# Copyright (C) 2012-2014 Zammad Foundation, http://zammad-foundation.org/

class Store
  class File < ApplicationModel
    include ApplicationLib
    after_destroy :destroy_provider

=begin

add new file to store

    store_file_id = Store::File.add(binary_data)

=end

    def self.add(data)
      sha = Digest::SHA256.hexdigest( data )

      file = Store::File.find_by( sha: sha )
      if file.nil?

        # load backend based on config
        adapter_name = Setting.get('storage_provider') || 'DB'
        if !adapter_name
          fail 'Missing storage_provider setting option'
        end
        adapter = load_adapter( "Store::Provider::#{adapter_name}" )
        adapter.add( data, sha )
        file = Store::File.create(
          provider: adapter_name,
          sha: sha,
        )
      end
      file
    end

=begin

read content of a file

    store = Store::File.find(123)

    store.content # returns binary

=end

    def content
      adapter = self.class.load_adapter("Store::Provider::#{provider}")
      if sha
        c = adapter.get( sha )
      else
        # fallback until migration is done
        c = Store::Provider::DB.find_by( md5: md5 ).data
      end
      c
    end

=begin

file system check of store, check data and sha (in case fix it)

    Store::File.verify

read each file which should be in backend and verify agsinst sha hash

in case of fixing sha hash use:

    Store::File.verify(true)

=end

    def self.verify(fix_it = nil)
      success = true
      Store::File.all.each {|item|
        content = item.content
        sha = Digest::SHA256.hexdigest( content )
        logger.info "CHECK: Store::File.find(#{item.id}) "

        next if sha == item.sha

        success = false
        logger.error "DIFF: sha diff of Store::File.find(#{item.id}) "
        if fix_it
          item.update_attribute( :sha, sha )
        end
      }
      success
    end

=begin

move file from one to other provider

move files from file backend to db

  Store::File.move('File', 'DB')

move files from db backend to fs

  Store::File.move('DB', 'File')

=end

    def self.move(source, target)
      adapter_source = load_adapter("Store::Provider::#{source}")
      adapter_target = load_adapter("Store::Provider::#{target}")

      Store::File.all.each {|item|
        next if item.provider == target
        content = item.content

        # add to new provider
        adapter_target.add( content, item.sha )

        # update meta data
        item.update_attribute( :provider, target )

        # remove from old provider
        adapter_source.delete( item.sha )

        logger.info "Moved file #{item.sha} from #{source} to #{target}"
      }
      true
    end

    private

    def destroy_provider
      adapter = self.class.load_adapter("Store::Provider::#{provider}")
      adapter.delete( sha )
    end
  end
end