module Gem::BundlerVersionFinder

# File lib/rubygems/bundler_version_finder.rb, line 4
def self.bundler_version
  return if bundle_config_version == "system"

  v = ENV["BUNDLER_VERSION"]
  v = nil if v&.empty?

  v ||= bundle_update_bundler_version
  return if v == true

  v ||= lockfile_version
  return unless v

  Gem::Version.new(v)
end

# File lib/rubygems/bundler_version_finder.rb, line 19
def self.prioritize!(specs)
  exact_match_index = specs.find_index {|spec| spec.version == bundler_version }
  return unless exact_match_index

  specs.unshift(specs.delete_at(exact_match_index))
end

# File lib/rubygems/bundler_version_finder.rb, line 84
def self.bundle_config_version
  config_file = bundler_config_file
  return unless config_file && File.file?(config_file)

  contents = File.read(config_file)
  contents =~ /^BUNDLE_VERSION:\s*["']?([^"'\s]+)["']?\s*$/

  $1
end

# File lib/rubygems/bundler_version_finder.rb, line 26
def self.bundle_update_bundler_version
  return unless ["bundle", "bundler"].include? File.basename($0)
  return unless "update".start_with?(ARGV.first || " ")
  bundler_version = nil
  update_index = nil
  ARGV.each_with_index do |a, i|
    if update_index && update_index.succ == i && a =~ Gem::Version::ANCHORED_VERSION_PATTERN
      bundler_version = a
    end
    next unless a =~ /\A--bundler(?:[= ](#{Gem::Version::VERSION_PATTERN}))?\z/
    bundler_version = $1 || true
    update_index = i
  end
  bundler_version
end

# File lib/rubygems/bundler_version_finder.rb, line 95
def self.bundler_config_file
  # see Bundler::Settings#global_config_file and local_config_file
  # global
  if ENV["BUNDLE_CONFIG"] && !ENV["BUNDLE_CONFIG"].empty?
    ENV["BUNDLE_CONFIG"]
  elsif ENV["BUNDLE_USER_CONFIG"] && !ENV["BUNDLE_USER_CONFIG"].empty?
    ENV["BUNDLE_USER_CONFIG"]
  elsif ENV["BUNDLE_USER_HOME"] && !ENV["BUNDLE_USER_HOME"].empty?
    ENV["BUNDLE_USER_HOME"] + "config"
  elsif Gem.user_home && !Gem.user_home.empty?
    Gem.user_home + ".bundle/config"
  else
    # local
    "config"
  end
end

# File lib/rubygems/bundler_version_finder.rb, line 51
def self.lockfile_contents
  gemfile = ENV["BUNDLE_GEMFILE"]
  gemfile = nil if gemfile&.empty?

  unless gemfile
    begin
      Gem::Util.traverse_parents(Dir.pwd) do |directory|
        next unless gemfile = Gem::GEM_DEP_FILES.find {|f| File.file?(f) }

        gemfile = File.join directory, gemfile
        break
      end
    rescue Errno::ENOENT
      return
    end
  end

  return unless gemfile

  lockfile = ENV["BUNDLE_LOCKFILE"]
  lockfile = nil if lockfile&.empty?

  lockfile ||= case gemfile
               when "gems.rb" then "gems.locked"
               else "#{gemfile}.lock"
  end

  return unless File.file?(lockfile)

  File.read(lockfile)
end

# File lib/rubygems/bundler_version_finder.rb, line 43
def self.lockfile_version
  return unless contents = lockfile_contents
  regexp = /\n\nBUNDLED WITH\n\s{2,}(#{Gem::Version::VERSION_PATTERN})\n/
  return unless contents =~ regexp
  $1
end