require "ostruct"
require "fileutils"
require "erb"
require "json"
require "pathname"
require "pry"
require "netaddr"

class Registry
  PATH = Pathname.new(File.expand_path("../../jails.json", __FILE__))
  def initialize
    @data = JSON.load(File.open(Registry::PATH))
  end
  attr_accessor :data
  def save
    f = File.open(Registry::PATH, "w+")
    f.puts JSON.pretty_generate(@data)
    f.close
  end
end

def atomic_write(path, content)
  dir = File.dirname(path)
  unless Dir.exist?(dir)
    FileUtils.mkdir_p(dir)
  end
  temp_path = path.to_s + ".tmp"
  File.open(temp_path, 'w+') do |f|
    f.write(content)
  end

  FileUtils.mv(temp_path, path)
end

def sh(cmd, *args)
  puts "$ #{cmd} "+ args.map {|a| "'#{a}'" }.join(" ")
  system(cmd, *args)
end

def die(msg)
  $stderr.puts(msg)
  exit(1)
end

def next_free_subnet(subnet, assigned_subnets)
  subnet.enumerate(Limit: 1E4, Short: true)[1..1E4].each do |cidr|
    assigned = assigned_subnets.find { |s| s.contains?(cidr) || s == cidr }
    return cidr unless assigned
  end
end

class TemplateContext < OpenStruct
  def get_binding
    binding
  end
end

class Template
  def initialize(path)
    @erb = ERB.new(File.read(path), nil, '-')
  end
  def render(params={})
    @erb.result(TemplateContext.new(params).get_binding)
  end
end