class NodeInstruction < ActiveRecord::Base
  STATUSES = [
    DISABLED    = 'disabled',
    READY       = 'ready',
    RESTARTING  = 'restarting',
    FAILED      = 'failed'
  ]

  LOCK_KEY = 'NodeInstruction::lock-key'

  belongs_to :user

  scope :duplicate, -> id, user_id {
    where.not(id: id.to_i).where(user_id: user_id, status: STATUSES - [DISABLED])
  }

  attr_encrypted :instruction, key: APP_CONFIG['keys']['node_instruction_secret_key']

  validates :user,        presence: true
  validates :instruction, presence: true, length: { maximum: 10000 }
  validates :status,      presence: true
  validate  -> {
    errors.add(:status, 'Can be only single active instruction for each node') if !disabled? && NodeInstruction.duplicate(id.to_i, user_id).exists?
  }

  state_machine :status, initial: :ready do

    after_transition(on: :restart) do |instruction, transition|
      instruction.perform_restart
    end

    event :ready do
      transition %i(ready restarting disabled failed) => :ready
    end

    event :disable do
      transition ready: :disabled
    end

    event :restart do
      transition ready: :restarting
    end

    event :restart_failed do
      transition restarting: :failed
    end
  end

  def perform_restart
    restart_failed if NodeInstruction.all_locked?

    success = false
    stdout  = ''
    instruction.lines.each do |command|
      next if command.blank?
      command.chomp!; command.strip!
      stdout << %x[ #{command} 2>&1 ]
      success = $?.success?
    end

    build_lists = BuildList.where(builder_id: user_id, external_nodes: [nil, '']).
      for_status(BuildList::BUILD_STARTED)

    build_lists.find_each do |bl|
      bl.update_column(:status, BuildList::BUILD_PENDING)
      bl.restart_job
    end

    update_column(:output, stdout)
    success ? ready : restart_failed
  end
  later :perform_restart, queue: :low

  def self.all_locked?
    Redis.current.get(LOCK_KEY).present?
  end

  def self.lock_all
    Redis.current.set(LOCK_KEY, 1)
  end

  def self.unlock_all
    Redis.current.del(LOCK_KEY)
  end

end