import { describe, it, expect } from 'vitest'
import * as fc from 'fast-check'
import { filterStockAlerts } from '../src/controllers/stockAlert'

// Generate a product with arbitrary stock values
const productArb = fc.record({
  id: fc.integer({ min: 1, max: 10000 }),
  name: fc.string({ minLength: 1, maxLength: 20 }),
  style_no: fc.string({ minLength: 0, maxLength: 10 }),
  stock: fc.integer({ min: 0, max: 10000 }),
  total_stock: fc.integer({ min: 0, max: 10000 }),
})

// Feature: jewelry-mall, Property 7: 库存预警阈值判断
// **Validates: Requirements 8.4**
describe('Property 7: 库存预警阈值判断', () => {
  it('预警列表应恰好包含所有低库存商品且按库存从少到多排序', () => {
    fc.assert(
      fc.property(
        fc.array(productArb, { minLength: 0, maxLength: 20 }),
        (products) => {
          const alerts = filterStockAlerts(products)

          // Every alert should satisfy the threshold condition
          for (const a of alerts) {
            expect(a.total_stock).toBeGreaterThan(0)
            expect(a.stock / a.total_stock).toBeLessThan(0.1)
          }

          // Every product meeting the condition should be in alerts
          const expectedIds = products
            .filter((p) => p.total_stock > 0 && p.stock / p.total_stock < 0.1)
            .map((p) => p.id)
          const alertIds = alerts.map((a) => a.id)
          expect(alertIds.sort()).toEqual(expectedIds.sort())

          // Alerts should be sorted by stock ascending
          for (let i = 1; i < alerts.length; i++) {
            expect(alerts[i].stock).toBeGreaterThanOrEqual(alerts[i - 1].stock)
          }
        }
      ),
      { numRuns: 100 }
    )
  })
})