import { NextResponse } from 'next/server'
import { loadBenchmarks } from '@/lib/benchmarks'
import { buildSystemPrompt, formatMetricsMessage } from '@/lib/prompts'
import { chat } from '@/lib/llm'
import { InterpretationReportSchema, MetricsInputSchema, TeamContextSchema } from '@/lib/schema'

export async function POST(req: Request) {
  try {
    const body = await req.json()

    const metricsResult = MetricsInputSchema.safeParse(body.metrics)
    const contextResult = TeamContextSchema.safeParse(body.context)

    if (!metricsResult.success || !contextResult.success) {
      return NextResponse.json(
        {
          error: 'Invalid input',
          details: {
            metrics: metricsResult.error?.issues,
            context: contextResult.error?.issues,
          },
        },
        { status: 400 }
      )
    }

    const benchmarks = await loadBenchmarks()

    const response = await chat({
      system: buildSystemPrompt(benchmarks),
      user: formatMetricsMessage(metricsResult.data, contextResult.data),
      jsonMode: true,
    })

    const content = response.choices[0]?.message?.content
    if (!content) {
      return NextResponse.json({ error: 'No response from LLM' }, { status: 502 })
    }

    // Extract JSON if wrapped in markdown fences
    const jsonMatch = content.match(/\{[\s\S]*\}/)
    const raw = jsonMatch ? JSON.parse(jsonMatch[0]) : JSON.parse(content)

    const reportResult = InterpretationReportSchema.safeParse(raw)
    if (!reportResult.success) {
      return NextResponse.json(
        { error: 'LLM returned invalid report structure', details: reportResult.error.issues },
        { status: 422 }
      )
    }

    return NextResponse.json(reportResult.data)
  } catch (err) {
    console.error('interpret error:', err)
    return NextResponse.json({ error: 'Internal server error' }, { status: 500 })
  }
}