require 'rubygems/command'
require 'rubygems/command_manager'
require 'rubygems/install_update_options'
require 'rubygems/local_remote_options'
require 'rubygems/spec_fetcher'
require 'rubygems/version_option'
require 'rubygems/commands/install_command'

class Gem::Commands::UpdateCommand < Gem::Command

  include Gem::InstallUpdateOptions
  include Gem::LocalRemoteOptions
  include Gem::VersionOption

  def initialize
    super 'update',
          'Update the named gems (or all installed gems) in the local repository',
      :generate_rdoc => true,
      :generate_ri   => true,
      :force         => false

    add_install_update_options

    OptionParser.accept Gem::Requirement do |value|
      Gem::Requirement.new value
    end

    add_option('--system [VERSION]', Gem::Requirement,
               'Update the RubyGems system software') do |value, options|
      options[:system] = value || Gem::Requirement.default
    end

    add_local_remote_options
    add_platform_option
    add_prerelease_option "as update targets"
  end

  def arguments # :nodoc:
    "GEMNAME       name of gem to update"
  end

  def defaults_str # :nodoc:
    "--rdoc --ri --no-force --install-dir #{Gem.dir}"
  end

  def usage # :nodoc:
    "#{program_name} GEMNAME [GEMNAME ...]"
  end

  def execute
    hig = {}

    if options[:system] then
      update_rubygems
      return
    else
      say "Updating installed gems"

      hig = {} # highest installed gems

      Gem.source_index.each do |name, spec|
        if hig[spec.name].nil? or hig[spec.name].version < spec.version then
          hig[spec.name] = spec
        end
      end
    end

    gems_to_update = which_to_update hig, options[:args]

    updated = []

    installer = Gem::DependencyInstaller.new options

    gems_to_update.uniq.sort.each do |name|
      next if updated.any? { |spec| spec.name == name }
      success = false

      say "Updating #{name}"
      begin
        installer.install name
        success = true
      rescue Gem::InstallError => e
        alert_error "Error installing #{name}:\n\t#{e.message}"
        success = false
      end

      installer.installed_gems.each do |spec|
        updated << spec
        say "Successfully installed #{spec.full_name}" if success
      end
    end

    if updated.empty? then
      say "Nothing to update"
    else
      say "Gems updated: #{updated.map { |spec| spec.name }.join ', '}"

      if options[:generate_ri] then
        updated.each do |gem|
          Gem::DocManager.new(gem, options[:rdoc_args]).generate_ri
        end

        Gem::DocManager.update_ri_cache
      end

      if options[:generate_rdoc] then
        updated.each do |gem|
          Gem::DocManager.new(gem, options[:rdoc_args]).generate_rdoc
        end
      end
    end
  end

  ##
  # Update RubyGems software to the latest version.

  def update_rubygems
    say "Updating RubyGems"

    unless options[:args].empty? then
      raise "No gem names are allowed with the --system option"
    end

    options[:user_install] = false

    Gem.source_index.refresh!

    req = if Gem::Requirement === options[:system] then
            options[:system]
          else
            Gem::Requirement.new
          end

    update_gems       = Gem.source_index.find_name 'rubygems-update', req
    latest_update_gem = update_gems.last

    say "Updating RubyGems to #{latest_update_gem.version}"
    version = latest_update_gem.version

    args = []
    args << '--prefix' << Gem.prefix if Gem.prefix
    args << '--no-rdoc' unless options[:generate_rdoc]
    args << '--no-ri' unless options[:generate_ri]
    args << '--no-format-executable' if options[:no_format_executable]

    update_dir = File.join Gem.dir, 'gems', "rubygems-update-#{version}"

    Dir.chdir update_dir do
      say "Installing RubyGems #{version}"
      setup_cmd = "#{Gem.ruby} setup.rb #{args.join ' '}"

      # Make sure old rubygems isn't loaded
      old = ENV["RUBYOPT"]
      ENV.delete("RUBYOPT") if old
      installed = system setup_cmd
      say "RubyGems system software updated" if installed
      ENV["RUBYOPT"] = old if old
    end
  end

  def which_to_update(highest_installed_gems, gem_names)
    result = []

    highest_installed_gems.each do |l_name, l_spec|
      next if not gem_names.empty? and
              gem_names.all? { |name| /#{name}/ !~ l_spec.name }

      dependency = Gem::Dependency.new l_spec.name, "> #{l_spec.version}"

      fetcher = Gem::SpecFetcher.fetcher
      spec_tuples = fetcher.find_matching dependency

      matching_gems = spec_tuples.select do |(name, _, platform),|
        name == l_name and Gem::Platform.match platform
      end

      highest_remote_gem = matching_gems.sort_by do |(_, version),|
        version
      end.last

      if highest_remote_gem and
         l_spec.version < highest_remote_gem.first[1] then
        result << l_name
      end
    end

    result
  end

end

