完全版 Discord収益化アーキテクチャ（プラットフォーム手数料0%）

import { REST } from '@discordjs/rest';
import { Routes } from 'discord-api-types/v10';
import Stripe from 'stripe';

export async function handleSubscriptionActive(
  event: Stripe.CustomerSubscriptionCreatedEvent,
  guildId: string,
  roleId: string,
  botToken: string
) {
  const customerId = event.data.object.customer as string;
  const discordUserId = event.data.object.metadata?.discord_user_id;

  if (!discordUserId) {
    throw new Error(`Missing discord_user_id metadata on customer ${customerId}`);
  }

  const rest = new REST({ version: '10' }).setToken(botToken);
  
  // Idempotent Role Assignment via Discord REST API
  await rest.put(
    Routes.guildMemberRole(guildId, discordUserId, roleId),
    { reason: `SovereignPatron Auto-Provision: Subscription ${event.data.object.id}` }
  );

  return { status: 'PROVISIONED', discordUserId, roleId };
}