class Gem::SpecificationRecord

def self.dirs_from(paths)
  paths.map do |path|
    File.join(path, "specifications")
  end
end

def self.from_path(path)
  new(dirs_from([path]))
end

def add_spec(spec)
  return if all.include? spec
  all << spec
  stubs << spec
  (@stubs_by_name[spec.name] ||= []) << spec
  Gem::Specification._resort!(@stubs_by_name[spec.name])
  Gem::Specification._resort!(stubs)
end

def all
  @all ||= stubs.map(&:to_spec)
end

def all=(specs)
  @stubs_by_name = specs.group_by(&:name)
  @all = @stubs = specs
end

def all_names
  all.map(&:full_name)
end

def each
  return enum_for(:each) unless block_given?
  all.each do |x|
    yield x
  end
end

def find_active_stub_by_path(path)
  stub = @active_stub_with_requirable_file[path] ||= stubs.find do |s|
    s.activated? && s.contains_requirable_file?(path)
  end || NOT_FOUND
  stub.this
end

def find_all_by_name(name, *requirements)
  req = Gem::Requirement.create(*requirements)
  env_req = Gem.env_requirement(name)
  matches = stubs_for(name).find_all do |spec|
    req.satisfied_by?(spec.version) && env_req.satisfied_by?(spec.version)
  end.map(&:to_spec)
  if name == "bundler" && !req.specific?
    require_relative "bundler_version_finder"
    Gem::BundlerVersionFinder.prioritize!(matches)
  end
  matches
end

def find_by_path(path)
  path = path.dup.freeze
  spec = @spec_with_requirable_file[path] ||= stubs.find do |s|
    s.contains_requirable_file? path
  end || NOT_FOUND
  spec.to_spec
end

def find_inactive_by_path(path)
  stub = stubs.find do |s|
    next if s.activated?
    s.contains_requirable_file? path
  end
  stub&.to_spec
end

def initialize(dirs)
  @all = nil
  @stubs = nil
  @stubs_by_name = {}
  @spec_with_requirable_file = {}
  @active_stub_with_requirable_file = {}
  @dirs = dirs
end

def installed_stubs(pattern)
  map_stubs(pattern) do |path, base_dir, gems_dir|
    Gem::StubSpecification.gemspec_stub(path, base_dir, gems_dir)
  end
end

def latest_spec_for(name)
  latest_specs(true).find {|installed_spec| installed_spec.name == name }
end

def latest_specs(prerelease)
  Gem::Specification._latest_specs stubs, prerelease
end

def map_stubs(pattern)
  @dirs.flat_map do |dir|
    base_dir = File.dirname dir
    gems_dir = File.join base_dir, "gems"
    Gem::Specification.gemspec_stubs_in(dir, pattern) {|path| yield path, base_dir, gems_dir }
  end
end

def remove_spec(spec)
  all.delete spec.to_spec
  stubs.delete spec
  (@stubs_by_name[spec.name] || []).delete spec
end

def stubs
  @stubs ||= begin
    pattern = "*.gemspec"
    stubs = stubs_for_pattern(pattern, false)
    @stubs_by_name = stubs.select {|s| Gem::Platform.match_spec? s }.group_by(&:name)
    stubs
  end
end

def stubs_for(name)
  if @stubs
    @stubs_by_name[name] || []
  else
    @stubs_by_name[name] ||= stubs_for_pattern("#{name}-*.gemspec").select do |s|
      s.name == name
    end
  end
end

def stubs_for_pattern(pattern, match_platform = true)
  installed_stubs = installed_stubs(pattern)
  installed_stubs.select! {|s| Gem::Platform.match_spec? s } if match_platform
  stubs = installed_stubs + Gem::Specification.default_stubs(pattern)
  Gem::Specification._resort!(stubs)
  stubs
end