# 文件路径: inventory-backend/app/api/v1/common/upload.py

import os
import uuid
from flask import Blueprint, request, jsonify, send_from_directory

# 定义蓝图
# 注意：在 app/__init__.py 或类似入口文件中，注册此蓝图时 url_prefix 通常应为 '/api/v1/common'
upload_bp = Blueprint('upload', __name__)


# =========================================================
# 配置上传路径
# =========================================================
def get_project_root():
    """获取项目根目录 inventory-backend"""
    current_path = os.path.abspath(__file__)
    # 向上回退直到找到根目录，根据你的目录结构可能需要调整层级
    # 假设结构: inventory-backend/app/api/v1/common/upload.py (回退5层)
    base = os.path.dirname(os.path.dirname(os.path.dirname(os.path.dirname(os.path.dirname(current_path)))))
    return base


BASE_DIR = get_project_root()
UPLOAD_FOLDER = os.path.join(BASE_DIR, 'uploads')

# 允许上传的文件后缀
ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif', 'bmp', 'webp', 'pdf', 'doc', 'docx', 'xls', 'xlsx'}

# ★ 文件上传安全加固：限制最大文件大小 (10MB)
MAX_CONTENT_LENGTH = 10 * 1024 * 1024  # 10MB


def allowed_file(filename):
    return '.' in filename and \
        filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS


def ensure_upload_folder_exists():
    if not os.path.exists(UPLOAD_FOLDER):
        try:
            os.makedirs(UPLOAD_FOLDER)
            print(f"✅ [Upload] 目录创建成功: {UPLOAD_FOLDER}")
        except Exception as e:
            print(f"❌ [Upload] 目录创建失败: {e}")


# ------------------------------------------------------------------
# 1. 文件上传接口
# 完整 URL: /api/v1/common/upload (POST)
# ------------------------------------------------------------------
@upload_bp.route('/upload', methods=['POST'])
def upload_file():
    ensure_upload_folder_exists()

    if 'file' not in request.files:
        return jsonify({"code": 400, "msg": "未找到文件部分"}), 400

    file = request.files['file']

    if file.filename == '':
        return jsonify({"code": 400, "msg": "未选择文件"}), 400

    # ★ 文件上传安全加固：检查文件大小
    file.seek(0, os.SEEK_END)
    file_size = file.tell()
    file.seek(0)  # 重置文件指针到开头
    if file_size > MAX_CONTENT_LENGTH:
        return jsonify({
            "code": 400,
            "msg": f"文件大小超过限制 ({MAX_CONTENT_LENGTH // (1024*1024)}MB)"
        }), 400

    if file and allowed_file(file.filename):
        try:
            # 获取后缀并生成唯一文件名
            ext = file.filename.rsplit('.', 1)[1].lower()
            new_filename = f"{uuid.uuid4().hex}.{ext}"

            save_path = os.path.join(UPLOAD_FOLDER, new_filename)
            file.save(save_path)

            print(f"💾 [Upload] 文件已保存: {save_path}")

            # 生成访问 URL (返回给前端的相对路径)
            # 前端展示时通常拼接 baseURL，或者直接使用此路径访问
            # 这里的 /api/v1/common 需与蓝图注册路径一致
            file_url = f"/api/v1/common/files/{new_filename}"

            return jsonify({
                "code": 200,
                "msg": "上传成功",
                "data": {
                    "url": file_url,
                    "filename": new_filename
                }
            })
        except Exception as e:
            print(f"❌ [Upload] 保存异常: {e}")
            return jsonify({"code": 500, "msg": "文件保存失败"}), 500

    return jsonify({"code": 400, "msg": "不支持的文件格式"}), 400


# ------------------------------------------------------------------
# 2. 静态文件访问接口 (回显)
# 完整 URL: /api/v1/common/files/<filename> (GET)
# ------------------------------------------------------------------
@upload_bp.route('/files/<filename>', methods=['GET'])
def uploaded_file(filename):
    full_path = os.path.join(UPLOAD_FOLDER, filename)
    if not os.path.exists(full_path):
        # 尝试调试路径问题
        print(f"❌ [File Access] 文件未找到: {full_path}")
        return jsonify({"code": 404, "msg": "文件不存在"}), 404

    return send_from_directory(UPLOAD_FOLDER, filename)


# ------------------------------------------------------------------
# 3. 文件删除接口 (同步删除物理文件)
# 完整 URL: /api/v1/common/files/<filename> (DELETE)
# ------------------------------------------------------------------
@upload_bp.route('/files/<filename>', methods=['DELETE'])
def delete_file(filename):
    try:
        # 安全处理文件名 (防止路径遍历)
        safe_filename = os.path.basename(filename)
        file_path = os.path.join(UPLOAD_FOLDER, safe_filename)

        print(f"🗑️ [Delete] 尝试删除文件: {file_path}")

        if os.path.exists(file_path):
            os.remove(file_path)
            print(f"✅ [Delete] 文件删除成功")
            return jsonify({"code": 200, "msg": "文件已删除"})
        else:
            print(f"⚠️ [Delete] 文件不存在，无需删除")
            # 即使文件不存在也返回成功，保证前端逻辑闭环
            return jsonify({"code": 200, "msg": "文件不存在或已删除"})

    except Exception as e:
        print(f"❌ [Delete] 删除异常: {e}")
        return jsonify({"code": 500, "msg": f"删除失败: {str(e)}"}), 500