// Create clients and set shared const values outside of the handler.

// Create a DocumentClient that represents the query to add an item
import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import { DynamoDBDocumentClient, GetCommand } from '@aws-sdk/lib-dynamodb';

//DynamoDB Endpoint
const ENDPOINT_OVERRIDE = process.env.ENDPOINT_OVERRIDE;
let ddbClient = undefined;

if(ENDPOINT_OVERRIDE){
  ddbClient = new DynamoDBClient({ endpoint: ENDPOINT_OVERRIDE });    
}
else{
  
  ddbClient = new DynamoDBClient({});    // Use default values for DynamoDB endpoint
  console.warn("No value for ENDPOINT_OVERRIDE provided for DynamoDB, using default");
}

const ddbDocClient = DynamoDBDocumentClient.from(ddbClient);

// Get the DynamoDB table name from environment variables
const tableName = process.env.SAMPLE_TABLE;

/**
 * A simple example includes a HTTP get method to get one item by id from a DynamoDB table.
 */
export const getByIdHandler = async (event) => {
  if (event.httpMethod !== 'GET') {
    throw new Error(`getMethod only accept GET method, you tried: ${event.httpMethod}`);
  }
  // All log statements are written to CloudWatch
  console.info('received:', event);
 
  // Get id from pathParameters from APIGateway because of `/{id}` at template.yaml
  const id = event.pathParameters.id;
 
  // Get the item from the table
  // https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#get-property
  var params = {
    TableName : tableName,
    Key: { id: id },
  };

  try {
    const data = await ddbDocClient.send(new GetCommand(params));
    var item = data.Item;
  } catch (err) {
    console.error("Error retrieving item:", err.message);
    console.error("Error code:", err.code);
    console.error("Error name:", err.name);
    console.error("Error stack:", err.stack);
  
  throw err;
  }
 
  const response = {
    statusCode: 200,
    headers: {
      "Access-Control-Allow-Headers" : "Content-Type",
      "Access-Control-Allow-Origin": "*", //DO NOT USE THIS VALUE IN PRODUCTION - https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-cors.html
      "Access-Control-Allow-Methods": "OPTIONS,POST,GET"
  },
    body: JSON.stringify(item)
  };
 
  // All log statements are written to CloudWatch
  console.info(`response from: ${event.path} statusCode: ${response.statusCode} body: ${response.body}`);
  return response;
}