AI整理优惠规则：满减与折扣先后顺序可重算

{
  "policy": "商品先打8折，再看折后是否满100元；满100减10元，不与其他券叠加。",
  "carts": [
    "125.00",
    "124.99"
  ]
}

python3 -m venv .venv
source .venv/bin/activate
python -m pip install -r requirements.txt
python run.py

{
  "model": "gemini-2.5-flash-lite",
  "messages": [
    {
      "role": "system",
      "content": "严格只输出单个JSON对象，不要Markdown代码围栏，不要解释。只处理给定原创虚构材料，只输出JSON。提取折扣规则discount（0到1的乘法系数字符串）、threshold（两位小数字符串）、reduction（两位小数字符串）、sequence数组；规则按先打折、再检查折后满减；不与其他券叠加。 输出结构：{\"discount\": \"string\", \"threshold\": \"string\", \"reduction\": \"string\", \"sequence\": [\"string\"], \"stack_other_coupon\": \"boolean\"}"
    },
    {
      "role": "user",
      "content": "任务约束（只输出JSON对象，不用代码围栏）：\n只处理给定原创虚构材料，只输出JSON。提取折扣规则discount（0到1的乘法系数字符串）、threshold（两位小数字符串）、reduction（两位小数字符串）、sequence数组；规则按先打折、再检查折后满减；不与其他券叠加。 输出结构：{\"discount\": \"string\", \"threshold\": \"string\", \"reduction\": \"string\", \"sequence\": [\"string\"], \"stack_other_coupon\": \"boolean\"}\n待处理合成材料：\n{\"policy\": \"商品先打8折，再看折后是否满100元；满100减10元，不与其他券叠加。\", \"carts\": [\"125.00\", \"124.99\"]}"
    }
  ],
  "temperature": 0,
  "max_tokens": 1024,
  "provider": {
    "sort": "success_rate"
  },
  "response_format": {
    "type": "json_object"
  }
}

rows = []
for cart in data['carts']:
    discounted = (D(cart) * D(output['discount'])).quantize(D('.01'), rounding=ROUND_HALF_UP)
    reduce = D(output['reduction']) if discounted >= D(output['threshold']) else D('0')
    rows.append({'original': cart, 'discounted': money(discounted), 'reduction': money(reduce), 'payable': money(discounted - reduce)})
check('折后100.00命中满减', rows[0]['payable'] == '90.00')
check('124.99先舍入后的金额为99.99不满减', rows[1]['payable'] == '99.99')
check('错误先减后折得出不同结果', (D('125') - D('10')) * D('.8') != D(rows[0]['payable']))
cout('discount-boundaries.csv', rows)
result = {'rules': output, 'calculations': rows, 'rounding_note': '本地约定折后先按人民币分四舍五入，再检查门槛。'}

{
  "rules": {
    "discount": "0.8",
    "threshold": "100.00",
    "reduction": "10.00",
    "sequence": [
      "discount",
      "threshold_reduction"
    ],
    "stack_other_coupon": false
  },
  "calculations": [
    {
      "original": "125.00",
      "discounted": "100.00",
      "reduction": "10.00",
      "payable": "90.00"
    },
    {
      "original": "124.99",
      "discounted": "99.99",
      "reduction": "0.00",
      "payable": "99.99"
    }
  ],
  "rounding_note": "本地约定折后先按人民币分四舍五入，再检查门槛。",
  "model_original": {
    "discount": "0.80",
    "threshold": "100.00",
    "reduction": "10.00",
    "sequence": [
      "discount",
      "reduction"
    ],
    "stack_other_coupon": false
  },
  "model_normalization": {
    "model_original": {
      "discount": "0.80",
      "threshold": "100.00",
      "reduction": "10.00",
      "sequence": [
        "discount",
        "reduction"
      ],
      "stack_other_coupon": false
    },
    "normalized_fields": {
      "discount": "0.8",
      "threshold": "100.00",
      "reduction": "10.00",
      "sequence": [
        "discount",
        "threshold_reduction"
      ],
      "stack_other_coupon": false
    },
    "rules": [
      {
        "field": "discount",
        "original": "0.80",
        "normalized": "0.8",
        "rule": "Decimal equality, not textual trailing-zero equality; amount remains source-bound."
      },
      {
        "field": "threshold",
        "original": "100.00",
        "normalized": "100.00",
        "rule": "Decimal equality, not textual trailing-zero equality; amount remains source-bound."
      },
      {
        "field": "reduction",
        "original": "10.00",
        "normalized": "10.00",
        "rule": "Decimal equality, not textual trailing-zero equality; amount remains source-bound."
      },
      {
        "field": "sequence",
        "original": [
          "discount",
          "reduction"
        ],
        "normalized": [
          "discount",
          "threshold_reduction"
        ],
        "rule": "Legacy reduction alias is accepted only with the correct explicit threshold and source order; reversed or missing actions are rejected."
      }
    ]
  }
}