/**
 * RAG API Proxy - Catch-all route
 * Proxies all /api/sdk/v1/rag/* requests to ai-compliance-sdk backend (Port 8090)
 */

import { NextRequest, NextResponse } from 'next/server'

const SDK_BACKEND_URL = process.env.SDK_API_URL || 'http://ai-compliance-sdk:8090'

async function proxyRequest(
  request: NextRequest,
  pathSegments: string[] | undefined,
  method: string
) {
  const pathStr = pathSegments?.join('/') || ''
  const searchParams = request.nextUrl.searchParams.toString()
  const basePath = `${SDK_BACKEND_URL}/sdk/v1/rag`
  const url = pathStr
    ? `${basePath}/${pathStr}${searchParams ? `?${searchParams}` : ''}`
    : `${basePath}${searchParams ? `?${searchParams}` : ''}`

  try {
    const headers: HeadersInit = {
      'Content-Type': 'application/json',
    }

    const authHeader = request.headers.get('authorization')
    if (authHeader) {
      headers['Authorization'] = authHeader
    }

    const uuidRegex = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i
    const userHeader = request.headers.get('x-user-id')
    headers['X-User-ID'] = (userHeader && uuidRegex.test(userHeader)) ? userHeader : '00000000-0000-0000-0000-000000000001'

    const tenantHeader = request.headers.get('x-tenant-id')
    headers['X-Tenant-ID'] = (tenantHeader && uuidRegex.test(tenantHeader)) ? tenantHeader : (process.env.DEFAULT_TENANT_ID || '9282a473-5c95-4b3a-bf78-0ecc0ec71d3e')

    const fetchOptions: RequestInit = {
      method,
      headers,
      signal: AbortSignal.timeout(30000),
    }

    if (['POST', 'PUT', 'PATCH'].includes(method)) {
      const contentType = request.headers.get('content-type')
      if (contentType?.includes('application/json')) {
        try {
          const text = await request.text()
          if (text && text.trim()) {
            fetchOptions.body = text
          }
        } catch {
          // Empty or invalid body - continue without
        }
      }
    }

    const response = await fetch(url, fetchOptions)

    if (!response.ok) {
      const errorText = await response.text()
      let errorJson
      try {
        errorJson = JSON.parse(errorText)
      } catch {
        errorJson = { error: errorText }
      }
      return NextResponse.json(
        { error: `Backend Error: ${response.status}`, ...errorJson },
        { status: response.status }
      )
    }

    const data = await response.json()
    return NextResponse.json(data)
  } catch (error) {
    console.error('RAG API proxy error:', error)
    return NextResponse.json(
      { error: 'Verbindung zum RAG Backend fehlgeschlagen' },
      { status: 503 }
    )
  }
}

export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ path?: string[] }> }
) {
  const { path } = await params
  return proxyRequest(request, path, 'GET')
}

export async function POST(
  request: NextRequest,
  { params }: { params: Promise<{ path?: string[] }> }
) {
  const { path } = await params
  return proxyRequest(request, path, 'POST')
}