class Bundler::Installer

def self.install(root, definition, options)
  new(root, definition).run(options)
end

def actual_dependencies
  @definition.actual_dependencies
end

def ambiguous?(dep)
  dep.requirement.requirements.any? { |op,_| op != '=' }
end

def dependencies
  @definition.dependencies
end

def remote_index
  @remote_index ||= Index.build do |idx|
    rubygems, other = sources.partition { |s| Source::Rubygems === s }
    other.each do |source|
      Bundler.ui.debug "Source: Processing index"
      idx.use source.specs
    end
    idx.use Index.installed_gems
    idx.use Index.cached_gems
    rubygems.each do |source|
      Bundler.ui.debug "Source: Processing index"
      idx.use source.specs
    end
  end
end

def resolve_locally
  # Return unless all the dependencies have = version requirements
  return if actual_dependencies.any? { |d| ambiguous?(d) }
  specs = super
  # Simple logic for now. Can improve later.
  specs.length == actual_dependencies.length && specs
rescue GemNotFound, PathError => e
  nil
end

def resolve_remotely
  resolve(:specs, remote_index)
end

def run(options)
  if actual_dependencies.empty?
    Bundler.ui.warn "The Gemfile specifies no dependencies"
    return
  end
  # Ensure that BUNDLE_PATH exists
  FileUtils.mkdir_p(Bundler.bundle_path)
  # Must install gems in the order that the resolver provides
  # as dependencies might actually affect the installation of
  # the gem.
  specs.each do |spec|
    spec.source.fetch(spec) if spec.source.respond_to?(:fetch)
    unless requested_specs.include?(spec)
      Bundler.ui.debug "  * Not in requested group; skipping."
      next
    end
    if [Source::Rubygems, Source::GemCache].include?(spec.source.class)
      Bundler.ui.info "Installing #{spec.name} (#{spec.version}) from #{spec.source}"
    else
      Bundler.ui.info "Using #{spec.name} (#{spec.version}) from #{spec.source}"
    end
    spec.source.install(spec)
  end
  if locked?
    write_rb_lock
  end
end