require 'shellwords'
class Specinfra::Command::Base
  class << self
    @@types = nil

    class NotImplementedError < Exception; end

    def create
      self
    end

    def escape(target)
      str = case target
            when Regexp
              target.source
            else
              target.to_s
            end

      Shellwords.shellescape(str)
    end

    def method_missing(meth, *args)
      action, resource_type, subaction = breakdown(meth)
      method =  action
      method += "_#{subaction}" if subaction
      command_class = create_command_class(resource_type)
      if command_class.respond_to?(method)
        command_class.send(method, *args)
      else
        raise NotImplementedError.new("#{method} is not implemented in #{command_class}")
      end
    end

    def create_command_class(resource_type)
      family  = os[:family]
      version = os[:release] ? "V#{os[:release].to_i}" : nil

      common_class = Specinfra::Command
      base_class   = common_class.const_get('Base')
      os_class     = family.nil? ? base_class : common_class.const_get(family.capitalize)

      if family && version
        begin
          version_class = os_class.const_get(version)
        rescue
          version_class = os_class.const_get('Base')
        end
      elsif family.nil?
        version_class = os_class
      elsif family != 'base' && version.nil?
        version_class = os_class.const_get('Base')
      end

      begin
        command_class = version_class.const_get(resource_type.to_camel_case)
      rescue
      end

      if command_class.nil? ||( (command_class < Specinfra::Command::Base).nil? && (command_class < Specinfra::Command::Windows::Base).nil? )
        command_class = base_class.const_get(resource_type.to_camel_case)
      end

      command_class.create
    end

    private
    def breakdown(meth)
      types = resource_types.map {|t| t.to_snake_case }.join('|')
      md = meth.to_s.match(/^([^_]+)_(#{types})_?(.+)?$/)
      if md.nil?
        message =  "Could not break down `#{meth}' to appropriate type and method.\n"
        message += "The method name shoud be in the form of `action_type_subaction'."
        raise message
      end
      return md[1], md[2], md[3]
    end

    def resource_types
      if @@types.nil?
        @@types = []
        Specinfra::Command::Base.subclasses.each do |s|
          @@types << s.to_s.split(':')[-1]
        end
        Specinfra::Command::Windows::Base.subclasses.each do |s|
          @@types << s.to_s.split(':')[-1]
        end
        @@types.uniq!
      end
      @@types
    end
  end
end