class ChefConfig::PathHelper

def self.all_homes(*args)
  paths = []
  if ChefConfig.windows?
    # By default, Ruby uses the the following environment variables to determine Dir.home:
    # HOME
    # HOMEDRIVE HOMEPATH
    # USERPROFILE
    # Ruby only checks to see if the variable is specified - not if the directory actually exists.
    # On Windows, HOMEDRIVE HOMEPATH can point to a different location (such as an unavailable network mounted drive)
    # while USERPROFILE points to the location where the user application settings and profile are stored.  HOME
    # is not defined as an environment variable (usually).  If the home path actually uses UNC, then the prefix is
    # HOMESHARE instead of HOMEDRIVE.
    #
    # We instead walk down the following and only include paths that actually exist.
    # HOME
    # HOMEDRIVE HOMEPATH
    # HOMESHARE HOMEPATH
    # USERPROFILE
    paths << ENV['HOME']
    paths << ENV['HOMEDRIVE'] + ENV['HOMEPATH'] if ENV['HOMEDRIVE'] && ENV['HOMEPATH']
    paths << ENV['HOMESHARE'] + ENV['HOMEPATH'] if ENV['HOMESHARE'] && ENV['HOMEPATH']
    paths << ENV['USERPROFILE']
  end
  paths << Dir.home if ENV['HOME']
  # Depending on what environment variables we're using, the slashes can go in any which way.
  # Just change them all to / to keep things consistent.
  # Note: Maybe this is a bad idea on some unixy systems where \ might be a valid character depending on
  # the particular brand of kool-aid you consume.  This code assumes that \ and / are both
  # path separators on any system being used.
  paths = paths.map { |home_path| home_path.gsub(path_separator, ::File::SEPARATOR) if home_path }
  # Filter out duplicate paths and paths that don't exist.
  valid_paths = paths.select { |home_path| home_path && Dir.exists?(home_path) }
  valid_paths = valid_paths.uniq
  # Join all optional path elements at the end.
  # If a block is provided, invoke it - otherwise just return what we've got.
  joined_paths = valid_paths.map { |home_path| File.join(home_path, *args) }
  if block_given?
    joined_paths.each { |p| yield p }
  else
    joined_paths
  end
end

def self.canonical_path(path, add_prefix=true)
  # First remove extra separators and resolve any relative paths
  abs_path = File.absolute_path(path)
  if ChefConfig.windows?
    # Add the \\?\ API prefix on Windows unless add_prefix is false
    # Downcase on Windows where paths are still case-insensitive
    abs_path.gsub!(::File::SEPARATOR, path_separator)
    if add_prefix && abs_path !~ /^\\\\?\\/
      abs_path.insert(0, "\\\\?\\")
    end
    abs_path.downcase!
  end
  abs_path
end

def self.cleanpath(path)
  path = Pathname.new(path).cleanpath.to_s
  # ensure all forward slashes are backslashes
  if ChefConfig.windows?
    path = path.gsub(File::SEPARATOR, path_separator)
  end
  path
end

def self.dirname(path)
  if ChefConfig.windows?
    # Find the first slash, not counting trailing slashes
    end_slash = path.size
    loop do
      slash = path.rindex(/[#{Regexp.escape(File::SEPARATOR)}#{Regexp.escape(path_separator)}]/, end_slash - 1)
      if !slash
        return end_slash == path.size ? '.' : path_separator
      elsif slash == end_slash - 1
        end_slash = slash
      else
        return path[0..slash-1]
      end
    end
  else
    ::File.dirname(path)
  end
end

def self.escape_glob(*parts)
  path = cleanpath(join(*parts))
  path.gsub(/[\\\{\}\[\]\*\?]/) { |x| "\\"+x }
end

def self.home(*args)
  @@home_dir ||= self.all_homes { |p| break p }
  if @@home_dir
    path = File.join(@@home_dir, *args)
    block_given? ? (yield path) : path
  end
end

def self.join(*args)
  path_separator_regex = Regexp.escape(File::SEPARATOR)
  unless path_separator == File::SEPARATOR
    path_separator_regex << Regexp.escape(path_separator)
  end
  trailing_slashes = /[#{path_separator_regex}]+$/
  leading_slashes = /^[#{path_separator_regex}]+/
  args.flatten.inject() do |joined_path, component|
    joined_path = joined_path.sub(trailing_slashes, '')
    component = component.sub(leading_slashes, '')
    joined_path += "#{path_separator}#{component}"
  end
end

def self.path_separator
  if ChefConfig.windows?
    File::ALT_SEPARATOR || BACKSLASH
  else
    File::SEPARATOR
  end
end

def self.paths_eql?(path1, path2)
  canonical_path(path1) == canonical_path(path2)
end

def self.printable?(string)
  # returns true if string is free of non-printable characters (escape sequences)
  # this returns false for whitespace escape sequences as well, e.g. \n\t
  if string =~ /[^[:print:]]/
    false
  else
    true
  end
end

def self.relative_path_from(from, to)
  Pathname.new(cleanpath(to)).relative_path_from(Pathname.new(cleanpath(from)))
end

def self.validate_path(path)
  if ChefConfig.windows?
    unless printable?(path)
      msg = "Path '#{path}' contains non-printable characters. Check that backslashes are escaped with another backslash (e.g. C:\\\\Windows) in double-quoted strings."
      ChefConfig.logger.error(msg)
      raise ChefConfig::InvalidPath, msg
    end
    if windows_max_length_exceeded?(path)
      ChefConfig.logger.debug("Path '#{path}' is longer than #{WIN_MAX_PATH}, prefixing with'\\\\?\\'")
      path.insert(0, "\\\\?\\")
    end
  end
  path
end

def self.windows_max_length_exceeded?(path)
  # Check to see if paths without the \\?\ prefix are over the maximum allowed length for the Windows API
  # http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247%28v=vs.85%29.aspx
  unless path =~ /^\\\\?\\/
    if path.length > WIN_MAX_PATH
      return true
    end
  end
  false
end