require "files/version"

module Files

  # class methods

  def self.default_options level = 2
    {:remove => true, :name => called_from(level)}
  end

  def self.called_from level = 1
    line = caller[level]
    line.gsub!(/^.:/, '') # correct for leading Windows C:
    File.basename line.split(':').first, ".rb"
  end

  def self.create options = default_options, &block
    require 'tmpdir'
    require 'fileutils'

    name = options[:name]
    root = Dir::tmpdir

    # if the user specified a root directory (instead of default Dir.tmpdir)
    if options[:path]
      # then we will create their directory for them (test context-be friendly)
      root = options[:path]
      FileUtils::mkdir_p(root)
      # if they gave relative path, this forces absolute
      root = File.expand_path(root)
    end

    path = File.join(root, "#{name}_#{Time.now.to_i}_#{rand(1000)}")
    Files.new path, block, options
  end

  # mixin methods
  def files options = ::Files.default_options   # todo: block
    @files ||= ::Files.create(options)
  end

  def file *args, &block
    files.file *args, &block
  end

  def dir *args, &block
    files.dir *args, &block
  end

  # concrete class for creating files and dirs under a temporary directory
  class Files

    attr_reader :root

    def initialize path, block, options
      @root = path
      @dirs = []
      dir nil, &block
      at_exit {remove} if options[:remove]
    end

    # only 1 option supported: 'src'. if specified, is copied into 'name'
    def dir name, options={}, &block
      if name.nil?
        path = current
      else
        path = File.join(current, name)
      end
      Dir.mkdir path
      @dirs << name if name

      if options[:src]
        # copy over remote dir to this one
        FileUtils.cp_r(options[:src], path)
      end

      Dir.chdir(path) do
        instance_eval &block if block
      end
      @dirs.pop
      path
    end

    def file name, contents = "contents of #{name}"
      if name.is_a? File
        FileUtils.cp name.path, current
        # todo: return path
      else
        path = File.join(current, name)
        if contents.is_a? File
          FileUtils.cp contents.path, path
        else
          file_path = File.open(path, "w") do |f|
            f.write contents
          end
        end
        path
      end
    end

    def remove
      FileUtils.rm_rf(@root) if File.exists?(@root)
    end

    private
    def current
      File.join @root, *@dirs
    end

  end
end

def Files options = ::Files.default_options, &block
  files = ::Files.create options, &block
  files.root
end