class Bundler::Index

def self.application_cached_gems
  path = "#{Bundler.root}/vendor/cache"
  if File.directory?(path)
    from_cached_specs(path)
  end
end

def self.build
  i = new
  yield i
  i
end

def self.bundler_gems
  Source::BundlerGems.new.specs
end

def self.cached_gems
  build do |idx|
    idx.use application_cached_gems
    idx.use system_cached_gems
  end
end

def self.from_cached_specs(path)
  Source::GemCache.new("path" => path).specs
end

def self.installed_gems
  build do |idx|
    idx.use bundler_gems
    idx.use system_gems
  end
end

def self.system_cached_gems
  from_cached_specs("#{Bundler.bundle_path}/cache")
end

def self.system_gems
  Source::SystemGems.new.specs
end

def <<(spec)
  arr = @specs[spec.name]
  arr.delete_if do |s|
    s.version == spec.version && s.platform == spec.platform
  end
  arr << spec
  spec
end

def each(&blk)
  @specs.values.each do |specs|
    specs.each(&blk)
  end
end

def empty?
  each { return false }
  true
end

def initialize
  @cache = {}
  @specs = Hash.new { |h,k| h[k] = [] }
end

def initialize_copy(o)
  super
  @cache = {}
  @specs = Hash.new { |h,k| h[k] = [] }
  merge!(o)
end

def search(query)
  case query
  when Gem::Specification, RemoteSpecification then search_by_spec(query)
  when String then @specs[query]
  else search_by_dependency(query)
  end
end

def search_by_dependency(dependency)
  @cache[dependency.hash] ||= begin
    specs = @specs[dependency.name]
    wants_prerelease = dependency.requirement.prerelease?
    only_prerelease  = specs.all? {|spec| spec.version.prerelease? }
    found = specs.select { |spec| dependency =~ spec }
    unless wants_prerelease || only_prerelease
      found.reject! { |spec| spec.version.prerelease? }
    end
    found.sort_by {|s| [s.version, s.platform.to_s == 'ruby' ? "\0" : s.platform.to_s] }
  end
end

def search_by_spec(spec)
  @specs[spec.name].select { |s| s.version == spec.version && s.platform == spec.platform }
end

def sources
  @specs.values.map do |specs|
    specs.map{|s| s.source.class }
  end.flatten.uniq
end

def use(other)
  return unless other
  other.each do |s|
    next if search_by_spec(s).any?
    @specs[s.name] << s
  end
  self
end