import io
from typing import Any

import pandas as pd
from fastapi import UploadFile

from app.core.base_schema import AuthSchema, BatchSetAvailable
from app.core.exceptions import CustomException
from app.core.logger import logger
from app.utils.excel_util import ExcelUtil

from .crud import DemoCRUD
from .schema import (
    DemoCreateSchema,
    DemoOutSchema,
    DemoQueryParam,
    DemoUpdateSchema,
)


class DemoService:
    """示例管理模块服务层"""

    def __init__(self, auth: AuthSchema) -> None:
        self.auth = auth

    async def detail(self, id: int) -> DemoOutSchema:
        obj = await DemoCRUD(self.auth).get(id=id)
        if not obj:
            raise CustomException(msg="该数据不存在")
        return DemoOutSchema.model_validate(obj)

    async def get_list(
        self,
        search: DemoQueryParam | None = None,
        order_by: list[dict[str, str]] | None = None,
    ) -> list[DemoOutSchema]:
        obj_list = await DemoCRUD(self.auth).get_list(search=vars(search) if search else None, order_by=order_by)
        return [DemoOutSchema.model_validate(obj) for obj in obj_list]

    async def page(
        self,
        page_no: int,
        page_size: int,
        search: DemoQueryParam | None = None,
        order_by: list[dict[str, str]] | None = None,
    ) -> dict:
        offset = (page_no - 1) * page_size
        return await DemoCRUD(self.auth).page(
            offset=offset,
            limit=page_size,
            order_by=order_by or [{"id": "asc"}],
            search=vars(search) if search else None,
            out_schema=DemoOutSchema,
        )

    async def create(self, data: DemoCreateSchema) -> DemoOutSchema:
        obj = await DemoCRUD(self.auth).get(name=data.name)
        if obj:
            raise CustomException(msg="创建失败，名称已存在")
        obj = await DemoCRUD(self.auth).create(data=data)
        return DemoOutSchema.model_validate(obj)

    async def update(self, id: int, data: DemoUpdateSchema) -> DemoOutSchema:
        obj = await DemoCRUD(self.auth).get(id=id)
        if not obj:
            raise CustomException(msg="更新失败，该数据不存在")

        exist_obj = await DemoCRUD(self.auth).get(name=data.name)
        if exist_obj and exist_obj.id != id:
            raise CustomException(msg="更新失败，名称重复")

        obj = await DemoCRUD(self.auth).update(id=id, data=data)
        return DemoOutSchema.model_validate(obj)

    async def delete(self, ids: list[int]) -> None:
        if len(ids) < 1:
            raise CustomException(msg="删除失败，删除对象不能为空")
        objs = await DemoCRUD(self.auth).get_list(search={"id": ("in", ids)})
        obj_map = {o.id: o for o in objs}
        for id_ in ids:
            if id_ not in obj_map:
                raise CustomException(msg="删除失败，该数据不存在")
        await DemoCRUD(self.auth).delete(ids=ids)

    async def set_available(self, data: BatchSetAvailable) -> None:
        await DemoCRUD(self.auth).set(ids=data.ids, status=data.status)

    @staticmethod
    def batch_export(obj_list: list[dict[str, Any]]) -> bytes:
        mapping_dict = {
            "id": "编号",
            "name": "名称",
            "status": "状态",
            "description": "备注",
            "created_time": "创建时间",
            "updated_time": "更新时间",
            "created_id": "创建者",
        }

        data = obj_list.copy()
        for item in data:
            item["status"] = "启用" if item.get("status") == 0 else "停用"
            creator_info = item.get("created_id")
            if isinstance(creator_info, dict):
                item["created_id"] = creator_info.get("name", "未知")
            else:
                item["created_id"] = "未知"

        return ExcelUtil.export_list2excel(list_data=data, mapping_dict=mapping_dict)

    async def batch_import(self, file: UploadFile, update_support: bool = False) -> str:
        header_dict = {"名称": "name", "状态": "status", "描述": "description"}

        try:
            contents = await file.read()
            df = pd.read_excel(io.BytesIO(contents))
            await file.close()

            if df.empty:
                raise CustomException(msg="导入文件为空")

            missing_headers = [header for header in header_dict if header not in df.columns]
            if missing_headers:
                raise CustomException(msg=f"导入文件缺少必要的列: {', '.join(missing_headers)}")

            df.rename(columns=header_dict, inplace=True)

            required_fields = ["name", "status"]
            errors = []
            for field in required_fields:
                missing_rows = df[df[field].isnull()].index.tolist()
                if missing_rows:
                    field_name = next(k for k, v in header_dict.items() if v == field)
                    rows_str = "、".join([str(i + 1) for i in missing_rows])
                    errors.append(f"{field_name}不能为空，第{rows_str}行")
            if errors:
                raise CustomException(msg=f"导入失败，以下行缺少必要字段：\n{'; '.join(errors)}")

            error_msgs = []
            success_count = 0
            count = 0

            for _index, row in df.iterrows():
                count += 1
                try:
                    try:
                        status = 0 if row["status"] == "正常" else 1
                    except ValueError:
                        error_msgs.append(f"第{count}行: 状态必须是'正常'或'停用'")
                        continue

                    data = {
                        "name": str(row["name"]),
                        "status": status,
                        "description": str(row["description"]),
                    }

                    exists_obj = await DemoCRUD(self.auth).get(name=data["name"])
                    if exists_obj:
                        if update_support:
                            await DemoCRUD(self.auth).update(id=exists_obj.id, data=data)
                            success_count += 1
                        else:
                            error_msgs.append(f"第{count}行: 对象 {data['name']} 已存在")
                    else:
                        await DemoCRUD(self.auth).create(data=data)
                        success_count += 1

                except Exception as e:
                    error_msgs.append(f"第{count}行: {e!s}")
                    continue

            result = f"成功导入 {success_count} 条数据"
            if error_msgs:
                result += "\n错误信息:\n" + "\n".join(error_msgs)
            return result

        except Exception as e:
            logger.error(f"批量导入用户失败: {e!s}")
            raise CustomException(msg=f"导入失败: {e!s}")

    @staticmethod
    def import_template_download() -> bytes:
        header_list = ["名称", "状态", "描述"]
        selector_header_list = ["状态"]
        option_list = [{"状态": ["正常", "停用"]}]
        return ExcelUtil.get_excel_template(
            header_list=header_list,
            selector_header_list=selector_header_list,
            option_list=option_list,
        )