class Bundler::SpecSet

def -(other)
  SpecSet.new(to_a - other.to_a)
end

def <<(spec)
  @specs << spec
end

def [](key)
  key = key.name if key.respond_to?(:name)
  lookup[key]&.reverse || []
end

def []=(key, value)
  @specs << value
  reset!
end

def add_extra_platforms!(platforms)
  return platforms.concat([Gem::Platform::RUBY]).uniq if @specs.empty?
  new_platforms = all_platforms.select do |platform|
    next if platforms.include?(platform)
    next unless GemHelpers.generic(platform) == Gem::Platform::RUBY
    complete_platform(platform)
  end
  return platforms if new_platforms.empty?
  platforms.concat(new_platforms)
  less_specific_platform = new_platforms.find {|platform| platform != Gem::Platform::RUBY && Bundler.local_platform === platform && platform === Bundler.local_platform }
  platforms.delete(Bundler.local_platform) if less_specific_platform
  platforms
end

def all_platforms
  @specs.flat_map {|spec| spec.source.specs.search([spec.name, spec.version]).map(&:platform) }.uniq
end

def complete_platform(platform)
  new_specs = []
  valid_platform = lookup.all? do |_, specs|
    spec = specs.first
    matching_specs = spec.source.specs.search([spec.name, spec.version])
    platform_spec = GemHelpers.select_best_platform_match(matching_specs, platform).find do |s|
      s.matches_current_metadata? && valid_dependencies?(s)
    end
    if platform_spec
      new_specs << LazySpecification.from_spec(platform_spec) unless specs.include?(platform_spec)
      true
    else
      false
    end
  end
  if valid_platform && new_specs.any?
    @specs.concat(new_specs)
    reset!
  end
  valid_platform
end

def complete_platforms!(platforms)
  platforms.each do |platform|
    complete_platform(platform)
  end
end

def delete(specs)
  specs.each {|spec| @specs.delete(spec) }
  reset!
end

def delete_by_name(name)
  @specs.reject! {|spec| spec.name == name }
  reset!
end

def each(&b)
  sorted.each(&b)
end

def empty?
  @specs.empty?
end

def extract_circular_gems(error)
  error.message.scan(/@name="(.*?)"/).flatten
end

def find_by_name_and_platform(name, platform)
  @specs.detect {|spec| spec.name == name && spec.match_platform(platform) }
end

def for(dependencies, check = false, platforms = [nil])
  handled = ["bundler"].product(platforms).map {|k| [k, true] }.to_h
  deps = dependencies.product(platforms)
  specs = []
  loop do
    break unless dep = deps.shift
    name = dep[0].name
    platform = dep[1]
    incomplete = false
    key = [name, platform]
    next if handled.key?(key)
    handled[key] = true
    specs_for_dep = specs_for_dependency(*dep)
    if specs_for_dep.any?
      specs.concat(specs_for_dep)
      specs_for_dep.first.dependencies.each do |d|
        next if d.type == :development
        incomplete = true if d.name != "bundler" && lookup[d.name].nil?
        deps << [d, dep[1]]
      end
    else
      incomplete = true
    end
    if incomplete && check
      @incomplete_specs += lookup[name] || [LazySpecification.new(name, nil, nil)]
    end
  end
  specs.uniq
end

def incomplete_for_platform?(deps, platform)
  return false if @specs.empty?
  @incomplete_specs = []
  self.for(deps, true, [platform])
  @incomplete_specs.any?
end

def initialize(specs, incomplete_specs = [])
  @specs = specs
  @incomplete_specs = incomplete_specs
end

def length
  @specs.length
end

def lookup
  @lookup ||= begin
    lookup = {}
    @specs.each do |s|
      lookup[s.name] ||= []
      lookup[s.name] << s
    end
    lookup
  end
end

def materialize(deps)
  materialized = self.for(deps, true)
  SpecSet.new(materialized, incomplete_specs)
end

def materialized_for_all_platforms
  @specs.map do |s|
    next s unless s.is_a?(LazySpecification)
    s.source.remote!
    spec = s.materialize_for_installation
    raise GemNotFound, "Could not find #{s.full_name} in any of the sources" unless spec
    spec
  end
end

def missing_specs
  @specs.select {|s| s.is_a?(LazySpecification) }
end

def names
  lookup.keys
end

def reset!
  @sorted = nil
  @lookup = nil
end

def size
  @specs.size
end

def sort!
  self
end

def sorted
  rake = @specs.find {|s| s.name == "rake" }
  begin
    @sorted ||= ([rake] + tsort).compact.uniq
  rescue TSort::Cyclic => error
    cgems = extract_circular_gems(error)
    raise CyclicDependencyError, "Your bundle requires gems that depend" \
      " on each other, creating an infinite loop. Please remove either" \
      " gem '#{cgems[0]}' or gem '#{cgems[1]}' and try again."
  end
end

def specs_for_dependency(dep, platform)
  specs_for_name = lookup[dep.name]
  return [] unless specs_for_name
  matching_specs = if dep.force_ruby_platform
    GemHelpers.force_ruby_platform(specs_for_name)
  else
    GemHelpers.select_best_platform_match(specs_for_name, platform || Bundler.local_platform)
  end
  matching_specs.map!(&:materialize_for_installation).compact! if platform.nil?
  matching_specs
end

def to_a
  sorted.dup
end

def to_hash
  lookup.dup
end

def tsort_each_child(s)
  s.dependencies.sort_by(&:name).each do |d|
    next if d.type == :development
    specs_for_name = lookup[d.name]
    next unless specs_for_name
    specs_for_name.each {|s2| yield s2 }
  end
end

def tsort_each_node
  # MUST sort by name for backwards compatibility
  @specs.sort_by(&:name).each {|s| yield s }
end

def valid_dependencies?(s)
  validate_deps(s) == :valid
end

def validate_deps(s)
  s.runtime_dependencies.each do |dep|
    next if dep.name == "bundler"
    return :missing unless names.include?(dep.name)
    return :invalid if none? {|spec| dep.matches_spec?(spec) }
  end
  :valid
end

def what_required(spec)
  unless req = find {|s| s.runtime_dependencies.any? {|d| d.name == spec.name } }
    return [spec]
  end
  what_required(req) << spec
end