// server/supabase/functions/llm-proxy/index.ts
// Anthropic Claude Messages API 프록시.
// 요청: application/json { messages, system?, max_tokens?, model? }
// 응답: JSON (non-stream) 또는 SSE (stream=true)

import { corsHeaders, handleCorsPreflightRequest } from '../_shared/cors.ts'
import { requireUser, authErrorResponse, type AuthError } from '../_shared/auth.ts'
import { checkQuota, consumeQuota, createServiceRoleClient, type Tier } from '../_shared/quota.ts'

interface LlmRequest {
  messages: Array<{ role: 'user' | 'assistant'; content: string }>
  system?: string
  max_tokens?: number
  model?: string
  stream?: boolean
}

/** 티어별 허용 모델 */
const TIER_MODELS: Record<Tier, string[]> = {
  free: ['claude-haiku-4-5-20251001'],
  pro: ['claude-haiku-4-5-20251001', 'claude-sonnet-4-6'],
  team: ['claude-haiku-4-5-20251001', 'claude-sonnet-4-6', 'claude-opus-4-6']
}

const DEFAULT_MODEL: Record<Tier, string> = {
  free: 'claude-haiku-4-5-20251001',
  pro: 'claude-sonnet-4-6',
  team: 'claude-sonnet-4-6'
}

// @ts-expect-error — Deno 런타임 전역
Deno.serve(async (req: Request) => {
  const preflight = handleCorsPreflightRequest(req)
  if (preflight) return preflight

  if (req.method !== 'POST') {
    return new Response(JSON.stringify({ error: 'Method not allowed' }), {
      status: 405,
      headers: { ...corsHeaders, 'Content-Type': 'application/json' }
    })
  }

  try {
    const user = await requireUser(req)
    const serviceClient = createServiceRoleClient()
    const quota = await checkQuota(user.id, 'llm_process', serviceClient)
    if (!quota.allowed) {
      return new Response(
        JSON.stringify({
          error: 'quota_exceeded',
          current: quota.current,
          limit: quota.limit,
          tier: quota.tier
        }),
        {
          status: 429,
          headers: { ...corsHeaders, 'Content-Type': 'application/json' }
        }
      )
    }

    const body = (await req.json()) as LlmRequest

    // 모델 선택 + 티어 검증
    const requestedModel = body.model ?? DEFAULT_MODEL[quota.tier]
    if (!TIER_MODELS[quota.tier].includes(requestedModel)) {
      return new Response(
        JSON.stringify({
          error: 'model_not_allowed',
          tier: quota.tier,
          requested: requestedModel,
          allowed: TIER_MODELS[quota.tier]
        }),
        {
          status: 403,
          headers: { ...corsHeaders, 'Content-Type': 'application/json' }
        }
      )
    }

    // Anthropic API 호출 — placeholder
    //
    // 실제 구현 시:
    //   const anthropicKey = Deno.env.get('ANTHROPIC_API_KEY')!
    //   const resp = await fetch('https://api.anthropic.com/v1/messages', {
    //     method: 'POST',
    //     headers: {
    //       'Content-Type': 'application/json',
    //       'x-api-key': anthropicKey,
    //       'anthropic-version': '2023-06-01'
    //     },
    //     body: JSON.stringify({
    //       model: requestedModel,
    //       max_tokens: body.max_tokens ?? 2048,
    //       system: body.system,
    //       messages: body.messages,
    //       stream: body.stream ?? false
    //     })
    //   })
    //   if (body.stream) {
    //     return new Response(resp.body, {
    //       headers: { ...corsHeaders, 'Content-Type': 'text/event-stream' }
    //     })
    //   }
    //   const data = await resp.json()
    //   ...

    await consumeQuota(user.id, 'llm_process', serviceClient, 1)

    const placeholder = {
      id: `msg_placeholder_${Date.now()}`,
      model: requestedModel,
      role: 'assistant',
      content: [
        {
          type: 'text',
          text: '[llm-proxy placeholder — Anthropic API not yet wired]'
        }
      ],
      stop_reason: 'end_turn',
      usage: { input_tokens: 0, output_tokens: 0 }
    }

    return new Response(JSON.stringify(placeholder), {
      status: 200,
      headers: { ...corsHeaders, 'Content-Type': 'application/json' }
    })
  } catch (err) {
    if (err && typeof err === 'object' && 'status' in err && 'message' in err) {
      return authErrorResponse(err as AuthError, corsHeaders)
    }
    const message = err instanceof Error ? err.message : 'Unknown error'
    return new Response(JSON.stringify({ error: message }), {
      status: 500,
      headers: { ...corsHeaders, 'Content-Type': 'application/json' }
    })
  }
})