# Core Pathname library used for traversal
require 'pathname'

module Middleman

  class << self
    def setup_load_paths
      @_is_setup ||= begin

        # Only look for config.rb if MM_ROOT isn't set
        if !ENV['MM_ROOT'] && (found_path = findup('config.rb'))
          ENV['MM_ROOT'] = found_path
        end

        # If we've found the root, try to setup Bundler
        if ENV['MM_ROOT']
          setup_bundler
        else
          # Automatically discover extensions in RubyGems
          require 'middleman-core/extensions'
          ::Middleman.load_extensions_in_path
        end

        true
      end
    end

    private

    # Set BUNDLE_GEMFILE and run Bundler setup. Raises an exception if there is no Gemfile
    def setup_bundler
      ENV['BUNDLE_GEMFILE'] ||= findup('Gemfile', ENV['MM_ROOT'])

      if !File.exists?(ENV['BUNDLE_GEMFILE'])
        ENV['BUNDLE_GEMFILE'] = File.expand_path('../../../../Gemfile', __FILE__)
      end

      if File.exists?(ENV['BUNDLE_GEMFILE'])
        require 'bundler/setup'
        Bundler.require
      else
        raise "Couldn't find your Gemfile. Middleman projects require a Gemfile for specifying dependencies."
      end
    end

    # Recursive method to find a file in parent directories
    def findup(filename, cwd = Pathname.new(Dir.pwd))
      return cwd.to_s if (cwd + filename).exist?
      return false if cwd.root?
      findup(filename, cwd.parent)
    end

  end

end