import { NextRequest } from 'next/server'

const LLM_API_URL = process.env.NODE_ENV === 'production'
  ? 'http://api-gateway.api.svc.cluster.local:8080/v1/chat/completions'
  : 'https://api.riotpiao.com/v1/chat/completions'
const MODEL = 'reasoning'

const SYSTEM_PROMPT = `Poimen. Rock Liang's AI assistant. Answer about technical background, projects, expertise. Specific facts + metrics.

## Background
6+ years Senior Software Engineer. Infrastructure + Backend + LLM Systems. Homelab K8s + vLLM optimization.

## Skills
Infra: Talos Linux K8s (4-node), Terraform GitOps, Cilium eBPF CNI, Longhorn 3-replica, MinIO, PostgreSQL
Backend: Go, Java, Python, C++. gRPC. Kafka KRaft. Data systems.
LLM: vLLM 60% latency cut. Model serving. Inference optimization.
DevOps: ArgoCD. cert-manager. SOPS encryption. AWS CDK/CloudFormation. CloudWatch.

## Achievements
AWS: Distributed-Map 57+ regions, <100ms P99. CDK infrastructure. CF stack mgmt. CloudWatch observability.
RBC: Terraform deploy 2hr→20min. 99.2% automation.
Homelab: 99.2% uptime. Production-grade HA.

## Operations (Deep)
Certs: cert-manager + Let's Encrypt. 30d renewal, no downtime. SOPS encrypted secrets. Git audit trail. Prometheus alerts 7d/1d pre-expiry. CertificateTask CRD tracks history.

Queues: SQS FIFO + DLQ. Exactly-once via idempotency keys + PostgreSQL. QueueTask CRD. Multi-region failover (SQS-A→B, ordered). Controller detects stalled tasks, exponential backoff. Inference batching by model/token/SLO. Workers scale 1-100.

K8s: CRDs + operators. Reconciliation (leader-election, backoff, finalizers). Go controllers (watch/queue/reconcile). API server internals (etcd, versioning, watch). Pod disruption budgets, PreStop hooks. Talos immutable, atomic updates, no SSH, GitOps state. Cilium eBPF policies.

Open source: go-flink (distributed DataLakeHouse).

## Response Style
Caveman ultra. Drop articles/filler. Fragments OK. Short terms. No prose. Facts + metrics. E.g., "Terraform 3-4yr. RBC: 2h→20m, 99.2% auto" not "Several years of experience with approximately..."

Pre-screen context: Technical depth for platform engineer role. Cert rotation, queue semantics, failure modes, scale. Demonstrate production-grade systems.`

export async function POST(request: NextRequest) {
  const token = process.env.LLM_API_TOKEN

  if (!token) {
    return new Response(
      JSON.stringify({ error: 'LLM_API_TOKEN not configured' }),
      { status: 500, headers: { 'Content-Type': 'application/json' } }
    )
  }

  try {
    const { message } = await request.json()

    const response = await fetch(LLM_API_URL, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        model: MODEL,
        messages: [
          { role: 'system', content: SYSTEM_PROMPT },
          { role: 'user', content: message },
        ],
        stream: true,
      }),
    })

    if (!response.ok) {
      const error = await response.text()
      throw new Error(`LLM API error: ${response.status} - ${error}`)
    }

    // Transform the SSE stream
    const encoder = new TextEncoder()
    const decoder = new TextDecoder()

    const stream = new ReadableStream({
      async start(controller) {
        const reader = response.body?.getReader()
        if (!reader) {
          controller.close()
          return
        }

        let reasoning = ''
        let content = ''

        try {
          // eslint-disable-next-line no-constant-condition
          while (true) {
            const { done, value } = await reader.read()
            if (done) break

            const chunk = decoder.decode(value, { stream: true })
            const lines = chunk.split('\n')

            for (const line of lines) {
              if (!line.startsWith('data: ')) continue
              const data = line.slice(6)
              if (data === '[DONE]') continue

              try {
                const json = JSON.parse(data)
                const delta = json.choices?.[0]?.delta

                if (delta?.reasoning_content) {
                  reasoning += delta.reasoning_content
                  controller.enqueue(
                    encoder.encode(`data: ${JSON.stringify({ type: 'reasoning', text: reasoning })}\n\n`)
                  )
                }

                if (delta?.content) {
                  content += delta.content
                  controller.enqueue(
                    encoder.encode(`data: ${JSON.stringify({ type: 'content', text: content })}\n\n`)
                  )
                }

                if (json.choices?.[0]?.finish_reason === 'stop') {
                  controller.enqueue(
                    encoder.encode(`data: ${JSON.stringify({ type: 'done' })}\n\n`)
                  )
                }
              } catch {
                // Skip invalid JSON
              }
            }
          }
        } finally {
          reader.releaseLock()
          controller.close()
        }
      },
    })

    return new Response(stream, {
      headers: {
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Connection': 'keep-alive',
      },
    })
  } catch (error) {
    console.error('Chat API error:', error)
    return new Response(
      JSON.stringify({ error: 'Failed to process chat request' }),
      { status: 500, headers: { 'Content-Type': 'application/json' } }
    )
  }
}
// LLM_API_TOKEN now in deployment