import { DynamoDBDocumentClient, GetCommand, PutCommand } from '@aws-sdk/lib-dynamodb';
import { DynamoDBClient } from '@aws-sdk/client-dynamodb';

const region = process.env.AWS_REGION!;
const tableName = process.env.RATE_LIMIT_TABLE_NAME!;

const ddb = new DynamoDBClient({ region });
const doc = DynamoDBDocumentClient.from(ddb);

export async function checkAndConsumeToken(userId: string, capacityPerMinute: number = 10): Promise<boolean> {
  const now = Date.now();
  const key = { userId };
  const resp = await doc.send(new GetCommand({ TableName: tableName, Key: key }));
  const item = resp.Item || { userId, tokens: capacityPerMinute, refillAt: now };
  let tokens: number = typeof item.tokens === 'number' ? item.tokens : capacityPerMinute;
  let refillAt: number = typeof item.refillAt === 'number' ? item.refillAt : now;
  if (now >= refillAt + 60_000) {
    tokens = capacityPerMinute;
    refillAt = now;
  }
  if (tokens <= 0) {
    return false;
  }
  tokens -= 1;
  await doc.send(new PutCommand({ TableName: tableName, Item: { userId, tokens, refillAt } }));
  return true;
}