not data or 'document_ids' not in data:
            return jsonify({"success": False, "error": "缺少必要参数 'document_ids'"}), 400

        document_ids = data['document_ids']
        if not isinstance(document_ids, list) or not document_ids:
            return jsonify({"success": False, "error": "文档ID列表无效"}), 400
        # Sanitize IDs to be integers
        try:
            document_ids = [int(doc_id) for doc_id in document_ids]
        except ValueError:
            return jsonify({"success": False, "error": "文档ID必须是数字"}), 400

        db = get_db()
        cursor = db.cursor(dictionary=True)

        # Query valid documents for the user
        placeholders = ', '.join(['%s'] * len(document_ids))
        query = f"""
        SELECT id, file_path, original_filename
        FROM documents
        WHERE id IN ({placeholders}) AND user_id = %s AND status = '已分类'
        """
        params = document_ids + [user_id]
        cursor.execute(query, params)
        documents = cursor.fetchall()

        if not documents:
            return jsonify({"success": False, "error": "没有找到符合条件的可下载文档"}), 404

        # Create temp zip file
        temp_dir = os.path.join(current_app.root_path, 'temp')
        os.makedirs(temp_dir, exist_ok=True)
        zip_filename = f"documents_{user_id}_{int(time.time())}.zip"
        zip_path = os.path.join(temp_dir, zip_filename)

        files_added = 0
        with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED) as zipf:
            for doc in documents:
                file_path = doc['file_path']
                original_filename = doc['original_filename']
                if os.path.exists(file_path):
                    zipf.write(file_path, arcname=original_filename)
                    files_added += 1
                    logger.info(f"添加到ZIP: {original_filename} (来自 {file_path})")
                else:
                    logger.warning(f"跳过丢失的文件: {original_filename} (路径: {file_path}, Doc ID: {doc['id']})")
                    # Optionally add a readme to the zip indicating missing files

        if files_added == 0:
             # This case means all selected files were missing on disk
             return jsonify({"success": False, "error": "所有选中的文件在服务器上都已丢失"}), 404


        logger.info(f"用户 {user_id} 请求下载 {files_added} 个文档打包为 {zip_filename}")
        # Use after_this_request to delete the temp file after sending
        @current_app.after_request
        def remove_file(response):
            try:
                if zip_path and os.path.exists(zip_path):
                    os.remove(zip_path)
                    logger.info(f"已删除临时ZIP文件: {zip_path}")
            except Exception as error:
                logger.error(f"删除临时ZIP文件错误 {zip_path}: {error}")
            return response

        return send_file(
            zip_path,
            as_attachment=True,
            download_name=zip_filename,
            mimetype='application/zip'
        )

    except Exception as e:
        logger.exception(f"下载多个文档时出错: {str(e)}")
        # Clean up zip file if created but error occurred before sending
        if zip_path and os.path.exists(zip_path):
             try: os.remove(zip_path)
             except OSError: pass
        return jsonify({"success": False, "error": f"下载文档失败: {str(e)}"}), 500

    finally:
        if cursor:
            cursor.close()


@classify_bp.route('/classify-text', methods=['POST'])
def classify_text_directly():
    """直接对文本进行分类（不保存文件）"""
    if 'user_id' not in session:
        return jsonify({"success": False, "error": "请先登录"}), 401

    try:
        data = request.get_json()
        if not data or 'text' not in data:
            return jsonify({"success": False, "error": "缺少必要参数 'text'"}), 400

        text = data['text']
        # Basic validation
        if not isinstance(text, str) or not text.strip():
            return jsonify({"success": False, "error": "文本内容不能为空或无效"}), 400

        # Limit text length?
        MAX_TEXT_LENGTH = 10000 # Example limit
        if len(text) > MAX_TEXT_LENGTH:
             return jsonify({"success": False, "error": f"文本过长，最大支持 {MAX_TEXT_LENGTH} 字符"}), 413


        # 调用模型进行分类
        # Ensure model is initialized - consider adding a check or lazy loading
        if not text_classifier or not text_classifier.is_initialized:
             logger.warning("文本分类器未初始化，尝试初始化...")
             if not text_classifier.initialize():
                 logger.error("文本分类器初始化失败。")
                 return jsonify({"success": False, "error": "分类服务暂时不可用"}), 503

        result = text_classifier.classify_text(text)

        if not result.get('success', False):
            error_msg = result.get('error', '未知的分类错误')
            logger.error(f"直接文本分类失败: {error_msg}")
            return jsonify({"success": False, "error": error_msg}), 500

        # 返回分类结果
        return jsonify({
            "success": True,
            "category": result.get('category'),
            "confidence": result.get('confidence'),
            "all_confidences": result.get('all_confidences') # Include all confidences if available
        })

    except Exception as e:
        logger.exception(f"直接文本分类过程中发生错误: {str(e)}")
        return jsonify({"success": False, "error": f"文本分类错误: {str(e)}"}), 500


@classify_bp.route('/categories', methods=['GET'])
def get_categories():
    """获取所有分类类别"""
    cursor = None
    try:
        db = get_db()
        cursor = db.cursor(dictionary=True)
        cursor.execute("SELECT id, name, description FROM categories ORDER BY name")
        categories = cursor.fetchall()

        return jsonify({
            "success": True,
            "categories": categories
        })

    except Exception as e:
        logger.exception(f"获取类别列表时出错: {str(e)}")
        return jsonify({"success": False, "error": f"获取类别列表失败: {str(e)}"}), 500
    finally:
        if cursor:
            cursor.close()