class Gem::Uninstaller

def abort_on_dependent? # :nodoc:
  @abort_on_dependent
end

def ask_if_ok spec # :nodoc:
  msg = ['']
  msg << 'You have requested to uninstall the gem:'
  msg << "\t#{spec.full_name}"
  msg << ''
  siblings = Gem::Specification.select do |s|
               s.name == spec.name && s.full_name != spec.full_name
             end
  spec.dependent_gems.each do |dep_spec, dep, satlist|
    unless siblings.any? { |s| s.satisfies_requirement? dep }
      msg << "#{dep_spec.name}-#{dep_spec.version} depends on #{dep}"
    end
  end
  msg << 'If you remove this gem, these dependencies will not be met.'
  msg << 'Continue with Uninstall?'
  return ask_yes_no(msg.join("\n"), false)
end

def dependencies_ok? spec # :nodoc:
  return true if @force_ignore
  deplist = Gem::DependencyList.from_specs
  deplist.ok_to_remove?(spec.full_name, @check_dev)
end

def formatted_program_filename filename # :nodoc:
  # TODO perhaps the installer should leave a small manifest
  # of what it did for us to find rather than trying to recreate
  # it again.
  if @format_executable then
    require 'rubygems/installer'
    Gem::Installer.exec_format % File.basename(filename)
  else
    filename
  end
end

def initialize(gem, options = {})
  # TODO document the valid options
  @gem                = gem
  @version            = options[:version] || Gem::Requirement.default
  @gem_home           = File.expand_path(options[:install_dir] || Gem.dir)
  @force_executables  = options[:executables]
  @force_all          = options[:all]
  @force_ignore       = options[:ignore]
  @bin_dir            = options[:bin_dir]
  @format_executable  = options[:format_executable]
  @abort_on_dependent = options[:abort_on_dependent]
  # Indicate if development dependencies should be checked when
  # uninstalling. (default: false)
  #
  @check_dev         = options[:check_dev]
  if options[:force]
    @force_all = true
    @force_ignore = true
  end
  # only add user directory if install_dir is not set
  @user_install = false
  @user_install = options[:user_install] unless options[:install_dir]
end

def path_ok?(gem_dir, spec)
  full_path     = File.join gem_dir, 'gems', spec.full_name
  original_path = File.join gem_dir, 'gems', spec.original_name
  full_path == spec.full_gem_path || original_path == spec.full_gem_path
end

def remove(spec)
  unless path_ok?(@gem_home, spec) or
         (@user_install and path_ok?(Gem.user_dir, spec)) then
    e = Gem::GemNotInHomeException.new \
          "Gem '#{spec.full_name}' is not installed in directory #{@gem_home}"
    e.spec = spec
    raise e
  end
  raise Gem::FilePermissionError, spec.base_dir unless
    File.writable?(spec.base_dir)
  FileUtils.rm_rf spec.full_gem_path
  FileUtils.rm_rf spec.extension_dir
  old_platform_name = spec.original_name
  gemspec           = spec.spec_file
  unless File.exist? gemspec then
    gemspec = File.join(File.dirname(gemspec), "#{old_platform_name}.gemspec")
  end
  FileUtils.rm_rf gemspec
  gem = spec.cache_file
  gem = File.join(spec.cache_dir, "#{old_platform_name}.gem") unless
    File.exist? gem
  FileUtils.rm_rf gem
  Gem::RDoc.new(spec).remove
  say "Successfully uninstalled #{spec.full_name}"
  Gem::Specification.reset
end

def remove_all(list)
  list.each { |spec| uninstall_gem spec }
end

def remove_executables(spec)
  return if spec.nil? or spec.executables.empty?
  executables = spec.executables.clone
  # Leave any executables created by other installed versions
  # of this gem installed.
  list = Gem::Specification.find_all { |s|
    s.name == spec.name && s.version != spec.version
  }
  list.each do |s|
    s.executables.each do |exe_name|
      executables.delete exe_name
    end
  end
  return if executables.empty?
  executables = executables.map { |exec| formatted_program_filename exec }
  remove = if @force_executables.nil? then
             ask_yes_no("Remove executables:\n" +
                        "\t#{executables.join ', '}\n\n" +
                        "in addition to the gem?",
                        true)
           else
             @force_executables
           end
  if remove then
    bin_dir = @bin_dir || Gem.bindir(spec.base_dir)
    raise Gem::FilePermissionError, bin_dir unless File.writable? bin_dir
    executables.each do |exe_name|
      say "Removing #{exe_name}"
      exe_file = File.join bin_dir, exe_name
      FileUtils.rm_f exe_file
      FileUtils.rm_f "#{exe_file}.bat"
    end
  else
    say "Executables and scripts will remain installed."
  end
end

def uninstall
  dependency = Gem::Dependency.new @gem, @version
  list = []
  dirs =
    Gem::Specification.dirs +
    [Gem::Specification.default_specifications_dir]
  Gem::Specification.each_spec dirs do |spec|
    next unless dependency.matches_spec? spec
    list << spec
  end
  default_specs, list = list.partition do |spec|
    spec.default_gem?
  end
  list, other_repo_specs = list.partition do |spec|
    @gem_home == spec.base_dir or
      (@user_install and spec.base_dir == Gem.user_dir)
  end
  list.sort!
  if list.empty? then
    if other_repo_specs.empty?
      if default_specs.empty?
        raise Gem::InstallError, "gem #{@gem.inspect} is not installed"
      else
        message =
          "gem #{@gem.inspect} cannot be uninstalled " +
          "because it is a default gem"
        raise Gem::InstallError, message
      end
    end
    other_repos = other_repo_specs.map { |spec| spec.base_dir }.uniq
    message = ["#{@gem} is not installed in GEM_HOME, try:"]
    message.concat other_repos.map { |repo|
      "\tgem uninstall -i #{repo} #{@gem}"
    }
    raise Gem::InstallError, message.join("\n")
  elsif @force_all then
    remove_all list
  elsif list.size > 1 then
    gem_names = list.map { |gem| gem.full_name }
    gem_names << "All versions"
    say
    _, index = choose_from_list "Select gem to uninstall:", gem_names
    if index == list.size then
      remove_all list
    elsif index >= 0 && index < list.size then
      uninstall_gem list[index]
    else
      say "Error: must enter a number [1-#{list.size+1}]"
    end
  else
    uninstall_gem list.first
  end
end

def uninstall_gem(spec)
  @spec = spec
  unless dependencies_ok? spec
    if abort_on_dependent? || !ask_if_ok(spec)
      raise Gem::DependencyRemovalException,
        "Uninstallation aborted due to dependent gem(s)"
    end
  end
  Gem.pre_uninstall_hooks.each do |hook|
    hook.call self
  end
  remove_executables @spec
  remove @spec
  Gem.post_uninstall_hooks.each do |hook|
    hook.call self
  end
  @spec = nil
end