/**
 * @module tests/unit/db/pad-frame-total
 * @description Pad-frame construction is TOTAL: every size from the minimum
 * through 4096+257 is constructible byte-exact (a production adoption found
 * the msgpack class-boundary hole at 291 bytes — sync died whole, and the
 * failure cascaded into a counter rewind after a successful append). Every
 * constructed pad decodes as skip-by-definition filler.
 */
import { describe, it, expect } from 'vitest'
import { encodePadFrame, minPadFrameBytes, decodeGroupV2 } from '../../../src/db/factLogFormat.js'

describe('pad frames are constructible at EVERY size', () => {
  it('exact construction from the minimum through a full sector + boundary spill', () => {
    const min = minPadFrameBytes()
    for (let size = min; size <= 4096 + 257; size++) {
      const frame = encodePadFrame(size)
      expect(frame.length, `size ${size}`).toBe(size)
    }
  })

  it('the production case (291) and its class-boundary siblings decode as invisible filler', () => {
    for (const size of [291, minPadFrameBytes(), 300, 511, 512, 513, 4096]) {
      const frame = encodePadFrame(size)
      const group = decodeGroupV2(frame)
      expect(group.facts, `size ${size} is reader-invisible`).toEqual([])
      expect(group.validBytes).toBe(size)
    }
  })
})