server.js

import 'dotenv/config'
import http from 'http'
import fs from 'fs'
import path from 'path'
import { fileURLToPath } from 'url'

const __dirname = path.dirname(fileURLToPath(import.meta.url))
const PORT         = process.env.PORT         || 7860
const WEBHOOK_URL  = process.env.WEBHOOK_URL  || `http://localhost:${PORT}`
const FROM_NUMBER  = process.env.FROM_NUMBER  || ''
const USER_API_KEY = process.env.USER_API_KEY || ''
const FLOW_API_KEY = process.env.FLOW_API_KEY || ''

// Session-aware SSE subscribers: Map<sessionId, Set<writer>>
const sessions = new Map()

function getSession(id) {
  if (!sessions.has(id)) sessions.set(id, new Set())
  return sessions.get(id)
}

function removeWriter(id, writer) {
  const s = sessions.get(id)
  if (!s) return
  s.delete(writer)
  if (s.size === 0) sessions.delete(id)
}

// Load call agent assets once at startup
const CALL_BASE = process.env.CALL_BASE || path.resolve(__dirname, 'assets')
let workflowTemplate, universityPrompt, realestatePrompt, coachingPrompt, medicalPrompt, hotelPrompt

try {
  workflowTemplate  = JSON.parse(fs.readFileSync(`${CALL_BASE}/jsons/restraunts/workflow.json`, 'utf8'))
  universityPrompt  = fs.readFileSync(`${CALL_BASE}/prompts/college/nims_admission_eng.md`, 'utf8')
  realestatePrompt  = fs.readFileSync(`${CALL_BASE}/prompts/realestate/apartment_sale_eng.md`, 'utf8')
  coachingPrompt    = fs.readFileSync(`${CALL_BASE}/prompts/coaching/coaching_admission_eng.md`, 'utf8')
  medicalPrompt     = fs.readFileSync(`${CALL_BASE}/prompts/medical/opd_reception_eng.md`, 'utf8')
  hotelPrompt       = fs.readFileSync(`${CALL_BASE}/prompts/hotel/concierge_prearrival_eng.md`, 'utf8')
  console.log('call agent assets loaded')
} catch (e) {
  console.warn('could not load call agent assets:', e.message)
}

// Each agent's prompt + greeting use a {{BRAND}} placeholder. The caller can
// override the brand from the UI; otherwise defaultBrand is substituted in.
const CALL_CONFIG = {
  university: {
    prompt:       universityPrompt,
    defaultBrand: 'NIMS University',
    greeting:     'Hello! Thank you for calling {{BRAND}}, this is Sneha from the admissions team. May I know your name, and which course you are interested in?',
  },
  realestate: {
    prompt:       realestatePrompt,
    defaultBrand: 'Skyline Greens',
    greeting:     'Hello! Main Riya bol rahi hoon {{BRAND}} ki taraf se — aapne recently ek flat ke liye inquiry ki thi. Kya abhi thodi baat ho sakti hai?',
  },
  coaching: {
    prompt:       coachingPrompt,
    defaultBrand: 'Bansal Classes',
    greeting:     'Namaste! Main Aarohi baat kar rahi hoon {{BRAND}} se — aapne abhi coaching ke liye enquiry ki thi na? Kya do minute baat ho sakti hai?',
  },
  medical: {
    prompt:       medicalPrompt,
    defaultBrand: 'Sanjeevani Hospital',
    greeting:     'Namaste, {{BRAND}} me aapka swagat hai, main Meera baat kar rahi hoon. Aapki kya help kar sakti hoon?',
  },
  hotel: {
    prompt:       hotelPrompt,
    defaultBrand: 'The Grand Rambagh',
    greeting:     'Namaste! Main Kabir baat kar raha hoon {{BRAND}} se — aapki booking confirm hai, bas aapka welcome ready karne ke liye call kiya. Do minute baat ho sakti hai?',
  },
}

// Static frontend assets
const distPath = path.resolve(__dirname, 'dist')
let indexHtml = null
try { indexHtml = fs.readFileSync(path.join(distPath, 'index.html'), 'utf8') } catch {}

const MIME = {
  '.html': 'text/html',
  '.js':   'application/javascript',
  '.mjs':  'application/javascript',
  '.css':  'text/css',
  '.svg':  'image/svg+xml',
  '.png':  'image/png',
  '.ico':  'image/x-icon',
  '.json': 'application/json',
  '.woff': 'font/woff',
  '.woff2': 'font/woff2',
}

const server = http.createServer(async (req, res) => {
  res.setHeader('Access-Control-Allow-Origin', '*')
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS')
  res.setHeader('Access-Control-Allow-Headers', '*')

  if (req.method === 'OPTIONS') {
    res.writeHead(204)
    res.end()
    return
  }

  // Webhook receiver — VX backend POSTs here with session_id in payload
  if (req.method === 'POST' && req.url === '/') {
    let body = ''
    for await (const chunk of req) body += chunk
    try {
      const data      = JSON.parse(body)
      const sessionId = data.session_id ?? data.responses?.find(r => r.session_id)?.session_id
      const clients   = sessionId ? sessions.get(sessionId) : null
      console.log(`[webhook] resolved session=${sessionId} subscribers=${clients?.size ?? 0}`)
      console.log('[webhook] payload keys:', Object.keys(data), '| responses count:', data.responses?.length ?? 'none')
      if (data.responses?.length) {
        console.log('[webhook] response nodes:', data.responses.map(r => `node=${r.node} streaming=${r.streaming} hasChunk=${!!r.chunk} hasOut=${!!r.out}`).join(' | '))
      }
      if (clients?.size) {
        for (const write of clients) write(data)
      }
    } catch (e) {
      console.error('[webhook] parse error:', e.message)
      console.error('[webhook] raw body snippet:', body.slice(0, 300))
    }
    res.writeHead(200, { 'Content-Type': 'application/json' })
    res.end(JSON.stringify({ ok: true }))
    return
  }

  // SSE stream — browser subscribes by session
  if (req.method === 'GET' && req.url.startsWith('/events')) {
    const url = new URL(req.url, 'http://localhost')
    const sid = url.searchParams.get('session')
    if (!sid) { res.writeHead(400); res.end('missing session param'); return }

    res.writeHead(200, {
      'Content-Type':     'text/event-stream',
      'Cache-Control':    'no-cache',
      'X-Accel-Buffering':'no',
      'Connection':       'keep-alive',
    })
    res.write(': connected\n\n')

    const write     = data => res.write(`data: ${JSON.stringify(data)}\n\n`)
    const heartbeat = setInterval(() => res.write(': heartbeat\n\n'), 25000)

    getSession(sid).add(write)
    console.log(`[sse] client connected session=${sid} total=${sessions.get(sid)?.size}`)
    req.on('close', () => {
      removeWriter(sid, write)
      clearInterval(heartbeat)
      console.log(`[sse] client disconnected session=${sid}`)
    })
    return
  }

  // Outbound call proxy — frontend POSTs here to initiate a call agent session
  if (req.method === 'POST' && req.url === '/call') {
    let body = ''
    for await (const chunk of req) body += chunk
    try {
      const { type, phone, session_id, voiceSettings, brand } = JSON.parse(body)
      const cfg = CALL_CONFIG[type]
      if (!cfg || !cfg.prompt) {
        res.writeHead(400, { 'Content-Type': 'application/json' })
        res.end(JSON.stringify({ error: `unknown call type: ${type}` }))
        return
      }

      // Substitute the {{BRAND}} placeholder with the caller-supplied brand,
      // falling back to this agent's default.
      const brandName    = (typeof brand === 'string' && brand.trim()) ? brand.trim() : cfg.defaultBrand
      const systemPrompt = cfg.prompt.split('{{BRAND}}').join(brandName)
      const greetingText = cfg.greeting.split('{{BRAND}}').join(brandName)

      // Deep-clone the workflow template and inject agent-specific fields
      const customs = JSON.parse(JSON.stringify(workflowTemplate))
      customs.agent_id.workflow.nodes.llm.parameters.system_prompt         = systemPrompt
      customs.agent_id.workflow.nodes.greeting.parameters.out_dict.speak   = greetingText
      customs.agent_id['webhook-url']                                       = WEBHOOK_URL

      // Default STT / pre-fire / inactivity for all outbound calls
      customs['stt_id']          = { service: 'soniox', language: ['hi', 'en'] }
      customs['pre-fire']        = true
      customs['pre-fire-config'] = { min: 10, max: 5000, current: 40 }
      customs['inactivity']      = true
      customs['inactivity-metadata'] = {
        'time-period':        1000,
        'max-times':          3,
        'inactivity-type':    'static',
        message:              "Are you still there? No rush — take your time and answer whenever you're ready.",
        'interruption-type':  'full',
        'interruption-metadata': {},
      }

      if (voiceSettings) {
        if (voiceSettings.tts_id)              customs.tts_id               = voiceSettings.tts_id
        if (voiceSettings.stt_id)              customs.stt_id               = voiceSettings.stt_id
        if (voiceSettings['grain-voice'] != null) customs['grain-voice']    = voiceSettings['grain-voice']
        if (voiceSettings['grain-level'] != null) customs['grain-level']    = voiceSettings['grain-level']
        if (voiceSettings['pre-fire']    != null) customs['pre-fire']       = voiceSettings['pre-fire']
        if (voiceSettings['pre-fire-config'])   customs['pre-fire-config']  = voiceSettings['pre-fire-config']
        if (voiceSettings.inactivity     != null) customs.inactivity        = voiceSettings.inactivity
        if (voiceSettings['inactivity-metadata']) customs['inactivity-metadata'] = voiceSettings['inactivity-metadata']
      }

      const payload = {
        'from-number': FROM_NUMBER,
        'to-number':   phone,
        session_id,
        customs,
      }

      const upstream = await fetch('https://call.voxio.in/plivo/outbound', {
        method:  'POST',
        headers: {
          'Content-Type': 'application/json',
          user_api_key:   USER_API_KEY,
          flow_api_key:   FLOW_API_KEY,
        },
        body: JSON.stringify(payload),
      })

      const result = await upstream.json()
      res.writeHead(upstream.status, { 'Content-Type': 'application/json' })
      res.end(JSON.stringify(result))
    } catch (e) {
      res.writeHead(500, { 'Content-Type': 'application/json' })
      res.end(JSON.stringify({ error: e.message }))
    }
    return
  }

  // Static files + SPA fallback
  if (req.method === 'GET') {
    const urlPath  = req.url.split('?')[0]
    const filePath = path.join(distPath, urlPath)
    try {
      const stat = fs.statSync(filePath)
      if (stat.isFile()) {
        const ext  = path.extname(filePath).toLowerCase()
        const mime = MIME[ext] || 'application/octet-stream'
        res.writeHead(200, { 'Content-Type': mime })
        fs.createReadStream(filePath).pipe(res)
        return
      }
    } catch {}
    if (indexHtml) {
      res.writeHead(200, { 'Content-Type': 'text/html' })
      res.end(indexHtml)
      return
    }
  }

  res.writeHead(404)
  res.end()
})

server.listen(PORT, '0.0.0.0', () =>
  console.log(`webhook+sse server on :${PORT}`)
)