class Bundler::Installer

def self.install(root, definition, options = {})
  installer = new(root, definition)
  installer.run(options)
  installer
end

def can_install_parallely?
  min_rubygems = "2.0.7"
  if Bundler.current_ruby.mri? || Bundler.rubygems.provides?(">= #{min_rubygems}")
    true
  else
    Bundler.ui.warn "Rubygems #{Gem::VERSION} is not threadsafe, so your "\
      "gems must be installed one at a time. Upgrade to Rubygems " \
      "#{min_rubygems} or higher to enable parallel gem installation."
    false
  end
end

def create_bundle_path
  Bundler.mkdir_p(Bundler.bundle_path.to_s) unless Bundler.bundle_path.exist?
rescue Errno::EEXIST
  raise PathError, "Could not install to path `#{Bundler.settings[:path]}` " +
    "because of an invalid symlink. Remove the symlink so the directory can be created."
end

def generate_bundler_executable_stubs(spec, options = {})
  if options[:binstubs_cmd] && spec.executables.empty?
    options = {}
    spec.runtime_dependencies.each do |dep|
      bins = @definition.specs[dep].first.executables
      options[dep.name] = bins unless bins.empty?
    end
    if options.any?
      Bundler.ui.warn "#{spec.name} has no executables, but you may want " +
        "one from a gem it depends on."
      options.each{|name,bins| Bundler.ui.warn "  #{name} has: #{bins.join(', ')}" }
    else
      Bundler.ui.warn "There are no executables for the gem #{spec.name}."
    end
    return
  end
  # double-assignment to avoid warnings about variables that will be used by ERB
  bin_path = bin_path = Bundler.bin_path
  template = template = File.read(File.expand_path('../templates/Executable', __FILE__))
  relative_gemfile_path = relative_gemfile_path = Bundler.default_gemfile.relative_path_from(bin_path)
  ruby_command = ruby_command = Thor::Util.ruby_command
  exists = []
  spec.executables.each do |executable|
    next if executable == "bundle"
    binstub_path = "#{bin_path}/#{executable}"
    if File.exist?(binstub_path) && !options[:force]
      exists << executable
      next
    end
    File.open(binstub_path, 'w', 0777 & ~File.umask) do |f|
      f.puts ERB.new(template, nil, '-').result(binding)
    end
  end
  if options[:binstubs_cmd] && exists.any?
    case exists.size
    when 1
      Bundler.ui.warn "Skipped #{exists[0]} since it already exists."
    when 2
      Bundler.ui.warn "Skipped #{exists.join(' and ')} since they already exist."
    else
      items = exists[0...-1].empty? ? nil : exists[0...-1].join(', ')
      skipped = [items, exists[-1]].compact.join(' and ')
      Bundler.ui.warn "Skipped #{skipped} since they already exist."
    end
    Bundler.ui.warn "If you want to overwrite skipped stubs, use --force."
  end
end

def generate_standalone(groups)
  standalone_path = Bundler.settings[:path]
  bundler_path = File.join(standalone_path, "bundler")
  FileUtils.mkdir_p(bundler_path)
  paths = []
  if groups.empty?
    specs = @definition.requested_specs
  else
    specs = @definition.specs_for groups.map { |g| g.to_sym }
  end
  specs.each do |spec|
    next if spec.name == "bundler"
    next if spec.require_paths.nil? # builtin gems
    spec.require_paths.each do |path|
      full_path = File.join(spec.full_gem_path, path)
      gem_path = Pathname.new(full_path).relative_path_from(Bundler.root.join(bundler_path))
      paths << gem_path.to_s.sub("#{Bundler.ruby_version.engine}/#{RbConfig::CONFIG['ruby_version']}", '#{ruby_engine}/#{ruby_version}')
    end
  end
  File.open File.join(bundler_path, "setup.rb"), "w" do |file|
    file.puts "require 'rbconfig'"
    file.puts "# ruby 1.8.7 doesn't define RUBY_ENGINE"
    file.puts "ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : 'ruby'"
    file.puts "ruby_version = RbConfig::CONFIG[\"ruby_version\"]"
    file.puts "path = File.expand_path('..', __FILE__)"
    paths.each do |path|
      file.puts %{$:.unshift File.expand_path("\#{path}/#{path}")}
    end
  end
end

def generate_standalone_bundler_executable_stubs(spec)
  # double-assignment to avoid warnings about variables that will be used by ERB
  bin_path = Bundler.bin_path
  template = File.read(File.expand_path('../templates/Executable.standalone', __FILE__))
  ruby_command = ruby_command = Thor::Util.ruby_command
  spec.executables.each do |executable|
    next if executable == "bundle"
    standalone_path = standalone_path = Pathname(Bundler.settings[:path]).expand_path.relative_path_from(bin_path)
    executable_path = executable_path = Pathname(spec.full_gem_path).join(spec.bindir, executable).relative_path_from(bin_path)
    File.open "#{bin_path}/#{executable}", 'w', 0755 do |f|
      f.puts ERB.new(template, nil, '-').result(binding)
    end
  end
end

def install_gem_from_spec(spec, standalone = false, worker = 0)
  # Fetch the build settings, if there are any
  settings             = Bundler.settings["build.#{spec.name}"]
  install_message      = nil
  post_install_message = nil
  debug_message        = nil
  Bundler.rubygems.with_build_args [settings] do
    install_message, post_install_message, debug_message = spec.source.install(spec)
    if install_message.include? 'Installing'
      Bundler.ui.confirm install_message
    else
      Bundler.ui.info install_message
    end
    Bundler.ui.debug debug_message if debug_message
    Bundler.ui.debug "#{worker}:  #{spec.name} (#{spec.version}) from #{spec.loaded_from}"
  end
  if Bundler.settings[:bin] && standalone
    generate_standalone_bundler_executable_stubs(spec)
  elsif Bundler.settings[:bin]
    generate_bundler_executable_stubs(spec, :force => true)
  end
  post_install_message
rescue Exception => e
  # if install hook failed or gem signature is bad, just die
  raise e if e.is_a?(Bundler::InstallHookError) || e.is_a?(Bundler::SecurityError)
  # other failure, likely a native extension build failure
  Bundler.ui.info ""
  Bundler.ui.warn "#{e.class}: #{e.message}"
  msg = "An error occurred while installing #{spec.name} (#{spec.version}),"
  msg << " and Bundler cannot continue."
  unless spec.source.options["git"]
    msg << "\nMake sure that `gem install"
    msg << " #{spec.name} -v '#{spec.version}'` succeeds before bundling."
  end
  Bundler.ui.debug e.backtrace.join("\n")
  raise Bundler::InstallError, msg
end

def install_in_parallel(size, standalone)
  name2spec = {}
  remains = {}
  enqueued = {}
  specs.each do |spec|
    name2spec[spec.name] = spec
    remains[spec.name] = true
  end
  worker_pool = ParallelWorkers.worker_pool size, lambda { |name, worker|
    spec = name2spec[name]
    message = install_gem_from_spec spec, standalone, worker
    { :name => spec.name, :post_install => message }
  }
  # Keys in the remains hash represent uninstalled gems specs.
  # We enqueue all gem specs that do not have any dependencies.
  # Later we call this lambda again to install specs that depended on
  # previously installed specifications. We continue until all specs
  # are installed.
  enqueue_remaining_specs = lambda do
    remains.keys.each do |name|
      next if enqueued[name]
      spec = name2spec[name]
      if ready_to_install?(spec, remains)
        worker_pool.enq name
        enqueued[name] = true
      end
    end
  end
  enqueue_remaining_specs.call
  until remains.empty?
    message = worker_pool.deq
    remains.delete message[:name]
    if message[:post_install]
      Installer.post_install_messages[message[:name]] = message[:post_install]
    end
    enqueue_remaining_specs.call
  end
  message
ensure
  worker_pool && worker_pool.stop
end

def install_sequentially(standalone)
  specs.each do |spec|
    message = install_gem_from_spec spec, standalone, 0
    if message
      Installer.post_install_messages[spec.name] = message
    end
  end
end

def ready_to_install?(spec, remains)
  spec.dependencies.none? do |dep|
    next if dep.type == :development || dep.name == spec.name
    remains[dep.name]
  end
end

def run(options)
  create_bundle_path
  if Bundler.settings[:frozen]
    @definition.ensure_equivalent_gemfile_and_lockfile(options[:deployment])
  end
  if dependencies.empty?
    Bundler.ui.warn "The Gemfile specifies no dependencies"
    lock
    return
  end
  if Bundler.default_lockfile.exist? && !options["update"]
    local = Bundler.ui.silence do
      begin
        tmpdef = Definition.build(Bundler.default_gemfile, Bundler.default_lockfile, nil)
        true unless tmpdef.new_platform? || tmpdef.missing_specs.any?
      rescue BundlerError
      end
    end
  end
  # Since we are installing, we can resolve the definition
  # using remote specs
  unless local
    options["local"] ? @definition.resolve_with_cache! : @definition.resolve_remotely!
  end
  # Must install gems in the order that the resolver provides
  # as dependencies might actually affect the installation of
  # the gem.
  Installer.post_install_messages = {}
  # the order that the resolver provides is significant, since
  # dependencies might actually affect the installation of a gem.
  # that said, it's a rare situation (other than rake), and parallel
  # installation is just SO MUCH FASTER. so we let people opt in.
  jobs = [Bundler.settings[:jobs].to_i-1, 1].max
  if jobs > 1 && can_install_parallely?
    install_in_parallel jobs, options[:standalone]
  else
    install_sequentially options[:standalone]
  end
  lock unless Bundler.settings[:frozen]
  generate_standalone(options[:standalone]) if options[:standalone]
end