package store

import (
	"errors"
	"fmt"
	"time"

	"gorm.io/gorm"

	"github.com/wangjia/pay/internal/model"
)

var ErrRefundNotFound = errors.New("store: refund not found")

type RefundStore struct{ db *gorm.DB }

func NewRefundStore(db *gorm.DB) *RefundStore { return &RefundStore{db: db} }

func (s *RefundStore) CreateRefund(r *model.Refund) error {
	if r.RefundID == "" {
		return fmt.Errorf("store.CreateRefund: empty RefundID")
	}
	if err := s.db.Create(r).Error; err != nil {
		return fmt.Errorf("store.CreateRefund: %w", err)
	}
	return nil
}

func (s *RefundStore) GetRefund(refundID string) (*model.Refund, error) {
	var r model.Refund
	if err := s.db.Where("refund_id = ?", refundID).First(&r).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrRefundNotFound
		}
		return nil, fmt.Errorf("store.GetRefund: %w", err)
	}
	return &r, nil
}

// RefundSum sums amount_minor of an order's refunds in the given statuses
// (no statuses = all). 用两种口径:守卫查非失败之和(占额度),态机查 succeeded 之和。
func (s *RefundStore) RefundSum(outTradeNo string, statuses ...model.RefundStatus) (int64, error) {
	var total int64
	q := s.db.Model(&model.Refund{}).Where("out_trade_no = ?", outTradeNo)
	if len(statuses) > 0 {
		q = q.Where("status IN ?", statuses)
	}
	if err := q.Select("COALESCE(SUM(amount_minor),0)").Scan(&total).Error; err != nil {
		return 0, fmt.Errorf("store.RefundSum: %w", err)
	}
	return total, nil
}

// MarkRefundStatus flips a refund from an expected status to a new one
// (conditional UPDATE + RowsAffected). Returns false if not in the from-status.
func (s *RefundStore) MarkRefundStatus(refundID string, from, to model.RefundStatus, providerRefundRef string, at time.Time) (bool, error) {
	updates := map[string]any{"status": to}
	if providerRefundRef != "" {
		updates["provider_refund_ref"] = providerRefundRef
	}
	if to == model.RefundSucceeded || to == model.RefundFailed {
		updates["completed_at"] = at
	}
	res := s.db.Model(&model.Refund{}).
		Where("refund_id = ? AND status = ?", refundID, from).
		Updates(updates)
	if res.Error != nil {
		return false, fmt.Errorf("store.MarkRefundStatus: %w", res.Error)
	}
	return res.RowsAffected > 0, nil
}

// ListManualPending lists refunds awaiting manual (crypto) settlement.
func (s *RefundStore) ListManualPending(limit int) ([]model.Refund, error) {
	if limit <= 0 || limit > 200 {
		limit = 50
	}
	var out []model.Refund
	if err := s.db.Where("status = ?", model.RefundManualPending).
		Order("id ASC").Limit(limit).Find(&out).Error; err != nil {
		return nil, fmt.Errorf("store.ListManualPending: %w", err)
	}
	return out, nil
}