package repository

import (
	"database/sql"
	"fmt"
	"strings"
)

// PDDPriceBackfillTarget 是一次性 Excel 价格回填需要的 PDD 原值。
// 原值同时用于 dry-run、乐观锁和本机回退备份。
type PDDPriceBackfillTarget struct {
	GoodsID       string
	SKUsJSON      string
	CollectStatus string
	CollectMsg    *string
	ArtifactRef   *string
	CollectedAt   *string
	UpdatedAt     string
}

// ListShopPDDPriceBackfillTargets 读取指定蝦皮店铺当前关联的活动 PDD 商品。
// 同一个 PDD 被多个蝦皮商品关联时只返回一份原值。
func ListShopPDDPriceBackfillTargets(q Execer, shopName string) ([]PDDPriceBackfillTarget, error) {
	rows, err := q.Query(`
		SELECT DISTINCT pp.goods_id, COALESCE(pp.skus_json, ''), pp.collect_status,
		       pp.collect_msg, pp.artifact_ref, pp.collected_at, pp.updated_at
		  FROM shopee_products sp
		  JOIN pdd_products pp ON pp.goods_id = sp.pdd_goods_id
		 WHERE sp.deleted_at IS NULL AND pp.deleted_at IS NULL
		   AND sp.shopee_shop_name = ?
		 ORDER BY pp.goods_id`, strings.TrimSpace(shopName))
	if err != nil {
		return nil, fmt.Errorf("读取店铺 PDD 价格回填目标失败: %w", err)
	}
	defer rows.Close()

	var targets []PDDPriceBackfillTarget
	for rows.Next() {
		var target PDDPriceBackfillTarget
		var collectMsg, artifactRef, collectedAt sql.NullString
		if err := rows.Scan(&target.GoodsID, &target.SKUsJSON, &target.CollectStatus,
			&collectMsg, &artifactRef, &collectedAt, &target.UpdatedAt); err != nil {
			return nil, fmt.Errorf("解析 PDD 价格回填目标失败: %w", err)
		}
		target.CollectMsg = nullableStringPointer(collectMsg)
		target.ArtifactRef = nullableStringPointer(artifactRef)
		target.CollectedAt = nullableStringPointer(collectedAt)
		targets = append(targets, target)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("遍历 PDD 价格回填目标失败: %w", err)
	}
	return targets, nil
}

func nullableStringPointer(value sql.NullString) *string {
	if !value.Valid {
		return nil
	}
	result := value.String
	return &result
}

// ReplacePDDPricesAndMarkCollected 使用完整原值作乐观锁，写入价格并标记已采集。
// 返回 false 表示 dry-run 后目标发生变化，调用方必须回滚整批，不能部分提交。
func ReplacePDDPricesAndMarkCollected(q Execer, target PDDPriceBackfillTarget,
	newSKUsJSON, collectedAt, updatedAt string) (bool, error) {
	result, err := q.Exec(`
		UPDATE pdd_products
		   SET skus_json = ?, collect_status = 'collected',
		       collect_msg = NULL, artifact_ref = NULL,
		       collected_at = ?, updated_at = ?
		 WHERE goods_id = ? AND deleted_at IS NULL
		   AND COALESCE(skus_json, '') = ?
		   AND collect_status = ? AND updated_at = ?`,
		newSKUsJSON, collectedAt, updatedAt, target.GoodsID,
		target.SKUsJSON, target.CollectStatus, target.UpdatedAt)
	if err != nil {
		return false, fmt.Errorf("更新 PDD 商品 %s 的正式价格失败: %w", target.GoodsID, err)
	}
	rows, err := result.RowsAffected()
	if err != nil {
		return false, fmt.Errorf("读取 PDD 商品 %s 的价格回填结果失败: %w", target.GoodsID, err)
	}
	return rows == 1, nil
}