export const dynamic = 'force-dynamic'
export const runtime = 'nodejs'

import { NextResponse } from 'next/server'
import Anthropic from '@anthropic-ai/sdk'
import { ProxyAgent } from 'undici'

import { voiceBus } from '@/lib/voice-bus'
import { systemPrompt } from '@/lib/voice-prompts'
import { TOOL_SCHEMAS } from '@/lib/voice-tool-schemas'
import { executeTool } from '@/lib/voice-executors'
import { cleanForSpeech, stripFillers, isResetCommand } from '@/lib/voice-text'
import {
  loadHistory, saveHistory, resetHistory,
  buildMessagesWithCache, stripCacheControl, HistoryMessage,
} from '@/lib/voice-history'

const MODEL = process.env.ANTHROPIC_MODEL || 'claude-haiku-4-5'
const MAX_TOKENS = parseInt(process.env.VOICE_MAX_TOKENS || '300', 10)
const MAX_TOOL_ROUNDS = 4
const RATE_LIMIT_PER_MINUTE = parseInt(process.env.VOICE_RATE_LIMIT || '20', 10)

// In-memory rate-limit per IP / cookie (host один — Docker контейнер).
// Защита от случайного бесконечного цикла или утечки PIN: даже если
// auth_token утечёт, вызов /api/voice/chat будет ограничен.
const rateBuckets = new Map<string, { count: number; resetAt: number }>()
function rateLimit(key: string): boolean {
  const now = Date.now()
  const b = rateBuckets.get(key)
  if (!b || b.resetAt <= now) {
    rateBuckets.set(key, { count: 1, resetAt: now + 60_000 })
    return true
  }
  if (b.count >= RATE_LIMIT_PER_MINUTE) return false
  b.count++
  return true
}
// Гигиена: чистим старые бакеты периодически (раз в 5 минут максимум).
let lastSweep = 0
function sweep() {
  const now = Date.now()
  if (now - lastSweep < 5 * 60_000) return
  lastSweep = now
  for (const [k, v] of rateBuckets) if (v.resetAt <= now) rateBuckets.delete(k)
}

let _client: Anthropic | null = null
function client(): Anthropic {
  if (_client) return _client
  const apiKey = process.env.ANTHROPIC_API_KEY
  if (!apiKey) throw new Error('ANTHROPIC_API_KEY not set')
  const proxy = process.env.ANTHROPIC_PROXY || process.env.HTTPS_PROXY || ''
  const fetchOptions = proxy
    ? ({ dispatcher: new ProxyAgent(proxy) } as any)
    : undefined
  _client = new Anthropic({ apiKey, fetchOptions })
  return _client
}

function emitVoice(event: string, agent: 'cosmo' | 'lusya', text?: string) {
  voiceBus.emit('voice', {
    event,
    agent,
    text,
    timestamp: new Date().toISOString(),
  })
}

type AgentId = 'cosmo' | 'lusya'

export async function POST(req: Request) {
  // Rate-limit по auth_token (или x-voice-internal — для loopback'а от tools).
  // Идентифицируем клиента: cookie auth_token > x-voice-internal > IP > 'anon'.
  const cookie = req.headers.get('cookie') || ''
  const tokenMatch = cookie.match(/auth_token=([a-f0-9]{32,})/i)
  const internal = req.headers.get('x-voice-internal') || ''
  const fwd = req.headers.get('x-forwarded-for') || ''
  const ratekey = tokenMatch?.[1] || (internal ? 'internal' : '') || fwd.split(',')[0].trim() || 'anon'
  sweep()
  if (!rateLimit(ratekey)) {
    return NextResponse.json({ error: 'rate_limited' }, { status: 429 })
  }

  const body = await req.json().catch(() => null)
  if (!body || typeof body.text !== 'string' || !body.text.trim()) {
    return NextResponse.json({ error: 'text required' }, { status: 400 })
  }
  const userText: string = body.text.trim().slice(0, 4000)  // защита от gigantic prompts
  const agent: AgentId = body.agent === 'lusya' ? 'lusya' : 'cosmo'

  // Echo command в орб
  emitVoice('command', agent, userText)

  // Reset-команда — стираем историю и отвечаем шаблонно
  if (isResetCommand(userText)) {
    await resetHistory(agent)
    const msg = 'Начинаю новую сессию.'
    emitVoice('response', agent, msg)
    return NextResponse.json({ text: msg, reset: true })
  }

  // Загружаем историю и добавляем новый user-turn
  const history = await loadHistory(agent)
  history.push({ role: 'user', content: userText })

  const systemBlocks: Anthropic.TextBlockParam[] = [
    {
      type: 'text',
      text: systemPrompt(agent),
      cache_control: { type: 'ephemeral' },
    },
  ]

  const apiMessages: Anthropic.MessageParam[] = buildMessagesWithCache(history) as any

  let finalText = ''
  const initialUserIdx = history.length - 1
  // Защита от tool-cycling: запоминаем последний (name, args) — если LLM
  // дважды подряд просит одно и то же, прерываем цикл.
  let lastToolSig = ''

  try {
    const c = client()
    for (let round = 0; round < MAX_TOOL_ROUNDS; round++) {
      const t0 = Date.now()
      const resp = await c.messages.create({
        model: MODEL,
        max_tokens: MAX_TOKENS,
        system: systemBlocks,
        messages: apiMessages,
        tools: TOOL_SCHEMAS,
      })

      const usage = resp.usage as any
      console.log(
        `[voice/chat] ${agent} round ${round + 1} ${Date.now() - t0}ms · ` +
        `stop=${resp.stop_reason} · in=${usage?.input_tokens} out=${usage?.output_tokens} ` +
        `cache_r=${usage?.cache_read_input_tokens || 0} cache_w=${usage?.cache_creation_input_tokens || 0}`
      )

      // Разбираем content на text + tool_use
      const toolUses: Anthropic.ToolUseBlock[] = []
      for (const block of resp.content) {
        if (block.type === 'text') finalText += block.text
        else if (block.type === 'tool_use') toolUses.push(block)
      }

      // Сохраняем assistant turn в API messages как есть (важно для tool_use_id)
      apiMessages.push({ role: 'assistant', content: resp.content as any })

      if (resp.stop_reason === 'tool_use' && toolUses.length) {
        // Сигнатура текущего раунда — для loop-guard.
        const sig = toolUses
          .map((t) => `${t.name}:${JSON.stringify(t.input)}`)
          .sort()
          .join('|')
        if (sig === lastToolSig) {
          console.warn('[voice/chat] tool cycle detected, breaking loop')
          finalText += '\nНе получилось выполнить запрос.'
          break
        }
        lastToolSig = sig

        const toolResults: Anthropic.ToolResultBlockParam[] = []
        for (const tu of toolUses) {
          console.log(`[voice/chat] tool ${tu.name}(${JSON.stringify(tu.input).slice(0, 200)})`)
          const result = await executeTool(tu.name, tu.input, agent)
          toolResults.push({
            type: 'tool_result',
            tool_use_id: tu.id,
            content: JSON.stringify(result),
          })
        }
        apiMessages.push({ role: 'user', content: toolResults })
        continue
      }

      // end_turn / max_tokens / stop_sequence — финальный ответ готов
      break
    }
  } catch (e: any) {
    console.error('[voice/chat] anthropic error:', e?.message || e)
    const msg = 'Что-то сломалось.'
    emitVoice('error', agent, msg)
    return NextResponse.json({ error: 'llm_failed', detail: String(e?.message || e), text: msg }, { status: 502 })
  }

  if (!finalText.trim()) {
    const msg = 'Не получил ответ.'
    emitVoice('error', agent, msg)
    return NextResponse.json({ text: msg }, { status: 200 })
  }

  // Сохраняем все turn'ы после initial user (включая tool_use / tool_result)
  const newTurns = apiMessages.slice(initialUserIdx + 1)
  for (const turn of newTurns) {
    history.push({
      role: turn.role as 'user' | 'assistant',
      content: stripCacheControl(turn.content),
    } as HistoryMessage)
  }
  await saveHistory(agent, history)

  const cleaned = cleanForSpeech(stripFillers(finalText))
  emitVoice('response', agent, cleaned)
  return NextResponse.json({ text: cleaned })
}