class Bundler::ParallelInstaller

def self.call(*args, **kwargs)
  new(*args, **kwargs).call
end

def bsd_make?
  return false unless Gem.freebsd_platform?
  make = ENV["MAKE"] || ENV["make"] || "make"
  !/\bgmake/i.match?(make)
end

def call
  if @rake
    do_download(@rake, 0)
    do_install(@rake, 0)
    Gem::Specification.reset
  end
  if @size > 1
    install_with_worker
  else
    install_serially
  end
  handle_error if failed_specs.any?
  @specs
ensure
  worker_pool&.stop
end

def do_download(spec_install, worker_num)
  Plugin.hook(Plugin::Events::GEM_BEFORE_INSTALL, spec_install)
  gem_installer = Bundler::GemInstaller.new(
    spec_install.spec, @installer, @standalone, worker_num, @force, @local
  )
  success, message = gem_installer.download
  if success
    spec_install.state = :downloaded
  else
    spec_install.error = "#{message}\n\n#{require_tree_for_spec(spec_install.spec)}"
    spec_install.state = :failed
  end
  spec_install
end

def do_install(spec_install, worker_num)
  gem_installer = Bundler::GemInstaller.new(
    spec_install.spec, @installer, @standalone, worker_num, @force, @local
  )
  success, message = gem_installer.install_from_spec
  if success
    spec_install.state = :installed
    spec_install.post_install_message = message unless message.nil?
  else
    spec_install.error = "#{message}\n\n#{require_tree_for_spec(spec_install.spec)}"
    spec_install.state = :failed
  end
  Plugin.hook(Plugin::Events::GEM_AFTER_INSTALL, spec_install)
  spec_install
end

def enqueue_specs(installed_specs)
  @specs.each do |spec|
    if spec.installed?
      installed_specs[spec.name] = true
      next
    end
    spec.state = :enqueued
    worker_pool.enq spec
  end
end

def failed_specs
  @specs.select(&:failed?)
end

def finished_installing?
  @specs.all? do |spec|
    return true if spec.failed?
    spec.installed?
  end
end

def handle_error
  errors = failed_specs.map(&:error)
  if exception = errors.find {|e| e.is_a?(Bundler::BundlerError) }
    raise exception
  end
  raise Bundler::InstallError, errors.join("\n\n")
end

def initialize(installer, all_specs, size, standalone, force, local: false, skip: nil)
  @installer = installer
  @size = size
  @standalone = standalone
  @force = force
  @local = local
  @specs = all_specs.map {|s| SpecInstallation.new(s) }
  specs_by_name = @specs.to_h {|s| [s.name, s] }
  @specs.each do |spec_install|
    spec_install.dependencies = spec_install.spec.dependencies.filter_map do |dep|
      specs_by_name[dep.name] unless dep.type == :development || dep.name == spec_install.name
    end
  end
  @specs.each do |spec_install|
    spec_install.state = :installed if skip.include?(spec_install.name)
  end if skip
  @spec_set = all_specs
  @rake = @specs.find {|s| s.name == "rake" unless s.installed? }
end

def install_serially
  until finished_installing?
    raise "failed to find a spec to enqueue while installing serially" unless spec_install = @specs.find(&:ready_to_enqueue?)
    spec_install.state = :enqueued
    do_download(spec_install, 0)
    do_install(spec_install, 0)
  end
end

def install_with_worker
  with_jobserver do
    installed_specs = {}
    enqueue_specs(installed_specs)
    process_specs(installed_specs) until finished_installing?
  end
end

def nmake?
  make = ENV["MAKE"] || ENV["make"]
  make ||= "nmake" if RUBY_PLATFORM.include?("mswin")
  /\bnmake/i.match?(make.to_s)
end

def process_specs(installed_specs)
  spec = worker_pool.deq
  if spec.installed?
    installed_specs[spec.name] = true
    return
  elsif spec.failed?
    return
  elsif spec.ready_to_install?(installed_specs)
    spec.state = :installable
  end
  worker_pool.enq(spec, priority: spec.enqueue_with_priority?)
end

def require_tree_for_spec(spec)
  tree = @spec_set.what_required(spec)
  t = String.new("In #{File.basename(SharedHelpers.default_gemfile)}:\n")
  tree.each_with_index do |s, depth|
    t << "  " * depth.succ << s.name
    unless tree.last == s
      t << %( was resolved to #{s.version}, which depends on)
    end
    t << %(\n)
  end
  t
end

def with_jobserver
  # The jobserver hands tokens to child `make` processes through MAKEFLAGS
  # using the GNU make `--jobserver-auth` protocol. nmake, the default make
  # on mswin, instead reads MAKEFLAGS as bare option letters and aborts
  # every native extension build with `fatal error U1065: invalid option
  # '-'`. Skip the jobserver when nmake is in use. Other Windows toolchains
  # such as mingw use GNU make and keep working through the inherited pipe.
  return yield if nmake? || bsd_make?
  begin
    r, w = IO.pipe
    r.close_on_exec = false
    w.close_on_exec = false
    w.write("*" * @size)
    old_makeflags = ENV["MAKEFLAGS"]
    ENV["MAKEFLAGS"] = [old_makeflags, "--jobserver-auth=#{r.fileno},#{w.fileno}"].compact.join(" ")
    yield
  ensure
    # Restore MAKEFLAGS before closing the pipe so a close failure can't
    # leave the process with descriptors that point at a closed pipe.
    old_makeflags ? ENV["MAKEFLAGS"] = old_makeflags : ENV.delete("MAKEFLAGS")
    r&.close
    w&.close
  end
end

def worker_pool
  @worker_pool ||= Bundler::Worker.new @size, "Parallel Installer", lambda {|spec_install, worker_num|
    case spec_install.state
    when :enqueued
      do_download(spec_install, worker_num)
    when :installable
      do_install(spec_install, worker_num)
    else
      spec_install
    end
  }
end