#--
# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
# All rights reserved.
# See LICENSE.txt for permissions.
#++

require 'fileutils'
require 'rubygems'
require 'rubygems/dependency_list'
require 'rubygems/doc_manager'
require 'rubygems/user_interaction'

##
# An Uninstaller.
#
class Gem::Uninstaller

  include Gem::UserInteraction

  ##
  # Constructs an Uninstaller instance
  #
  # gem:: [String] The Gem name to uninstall
  #
  def initialize(gem, options)
    @gem = gem
    @version = options[:version] || Gem::Requirement.default
    @force_executables = options[:executables]
    @force_all = options[:all]
    @force_ignore = options[:ignore]
  end

  ##
  # Performs the uninstall of the Gem.  This removes the spec, the
  # Gem directory, and the cached .gem file,
  #
  def uninstall
    list = Gem.source_index.search(/^#{@gem}$/, @version)

    if list.empty? then
      raise Gem::InstallError, "Unknown gem #{@gem}-#{@version}"
    elsif list.size > 1 && @force_all
      remove_all(list.dup) 
      remove_executables(list.last)
    elsif list.size > 1 
      say 
      gem_names = list.collect {|gem| gem.full_name} + ["All versions"]
      gem_name, index =
        choose_from_list("Select gem to uninstall:", gem_names)
      if index == list.size
        remove_all(list.dup) 
        remove_executables(list.last)
      elsif index >= 0 && index < list.size
        to_remove = list[index]
        remove(to_remove, list)
        remove_executables(to_remove)
      else
        say "Error: must enter a number [1-#{list.size+1}]"
      end
    else
      remove(list[0], list.dup)
      remove_executables(list.last)
    end
  end
  
  ##
  # Remove executables and batch files (windows only) for the gem as
  # it is being installed
  #
  # gemspec::[Specification] the gem whose executables need to be removed.
  #
  def remove_executables(gemspec)
    return if gemspec.nil?
    if(gemspec.executables.size > 0)
      raise Gem::FilePermissionError.new(Gem.bindir) unless
        File.writable?(Gem.bindir)
      list = Gem.source_index.search(gemspec.name).delete_if { |spec|
        spec.version == gemspec.version
      }
      executables = gemspec.executables.clone
      list.each do |spec|
        spec.executables.each do |exe_name|
          executables.delete(exe_name)
        end
      end
      return if executables.size == 0
      answer = @force_executables || ask_yes_no(
        "Remove executables and scripts for\n" +
        "'#{gemspec.executables.join(", ")}' in addition to the gem?",
        true) # " # appease ruby-mode - don't ask
      unless answer
        say "Executables and scripts will remain installed."
        return
      else
        gemspec.executables.each do |exe_name|
          say "Removing #{exe_name}"
          File.unlink File.join(Gem.bindir, exe_name) rescue nil
          File.unlink File.join(Gem.bindir, exe_name + ".bat") rescue nil
        end
      end
    end
  end
  
  #
  # list:: the list of all gems to remove
  #
  # Warning: this method modifies the +list+ parameter.  Once it has
  # uninstalled a gem, it is removed from that list.
  #
  def remove_all(list)
    list.dup.each { |gem| remove(gem, list) }
  end

  #
  # spec:: the spec of the gem to be uninstalled
  # list:: the list of all such gems
  #
  # Warning: this method modifies the +list+ parameter.  Once it has
  # uninstalled a gem, it is removed from that list.
  #
  def remove(spec, list)
    unless ok_to_remove? spec then
      raise Gem::DependencyRemovalException,
            "Uninstallation aborted due to dependent gem(s)"
    end

    raise Gem::FilePermissionError, spec.installation_path unless
      File.writable?(spec.installation_path)

    FileUtils.rm_rf spec.full_gem_path

    original_platform_name = [
      spec.name, spec.version, spec.original_platform].join '-'

    spec_dir = File.join spec.installation_path, 'specifications'
    gemspec = File.join spec_dir, "#{spec.full_name}.gemspec"

    unless File.exist? gemspec then
      gemspec = File.join spec_dir, "#{original_platform_name}.gemspec"
    end

    FileUtils.rm_rf gemspec

    cache_dir = File.join spec.installation_path, 'cache'
    gem = File.join cache_dir, "#{spec.full_name}.gem"

    unless File.exist? gem then
      gem = File.join cache_dir, "#{original_platform_name}.gem"
    end

    FileUtils.rm_rf gem

    Gem::DocManager.new(spec).uninstall_doc

    say "Successfully uninstalled #{spec.full_name}"

    list.delete spec
  end

  def ok_to_remove?(spec)
    return true if @force_ignore

    srcindex = Gem::SourceIndex.from_installed_gems
    deplist = Gem::DependencyList.from_source_index srcindex
    deplist.ok_to_remove?(spec.full_name) || ask_if_ok(spec)
  end

  def ask_if_ok(spec)
    msg = ['']
    msg << 'You have requested to uninstall the gem:'
    msg << "\t#{spec.full_name}"
    spec.dependent_gems.each do |gem,dep,satlist|
      msg <<
        ("#{gem.name}-#{gem.version} depends on " +
        "[#{dep.name} (#{dep.version_requirements})]")
    end
    msg << 'If you remove this gems, one or more dependencies will not be met.'
    msg << 'Continue with Uninstall?'
    return ask_yes_no(msg.join("\n"), true)
  end

end