#
# Author:: John Keiser (<jkeiser@chef.io>)
# Copyright:: Copyright (c) Chef Software Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require_relative "../../file_system_cache"

class Chef
  module ChefFS
    module FileSystem
      module Repository

        class Directory

          attr_reader :name
          attr_reader :parent
          attr_reader :path
          attr_reader :file_path

          alias_method :display_path, :path
          alias_method :display_name, :name
          alias_method :bare_name, :name

          def initialize(name, parent, file_path = nil)
            @parent = parent
            @name = name
            @path = Chef::ChefFS::PathUtils.join(parent.path, name)
            @file_path = file_path || "#{parent.file_path}/#{name}"
          end

          def name_valid?
            !name.start_with?(".")
          end

          # Whether or not the file system entry this object represents is
          # valid. Mainly used to trim dotfiles/dotdirs and non directories
          # from the list of children when enumerating items on the filesystem
          def fs_entry_valid?
            name_valid? && File.directory?(file_path)
          end

          # ChefFS API:

          # Public API called by multiplexed_dir
          def can_have_child?(name, is_dir)
            possible_child = make_child_entry(name)
            possible_child.dir? == is_dir && possible_child.name_valid?
          end

          # Public API called by chef_fs/file_system
          def dir?
            true
          end

          def path_for_printing
            file_path
          end

          def children
            return FileSystemCache.instance.children(file_path) if FileSystemCache.instance.exist?(file_path)

            children = dir_ls.sort
              .map { |child_name| make_child_entry(child_name) }
              .select { |new_child| new_child.fs_entry_valid? && can_have_child?(new_child.name, new_child.dir?) }
            FileSystemCache.instance.set_children(file_path, children)
          rescue Errno::ENOENT => e
            raise Chef::ChefFS::FileSystem::NotFoundError.new(self, e)
          end

          def create_child(child_name, file_contents = nil)
            child = make_child_entry(child_name)
            if child.exists?
              raise Chef::ChefFS::FileSystem::AlreadyExistsError.new(:create_child, child)
            end

            FileSystemCache.instance.delete!(child.file_path)
            if file_contents
              child.write(file_contents)
            else
              begin
                Dir.mkdir(child.file_path)
              rescue Errno::EEXIST
                raise Chef::ChefFS::FileSystem::AlreadyExistsError.new(:create_child, child)
              end
            end
            child
          end

          # An empty children array is an empty dir
          def empty?
            children.empty?
          end

          # Public API callied by chef_fs/file_system
          def child(name)
            possible_child = make_child_entry(name)
            if possible_child.name_valid?
              possible_child
            else
              NonexistentFSObject.new(name, self)
            end
          end

          def root
            parent.root
          end

          # File system wrappers

          def create(file_contents = nil)
            if exists?
              raise Chef::ChefFS::FileSystem::AlreadyExistsError.new(:create_child, self)
            end

            begin
              FileSystemCache.instance.delete!(file_path)
              Dir.mkdir(file_path)
            rescue Errno::EEXIST
              raise Chef::ChefFS::FileSystem::AlreadyExistsError.new(:create_child, self)
            end
          end

          def dir_ls
            Dir.entries(file_path).select { |p| !p.start_with?(".") }
          end

          def delete(recurse)
            if exists?
              unless recurse
                raise MustDeleteRecursivelyError.new(self, $!)
              end

              FileUtils.rm_r(file_path)
              FileSystemCache.instance.delete!(file_path)
            else
              raise Chef::ChefFS::FileSystem::NotFoundError.new(self, $!)
            end
          end

          def exists?
            File.exists?(file_path)
          end

          protected

          def write(data)
            raise FileSystemError.new(self, nil, "attempted to write to a directory entry")
          end

          def make_child_entry(child_name)
            raise "Not Implemented"
          end

        end
      end
    end
  end
end