/**
 * 聚合函数测试（对应设计文档 §16 阶段 3 的"跨页合计"能力基础）。
 *
 * 语义约定：
 * - 空数组：sum → 0，avg/min/max → null，count → 0
 * - "合计为 0" 与 "没有数据" 是两种不同语义，前者显示 0，后者显示空白
 */
import { describe, expect, it } from "vitest"
import { evaluateValue } from "../src/evaluator.js"
import type { EvalScope } from "../src/scope.js"

const scope: EvalScope = {
  row: {
    amounts: [10, 20, 30],
    prices: [1.5, 2.5],
    mixed: [1, "abc", 3, null],
    empty: [],
    names: ["甲", "乙", "丙"],
  },
  params: {},
}

describe("sum", () => {
  it("数组求和", () => {
    expect(evaluateValue("sum(row.amounts)", scope)).toBe(60)
  })

  it("空数组返回 0（合计为零应显示 0）", () => {
    expect(evaluateValue("sum(row.empty)", scope)).toBe(0)
  })

  it("忽略非数字元素", () => {
    expect(evaluateValue("sum(row.mixed)", scope)).toBe(4)
  })

  it("标量视为单元素", () => {
    expect(evaluateValue("sum(5)", scope)).toBe(5)
  })

  it("null 返回 0", () => {
    expect(evaluateValue("sum(row.nothing)", scope)).toBe(0)
  })

  it("小数求和", () => {
    expect(evaluateValue("sum(row.prices)", scope)).toBe(4)
  })

  it("可与其他运算组合", () => {
    expect(evaluateValue("sum(row.amounts) * 2", scope)).toBe(120)
  })
})

describe("avg", () => {
  it("平均值为数字", () => {
    expect(evaluateValue("avg(row.amounts)", scope)).toBe(20)
  })

  it("空数组返回 null（无数据应显示空白）", () => {
    expect(evaluateValue("avg(row.empty)", scope)).toBeNull()
  })

  it("忽略非数字元素后再平均", () => {
    // 1 和 3 是有效数字，'abc' 与 null 被忽略
    expect(evaluateValue("avg(row.mixed)", scope)).toBe(2)
  })

  it("小数的平均值", () => {
    expect(evaluateValue("avg(row.prices)", scope)).toBe(2)
  })
})

describe("count", () => {
  it("统计元素个数", () => {
    expect(evaluateValue("count(row.amounts)", scope)).toBe(3)
  })

  it("空数组返回 0", () => {
    expect(evaluateValue("count(row.empty)", scope)).toBe(0)
  })

  it("统计非空元素个数", () => {
    // mixed = [1, 'abc', 3, null]，null 不计入
    expect(evaluateValue("count(row.mixed)", scope)).toBe(3)
  })

  it("无参数返回 0", () => {
    expect(evaluateValue("count()", scope)).toBe(0)
  })

  it("标量计为 1", () => {
    expect(evaluateValue("count(5)", scope)).toBe(1)
  })

  it("null 计为 0", () => {
    expect(evaluateValue("count(row.nothing)", scope)).toBe(0)
  })
})

describe("min / max 双形态", () => {
  it("多参数形态（标量比较）", () => {
    expect(evaluateValue("min(3, 1, 2)", scope)).toBe(1)
    expect(evaluateValue("max(3, 1, 2)", scope)).toBe(3)
  })

  it("单参数数组形态（聚合）", () => {
    expect(evaluateValue("min(row.amounts)", scope)).toBe(10)
    expect(evaluateValue("max(row.amounts)", scope)).toBe(30)
  })

  it("空数组返回 null", () => {
    expect(evaluateValue("min(row.empty)", scope)).toBeNull()
    expect(evaluateValue("max(row.empty)", scope)).toBeNull()
  })

  it("忽略非数字", () => {
    expect(evaluateValue("max(row.mixed)", scope)).toBe(3)
  })

  it("单元素数组与标量结果一致", () => {
    expect(evaluateValue("min(5)", scope)).toBe(5)
    expect(evaluateValue("min(row.prices)", scope)).toBe(1.5)
  })
})

describe("聚合与分组作用域协作", () => {
  it("可通过 group 作用域聚合", () => {
    const groupScope: EvalScope = {
      row: { name: "甲" },
      group: {
        key: "华北",
        amounts: [100, 200, 300],
        count: 3,
      },
      params: {},
    }
    expect(evaluateValue("sum(group.amounts)", groupScope)).toBe(600)
    expect(evaluateValue("avg(group.amounts)", groupScope)).toBe(200)
    expect(evaluateValue("group.count", groupScope)).toBe(3)
  })

  it("可通过 dataset 作用域做全表合计", () => {
    const datasetScope: EvalScope = {
      row: {},
      dataset: { amounts: [1, 2, 3, 4], count: 4 },
      params: {},
    }
    expect(evaluateValue("sum(dataset.amounts)", datasetScope)).toBe(10)
  })

  it("聚合结果可被格式化", () => {
    const groupScope: EvalScope = {
      row: {},
      group: { amounts: [1234.5, 2.25] },
      params: {},
    }
    expect(evaluateValue("format(sum(group.amounts), '#,##0.00')", groupScope)).toBe("1,236.75")
  })

  it("空组不产生 NaN", () => {
    const groupScope: EvalScope = { row: {}, group: { amounts: [] }, params: {} }
    const sum = evaluateValue("sum(group.amounts)", groupScope)
    expect(sum).toBe(0)
    expect(Number.isNaN(sum as number)).toBe(false)
  })
})

describe("聚合函数仍在安全白名单内", () => {
  it("sum/avg/count 可调用", () => {
    expect(evaluateValue("sum(1)", scope)).toBe(1)
    expect(evaluateValue("avg(1)", scope)).toBe(1)
    expect(evaluateValue("count(1)", scope)).toBe(1)
  })

  it("未登记的聚合名仍被拒绝", () => {
    // median 等未实现，应在解析期就被拒绝
    const scope2: EvalScope = { row: {} }
    const result = evaluateValue("median(row.x)", scope2)
    expect(result).toBeNull()
  })
})