import express from 'express'
import cors from 'cors'
import fetch from 'node-fetch'

const app = express()

// Считываем ключ Helix из переменных окружения
const HELIX_API_KEY = process.env.HELIX_API_KEY || ''

// CORS
app.use(cors({
  origin: '*',
  methods: ['GET', 'POST', 'OPTIONS'],
  allowedHeaders: ['Content-Type', 'Authorization']
}))
app.use(express.json())
app.options('*', (req, res) => res.sendStatus(204))

// Список доступных моделей
app.get(['/models', '/v1/models'], (req, res) => {
  res.json({
    object: 'list',
    data: [
      // OpenAI — GPT‑4.1 / 4.5
      { id: 'gpt-4.1',                    object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.1-2025-04-14',         object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.1-mini',               object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.1-mini-2025-04-14',    object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.1-nano',               object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.1-nano-2025-04-14',    object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.5-preview',            object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4.5-preview-2025-02-27', object: 'model', created: 0, owned_by: 'helix' },

      // OpenAI — GPT‑4o
      { id: 'gpt-4o',                           object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-2024-05-13',                object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-2024-08-06',                object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-2024-11-20',                object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-mini',                      object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-mini-2024-07-18',           object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-search-preview',            object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-search-preview-2025-03-11', object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-mini-search-preview',       object: 'model', created: 0, owned_by: 'helix' },
      { id: 'gpt-4o-mini-search-preview-2025-03-11', object: 'model', created: 0, owned_by: 'helix' },

      // Helix — GPT‑3.5 Turbo
      { id: 'gpt-3.5-turbo', object: 'model', created: 0, owned_by: 'helix' }
    ]
  })
})

// Прокси для /chat/completions
app.post(['/chat/completions', '/v1/chat/completions'], async (req, res) => {
  const {
    model,
    messages = [],
    stream = false,
    temperature,
    top_p,
    presence_penalty,
    frequency_penalty,
    ...rest
  } = req.body

  // Собираем историю, заменяя китайские префиксы на English
  const historyText = messages
    .map(m => (m.role === 'user' ? 'User: ' : 'Assistant: ') + m.content)
    .join('\n')

  // Формируем полезную нагрузку для Helix
  const helixPayload = {
    type: 'text',
    stream,
    provider: getProvider(model),
    model,
    messages: [
      {
        role: 'user',
        content: { content_type: 'text', parts: [historyText] }
      }
    ],
    temperature,
    top_p,
    presence_penalty,
    frequency_penalty,
    ...rest
  }

  // Заголовок авторизации для Helix
  const authHeader = HELIX_API_KEY
    ? `Bearer ${HELIX_API_KEY}`
    : (req.header('authorization') || '')

  // Отправляем запрос в Helix
  const helixRes = await fetch(
    'https://app.tryhelix.ai/api/v1/sessions/chat',
    {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: authHeader
      },
      body: JSON.stringify(helixPayload)
    }
  )

  if (!stream) {
    const data = await helixRes.json()
    const reply = data?.choices?.[0]?.message?.content ?? ''
    return res.status(helixRes.status).json({
      id: `chatcmpl-proxy-${data.id ?? Date.now()}`,
      object: 'chat.completion',
      created: Math.floor(Date.now() / 1000),
      model,
      choices: [
        {
          index: 0,
          message: { role: 'assistant', content: reply },
          finish_reason: 'stop'
        }
      ]
    })
  }

  // При стриме прокидываем SSE напрямую
  res.status(helixRes.status)
  res.set('Content-Type', 'text/event-stream')
  helixRes.body.pipe(res)
})

// Определяем провайдера по имени модели
function getProvider(modelId) {
  if (/^gpt-[34]|^gpt-3\.5/.test(modelId)) return 'openai'
  if (/^(llama|phi|aya|gemma|deepseek|qwen)/.test(modelId)) return 'helix'
  return 'togetherai'
}

const PORT = process.env.PORT || 7860
app.listen(PORT, () => {
  console.log(`🚀 Server listening on port ${PORT}`)
})