// server/supabase/functions/stripe-checkout/index.ts
// Stripe Checkout Session 생성 — 사용자가 업그레이드 버튼 클릭 시 호출.
// 응답: { url: 'https://checkout.stripe.com/...' } → 클라이언트가 redirect.

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

interface CheckoutRequest {
  tier: 'pro' | 'team'
  success_url: string
  cancel_url: string
}

// Stripe Price ID는 환경변수로 주입 (대시보드에서 생성한 product의 price ID)
// 실제 운영 시:
//   supabase secrets set STRIPE_PRICE_PRO=price_xxx
//   supabase secrets set STRIPE_PRICE_TEAM=price_yyy
//   supabase secrets set STRIPE_SECRET_KEY=sk_live_xxx

// @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 body = (await req.json()) as CheckoutRequest

    // @ts-expect-error — Deno.env
    const stripeKey = Deno.env.get('STRIPE_SECRET_KEY') ?? ''
    // @ts-expect-error — Deno.env
    const priceMap: Record<string, string> = {
      pro: Deno.env.get('STRIPE_PRICE_PRO') ?? '',
      team: Deno.env.get('STRIPE_PRICE_TEAM') ?? ''
    }
    const priceId = priceMap[body.tier]

    if (!stripeKey || !priceId) {
      return new Response(
        JSON.stringify({
          error: 'stripe_not_configured',
          message: 'STRIPE_SECRET_KEY 또는 STRIPE_PRICE_* 환경변수가 설정되지 않았습니다.'
        }),
        {
          status: 503,
          headers: { ...corsHeaders, 'Content-Type': 'application/json' }
        }
      )
    }

    // 기존 customer_id 조회 (subscriptions 테이블에서)
    const serviceClient = createServiceRoleClient()
    const { data: sub } = await serviceClient
      .from('subscriptions')
      .select('stripe_customer_id')
      .eq('user_id', user.id)
      .maybeSingle()

    let customerId = (sub?.stripe_customer_id as string | null | undefined) ?? null

    // 없으면 새 customer 생성
    if (!customerId) {
      const customerResp = await fetch('https://api.stripe.com/v1/customers', {
        method: 'POST',
        headers: {
          Authorization: `Bearer ${stripeKey}`,
          'Content-Type': 'application/x-www-form-urlencoded'
        },
        body: new URLSearchParams({
          email: user.email ?? '',
          'metadata[user_id]': user.id
        })
      })

      if (!customerResp.ok) {
        const errText = await customerResp.text()
        throw new Error(`Stripe customer 생성 실패: ${errText}`)
      }

      const customerData = (await customerResp.json()) as { id: string }
      customerId = customerData.id

      // subscriptions에 저장
      await serviceClient
        .from('subscriptions')
        .upsert({ user_id: user.id, stripe_customer_id: customerId, tier: 'free' })
    }

    // Checkout session 생성
    const sessionResp = await fetch('https://api.stripe.com/v1/checkout/sessions', {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${stripeKey}`,
        'Content-Type': 'application/x-www-form-urlencoded'
      },
      body: new URLSearchParams({
        customer: customerId,
        mode: 'subscription',
        'line_items[0][price]': priceId,
        'line_items[0][quantity]': '1',
        success_url: body.success_url,
        cancel_url: body.cancel_url,
        'metadata[user_id]': user.id,
        'metadata[tier]': body.tier
      })
    })

    if (!sessionResp.ok) {
      const errText = await sessionResp.text()
      throw new Error(`Stripe checkout 생성 실패: ${errText}`)
    }

    const sessionData = (await sessionResp.json()) as { url: string }

    return new Response(JSON.stringify({ url: sessionData.url }), {
      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' }
    })
  }
})