require "pathname"
require "tmpdir"
require "active_support/message_encryptor"
require "active_support/core_ext/hash/keys"

module SmartMachine
  class Credentials < SmartMachine::Base

    CIPHER = "aes-256-gcm"

    def initialize
    end

    def create
      write_key
      write credentials_template
    end

    def edit
      content_path = Pathname.new "config/credentials.yml.enc"
      tmp_file = "#{Process.pid}.#{content_path.basename.to_s.chomp('.enc')}"
      tmp_path = Pathname.new File.join(Dir.tmpdir, tmp_file)
      contents = read
      tmp_path.binwrite contents

      system("#{ENV['EDITOR']} #{tmp_path}")

      updated_contents = tmp_path.binread

      if updated_contents != contents
        write(updated_contents)
        puts "File encrypted and saved."
      else
        puts "File contents were not changed."
      end
    ensure
      FileUtils.rm(tmp_path) if tmp_path&.exist?
    end

    def read_key
      read_env_key || read_key_file || handle_missing_key
    end

    def config
      @config ||= deserialize(read).deep_symbolize_keys
    end

    private

    def credentials_template
			<<~YAML
			  machine:
			    name: #{SecureRandom.hex(8)}
			    address: 127.0.0.1
			    port: 22
			    root_password: #{SecureRandom.hex(16)}
			    username: #{SecureRandom.hex(8)}
			    password: #{SecureRandom.hex(16)}
			  minioone:
  			    access_key: #{SecureRandom.hex(8)}
  			    secret_key: #{SecureRandom.hex(16)}
			  mysqlone:
			    root_password: #{SecureRandom.hex(16)}
			    username: #{SecureRandom.hex(8)}
			    password: #{SecureRandom.hex(16)}
			    database_name: #{SecureRandom.hex(8)}
			  redisone:
			    password: #{SecureRandom.hex(16)}
			YAML
    end

    def read
      if File.exist? "config/credentials.yml.enc"
        decrypt IO.binread "config/credentials.yml.enc"
      elsif File.exist? "#{File.expand_path('~')}/machine/config/credentials.yml.enc"
        decrypt IO.binread "#{File.expand_path('~')}/machine/config/credentials.yml.enc"
      else
        raise "Could not find credentials file."
      end
    end

    def write(contents)
      IO.binwrite "config/credentials.yml.enc.tmp", encrypt(contents)
      FileUtils.mv "config/credentials.yml.enc.tmp", "config/credentials.yml.enc"
    end

    def encrypt(contents)
      encryptor.encrypt_and_sign contents
    end

    def decrypt(contents)
      encryptor.decrypt_and_verify contents
    end

    def encryptor
      @encryptor ||= ActiveSupport::MessageEncryptor.new([ read_key ].pack("H*"), cipher: CIPHER)
    end

    def create_key
      SecureRandom.hex(ActiveSupport::MessageEncryptor.key_len(CIPHER))
    end

    def write_key
      IO.binwrite "config/master.key.tmp", create_key
      FileUtils.mv "config/master.key.tmp", "config/master.key"
    end

    def read_env_key
      ENV['SMARTMACHINE_MASTER_KEY']
    end

    def read_key_file
      IO.binread("config/master.key").strip if File.file?("config/master.key")
    end

    def handle_missing_key
      raise "Missing SMARTMACHINE_MASTER_KEY. Please add SMARTMACHINE_MASTER_KEY to your environment."
    end

    def deserialize(config)
      YAML.load(config).presence || {}
    end
  end
end