// PremiumLLMService.chatStream 계약 회귀 테스트 (red-team r1-6)
// - system 메시지 보존 (회의 전사 / 음성 대화 페르소나)
// - 끊긴 스트림·오류 이벤트·빈 응답은 성공이 아니다
// - 프록시 HTTP 오류는 비스트리밍으로 재요청하지 않는다 (쿼터 이중 소비 방지)
// - 호출 단위 취소
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
import { ErrorCode } from '@d3ro/core/errors'
import { parseLlmRequest } from '../../../../../server/supabase/functions/_shared/llm-contract'

const cloud = vi.hoisted(() => ({
  isEnabled: (): boolean => true,
  isAuthenticated: (): boolean => true,
  invokeFunctionStream: vi.fn(),
  invokeFunction: vi.fn(),
}))

vi.mock('../../../src/main/services/CloudSyncService', () => ({
  getCloudSyncService: () => cloud,
}))

import {
  getPremiumLLMService,
  resetPremiumLLMServiceForTests,
  proxyHttpStatus,
} from '../../../src/main/services/PremiumLLMService'

const encoder = new TextEncoder()

interface SseFrame {
  event: string
  data: unknown
}

function sseText(frames: SseFrame[]): string {
  return frames.map((f) => `event: ${f.event}\ndata: ${JSON.stringify(f.data)}\n\n`).join('')
}

function sseStream(frames: SseFrame[]): ReadableStream<Uint8Array> {
  return new ReadableStream({
    start(controller) {
      controller.enqueue(encoder.encode(sseText(frames)))
      controller.close()
    },
  })
}

const delta = (text: string): SseFrame => ({
  event: 'content_block_delta',
  data: { type: 'content_block_delta', index: 0, delta: { type: 'text_delta', text } },
})
const messageStart: SseFrame = { event: 'message_start', data: { type: 'message_start', message: {} } }
const messageStop: SseFrame = { event: 'message_stop', data: { type: 'message_stop' } }
const overloaded: SseFrame = {
  event: 'error',
  data: { type: 'error', error: { type: 'overloaded_error', message: 'Overloaded' } },
}

/** 신호가 abort 되기 전까지 끝나지 않는 SSE 스트림 */
function hangingStream(signal: AbortSignal): ReadableStream<Uint8Array> {
  return new ReadableStream({
    start(controller) {
      controller.enqueue(encoder.encode(sseText([messageStart, delta('partial ')])))
      signal.addEventListener('abort', () => {
        controller.error(new DOMException('Aborted', 'AbortError'))
      }, { once: true })
    },
  })
}

async function collect(gen: AsyncGenerator<string, string>): Promise<{ tokens: string[]; result: string }> {
  const tokens: string[] = []
  for (let next = await gen.next(); ; next = await gen.next()) {
    if (next.done) return { tokens, result: next.value }
    tokens.push(next.value)
  }
}

function lastStreamBody(): Record<string, unknown> {
  const call = cloud.invokeFunctionStream.mock.calls.at(-1)
  if (!call) throw new Error('invokeFunctionStream was not called')
  return call[1] as Record<string, unknown>
}

describe('PremiumLLMService.chatStream contract', () => {
  beforeEach(() => {
    resetPremiumLLMServiceForTests()
    cloud.invokeFunctionStream.mockReset()
    cloud.invokeFunction.mockReset()
  })

  afterEach(() => {
    resetPremiumLLMServiceForTests()
  })

  it('sends role:system content as body.system instead of dropping it', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: sseStream([messageStart, delta('short answer.'), messageStop]),
      error: null,
    })

    const { tokens, result } = await collect(getPremiumLLMService().chatStream([
      { role: 'system', content: 'Keep answers brief (2-3 sentences).' },
      { role: 'user', content: 'hello' },
    ]))

    expect(tokens).toEqual(['short answer.'])
    expect(result).toBe('short answer.')
    const body = lastStreamBody()
    expect(body.system).toBe('Keep answers brief (2-3 sentences).')
    expect(body.messages).toEqual([{ role: 'user', content: 'hello' }])
    expect(body.stream).toBe(true)
  })

  it('keeps a meeting transcript system prompt within the llm-proxy contract', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: sseStream([delta('answer'), messageStop]),
      error: null,
    })
    const transcript = '회의 발언 '.repeat(4_000)
    const systemPrompt = `당신은 회의 내용을 분석하는 AI 어시스턴트입니다.\n\n## 회의 전사\n${transcript}`
    const history = Array.from({ length: 60 }, (_, i) => ({
      role: i % 2 === 0 ? 'user' : 'assistant',
      content: `turn ${i}`,
    }))

    await collect(getPremiumLLMService().chatStream([
      { role: 'system', content: systemPrompt },
      ...history,
      { role: 'user', content: '결정 사항은?' },
    ]))

    const body = lastStreamBody()
    const validated = parseLlmRequest(body)
    expect(validated.system?.startsWith('당신은 회의 내용을 분석하는 AI 어시스턴트입니다.')).toBe(true)
    expect(validated.system).toContain('## 회의 전사')
    expect(validated.messages.at(-1)).toEqual({ role: 'user', content: '결정 사항은?' })
  })

  it('removes an empty assistant turn so a previous failure cannot poison later turns', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: sseStream([delta('ok'), messageStop]),
      error: null,
    })

    await collect(getPremiumLLMService().chatStream([
      { role: 'system', content: 'persona' },
      { role: 'user', content: 'first' },
      { role: 'assistant', content: '' },
      { role: 'user', content: 'second' },
    ]))

    const body = lastStreamBody()
    expect(() => parseLlmRequest(body)).not.toThrow()
    expect(body.messages).toEqual([
      { role: 'user', content: 'first' },
      { role: 'user', content: 'second' },
    ])
  })

  it('rejects when the provider sends an error event mid-stream', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: sseStream([messageStart, delta('partial '), overloaded]),
      error: null,
    })

    const tokens: string[] = []
    await expect((async () => {
      for await (const token of getPremiumLLMService().chatStream([{ role: 'user', content: 'q' }])) {
        tokens.push(token)
      }
    })()).rejects.toMatchObject({ code: ErrorCode.LLMProcessingFailed })
    expect(tokens).toEqual(['partial '])
  })

  it('rejects when the stream ends without message_stop', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: sseStream([messageStart, delta('cut off')]),
      error: null,
    })

    await expect(collect(getPremiumLLMService().chatStream([{ role: 'user', content: 'q' }])))
      .rejects.toMatchObject({ code: ErrorCode.LLMProcessingFailed })
  })

  it('rejects an empty completed reply instead of returning ""', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: sseStream([messageStart, messageStop]),
      error: null,
    })

    await expect(collect(getPremiumLLMService().chatStream([{ role: 'user', content: 'q' }])))
      .rejects.toMatchObject({ code: ErrorCode.LLMProcessingFailed })
  })

  it('does not resend a proxy 502 as a non-streaming request', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: null,
      error: { message: '502: {"error":"provider_request_failed"}' },
    })

    await expect(collect(getPremiumLLMService().chatStream([{ role: 'user', content: 'q' }])))
      .rejects.toMatchObject({ code: ErrorCode.LLMProcessingFailed })
    expect(cloud.invokeFunction).not.toHaveBeenCalled()
  })

  it('reports quota_exceeded from the stream call without a second request', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({
      stream: null,
      error: { message: '429: {"error":"quota_exceeded"}' },
    })
    const upgrade = vi.fn()
    const service = getPremiumLLMService()
    service.on('upgrade-required', upgrade)

    await expect(collect(service.chatStream([{ role: 'user', content: 'q' }]))).rejects.toBeTruthy()
    expect(upgrade).toHaveBeenCalledWith({ reason: 'quota_exceeded' })
    expect(cloud.invokeFunction).not.toHaveBeenCalled()
  })

  it('falls back to non-streaming only on transport failure, keeping system and max_tokens', async () => {
    cloud.invokeFunctionStream.mockResolvedValue({ stream: null, error: { message: 'fetch failed' } })
    cloud.invokeFunction.mockResolvedValue({
      data: {
        id: 'm', model: 'claude', role: 'assistant',
        content: [{ type: 'text', text: 'fallback answer' }],
        stop_reason: 'end_turn', usage: { input_tokens: 1, output_tokens: 1 },
      },
      error: null,
    })

    const { tokens, result } = await collect(getPremiumLLMService().chatStream(
      [{ role: 'system', content: 'persona' }, { role: 'user', content: 'q' }],
      { maxTokens: 512 },
    ))

    expect(tokens).toEqual(['fallback answer'])
    expect(result).toBe('fallback answer')
    const [name, body, options] = cloud.invokeFunction.mock.calls[0] as [string, Record<string, unknown>, { signal?: AbortSignal }]
    expect(name).toBe('llm-proxy')
    expect(body).toMatchObject({ system: 'persona', stream: false, max_tokens: 512 })
    expect(options?.signal).toBeInstanceOf(AbortSignal)
  })

  it('cancelGeneration cancels every active call, not only the latest one', async () => {
    cloud.invokeFunctionStream.mockImplementation(async (_n: string, _b: unknown, signal: AbortSignal) => ({
      stream: hangingStream(signal),
      error: null,
    }))
    const service = getPremiumLLMService()
    const first = service.chatStream([{ role: 'user', content: 'a' }])
    const second = service.chatStream([{ role: 'user', content: 'b' }])
    expect((await first.next()).value).toBe('partial ')
    expect((await second.next()).value).toBe('partial ')

    const firstRest = first.next()
    const secondRest = second.next()
    service.cancelGeneration()

    await expect(firstRest).rejects.toMatchObject({ code: ErrorCode.LLMProcessingCancelled })
    await expect(secondRest).rejects.toMatchObject({ code: ErrorCode.LLMProcessingCancelled })
  })

  it('honors a caller signal and a per-call timeout', async () => {
    cloud.invokeFunctionStream.mockImplementation(async (_n: string, _b: unknown, signal: AbortSignal) => ({
      stream: hangingStream(signal),
      error: null,
    }))
    const service = getPremiumLLMService()

    const external = new AbortController()
    const cancelled = service.chatStream([{ role: 'user', content: 'a' }], { signal: external.signal })
    await cancelled.next()
    const pending = cancelled.next()
    external.abort()
    await expect(pending).rejects.toMatchObject({ code: ErrorCode.LLMProcessingCancelled })

    const timed = service.chatStream([{ role: 'user', content: 'b' }], { timeoutMs: 20 })
    await timed.next()
    await expect(timed.next()).rejects.toMatchObject({ code: ErrorCode.LLMProcessingTimeout })
  })

  it('aborts the underlying request when the consumer stops early', async () => {
    const signals: AbortSignal[] = []
    cloud.invokeFunctionStream.mockImplementation(async (_n: string, _b: unknown, signal: AbortSignal) => {
      signals.push(signal)
      return { stream: hangingStream(signal), error: null }
    })

    for await (const token of getPremiumLLMService().chatStream([{ role: 'user', content: 'q' }])) {
      expect(token).toBe('partial ')
      break
    }
    expect(signals[0].aborted).toBe(true)
  })
})

describe('proxyHttpStatus', () => {
  it('detects proxy HTTP responses and ignores transport errors', () => {
    expect(proxyHttpStatus('502: {"error":"provider_request_failed"}')).toBe(502)
    expect(proxyHttpStatus('429: {"error":"quota_exceeded"}')).toBe(429)
    expect(proxyHttpStatus('fetch failed')).toBeNull()
    expect(proxyHttpStatus('No active session — 로그인 필요')).toBeNull()
  })
})