import { mkdtemp, rm, writeFile } from 'node:fs/promises'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import { afterEach, describe, expect, it } from 'vitest'
import {
  nativeChatLineDecoderForAgent,
  readNativeChatTranscriptTailFile
} from './transcript-tail-reader'

let tempRoots: string[] = []

afterEach(async () => {
  await Promise.all(tempRoots.map((root) => rm(root, { recursive: true, force: true })))
  tempRoots = []
})

function jsonLines(records: unknown[]): string {
  return records.map((record) => JSON.stringify(record)).join('\n')
}

async function writeFixture(prefix: string, records: unknown[]): Promise<string> {
  const root = await mkdtemp(join(tmpdir(), prefix))
  tempRoots.push(root)
  const filePath = join(root, 'transcript.jsonl')
  await writeFile(filePath, jsonLines(records))
  return filePath
}

describe('readNativeChatTranscriptTailFile', () => {
  it('windows to nothing for a non-positive limit instead of the whole tail', async () => {
    const decode = nativeChatLineDecoderForAgent('claude')!
    const filePath = await writeFixture('orca-native-chat-tail-limit-', [
      {
        type: 'assistant',
        uuid: 'a-1',
        message: { role: 'assistant', content: [{ type: 'text', text: 'one' }] }
      },
      {
        type: 'assistant',
        uuid: 'a-2',
        message: { role: 'assistant', content: [{ type: 'text', text: 'two' }] }
      }
    ])

    const result = await readNativeChatTranscriptTailFile(filePath, 0, decode, true)

    expect(result.messages).toEqual([])
    expect(result.hasMore).toBe(false)
  })
})