const AWS = require('aws-sdk');

const lambda = new AWS.Lambda({
  credentials: {
    accessKeyId: process.env.AWS_LAMBDA_EXECUTE_KEY,
    secretAccessKey: process.env.AWS_LAMBDA_EXECUTE_SECRET
  },
  region: 'us-east-1'
});

module.exports = function getUrlHash (targetUrl, algorithm = 'sha256') {
  return new Promise((resolve, reject) => {
    lambda.invoke({
      FunctionName: 'hasher',
      Payload: JSON.stringify({
        targetUrl,
        algorithm
      })
    }, (err, data) => {
      if (err) return reject(err);
      try {
        const response = JSON.parse(data.Payload);
        if (response.statusCode !== 200) return reject(new Error('non-200 status code received from hasher function'));
        if (!response.hash) return reject(new Error('Successful lambda call but failed to get valid hash'));
        resolve(response.hash);
      } catch (err) {
        return reject(err);
      }
    });
  });
};