package services

import (
	"context"
	"time"

	"quyun/v2/app/requests"
	"quyun/v2/database/models"
	"quyun/v2/pkg/fields"

	"github.com/pkg/errors"
	"github.com/samber/lo"
	"go.ipao.vip/gen"
	"go.ipao.vip/gen/types"
)

// @provider
type orders struct{}

// List 订单列表（支持按订单号模糊查询、按用户过滤）。
func (m *orders) List(
	ctx context.Context,
	pagination *requests.Pagination,
	conds ...gen.Condition,
) (*requests.Pager, error) {
	pagination.Format()

	tbl, query := models.OrderQuery.QueryContext(ctx)

	orders, cnt, err := query.
		Where(conds...).
		Order(tbl.ID.Desc()).
		FindByPage(int(pagination.Offset()), int(pagination.Limit))
	if err != nil {
		return nil, errors.Wrap(err, "failed to list orders")
	}

	// 这里刻意使用“先查订单，再批量查关联”的方式，避免在分页时 JOIN 造成重复行/分页不稳定。
	postIDs := lo.Uniq(lo.Map(orders, func(o *models.Order, _ int) int64 { return o.PostID }))
	userIDs := lo.Uniq(lo.Map(orders, func(o *models.Order, _ int) int64 { return o.UserID }))

	posts, err := models.PostQuery.WithContext(ctx).GetByIDs(postIDs...)
	if err != nil {
		return nil, errors.Wrap(err, "failed to get posts by ids")
	}
	users, err := models.UserQuery.WithContext(ctx).GetByIDs(userIDs...)
	if err != nil {
		return nil, errors.Wrap(err, "failed to get users by ids")
	}

	postMap := lo.SliceToMap(posts, func(p *models.Post) (int64, *models.Post) { return p.ID, p })
	userMap := lo.SliceToMap(users, func(u *models.User) (int64, *models.User) { return u.ID, u })

	// OrderListItem 用于订单列表展示，补充作品标题与用户名等冗余信息，避免前端二次查询。
	type orderListItem struct {
		*models.Order
		PostTitle string `json:"post_title"`
		Username  string `json:"username"`
	}

	items := lo.Map(orders, func(o *models.Order, _ int) *orderListItem {
		item := &orderListItem{Order: o}
		if post, ok := postMap[o.PostID]; ok {
			item.PostTitle = post.Title
		}
		if user, ok := userMap[o.UserID]; ok {
			item.Username = user.Username
		}
		return item
	})

	return &requests.Pager{
		Items:      items,
		Total:      cnt,
		Pagination: *pagination,
	}, nil
}

// Refund 订单退款（余额支付走本地退款；微信支付走微信退款并标记为退款处理中）。
func (m *orders) Refund(ctx context.Context, id int64) error {
	// 余额支付：这里强调“状态一致性”，必须在一个事务中完成：余额退回 + 撤销购买权益 + 更新订单状态。
	return models.Q.Transaction(func(tx *models.Query) error {
		order, err := tx.Order.WithContext(ctx).GetByID(id)
		if err != nil {
			return errors.Wrap(err, "failed to get order in tx")
		}

		// 退回余额（使用原子自增，避免并发覆盖）。
		costBalance := order.Meta.Data().CostBalance
		if costBalance > 0 {
			if _, err := tx.User.
				WithContext(ctx).
				Where(tx.User.ID.Eq(order.UserID)).
				Inc(tx.User.Balance, costBalance); err != nil {
				return errors.Wrap(err, "failed to refund balance")
			}
		}

		// 撤销已购买的作品权限（删除 user_posts 记录）。
		if _, err := tx.UserPost.
			WithContext(ctx).
			Where(
				tx.UserPost.UserID.Eq(order.UserID),
				tx.UserPost.PostID.Eq(order.PostID),
			).
			Delete(); err != nil {
			return errors.Wrap(err, "failed to revoke user post")
		}

		// 更新订单状态为“退款成功”。
		if _, err := tx.Order.
			WithContext(ctx).
			Where(tx.Order.ID.Eq(order.ID)).
			Update(tx.Order.Status, fields.OrderStatusRefundSuccess); err != nil {
			return errors.Wrap(err, "failed to update order status")
		}

		return nil
	})
}

// GetByOrderNO
func (m *orders) GetByOrderNO(ctx context.Context, orderNo string) (*models.Order, error) {
	return models.OrderQuery.WithContext(ctx).Where(models.OrderQuery.OrderNo.Eq(orderNo)).First()
}

func (o *orders) CreateFromUserPostID(ctx context.Context, userId, postId int64) (*models.Order, error) {
	post, err := Posts.FindByID(ctx, postId)
	if err != nil {
		return nil, errors.Wrap(err, "failed to get post")
	}

	m := &models.Order{}
	m.Status = fields.OrderStatusPending
	m.OrderNo = time.Now().Format("20060102150405")
	m.SubOrderNo = m.OrderNo
	m.UserID = userId
	m.PostID = postId
	m.Meta = types.NewJSONType(fields.OrderMeta{})
	m.Price = post.Price
	m.Discount = post.Discount

	if err := m.Create(ctx); err != nil {
		return m, err
	}
	return m, nil
}

// FindByID
func (m *orders) FindByID(ctx context.Context, orderID int64) (*models.Order, error) {
	return models.OrderQuery.WithContext(ctx).Where(models.OrderQuery.ID.Eq(orderID)).First()
}

func (m *orders) SetMeta(ctx context.Context, orderID int64, metaFunc func(fields.OrderMeta) fields.OrderMeta) error {
	order, err := m.FindByID(ctx, orderID)
	if err != nil {
		return err
	}
	order.Meta = types.NewJSONType(metaFunc(order.Meta.Data()))
	_, err = order.Update(ctx)

	return err
}

// SetStatus
func (m *orders) SetStatus(ctx context.Context, orderID int64, status fields.OrderStatus) error {
	tbl, query := models.OrderQuery.QueryContext(ctx)

	_, err := query.Where(tbl.ID.Eq(orderID)).Update(tbl.Status, status)
	return err
}

// SumAmount
func (m *orders) SumAmount(ctx context.Context) (int64, error) {
	tbl, query := models.OrderQuery.QueryContext(ctx)
	var calc struct {
		Amount int64 `json:"amount"`
	}

	err := query.Select(tbl.Price.Sum().As("amount")).Scan(&calc)
	if err != nil {
		return 0, errors.Wrap(err, "failed to sum amount")
	}

	return calc.Amount, nil
}

// Count
func (m *orders) Count(ctx context.Context, conds ...gen.Condition) (int64, error) {
	_, query := models.OrderQuery.QueryContext(ctx)
	if len(conds) > 0 {
		query = query.Where(conds...)
	}
	return query.Count()
}