package logic

import (
	"context"
	"database/sql"
	"errors"
	"time"

	"godemo/category/category"
	"godemo/category/internal/model"
	"godemo/category/internal/svc"

	"github.com/google/uuid"
	"github.com/zeromicro/go-zero/core/logx"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type CreateCategoryLogic struct {
	ctx    context.Context
	svcCtx *svc.ServiceContext
	logx.Logger
}

func NewCreateCategoryLogic(ctx context.Context, svcCtx *svc.ServiceContext) *CreateCategoryLogic {
	return &CreateCategoryLogic{
		ctx:    ctx,
		svcCtx: svcCtx,
		Logger: logx.WithContext(ctx),
	}
}

func (l *CreateCategoryLogic) CreateCategory(in *category.CreateCategoryRequest) (*category.CategoryInfoResponse, error) {
	// 参数校验
	if in.SystemId == "" || in.Name == "" {
		return nil, status.Error(codes.InvalidArgument, "system_id 和 name 不能为空")
	}

	// 检查唯一性
	exists, err := l.checkCategoryExists(in)
	if err != nil {
		logx.Error("唯一性检查失败: ", err)
		return nil, status.Error(codes.Internal, "内部错误")
	}
	if exists {
		return nil, status.Error(codes.AlreadyExists, "分类已存在")
	}

	// 构建模型
	newCategory := &model.Categories{
		Id:          uuid.New().String(),
		SystemId:    in.SystemId,
		Name:        in.Name,
		Alias:       toNullString(in.Alias),
		ParentId:    toNullString(in.ParentId),
		Description: toNullString(in.Description),
		CreatedAt:   time.Now(),
		UpdatedAt:   sql.NullTime{Time: time.Now(), Valid: true},
	}

	// 插入数据库
	if _, err := l.svcCtx.CategoryModel.Insert(l.ctx, newCategory); err != nil {
		logx.Error("插入失败: ", err)
		return nil, status.Error(codes.Internal, "创建分类失败")
	}

	// 返回响应
	return &category.CategoryInfoResponse{
		Category: &category.CategoryInfo{
			Id:          newCategory.Id,
			SystemId:    newCategory.SystemId,
			Name:        newCategory.Name,
			Alias:       in.Alias,
			ParentId:    in.ParentId,
			Description: in.Description,
			CreatedAt:   newCategory.CreatedAt.Unix(),
			UpdatedAt:   newCategory.UpdatedAt.Time.Unix(),
		},
	}, nil
}

// 空字符串转换为 sql.NullString
func toNullString(s string) sql.NullString {
	return sql.NullString{String: s, Valid: s != ""}
}

// 唯一性检查逻辑
func (l *CreateCategoryLogic) checkCategoryExists(in *category.CreateCategoryRequest) (bool, error) {
	// 检查名称唯一性
	_, err := l.svcCtx.CategoryModel.FindBySystemParentName(
		l.ctx,
		in.SystemId,
		in.ParentId,
		in.Name,
	)
	if err == nil {
		return true, nil
	} else if !errors.Is(err, model.ErrNotFound) {
		return false, err
	}

	// 检查别名唯一性（如果提供了别名）
	if in.Alias != "" {
		_, err := l.svcCtx.CategoryModel.FindBySystemParentAlias(
			l.ctx,
			in.SystemId,
			in.ParentId,
			in.Alias,
		)
		if err == nil {
			return true, nil
		} else if !errors.Is(err, model.ErrNotFound) {
			return false, err
		}
	}

	return false, nil
}