class Strongboxio

# File lib/strongboxio.rb, line 23
def self.decrypt(sbox_filename, password)
        # open the xml file
        f = File.open(sbox_filename)
        data = Nokogiri::XML(f)
        f.close

        # extract the Data node
        data = data.xpath('//Data').text
        base64_error_msg = 'expected Base64 encoded byte string from the StrongBox.Payload.Data element of the xml of a Strongbox file'
        raise "#{base64_error_msg}, but got nothing" if data.length == 0
        raise "#{base64_error_msg}, but it does not resemble Base64" unless self.resembles_base64?(data)

        data = Base64.decode64(data)

        #version = data.getbyte(0)   # ruby 1.9
        version = data.bytes.to_a[0] # ruby 1.8 friendly
        raise "expected version number #{STRONGBOX_VERSION}, but got #{version}" unless version == STRONGBOX_VERSION

        salt = data.slice(1, SALT_LENGTH)
        raise "expected salt length #{SALT_LENGTH}, but got #{salt.length}" unless salt.length == SALT_LENGTH

        iv = data.bytes.to_a.slice((1+64), IV_LENGTH).pack('C*')
        raise "expected iv length #{IV_LENGTH}, but got #{iv.length}" unless iv.length == IV_LENGTH

        key = Digest::SHA256.digest(salt + password)
        raise "expected key length #{KEY_LENGTH}, but got #{key.length}" unless key.length == KEY_LENGTH

        # prepare for decryption
        d = OpenSSL::Cipher.new(CIPHER)
        d.decrypt
        d.key = key
        d.iv  = iv

        # decrypt the portion beyond the header
        begin
                data = '' << d.update(data.slice((VERSION_LENGTH+SALT_LENGTH+IV_LENGTH)..-1)) << d.final
        rescue => e
                raise "Error decrypting. You probably entered the password incorrectly. Specific error: #{e}"
        end

        # decompress the portion beyond the random value
        #z = Zlib::Inflate.new
        #z = Zlib::Inflate.new(-Zlib::BEST_COMPRESSION) # works for Strongbox
        z = Zlib::Inflate.new(-Zlib::MAX_WBITS) # works for Strongbox!
        #z = Zlib::Inflate.new(Zlib::MAX_WBITS) # works for roundtrip
        data = z.inflate(data.slice(RANDOM_VALUE_LENGTH..-1))
        z.finish
        z.close

        data
end

# File lib/strongboxio.rb, line 106
def initialize(decrypted_sbox, continue_despite_unexpected_payload_schema_version=false)
        super()

        data = Nokogiri::XML(decrypted_sbox)

        payload_schema_version = data.xpath('//Payload').xpath('SchemaVersion').text
        unless payload_schema_version == PAYLOAD_SCHEMA_VERSION
                raise "expected schema version #{PAYLOAD_SCHEMA_VERSION}, but got #{payload_schema_version}" unless continue_despite_unexpected_payload_schema_version
        end

        @sbox = {}

        mt = data.xpath('//Payload').xpath('PayloadInfo').xpath('MT').text
        @sbox['MT'] = mt

        data.xpath('//PayloadData').each { |payload_data|

                @sbox['PayloadData'] = []

                payload_data.xpath('//SBE').each_with_index { |strongbox_entity, sbe_index|

                        @sbox['PayloadData'][sbe_index] = {}

                        sbe_mt = strongbox_entity.attr('MT') # ModifiedTimestamp.Ticks
                        @sbox['PayloadData'][sbe_index]['MT'] = sbe_mt if sbe_mt.length > 0

                        sbe_ct = strongbox_entity.attr('CT') # CreatedTimestamp.Ticks
                        @sbox['PayloadData'][sbe_index]['CT'] = sbe_ct if sbe_ct.length > 0

                        sbe_ac = strongbox_entity.attr('AC') # accessCount
                        @sbox['PayloadData'][sbe_index]['AC'] = sbe_ac if defined?sbe_ac && sbe_ac.length > 0

                        sbe_name = strongbox_entity.xpath('N').text
                        @sbox['PayloadData'][sbe_index]['N'] = sbe_name if sbe_name.length > 0

                        sbe_description = strongbox_entity.xpath('D').text
                        @sbox['PayloadData'][sbe_index]['D'] = sbe_description if sbe_description.length > 0

                        sbe_tags = strongbox_entity.xpath('T').text
                        @sbox['PayloadData'][sbe_index]['T'] = sbe_tags if sbe_tags.length > 0

                        child_entity = strongbox_entity.xpath('CE')
                        if child_entity.length > 0
                                @sbox['PayloadData'][sbe_index]['CE'] = []

                                child_entity.xpath('TFE').each_with_index { |text_field_entity, ce_index|

                                        @sbox['PayloadData'][sbe_index]['CE'][ce_index] = {}

                                        tfe_name = text_field_entity.xpath('N').text
                                        @sbox['PayloadData'][sbe_index]['CE'][ce_index]['N'] = tfe_name if tfe_name.length > 0

                                        tfe_content = text_field_entity.xpath('C').text
                                        @sbox['PayloadData'][sbe_index]['CE'][ce_index]['C'] = tfe_content if tfe_content.length > 0
                                }
                        end
                }
        }
end

# File lib/strongboxio.rb, line 75
def self.render(decrypted_sbox, continue_despite_unexpected_payload_schema_version=false)
        data = Nokogiri::XML(decrypted_sbox)

        payload_schema_version = data.xpath('//Payload').xpath('SchemaVersion').text
        unless payload_schema_version == PAYLOAD_SCHEMA_VERSION
                raise "expected schema version #{PAYLOAD_SCHEMA_VERSION}, but got #{payload_schema_version}" unless continue_despite_unexpected_payload_schema_version
        end

        puts data.xpath('//Payload').xpath('PayloadInfo').xpath('MT').text

        data.xpath('//PayloadData').each { |payload_data|
                payload_data.xpath('//SBE').each { |entity|
                        puts
                        name = entity.xpath('N').text
                        puts "#{name}" if name.length > 0
                        description = entity.xpath('D').text
                        puts "#{description}" if description.length > 0
                        tags = entity.xpath('T').text
                        puts "#{tags}" if tags.length > 0
                        ce = entity.xpath('CE')
                        ce.xpath('TFE').each { |tfe|
                                name = tfe.xpath('N').text
                                puts "#{name}:" if name.length > 0
                                content = tfe.xpath('C').text
                                puts "#{content}" if content.length > 0
                        }
                }
        }
        0
end

# File lib/strongboxio.rb, line 187
def self.resembles_base64?(string)
        string.length % 4 == 0 && string =~ /^[A-Za-z0-9+\/=]+\Z/
end

# File lib/strongboxio.rb, line 166
def render(verbose=false)
        puts sbox['MT']

        sbox['PayloadData'].each { |payload_data|
                puts
                puts payload_data['N'] unless payload_data['N'].nil?
                puts payload_data['D'] unless payload_data['D'].nil?
                puts payload_data['T'] unless payload_data['T'].nil?
                payload_data['CE'].each { |strongbox_entity|
                        puts strongbox_entity['N'] + ': ' unless strongbox_entity['N'].nil?
                        puts strongbox_entity['C']        unless strongbox_entity['C'].nil?
                }
                puts "Access Count: #{payload_data['AC']}" if !payload_data['AC'].nil? && verbose
                puts "#{convert_time_from_dot_net_epoch(payload_data['MT'].to_i)} (modify time)" if !payload_data['MT'].nil? && verbose
                puts "#{convert_time_from_dot_net_epoch(payload_data['CT'].to_i)} (create time)" if !payload_data['CT'].nil? && verbose
        }
        0
end

# File lib/strongboxio.rb, line 191
def convert_time_from_dot_net_epoch(t)
        Time.at((t-UNIX_EPOCH_IN_100NS_INTERVALS)*1e-7).utc.getlocal
end