compile

#!/usr/bin/env ruby

require 'fileutils'
require 'pathname'
require 'tmpdir'

BUILD_DIR    = ARGV[0]
CACHE_DIR    = ARGV[1]
ENV_DIR      = ARGV[2]
SSH_DIR      = File.expand_path "#{ENV['HOME']}/.ssh"

def alert(str)
  str.split('\n').each do |line|
    puts "       !!!! #{line}"
  end
end

def arrow(str)
  str.split("\n").each do |line|
    puts ":::::> #{line}"
  end
end

def read_env(env_file)
  env_file_path = File.join(ENV_DIR, env_file)

  if env_file.include?('GITHUB') && File.exist?(env_file_path)
    alert "#{env_file} is deprecated, please switch to #{env_file.sub('GITHUB','GIT')}"
  end

  File.exist?(env_file_path) && File.read(env_file_path) || nil
end

arrow "############################################"
arrow "         GIT DEPLOY KEY BUILDPACK           "
arrow "############################################"

arrow "ssh dir is #{SSH_DIR}"
################# Get the key from heroku's environment config #################
ssh_key = read_env('GIT_DEPLOY_KEY')
key_file_path = File.join(ENV_DIR, 'GIT_DEPLOY_KEY') if ssh_key

ssh_key ||= read_env('GITHUB_DEPLOY_KEY')
key_file_path ||= File.join(ENV_DIR, 'GITHUB_DEPLOY_KEY')

if ssh_key.nil?
  alert "GIT_DEPLOY_KEY not set"
  alert "  Try `heroku config:add GIT_DEPLOY_KEY=<your private token>`"
  exit 1
end

############# Get the known host from heroku's environment config ##############
host_hash = read_env('GIT_HOST_HASH')
host_hash ||= read_env('GITHUB_HOST_HASH')

if host_hash.nil?
  alert "GIT_HOST_HASH not set"
  alert "  Try `heroku config:add GIT_HOST_HASH=<hash>`"
  exit 1
end


############# Get the git host from heroku's environment config ################
git_host = read_env('GIT_HOST')

if git_host.nil?
  arrow 'GIT_HOST not set, assuming github.com'
  git_user = 'github.com'
end

############# Get the git user from heroku's environment config ################
git_host = read_env('GIT_USER')

if git_host.nil?
  arrow "GIT_USER not set, assuming 'git'"
  git_user = 'git'
end

###################### Process and clean up the ssh keys #######################
fingerprint = nil
temp_key = nil
clean_host_hash = nil

Dir.mktmpdir 'ssh_buidpack' do |dir|
  # Process key to standardise it's format
  `ssh-keygen -e -P '' -f #{key_file_path} < /dev/null > #{dir}/ssh_buildpack_key.pub.rfc 2>/dev/null`
  `ssh-keygen -i -P '' -f #{dir}/ssh_buildpack_key.pub.rfc > #{dir}/ssh_buildpack_key.pub 2>/dev/null`

  # # Process host hash to standardise it's format
  # `ssh-keygen -e -P '' -f #{key_file_path} < /dev/null > #{dir}/host_hash.pub.rfc 2>/dev/null`
  # `ssh-keygen -i -P '' -f #{dir}/host_hash.pub.rfc > #{dir}/host_hash.pub 2>/dev/null`

  fingerprint = `ssh-keygen -l -f #{dir}/ssh_buildpack_key.pub | awk '{print $2}'`

  # only used to be sure the passed key was valid
  temp_key = `echo "#{fingerprint}" | tr -ds ':' '' | egrep -ie "[a-f0-9]{32}" 2>/dev/null`

  # clean_host_hash = `cat "#{dir}/host_hash.pub"`

  if temp_key.strip == ''
    alert "GIT_DEPLOY_KEY was invalid"
    exit 1
  else
    arrow "Using GIT_DEPLOY_KEY #{fingerprint}"
  end

end

# Create the ssh directory on the server
Dir.mkdir(SSH_DIR, 0700) unless File.exists?(SSH_DIR)

# Create id_rsa file and write contents
File.open "#{SSH_DIR}/id_rsa", 'w' do |f|
  f.write ssh_key
end
FileUtils.chmod 0600, "#{SSH_DIR}/id_rsa"
arrow "Wrote ssh key to user's ssh dir"

#create known_hosts file and write contents
File.open "#{SSH_DIR}/known_hosts", 'w' do |f|
  f.write host_hash
end
FileUtils.chmod 0600, "#{SSH_DIR}/known_hosts"
arrow "Wrote host hash to user's known hosts"

File.open "#{SSH_DIR}/config", 'w' do |f|
  f.puts "IdentityFile #{SSH_DIR}/id_rsa"
  f.puts "host #{git_host}"
  f.puts "     user #{git_user}"
  f.puts "     IdentityFile #{SSH_DIR}/id_rsa"
end
FileUtils.chmod 0600, "#{SSH_DIR}/config"
arrow "Wrote config to user's config"