import { describe, expect, test } from 'bun:test'
import { looksLikeGeodata, looksLikeMmdb } from './geo.ts'

describe('GEO 文件的形状检查', () => {
  test('末尾带 MaxMind 标记的通过，纯垃圾不通过', () => {
    const marker = new Uint8Array([
      0xab,
      0xcd,
      0xef,
      ...Array.from('MaxMind.com', (c) => c.charCodeAt(0)),
    ])
    const good = new Uint8Array(4096)
    good.set(marker, 4000)
    expect(looksLikeMmdb(good)).toBe(true)
    expect(looksLikeMmdb(new Uint8Array(4096))).toBe(false)
  })

  test('标记只认末尾 128KB，太靠前算无效', () => {
    const marker = new Uint8Array([
      0xab,
      0xcd,
      0xef,
      ...Array.from('MaxMind.com', (c) => c.charCodeAt(0)),
    ])
    const bytes = new Uint8Array(300 * 1024)
    bytes.set(marker, 100)
    expect(looksLikeMmdb(bytes)).toBe(false)
  })

  test('geodata 认首字节 0x0a，HTML 错误页和小文件被挡下', () => {
    const good = new Uint8Array(2048)
    good[0] = 0x0a
    expect(looksLikeGeodata(good)).toBe(true)

    const html = new Uint8Array(2048)
    html[0] = '<'.charCodeAt(0)
    expect(looksLikeGeodata(html)).toBe(false)

    const tiny = new Uint8Array(10)
    tiny[0] = 0x0a
    expect(looksLikeGeodata(tiny)).toBe(false)
  })
})