module Bundler::SharedHelpers

def clean_load_path
  # handle 1.9 where system gems are always on the load path
  if defined?(::Gem)
    me = File.expand_path("../../", __FILE__)
    $LOAD_PATH.reject! do |p|
      next if File.expand_path(p) =~ /^#{me}/
      p != File.dirname(__FILE__) &&
        Gem.path.any?{|gp| p =~ /^#{gp}/ }
    end
    $LOAD_PATH.uniq!
  end
end

def cripple_rubygems(specs)
  reverse_rubygems_kernel_mixin
  executables = specs.map { |s| s.executables }.flatten
  Gem.source_index # ensure RubyGems is fully loaded
  ::Kernel.send(:define_method, :gem) do |dep, *reqs|
    if executables.include? File.basename(caller.first.split(':').first)
      return
    end
    opts = reqs.last.is_a?(Hash) ? reqs.pop : {}
    unless dep.respond_to?(:name) && dep.respond_to?(:requirement)
      dep = Gem::Dependency.new(dep, reqs)
    end
    spec = specs.find  { |s| s.name == dep.name }
    if spec.nil?
      e = Gem::LoadError.new "#{dep.name} is not part of the bundle. Add it to Gemfile."
      e.name = dep.name
      e.version_requirement = dep.requirement
      raise e
    elsif dep !~ spec
      e = Gem::LoadError.new "can't activate #{dep}, already activated #{spec.full_name}. " \
                             "Make sure all dependencies are added to Gemfile."
      e.name = dep.name
      e.version_requirement = dep.requirement
      raise e
    end
    true
  end
  # === Following hacks are to improve on the generated bin wrappers ===
  # Yeah, talk about a hack
  source_index_class = (class << Gem::SourceIndex ; self ; end)
  source_index_class.send(:remove_method, :from_gems_in)
  source_index_class.send(:define_method, :from_gems_in) do |*args|
    source_index = Gem::SourceIndex.new
    source_index.spec_dirs = *args
    source_index.add_specs(*specs)
    source_index
  end
  # OMG more hacks
  gem_class = (class << Gem ; self ; end)
  gem_class.send(:remove_method, :refresh)
  gem_class.send(:define_method, :refresh) { }
  gem_class.send(:remove_method, :bin_path)
  gem_class.send(:define_method, :bin_path) do |name, *args|
    exec_name, *reqs = args
    if exec_name == 'bundle'
      return ENV['BUNDLE_BIN_PATH']
    end
    spec = nil
    if exec_name
      spec = specs.find { |s| s.executables.include?(exec_name) }
      spec or raise Gem::Exception, "can't find executable #{exec_name}"
    else
      spec = specs.find  { |s| s.name == name }
      exec_name = spec.default_executable or raise Gem::Exception, "no default executable for #{spec.full_name}"
    end
    gem_bin = File.join(spec.full_gem_path, spec.bindir, exec_name)
    gem_from_path_bin = File.join(File.dirname(spec.loaded_from), spec.bindir, exec_name)
    File.exist?(gem_bin) ? gem_bin : gem_from_path_bin
  end
  Gem.clear_paths
end

def default_gemfile
  gemfile = find_gemfile
  raise GemfileNotFound, "Could not locate Gemfile" unless gemfile
  Pathname.new(gemfile)
end

def default_lockfile
  Pathname.new("#{default_gemfile}.lock")
end

def find_gemfile
  given = ENV['BUNDLE_GEMFILE']
  return given if given && !given.empty?
  previous = nil
  current  = File.expand_path(Dir.pwd)
  until !File.directory?(current) || current == previous
    if ENV['BUNDLE_SPEC_RUN']
      # avoid stepping above the tmp directory when testing
      return nil if File.file?(File.join(current, 'bundler.gemspec'))
    end
    # otherwise return the Gemfile if it's there
    filename = File.join(current, 'Gemfile')
    return filename if File.file?(filename)
    current, previous = File.expand_path("..", current), current
  end
end

def in_bundle?
  find_gemfile
end

def reverse_rubygems_kernel_mixin
  # Disable rubygems' gem activation system
  ::Kernel.class_eval do
    if private_method_defined?(:gem_original_require)
      alias rubygems_require require
      alias require gem_original_require
    end
    undef gem
  end
end