// src/gemini.js
import { GoogleGenAI } from '@google/genai'

const apiKey = import.meta.env.VITE_GEMINI_API_KEY
export const modelName = import.meta.env.VITE_GEMINI_MODEL || 'gemini-2.0-flash-001'

export const ai = new GoogleGenAI({ apiKey })

export async function generate(text) {
  const res = await ai.models.generateContent({
    model: modelName,
    contents: text,
  })
  return res.text
}

// src/gemini.js (continued)
export async function* stream(text, opts = {}) {
  const { signal } = opts
  const stream = await ai.models.generateContentStream({
    model: modelName,
    contents: text,
    // Optional: config: { temperature: 0.6, maxOutputTokens: 1024 }
    // Optional: safety settings / tool calling here
  })
  for await (const chunk of stream) {
    if (signal?.aborted) break
    yield chunk.text
  }
}

// src/main.js
import { stream } from './gemini.js'
import { el, appendMessage, setTyping, stopTyping } from './ui.js'

const form = document.getElementById('composer')
const input = document.getElementById('prompt')
const messages = document.getElementById('messages')
let controller = null

form.addEventListener('submit', async (e) => {
  e.preventDefault()
  const text = input.value.trim()
  if (!text) return

  // Cancel previous stream if any
  controller?.abort()
  controller = new AbortController()

  appendMessage(messages, { role: 'user', text })
  input.value = ''

  const node = appendMessage(messages, { role: 'model', text: '' })
  setTyping(node)

  try {
    for await (const token of stream(text, { signal: controller.signal })) {
      node.textContent += token
      node.scrollIntoView({ behavior: 'instant', block: 'end' })
    }
  } finally {
    stopTyping(node)
  }
})

// src/ui.js
export function el(tag, className, text) {
  const n = document.createElement(tag)
  if (className) n.className = className
  if (text) n.textContent = text
  return n
}

export function appendMessage(container, { role, text }) {
  const bubble = el('div', `bubble ${role}`)
  const content = el('div', 'content', text)
  bubble.appendChild(content)
  container.appendChild(bubble)
  return content
}

export function setTyping(node) { node.classList.add('typing') }
export function stopTyping(node) { node.classList.remove('typing') }

// server/index.js
import express from 'express'
import cors from 'cors'
import { GoogleGenAI } from '@google/genai'

const app = express()
app.use(cors())
app.use(express.json())

const ai = new GoogleGenAI({ apiKey: process.env.GEMINI_API_KEY })
const model = process.env.GEMINI_MODEL || 'gemini-2.0-flash-001'

app.post('/api/chat', async (req, res) => {
  const { prompt } = req.body
  res.setHeader('Content-Type', 'text/event-stream')
  res.setHeader('Cache-Control', 'no-cache')
  res.setHeader('Connection', 'keep-alive')

  try {
    const stream = await ai.models.generateContentStream({ model, contents: prompt })
    for await (const chunk of stream) {
      res.write(`data: ${JSON.stringify({ token: chunk.text })}\n\n`)
    }
    res.end()
  } catch (e) {
    res.write(`event: error\n`)
    res.write(`data: ${JSON.stringify({ message: e.message })}\n\n`)
    res.end()
  }
})

app.listen(8787, () => console.log('API on :8787'))