require 'yaml'
require 'active_support'
require 'active_support/json/encoding'

class UserJsonGenerator

  def initialize(key_path, env, opts = {})
    @key_path = key_path

    data = YAML.load_file("users.yml")

    @default_hash = data["default_hash"]
    @users = data["users"]
    @groups = data["groups"]
    @env = data["envs"][env]
    @opts = { :home => "/home" }.merge(opts)
  end

  def generate(target)
    if ENV['DEBUG_USER_JSON']
      require 'pp'
      ::PP.pp generate_json
      exit 0
    end
    File.open(target, 'w') { |f| f.write(generate_json) }
  end

  def self.generate!(env, opts = {})
    UserJsonGenerator.new("public_keys", env, opts).generate("envs/#{env}/chef/roles/users.json")
  end

  private

  def generate_json
    {
      :name => "Users",
      :chef_type => "role",
      :json_class => "Chef::Role",
      :override_attributes => {
        :users => env_users.inject({}) { |h, user|
          h[user] = {
              :password => (@users[user] || {})["hash"] || @default_hash,
              :home => (user == 'root' ? '/root' : [ @opts[:home], user ].join('/')),
              :hidden_home => !!(@users[user] || {})["hidden_home"]
          }; h
        },
        :ssh_keys => env_users.inject({}) { |h, user|
          h[user] = get_keys(user); h
        },
        :authorization => {
          :sudo => { :users => env_sudo_users }
        }
      },
      :run_list => [ "recipe[users]", "recipe[sudo]" ]
    }.send(ENV['DEBUG_USER_JSON'] ? 'to_hash' : 'to_json')
    #.gsub(/\{/, "{\n").gsub(/\}/, "}\n")
  end

  def env_users
    resolve_users(@env["users"].split)
  end

  def env_sudo_users
    @env["sudo"] && resolve_users(@env["sudo"].split)
  end

  def resolve_users(list)
    list.map { |item|
      if item.include?("group")
        fetch_group_users(item)
      else
        item
      end
    }.flatten
  end

  def get_keys(user)
    (@users[user] || {})["keys"].to_s.split.map do |key_name|
      if key_name.include?("group")
        keys_from_group(key_name)
      else
        key_file = "#{@key_path}/#{key_name}.pub"
        if File.exists?(key_file)
          File.read(key_file).chomp
        else
          raise "Could not find key file: #{key_file}."
        end
      end
    end.join("\n")
  end

  def fetch_group_users(name)
    @groups[name.split('/').last].split
  end

  def keys_from_group(name)
    @groups[name.split("/").last].split.map { |user| get_keys(user) }
  end
end