# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0

# Purpose:
# ec2-ruby-example-create-key-pair.rb demonstrates how to
# create a key pair in Amazon Elastic Compute Cloud (Amazon EC2) and
# saves the resulting RSA private key file locally in the calling
# user's home directory.

# snippet-start:[ec2.Ruby.createKeyPair]

require 'aws-sdk-ec2'

# @param ec2_client [Aws::EC2::Client] An initialized EC2 client.
# @param key_pair_name [String] The name for the key pair and private
#   key file.
# @return [Boolean] true if the key pair and private key file were
#   created; otherwise, false.
# @example
#   exit 1 unless key_pair_created?(
#     Aws::EC2::Client.new(region: 'us-west-2'),
#     'my-key-pair'
#   )
def key_pair_created?(ec2_client, key_pair_name)
  key_pair = ec2_client.create_key_pair(key_name: key_pair_name)
  puts "Created key pair '#{key_pair.key_name}' with fingerprint " \
    "'#{key_pair.key_fingerprint}' and ID '#{key_pair.key_pair_id}'."
  filename = File.join(Dir.home, "#{key_pair_name}.pem")
  File.open(filename, 'w') { |file| file.write(key_pair.key_material) }
  puts "Private key file saved locally as '#{filename}'."
  true
rescue StandardError => e
  puts "Error creating key pair or saving private key file: #{e.message}"
  false
end

# Example usage:
def run_me
  key_pair_name = ''
  region = ''
  # Print usage information and then stop.
  if ARGV[0] == '--help' || ARGV[0] == '-h'
    puts 'Usage: ruby ec2-ruby-example-create-key-pair.rb ' \
      'KEY_PAIR_NAME REGION'
    # Replace us-west-2 with the AWS Region you're using for Amazon EC2.
    puts 'Example: ruby ec2-ruby-example-create-key-pair.rb ' \
      'my-key-pair us-west-2'
    exit 1
  # If no values are specified at the command prompt, use these default values.
  elsif ARGV.count.zero?
    key_pair_name = 'my-key-pair'
    # Replace us-west-2 with the AWS Region you're using for Amazon EC2.
    region = 'us-west-2 '
  # Otherwise, use the values as specified at the command prompt.
  else
    key_pair_name = ARGV[0]
    region = ARGV[1]
  end

  ec2_client = Aws::EC2::Client.new(region: region)

  if key_pair_created?(ec2_client, key_pair_name)
    puts 'Key pair created and private key file saved.'
  else
    puts 'Key pair not created or private key file not saved.'
  end
end

run_me if $PROGRAM_NAME == __FILE__
# snippet-end:[ec2.Ruby.createKeyPair]