#
# Author:: Tim Hinderliter (<tim@opscode.com>)
# Copyright:: Copyright (c) 2010 Opscode, 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 'chef/log'
require 'uuidtools'

class Chef
  # == Chef::Checksum
  # Checksum for an individual file; e.g., used for sandbox/cookbook uploading
  # to track which files the system already manages.
  class Checksum
    attr_accessor :checksum, :create_time

    # Creates a new Chef::Checksum object.
    # === Arguments
    # checksum::: the MD5 content hash of the file
    #
    # === Returns
    # object<Chef::Checksum>:: Duh. :)
    def initialize(checksum=nil)
      @create_time = Time.now.iso8601
      @checksum = checksum
      @original_committed_file_location = nil
    end

    def to_json(*a)
      result = {
        :checksum => checksum,
        :create_time => create_time,
        :json_class => self.class.name,
        :chef_type => 'checksum',
        :name => checksum
      }
      result.to_json(*a)
    end

    def self.json_create(o)
      checksum = new(o['checksum'])
      checksum.create_time = o['create_time']

      checksum
    end


    ##
    # On-Disk Checksum File Repo (Chef Server API)
    ##

    def file_location
      File.join(checksum_repo_directory, checksum)
    end

    def checksum_repo_directory
      File.join(Chef::Config.checksum_path, checksum[0..1])
    end

    private

    # Deletes the file backing this checksum from the on-disk repo.
    # Purging the checksums is how users can get back to a valid state if
    # they've deleted files, so we silently swallow Errno::ENOENT here.
    def purge_file
      FileUtils.rm(file_location)
    rescue Errno::ENOENT
      true
    end

  end
end