class Bundler::CompactIndexClient::Cache

def checksums
  checksums = {}
  lines(versions_path).each do |line|
    name, _, checksum = line.split(" ", 3)
    checksums[name] = checksum
  end
  checksums
end

def dependencies(name)
  lines(info_path(name)).map do |line|
    parse_gem(line)
  end
end

def info_path(name)
  directory.join("info", name.to_s)
end

def initialize(directory)
  @directory = Pathname.new(directory).expand_path
  FileUtils.mkdir_p info_path(nil)
end

def lines(path)
  return [] unless path.file?
  lines = path.read.split("\n")
  header = lines.index("---")
  lines = header ? lines[header + 1..-1] : lines
end

def names
  lines(names_path)
end

def names_path
  directory.join("names")
end

def parse_dependency(string)
  dependency = string.split(":")
  dependency[-1] = dependency[-1].split("&") if dependency.size > 1
  dependency
end

def parse_gem(string)
  version_and_platform, rest = string.split(" ", 2)
  version, platform = version_and_platform.split("-", 2)
  dependencies, requirements = rest.split("|", 2).map {|s| s.split(",") } if rest
  dependencies = dependencies ? dependencies.map {|d| parse_dependency(d) } : []
  requirements = requirements ? requirements.map {|r| parse_dependency(r) } : []
  [version, platform, dependencies, requirements]
end

def specific_dependency(name, version, platform)
  pattern = [version, platform].compact.join("-")
  return nil if pattern.empty?
  gem_lines = info_path(name).read
  gem_line = gem_lines[/^#{Regexp.escape(pattern)}\b.*/, 0]
  gem_line ? parse_gem(gem_line) : nil
end

def versions
  versions_by_name = Hash.new {|hash, key| hash[key] = [] }
  info_checksums_by_name = {}
  lines(versions_path).each do |line|
    name, versions_string, info_checksum = line.split(" ", 3)
    info_checksums_by_name[name] = info_checksum || ""
    versions_string.split(",").each do |version|
      if version.start_with?("-")
        version = version[1..-1].split("-", 2).unshift(name)
        versions_by_name[name].delete(version)
      else
        version = version.split("-", 2).unshift(name)
        versions_by_name[name] << version
      end
    end
  end
  [versions_by_name, info_checksums_by_name]
end

def versions_path
  directory.join("versions")
end