/** 重复检查分布视图（任务 116）：按国家/站点聚合撞款与 top 店铺分布；纯逻辑。 */
import type { DuplicateShop } from './duplicate-model.ts'

export interface CountryDistributionRow {
  country: string
  asinCount: number
  shopCount: number
}

/** 按国家聚合分布(每店铺 country_codes 全量计入)。 */
export function countryDistribution(shops: readonly DuplicateShop[]): CountryDistributionRow[] {
  const byCountry = new Map<string, { asinCount: number; shopCount: number }>()
  for (const item of shops) {
    for (const code of item.countryCodes) {
      const country = code.trim().toUpperCase()
      if (!country) continue
      const entry = byCountry.get(country) ?? { asinCount: 0, shopCount: 0 }
      entry.asinCount += item.asinCount
      entry.shopCount += 1
      byCountry.set(country, entry)
    }
  }
  return [...byCountry.entries()]
    .map(([country, entry]) => ({ country, asinCount: entry.asinCount, shopCount: entry.shopCount }))
    .sort((a, b) => b.asinCount - a.asinCount || a.country.localeCompare(b.country))
}

export interface SiteDistributionRow {
  site: string
  asinCount: number
  shopCount: number
}

/** 按站点(site)聚合：以单国家维度汇总撞款，站点取国家码。 */
export function duplicateSiteDistribution(shops: readonly DuplicateShop[]): SiteDistributionRow[] {
  const rows = countryDistribution(shops)
  return rows.map((row) => ({ site: row.country, asinCount: row.asinCount, shopCount: row.shopCount }))
}

/** 按撞款 ASIN 数取 top 店铺(降序)，limit<=0 返回空。 */
export function topShopsByAsin(shops: readonly DuplicateShop[], limit: number): DuplicateShop[] {
  if (!(limit > 0)) return []
  return [...shops]
    .sort((a, b) => b.asinCount - a.asinCount || a.shopName.localeCompare(b.shopName))
    .slice(0, Math.floor(limit))
}