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

async function requireAdmin() {
  const session = await auth()
  if (!session?.user?.id || (session.user as any).role !== 'ADMIN') return null
  return session
}

/**
 * GET /api/admin/models?type=ollama&url=<base_url>
 * GET /api/admin/models?type=custom&url=<base_url>&key=<api_key>&kind=tags|embeddings
 * GET /api/admin/models?type=deepseek&key=<api_key>&kind=tags|embeddings
 * GET /api/admin/models?type=openrouter&key=<api_key>&kind=tags|embeddings
 * GET /api/admin/models?type=mistral&key=<api_key>&kind=tags|embeddings
 * GET /api/admin/models?type=zai&key=<api_key>&kind=tags|embeddings
 * GET /api/admin/models?type=lmstudio&url=<base_url>
 *
 * Route API for fetching AI model lists from providers.
 */
export async function GET(request: NextRequest) {
  if (!(await requireAdmin())) {
    return NextResponse.json({ success: false, error: 'Unauthorized' }, { status: 401 })
  }

  const { searchParams } = request.nextUrl
  const type = searchParams.get('type')
  const rawUrl = searchParams.get('url') ?? ''
  const apiKey = searchParams.get('key') ?? undefined
  const kind = searchParams.get('kind') ?? 'tags'

  // Provider-specific base URLs (used when url param is empty)
  const PROVIDER_URLS: Record<string, string> = {
    deepseek: 'https://api.deepseek.com/v1',
    openrouter: 'https://openrouter.ai/api/v1',
    mistral: 'https://api.mistral.ai/v1',
    zai: 'https://api.zukijourney.com/v1',
    lmstudio: 'http://localhost:1234/v1',
  }

  try {
    // Ollama: uses native /api/tags endpoint
    if (type === 'ollama') {
      if (!rawUrl) {
        return NextResponse.json({ success: false, models: [], error: 'url parameter is required for Ollama' })
      }
      const baseUrl = rawUrl.replace(/\/$/, '').replace(/\/api$/, '')
      const res = await fetch(`${baseUrl}/api/tags`, {
        headers: { 'Content-Type': 'application/json' },
        signal: AbortSignal.timeout(5000),
      })
      if (!res.ok) {
        return NextResponse.json({ success: false, models: [], error: `Ollama ${res.status}` })
      }
      const data = await res.json()
      const models: string[] = (data.models ?? []).map((m: { name: string }) => m.name)
      return NextResponse.json({ success: true, models })
    }

    // All other providers: use OpenAI-compatible /v1/models endpoint
    const baseUrl = rawUrl
      ? rawUrl.replace(/\/$/, '')
      : (PROVIDER_URLS[type || ''] || '')

    if (!baseUrl) {
      return NextResponse.json({ success: false, models: [], error: 'url parameter is required' })
    }

    const headers: Record<string, string> = { 'Content-Type': 'application/json' }
    if (apiKey) headers['Authorization'] = `Bearer ${apiKey}`

    // For OpenRouter, add required headers
    if (type === 'openrouter') {
      headers['HTTP-Referer'] = 'https://localhost:3000'
      headers['X-Title'] = 'Memento AI'
    }

    // Try provider-specific embeddings endpoint first for embeddings kind
    if (kind === 'embeddings') {
      try {
        const embRes = await fetch(`${baseUrl}/embeddings/models`, {
          headers,
          signal: AbortSignal.timeout(8000),
        })
        if (embRes.ok) {
          const embData = await embRes.json()
          const embModels: string[] = (embData.data ?? [])
            .map((m: { id: string }) => m.id)
            .filter(Boolean)
            .sort()
          if (embModels.length > 0) {
            return NextResponse.json({ success: true, models: embModels })
          }
        }
      } catch {
        // Fall through to /v1/models with keyword filter
      }
    }

    const res = await fetch(`${baseUrl}/models`, {
      headers,
      signal: AbortSignal.timeout(8000),
    })
    if (!res.ok) {
      return NextResponse.json({ success: false, models: [], error: `Provider ${res.status}` })
    }

    const data = await res.json()
    let models: string[] = (data.data ?? [])
      .map((m: { id: string }) => m.id)
      .filter(Boolean)
      .sort()

    if (kind === 'embeddings') {
      const keywords = ['embed', 'embedding', 'ada', 'e5', 'bge', 'gte', 'minilm']
      const filtered = models.filter((id) =>
        keywords.some((kw) => id.toLowerCase().includes(kw))
      )
      if (filtered.length > 0) models = filtered
    }

    return NextResponse.json({ success: true, models })
  } catch (err: any) {
    return NextResponse.json({ success: false, models: [], error: err.message ?? 'Request failed' })
  }
}