import { describe, expect, test } from 'bun:test'
import {
  lastRate,
  pushWindow,
  routeDeltas,
  windowBytes,
  type ConnTotals,
  type RouteSample,
} from './telemetry.ts'
import type { ConnectionItem } from './connections.ts'

function conn(id: string, inbound: string, upload: number, download: number): ConnectionItem {
  return {
    id,
    upload,
    download,
    start: '2026-08-11T00:00:00+08:00',
    chains: ['DIRECT'],
    rule: 'Match',
    rulePayload: '',
    metadata: {
      host: 'example.com',
      destinationIP: '1.2.3.4',
      destinationPort: '443',
      inboundName: inbound,
      inboundPort: '7890',
    },
  }
}

describe('pushWindow', () => {
  test('把窗口外的老点挤掉，保留窗口内的', () => {
    const list = [{ t: 0 }, { t: 5_000 }, { t: 9_000 }]
    const next = pushWindow(list, { t: 12_000 }, 5_000)
    expect(next.map((p) => p.t)).toEqual([9_000, 12_000])
  })

  test('全部过期时只剩新点', () => {
    const next = pushWindow([{ t: 0 }], { t: 60_000 }, 5_000)
    expect(next.map((p) => p.t)).toEqual([60_000])
  })
})

describe('routeDeltas', () => {
  test('已有连接算差值，并按入站聚合', () => {
    const prev: ConnTotals = new Map([
      ['a', { up: 100, down: 200 }],
      ['b', { up: 10, down: 20 }],
    ])
    const { deltas } = routeDeltas(prev, [
      conn('a', 'lan-a', 150, 260),
      conn('b', 'lan-a', 30, 21),
    ])
    expect(deltas['lan-a']).toEqual({ up: 70, down: 61 })
  })

  test('新连接把累计全部记入本次间隔', () => {
    const { deltas } = routeDeltas(new Map(), [conn('a', 'lan-a', 500, 700)])
    expect(deltas['lan-a']).toEqual({ up: 500, down: 700 })
  })

  test('累计变小（内核重启）按全新连接处理，不出负数', () => {
    const prev: ConnTotals = new Map([['a', { up: 900, down: 900 }]])
    const { deltas } = routeDeltas(prev, [conn('a', 'lan-a', 50, 60)])
    expect(deltas['lan-a']).toEqual({ up: 50, down: 60 })
  })

  test('消失的连接不再出现在 next 里', () => {
    const prev: ConnTotals = new Map([['gone', { up: 1, down: 1 }]])
    const { next } = routeDeltas(prev, [conn('a', 'lan-a', 5, 5)])
    expect(next.has('gone')).toBe(false)
    expect(next.get('a')).toEqual({ up: 5, down: 5 })
  })

  test('没有名字的入站退回端口做键', () => {
    const item = conn('a', '', 5, 5)
    const { deltas } = routeDeltas(new Map(), [item])
    expect(Object.keys(deltas)).toEqual(['7890'])
  })
})

describe('windowBytes / lastRate', () => {
  const samples: RouteSample[] = [
    { t: 0, ms: 3_000, up: 100, down: 100 },
    { t: 3_000, ms: 3_000, up: 300, down: 300 },
    { t: 6_000, ms: 2_000, up: 400, down: 600 },
  ]

  test('windowBytes 只算窗口内的样本', () => {
    expect(windowBytes(samples, 3_000)).toBe(300 + 300 + 400 + 600)
  })

  test('lastRate 按实际间隔换算成每秒', () => {
    expect(lastRate(samples)).toEqual({ up: 200, down: 300 })
  })

  test('lastRate 没有样本时是 null', () => {
    expect(lastRate([])).toBeNull()
  })
})