/*
 * Copyright (C) 2015-2019 Benjamin Fry <benjaminfry@me.com>
 *
 * 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.
 */

//! record data enum variants

use std::cmp::Ordering;
#[cfg(test)]
use std::convert::From;
use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};

use super::domain::Name;
use super::rdata;
use super::rdata::{CAA, MX, NAPTR, NULL, OPENPGPKEY, OPT, SOA, SRV, SSHFP, TLSA, TXT};
use super::record_type::RecordType;
use crate::error::*;
use crate::serialize::binary::*;

#[cfg(feature = "dnssec")]
use super::dnssec::rdata::DNSSECRData;

/// Record data enum variants
///
/// [RFC 1035](https://tools.ietf.org/html/rfc1035), DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION, November 1987
///
/// ```text
/// 3.3. Standard RRs
///
/// The following RR definitions are expected to occur, at least
/// potentially, in all classes.  In particular, NS, SOA, CNAME, and PTR
/// will be used in all classes, and have the same format in all classes.
/// Because their RDATA format is known, all domain names in the RDATA
/// section of these RRs may be compressed.
///
/// <domain-name> is a domain name represented as a series of labels, and
/// terminated by a label with zero length.  <character-string> is a single
/// length octet followed by that number of characters.  <character-string>
/// is treated as binary information, and can be up to 256 characters in
/// length (including the length octet).
/// ```
#[derive(Debug, EnumAsInner, PartialEq, Clone, Eq)]
pub enum RData {
    /// ```text
    /// -- RFC 1035 -- Domain Implementation and Specification    November 1987
    ///
    /// 3.4. Internet specific RRs
    ///
    /// 3.4.1. A RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    ADDRESS                    |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// ADDRESS         A 32 bit Internet address.
    ///
    /// Hosts that have multiple Internet addresses will have multiple A
    /// records.
    ///
    /// A records cause no additional section processing.  The RDATA section of
    /// an A line in a master file is an Internet address expressed as four
    /// decimal numbers separated by dots without any imbedded spaces (e.g.,
    /// "10.2.0.52" or "192.0.5.6").
    /// ```
    A(Ipv4Addr),

    /// ```text
    /// -- RFC 1886 -- IPv6 DNS Extensions              December 1995
    ///
    /// 2.2 AAAA data format
    ///
    ///    A 128 bit IPv6 address is encoded in the data portion of an AAAA
    ///    resource record in network byte order (high-order byte first).
    /// ```
    AAAA(Ipv6Addr),

    /// ```text
    /// 2.  The ANAME resource record
    ///
    ///   This document defines the "ANAME" DNS resource record type, with RR
    ///   TYPE value [TBD].
    ///
    /// 2.1.  Presentation and wire format
    ///
    ///   The ANAME presentation format is identical to that of CNAME
    ///   [RFC1033]:
    ///
    ///       owner ttl class ANAME target
    /// ```
    ANAME(Name),

    /// ```text
    /// -- RFC 6844          Certification Authority Authorization     January 2013
    ///
    /// 5.1.  Syntax
    ///
    /// A CAA RR contains a single property entry consisting of a tag-value
    /// pair.  Each tag represents a property of the CAA record.  The value
    /// of a CAA property is that specified in the corresponding value field.
    ///
    /// A domain name MAY have multiple CAA RRs associated with it and a
    /// given property MAY be specified more than once.
    ///
    /// The CAA data field contains one property entry.  A property entry
    /// consists of the following data fields:
    ///
    /// +0-1-2-3-4-5-6-7-|0-1-2-3-4-5-6-7-|
    /// | Flags          | Tag Length = n |
    /// +----------------+----------------+...+---------------+
    /// | Tag char 0     | Tag char 1     |...| Tag char n-1  |
    /// +----------------+----------------+...+---------------+
    /// +----------------+----------------+.....+----------------+
    /// | Value byte 0   | Value byte 1   |.....| Value byte m-1 |
    /// +----------------+----------------+.....+----------------+

    /// Where n is the length specified in the Tag length field and m is the
    /// remaining octets in the Value field (m = d - n - 2) where d is the
    /// length of the RDATA section.
    /// ```
    CAA(CAA),

    /// ```text
    ///   3.3. Standard RRs
    ///
    /// The following RR definitions are expected to occur, at least
    /// potentially, in all classes.  In particular, NS, SOA, CNAME, and PTR
    /// will be used in all classes, and have the same format in all classes.
    /// Because their RDATA format is known, all domain names in the RDATA
    /// section of these RRs may be compressed.
    ///
    /// <domain-name> is a domain name represented as a series of labels, and
    /// terminated by a label with zero length.  <character-string> is a single
    /// length octet followed by that number of characters.  <character-string>
    /// is treated as binary information, and can be up to 256 characters in
    /// length (including the length octet).
    ///
    /// 3.3.1. CNAME RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                     CNAME                     /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// CNAME           A <domain-name> which specifies the canonical or primary
    ///                 name for the owner.  The owner name is an alias.
    ///
    /// CNAME RRs cause no additional section processing, but name servers may
    /// choose to restart the query at the canonical name in certain cases.  See
    /// the description of name server logic in [RFC-1034] for details.
    /// ```
    CNAME(Name),

    /// ```text
    /// 3.3.9. MX RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                  PREFERENCE                   |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   EXCHANGE                    /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// PREFERENCE      A 16 bit integer which specifies the preference given to
    ///                 this RR among others at the same owner.  Lower values
    ///                 are preferred.
    ///
    /// EXCHANGE        A <domain-name> which specifies a host willing to act as
    ///                 a mail exchange for the owner name.
    ///
    /// MX records cause type A additional section processing for the host
    /// specified by EXCHANGE.  The use of MX RRs is explained in detail in
    /// [RFC-974].
    /// ```
    MX(MX),

    /// [RFC 3403 DDDS DNS Database, October 2002](https://tools.ietf.org/html/rfc3403#section-4)
    ///
    /// ```text
    /// 4.1 Packet Format
    ///
    ///   The packet format of the NAPTR RR is given below.  The DNS type code
    ///   for NAPTR is 35.
    ///
    ///      The packet format for the NAPTR record is as follows
    ///                                       1  1  1  1  1  1
    ///         0  1  2  3  4  5  6  7  8  9  0  1  2  3  4  5
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///       |                     ORDER                     |
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///       |                   PREFERENCE                  |
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///       /                     FLAGS                     /
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///       /                   SERVICES                    /
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///       /                    REGEXP                     /
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///       /                  REPLACEMENT                  /
    ///       /                                               /
    ///       +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    ///   <character-string> and <domain-name> as used here are defined in RFC
    ///   1035 [7].
    ///
    ///   ORDER
    ///      A 16-bit unsigned integer specifying the order in which the NAPTR
    ///      records MUST be processed in order to accurately represent the
    ///      ordered list of Rules.  The ordering is from lowest to highest.
    ///      If two records have the same order value then they are considered
    ///      to be the same rule and should be selected based on the
    ///      combination of the Preference values and Services offered.
    ///
    ///   PREFERENCE
    ///      Although it is called "preference" in deference to DNS
    ///      terminology, this field is equivalent to the Priority value in the
    ///      DDDS Algorithm.  It is a 16-bit unsigned integer that specifies
    ///      the order in which NAPTR records with equal Order values SHOULD be
    ///      processed, low numbers being processed before high numbers.  This
    ///      is similar to the preference field in an MX record, and is used so
    ///      domain administrators can direct clients towards more capable
    ///      hosts or lighter weight protocols.  A client MAY look at records
    ///      with higher preference values if it has a good reason to do so
    ///      such as not supporting some protocol or service very well.
    ///
    ///      The important difference between Order and Preference is that once
    ///      a match is found the client MUST NOT consider records with a
    ///      different Order but they MAY process records with the same Order
    ///      but different Preferences.  The only exception to this is noted in
    ///      the second important Note in the DDDS algorithm specification
    ///      concerning allowing clients to use more complex Service
    ///      determination between steps 3 and 4 in the algorithm.  Preference
    ///      is used to give communicate a higher quality of service to rules
    ///      that are considered the same from an authority standpoint but not
    ///      from a simple load balancing standpoint.
    ///
    ///      It is important to note that DNS contains several load balancing
    ///      mechanisms and if load balancing among otherwise equal services
    ///      should be needed then methods such as SRV records or multiple A
    ///      records should be utilized to accomplish load balancing.
    ///
    ///   FLAGS
    ///      A <character-string> containing flags to control aspects of the
    ///      rewriting and interpretation of the fields in the record.  Flags
    ///      are single characters from the set A-Z and 0-9.  The case of the
    ///      alphabetic characters is not significant.  The field can be empty.
    ///
    ///      It is up to the Application specifying how it is using this
    ///      Database to define the Flags in this field.  It must define which
    ///      ones are terminal and which ones are not.
    ///
    ///   SERVICES
    ///      A <character-string> that specifies the Service Parameters
    ///      applicable to this this delegation path.  It is up to the
    ///      Application Specification to specify the values found in this
    ///      field.
    ///
    ///   REGEXP
    ///      A <character-string> containing a substitution expression that is
    ///      applied to the original string held by the client in order to
    ///      construct the next domain name to lookup.  See the DDDS Algorithm
    ///      specification for the syntax of this field.
    ///
    ///      As stated in the DDDS algorithm, The regular expressions MUST NOT
    ///      be used in a cumulative fashion, that is, they should only be
    ///      applied to the original string held by the client, never to the
    ///      domain name p  roduced by a previous NAPTR rewrite.  The latter is
    ///      tempting in some applications but experience has shown such use to
    ///      be extremely fault sensitive, very error prone, and extremely
    ///      difficult to debug.
    ///
    ///   REPLACEMENT
    ///      A <domain-name> which is the next domain-name to query for
    ///      depending on the potential values found in the flags field.  This
    ///      field is used when the regular expression is a simple replacement
    ///      operation.  Any value in this field MUST be a fully qualified
    ///      domain-name.  Name compression is not to be used for this field.
    ///
    ///      This field and the REGEXP field together make up the Substitution
    ///      Expression in the DDDS Algorithm.  It is simply a historical
    ///      optimization specifically for DNS compression that this field
    ///      exists.  The fields are also mutually exclusive.  If a record is
    ///      returned that has values for both fields then it is considered to
    ///      be in error and SHOULD be either ignored or an error returned.
    /// ```
    NAPTR(NAPTR),

    /// ```text
    /// 3.3.10. NULL RDATA format (EXPERIMENTAL)
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                  <anything>                   /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// Anything at all may be in the RDATA field so long as it is 65535 octets
    /// or less.
    ///
    /// NULL records cause no additional section processing.  NULL RRs are not
    /// allowed in master files.  NULLs are used as placeholders in some
    /// experimental extensions of the DNS.
    /// ```
    NULL(NULL),

    /// ```text
    /// 3.3.11. NS RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   NSDNAME                     /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// NSDNAME         A <domain-name> which specifies a host which should be
    ///                 authoritative for the specified class and domain.
    ///
    /// NS records cause both the usual additional section processing to locate
    /// a type A record, and, when used in a referral, a special search of the
    /// zone in which they reside for glue information.
    ///
    /// The NS RR states that the named host should be expected to have a zone
    /// starting at owner name of the specified class.  Note that the class may
    /// not indicate the protocol family which should be used to communicate
    /// with the host, although it is typically a strong hint.  For example,
    /// hosts which are name servers for either Internet (IN) or Hesiod (HS)
    /// class information are normally queried using IN class protocols.
    /// ```
    NS(Name),

    /// [RFC 7929](https://tools.ietf.org/html/rfc7929#section-2.1)
    ///
    /// ```text
    /// The RDATA portion of an OPENPGPKEY resource record contains a single
    /// value consisting of a Transferable Public Key formatted as specified
    /// in [RFC4880].
    /// ```
    OPENPGPKEY(OPENPGPKEY),

    /// ```text
    /// RFC 6891                   EDNS(0) Extensions                 April 2013
    /// 6.1.2.  Wire Format
    ///
    ///        +------------+--------------+------------------------------+
    ///        | Field Name | Field Type   | Description                  |
    ///        +------------+--------------+------------------------------+
    ///        | NAME       | domain name  | MUST be 0 (root domain)      |
    ///        | TYPE       | u_int16_t    | OPT (41)                     |
    ///        | CLASS      | u_int16_t    | requestor's UDP payload size |
    ///        | TTL        | u_int32_t    | extended RCODE and flags     |
    ///        | RDLEN      | u_int16_t    | length of all RDATA          |
    ///        | RDATA      | octet stream | {attribute,value} pairs      |
    ///        +------------+--------------+------------------------------+
    ///
    /// The variable part of an OPT RR may contain zero or more options in
    ///    the RDATA.  Each option MUST be treated as a bit field.  Each option
    ///    is encoded as:
    ///
    ///                   +0 (MSB)                            +1 (LSB)
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    ///     0: |                          OPTION-CODE                          |
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    ///     2: |                         OPTION-LENGTH                         |
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    ///     4: |                                                               |
    ///        /                          OPTION-DATA                          /
    ///        /                                                               /
    ///        +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
    /// ```
    OPT(OPT),

    /// ```text
    /// 3.3.12. PTR RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   PTRDNAME                    /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// PTRDNAME        A <domain-name> which points to some location in the
    ///                 domain name space.
    ///
    /// PTR records cause no additional section processing.  These RRs are used
    /// in special domains to point to some other location in the domain space.
    /// These records are simple data, and don't imply any special processing
    /// similar to that performed by CNAME, which identifies aliases.  See the
    /// description of the IN-ADDR.ARPA domain for an example.
    /// ```
    PTR(Name),

    /// ```text
    /// 3.3.13. SOA RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                     MNAME                     /
    ///     /                                               /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                     RNAME                     /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    SERIAL                     |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    REFRESH                    |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                     RETRY                     |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    EXPIRE                     |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     |                    MINIMUM                    |
    ///     |                                               |
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// MNAME           The <domain-name> of the name server that was the
    ///                 original or primary source of data for this zone.
    ///
    /// RNAME           A <domain-name> which specifies the mailbox of the
    ///                 person responsible for this zone.
    ///
    /// SERIAL          The unsigned 32 bit version number of the original copy
    ///                 of the zone.  Zone transfers preserve this value.  This
    ///                 value wraps and should be compared using sequence space
    ///                 arithmetic.
    ///
    /// REFRESH         A 32 bit time interval before the zone should be
    ///                 refreshed.
    ///
    /// RETRY           A 32 bit time interval that should elapse before a
    ///                 failed refresh should be retried.
    ///
    /// EXPIRE          A 32 bit time value that specifies the upper limit on
    ///                 the time interval that can elapse before the zone is no
    ///                 longer authoritative.
    ///
    /// MINIMUM         The unsigned 32 bit minimum TTL field that should be
    ///                 exported with any RR from this zone.
    ///
    /// SOA records cause no additional section processing.
    ///
    /// All times are in units of seconds.
    ///
    /// Most of these fields are pertinent only for name server maintenance
    /// operations.  However, MINIMUM is used in all query operations that
    /// retrieve RRs from a zone.  Whenever a RR is sent in a response to a
    /// query, the TTL field is set to the maximum of the TTL field from the RR
    /// and the MINIMUM field in the appropriate SOA.  Thus MINIMUM is a lower
    /// bound on the TTL field for all RRs in a zone.  Note that this use of
    /// MINIMUM should occur when the RRs are copied into the response and not
    /// when the zone is loaded from a master file or via a zone transfer.  The
    /// reason for this provison is to allow future dynamic update facilities to
    /// change the SOA RR with known semantics.
    /// ```
    SOA(SOA),

    /// ```text
    /// RFC 2782                       DNS SRV RR                  February 2000
    ///
    /// The format of the SRV RR
    ///
    ///  _Service._Proto.Name TTL Class SRV Priority Weight Port Target
    /// ```
    SRV(SRV),

    /// [RFC 4255](https://tools.ietf.org/html/rfc4255#section-3.1)
    ///
    /// ```text
    /// 3.1.  The SSHFP RDATA Format
    ///
    ///    The RDATA for a SSHFP RR consists of an algorithm number, fingerprint
    ///    type and the fingerprint of the public host key.
    ///
    ///        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///        |   algorithm   |    fp type    |                               /
    ///        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               /
    ///        /                                                               /
    ///        /                          fingerprint                          /
    ///        /                                                               /
    ///        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///
    /// 3.1.1.  Algorithm Number Specification
    ///
    ///    This algorithm number octet describes the algorithm of the public
    ///    key.  The following values are assigned:
    ///
    ///           Value    Algorithm name
    ///           -----    --------------
    ///           0        reserved
    ///           1        RSA
    ///           2        DSS
    ///
    ///    Reserving other types requires IETF consensus [4].
    ///
    /// 3.1.2.  Fingerprint Type Specification
    ///
    ///    The fingerprint type octet describes the message-digest algorithm
    ///    used to calculate the fingerprint of the public key.  The following
    ///    values are assigned:
    ///
    ///           Value    Fingerprint type
    ///           -----    ----------------
    ///           0        reserved
    ///           1        SHA-1
    ///
    ///    Reserving other types requires IETF consensus [4].
    ///
    ///    For interoperability reasons, as few fingerprint types as possible
    ///    should be reserved.  The only reason to reserve additional types is
    ///    to increase security.
    ///
    /// 3.1.3.  Fingerprint
    ///
    ///    The fingerprint is calculated over the public key blob as described
    ///    in [7].
    ///
    ///    The message-digest algorithm is presumed to produce an opaque octet
    ///    string output, which is placed as-is in the RDATA fingerprint field.
    /// ```
    ///
    /// The algorithm and fingerprint type values have been updated in
    /// [RFC 6594](https://tools.ietf.org/html/rfc6594) and
    /// [RFC 7479](https://tools.ietf.org/html/rfc7479).
    SSHFP(SSHFP),

    /// [RFC 6698, DNS-Based Authentication for TLS](https://tools.ietf.org/html/rfc6698#section-2.1)
    ///
    /// ```text
    ///                         1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
    ///     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ///    |  Cert. Usage  |   Selector    | Matching Type |               /
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               /
    ///    /                                                               /
    ///    /                 Certificate Association Data                  /
    ///    /                                                               /
    ///    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    /// ```
    TLSA(TLSA),

    /// ```text
    /// 3.3.14. TXT RDATA format
    ///
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///     /                   TXT-DATA                    /
    ///     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
    ///
    /// where:
    ///
    /// TXT-DATA        One or more <character-string>s.
    ///
    /// TXT RRs are used to hold descriptive text.  The semantics of the text
    /// depends on the domain where it is found.
    /// ```
    TXT(TXT),

    /// A DNSSEC- or SIG(0)- specific record. See `DNSSECRData` for details.
    ///
    /// These types are in `DNSSECRData` to make them easy to disable when
    /// crypto functionality isn't needed.
    #[cfg(feature = "dnssec")]
    DNSSEC(DNSSECRData),

    /// Unknown RecordData is for record types not supported by Trust-DNS
    Unknown {
        /// RecordType code
        code: u16,
        /// RData associated to the record
        rdata: NULL,
    },

    /// This corresponds to a record type of 0, unspecified
    ZERO,
}

impl RData {
    fn to_bytes(&self) -> Vec<u8> {
        let mut buf: Vec<u8> = Vec::new();
        {
            let mut encoder: BinEncoder = BinEncoder::new(&mut buf);
            self.emit(&mut encoder).unwrap_or_else(|_| {
                warn!("could not encode RDATA: {:?}", self);
            });
        }
        buf
    }

    /// Read the RData from the given Decoder
    pub fn read(
        decoder: &mut BinDecoder,
        record_type: RecordType,
        rdata_length: Restrict<u16>,
    ) -> ProtoResult<Self> {
        let start_idx = decoder.index();

        let result = match record_type {
            RecordType::A => {
                debug!("reading A");
                rdata::a::read(decoder).map(RData::A)
            }
            RecordType::AAAA => {
                debug!("reading AAAA");
                rdata::aaaa::read(decoder).map(RData::AAAA)
            }
            RecordType::ANAME => {
                debug!("reading ANAME");
                rdata::name::read(decoder).map(RData::ANAME)
            }
            rt @ RecordType::ANY | rt @ RecordType::AXFR | rt @ RecordType::IXFR => {
                return Err(ProtoErrorKind::UnknownRecordTypeValue(rt.into()).into());
            }
            RecordType::CAA => {
                debug!("reading CAA");
                rdata::caa::read(decoder, rdata_length).map(RData::CAA)
            }
            RecordType::CNAME => {
                debug!("reading CNAME");
                rdata::name::read(decoder).map(RData::CNAME)
            }
            RecordType::ZERO => {
                debug!("reading EMPTY");
                return Ok(RData::ZERO);
            }
            RecordType::MX => {
                debug!("reading MX");
                rdata::mx::read(decoder).map(RData::MX)
            }
            RecordType::NAPTR => {
                debug!("reading NAPTR");
                rdata::naptr::read(decoder).map(RData::NAPTR)
            }
            RecordType::NULL => {
                debug!("reading NULL");
                rdata::null::read(decoder, rdata_length).map(RData::NULL)
            }
            RecordType::NS => {
                debug!("reading NS");
                rdata::name::read(decoder).map(RData::NS)
            }
            RecordType::OPENPGPKEY => {
                debug!("reading OPENPGPKEY");
                rdata::openpgpkey::read(decoder, rdata_length).map(RData::OPENPGPKEY)
            }
            RecordType::OPT => {
                debug!("reading OPT");
                rdata::opt::read(decoder, rdata_length).map(RData::OPT)
            }
            RecordType::PTR => {
                debug!("reading PTR");
                rdata::name::read(decoder).map(RData::PTR)
            }
            RecordType::SOA => {
                debug!("reading SOA");
                rdata::soa::read(decoder).map(RData::SOA)
            }
            RecordType::SRV => {
                debug!("reading SRV");
                rdata::srv::read(decoder).map(RData::SRV)
            }
            RecordType::SSHFP => {
                debug!("reading SSHFP");
                rdata::sshfp::read(decoder, rdata_length).map(RData::SSHFP)
            }
            RecordType::TLSA => {
                debug!("reading TLSA");
                rdata::tlsa::read(decoder, rdata_length).map(RData::TLSA)
            }
            RecordType::TXT => {
                debug!("reading TXT");
                rdata::txt::read(decoder, rdata_length).map(RData::TXT)
            }
            #[cfg(feature = "dnssec")]
            RecordType::DNSSEC(record_type) => {
                DNSSECRData::read(decoder, record_type, rdata_length).map(RData::DNSSEC)
            }
            RecordType::Unknown(code) => {
                debug!("reading Unknown");
                rdata::null::read(decoder, rdata_length).map(|rdata| RData::Unknown { code, rdata })
            }
        };

        // we should have read rdata_length, but we did not
        let read = decoder.index() - start_idx;
        rdata_length
            .map(|u| u as usize)
            .verify_unwrap(|rdata_length| read == *rdata_length)
            .map_err(|rdata_length| {
                ProtoError::from(ProtoErrorKind::IncorrectRDataLengthRead {
                    read,
                    len: rdata_length,
                })
            })?;

        result
    }

    /// [RFC 4034](https://tools.ietf.org/html/rfc4034#section-6), DNSSEC Resource Records, March 2005
    ///
    /// ```text
    /// 6.2.  Canonical RR Form
    ///
    ///    For the purposes of DNS security, the canonical form of an RR is the
    ///    wire format of the RR where:
    ///
    ///    ...
    ///
    ///    3.  if the type of the RR is NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
    ///        HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX,
    ///        SRV, DNAME, A6, RRSIG, or (rfc6840 removes NSEC), all uppercase
    ///        US-ASCII letters in the DNS names contained within the RDATA are replaced
    ///        by the corresponding lowercase US-ASCII letters;
    /// ```
    ///
    /// Canonical name form for all non-1035 records:
    ///   [RFC 3579](https://tools.ietf.org/html/rfc3597)
    /// ```text
    ///  4.  Domain Name Compression
    ///
    ///   RRs containing compression pointers in the RDATA part cannot be
    ///   treated transparently, as the compression pointers are only
    ///   meaningful within the context of a DNS message.  Transparently
    ///   copying the RDATA into a new DNS message would cause the compression
    ///   pointers to point at the corresponding location in the new message,
    ///   which now contains unrelated data.  This would cause the compressed
    ///   name to be corrupted.
    ///
    ///   To avoid such corruption, servers MUST NOT compress domain names
    ///   embedded in the RDATA of types that are class-specific or not well-
    ///   known.  This requirement was stated in [RFC1123] without defining the
    ///   term "well-known"; it is hereby specified that only the RR types
    ///   defined in [RFC1035] are to be considered "well-known".
    ///
    ///   The specifications of a few existing RR types have explicitly allowed
    ///   compression contrary to this specification: [RFC2163] specified that
    ///   compression applies to the PX RR, and [RFC2535] allowed compression
    ///   in SIG RRs and NXT RRs records.  Since this specification disallows
    ///   compression in these cases, it is an update to [RFC2163] (section 4)
    ///   and [RFC2535] (sections 4.1.7 and 5.2).
    ///
    ///   Receiving servers MUST decompress domain names in RRs of well-known
    ///   type, and SHOULD also decompress RRs of type RP, AFSDB, RT, SIG, PX,
    ///   NXT, NAPTR, and SRV (although the current specification of the SRV RR
    ///   in [RFC2782] prohibits compression, [RFC2052] mandated it, and some
    ///   servers following that earlier specification are still in use).
    ///
    ///   Future specifications for new RR types that contain domain names
    ///   within their RDATA MUST NOT allow the use of name compression for
    ///   those names, and SHOULD explicitly state that the embedded domain
    ///   names MUST NOT be compressed.
    ///
    ///   As noted in [RFC1123], the owner name of an RR is always eligible for
    ///   compression.
    ///
    ///   ...
    ///   As a courtesy to implementors, it is hereby noted that the complete
    ///    set of such previously published RR types that contain embedded
    ///    domain names, and whose DNSSEC canonical form therefore involves
    ///   downcasing according to the DNS rules for character comparisons,
    ///   consists of the RR types NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR,
    ///   HINFO, MINFO, MX, HINFO, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX, SRV,
    ///   DNAME, and A6.
    ///   ...
    /// ```
    pub fn emit(&self, encoder: &mut BinEncoder) -> ProtoResult<()> {
        match *self {
            RData::A(address) => rdata::a::emit(encoder, address),
            RData::AAAA(ref address) => rdata::aaaa::emit(encoder, address),
            RData::ANAME(ref name) => {
                encoder.with_canonical_names(|encoder| rdata::name::emit(encoder, name))
            }
            RData::CAA(ref caa) => {
                encoder.with_canonical_names(|encoder| rdata::caa::emit(encoder, caa))
            }
            // to_lowercase for rfc4034 and rfc6840
            RData::CNAME(ref name) | RData::NS(ref name) | RData::PTR(ref name) => {
                rdata::name::emit(encoder, name)
            }
            RData::ZERO => Ok(()),
            // to_lowercase for rfc4034 and rfc6840
            RData::MX(ref mx) => rdata::mx::emit(encoder, mx),
            RData::NAPTR(ref naptr) => {
                encoder.with_canonical_names(|encoder| rdata::naptr::emit(encoder, naptr))
            }
            RData::NULL(ref null) => rdata::null::emit(encoder, null),
            RData::OPENPGPKEY(ref openpgpkey) => {
                encoder.with_canonical_names(|encoder| rdata::openpgpkey::emit(encoder, openpgpkey))
            }
            RData::OPT(ref opt) => rdata::opt::emit(encoder, opt),
            // to_lowercase for rfc4034 and rfc6840
            RData::SOA(ref soa) => rdata::soa::emit(encoder, soa),
            // to_lowercase for rfc4034 and rfc6840
            RData::SRV(ref srv) => {
                encoder.with_canonical_names(|encoder| rdata::srv::emit(encoder, srv))
            }
            RData::SSHFP(ref sshfp) => {
                encoder.with_canonical_names(|encoder| rdata::sshfp::emit(encoder, sshfp))
            }
            RData::TLSA(ref tlsa) => {
                encoder.with_canonical_names(|encoder| rdata::tlsa::emit(encoder, tlsa))
            }
            RData::TXT(ref txt) => rdata::txt::emit(encoder, txt),
            #[cfg(feature = "dnssec")]
            RData::DNSSEC(ref rdata) => encoder.with_canonical_names(|encoder| rdata.emit(encoder)),
            RData::Unknown { ref rdata, .. } => rdata::null::emit(encoder, rdata),
        }
    }

    /// Converts this to a Recordtype
    pub fn to_record_type(&self) -> RecordType {
        match *self {
            RData::A(..) => RecordType::A,
            RData::AAAA(..) => RecordType::AAAA,
            RData::ANAME(..) => RecordType::ANAME,
            RData::CAA(..) => RecordType::CAA,
            RData::CNAME(..) => RecordType::CNAME,
            RData::MX(..) => RecordType::MX,
            RData::NAPTR(..) => RecordType::NAPTR,
            RData::NS(..) => RecordType::NS,
            RData::NULL(..) => RecordType::NULL,
            RData::OPENPGPKEY(..) => RecordType::OPENPGPKEY,
            RData::OPT(..) => RecordType::OPT,
            RData::PTR(..) => RecordType::PTR,
            RData::SOA(..) => RecordType::SOA,
            RData::SRV(..) => RecordType::SRV,
            RData::SSHFP(..) => RecordType::SSHFP,
            RData::TLSA(..) => RecordType::TLSA,
            RData::TXT(..) => RecordType::TXT,
            #[cfg(feature = "dnssec")]
            RData::DNSSEC(ref rdata) => RecordType::DNSSEC(DNSSECRData::to_record_type(rdata)),
            RData::Unknown { code, .. } => RecordType::Unknown(code),
            RData::ZERO => RecordType::ZERO,
        }
    }

    /// If this is an A or AAAA record type, then an IpAddr will be returned
    pub fn to_ip_addr(&self) -> Option<IpAddr> {
        match *self {
            RData::A(a) => Some(IpAddr::from(a)),
            RData::AAAA(aaaa) => Some(IpAddr::from(aaaa)),
            _ => None,
        }
    }
}

impl PartialOrd<RData> for RData {
    fn partial_cmp(&self, other: &RData) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl Ord for RData {
    // RFC 4034                DNSSEC Resource Records               March 2005
    //
    // 6.3.  Canonical RR Ordering within an RRset
    //
    //    For the purposes of DNS security, RRs with the same owner name,
    //    class, and type are sorted by treating the RDATA portion of the
    //    canonical form of each RR as a left-justified unsigned octet sequence
    //    in which the absence of an octet sorts before a zero octet.
    //
    //    [RFC2181] specifies that an RRset is not allowed to contain duplicate
    //    records (multiple RRs with the same owner name, class, type, and
    //    RDATA).  Therefore, if an implementation detects duplicate RRs when
    //    putting the RRset in canonical form, it MUST treat this as a protocol
    //    error.  If the implementation chooses to handle this protocol error
    //    in the spirit of the robustness principle (being liberal in what it
    //    accepts), it MUST remove all but one of the duplicate RR(s) for the
    //    purposes of calculating the canonical form of the RRset.
    fn cmp(&self, other: &Self) -> Ordering {
        // TODO: how about we just store the bytes with the decoded data?
        //  the decoded data is useful for queries, the encoded data is needed for transfers, signing
        //  and ordering.
        self.to_bytes().cmp(&other.to_bytes())
    }
}

#[cfg(test)]
mod tests {
    use std::net::Ipv4Addr;
    use std::net::Ipv6Addr;
    use std::str::FromStr;

    use super::*;
    use crate::rr::domain::Name;
    use crate::rr::rdata::{MX, SOA, SRV, TXT};
    use crate::serialize::binary::bin_tests::test_emit_data_set;
    #[allow(clippy::useless_attribute)]
    #[allow(unused)]
    use crate::serialize::binary::*;

    fn get_data() -> Vec<(RData, Vec<u8>)> {
        vec![
            (
                RData::CNAME(Name::from_str("www.example.com").unwrap()),
                vec![
                    3, b'w', b'w', b'w', 7, b'e', b'x', b'a', b'm', b'p', b'l', b'e', 3, b'c',
                    b'o', b'm', 0,
                ],
            ),
            (
                RData::MX(MX::new(256, Name::from_str("n").unwrap())),
                vec![1, 0, 1, b'n', 0],
            ),
            (
                RData::NS(Name::from_str("www.example.com").unwrap()),
                vec![
                    3, b'w', b'w', b'w', 7, b'e', b'x', b'a', b'm', b'p', b'l', b'e', 3, b'c',
                    b'o', b'm', 0,
                ],
            ),
            (
                RData::PTR(Name::from_str("www.example.com").unwrap()),
                vec![
                    3, b'w', b'w', b'w', 7, b'e', b'x', b'a', b'm', b'p', b'l', b'e', 3, b'c',
                    b'o', b'm', 0,
                ],
            ),
            (
                RData::SOA(SOA::new(
                    Name::from_str("www.example.com").unwrap(),
                    Name::from_str("xxx.example.com").unwrap(),
                    u32::max_value(),
                    -1 as i32,
                    -1 as i32,
                    -1 as i32,
                    u32::max_value(),
                )),
                vec![
                    3, b'w', b'w', b'w', 7, b'e', b'x', b'a', b'm', b'p', b'l', b'e', 3, b'c',
                    b'o', b'm', 0, 3, b'x', b'x', b'x', 0xC0, 0x04, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
                    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
                    0xFF, 0xFF,
                ],
            ),
            (
                RData::TXT(TXT::new(vec![
                    "abcdef".to_string(),
                    "ghi".to_string(),
                    "".to_string(),
                    "j".to_string(),
                ])),
                vec![
                    6, b'a', b'b', b'c', b'd', b'e', b'f', 3, b'g', b'h', b'i', 0, 1, b'j',
                ],
            ),
            (
                RData::A(Ipv4Addr::from_str("0.0.0.0").unwrap()),
                vec![0, 0, 0, 0],
            ),
            (
                RData::AAAA(Ipv6Addr::from_str("::").unwrap()),
                vec![0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
            ),
            (
                RData::SRV(SRV::new(
                    1,
                    2,
                    3,
                    Name::from_str("www.example.com").unwrap(),
                )),
                vec![
                    0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 3, b'w', b'w', b'w', 7, b'e', b'x', b'a',
                    b'm', b'p', b'l', b'e', 3, b'c', b'o', b'm', 0,
                ],
            ),
        ]
    }

    // TODO this test kinda sucks, shows the problem with not storing the binary parts
    #[test]
    fn test_order() {
        let ordered: Vec<RData> = vec![
            RData::A(Ipv4Addr::from_str("0.0.0.0").unwrap()),
            RData::AAAA(Ipv6Addr::from_str("::").unwrap()),
            RData::SRV(SRV::new(
                1,
                2,
                3,
                Name::from_str("www.example.com").unwrap(),
            )),
            RData::MX(MX::new(256, Name::from_str("n").unwrap())),
            RData::CNAME(Name::from_str("www.example.com").unwrap()),
            RData::PTR(Name::from_str("www.example.com").unwrap()),
            RData::NS(Name::from_str("www.example.com").unwrap()),
            RData::SOA(SOA::new(
                Name::from_str("www.example.com").unwrap(),
                Name::from_str("xxx.example.com").unwrap(),
                u32::max_value(),
                -1 as i32,
                -1 as i32,
                -1 as i32,
                u32::max_value(),
            )),
            RData::TXT(TXT::new(vec![
                "abcdef".to_string(),
                "ghi".to_string(),
                "".to_string(),
                "j".to_string(),
            ])),
        ];
        let mut unordered = vec![
            RData::CNAME(Name::from_str("www.example.com").unwrap()),
            RData::MX(MX::new(256, Name::from_str("n").unwrap())),
            RData::PTR(Name::from_str("www.example.com").unwrap()),
            RData::NS(Name::from_str("www.example.com").unwrap()),
            RData::SOA(SOA::new(
                Name::from_str("www.example.com").unwrap(),
                Name::from_str("xxx.example.com").unwrap(),
                u32::max_value(),
                -1 as i32,
                -1 as i32,
                -1 as i32,
                u32::max_value(),
            )),
            RData::TXT(TXT::new(vec![
                "abcdef".to_string(),
                "ghi".to_string(),
                "".to_string(),
                "j".to_string(),
            ])),
            RData::A(Ipv4Addr::from_str("0.0.0.0").unwrap()),
            RData::AAAA(Ipv6Addr::from_str("::").unwrap()),
            RData::SRV(SRV::new(
                1,
                2,
                3,
                Name::from_str("www.example.com").unwrap(),
            )),
        ];

        unordered.sort();
        assert_eq!(ordered, unordered);
    }

    #[test]
    fn test_read() {
        for (test_pass, (expect, binary)) in get_data().into_iter().enumerate() {
            println!("test {}: {:?}", test_pass, binary);
            let length = binary.len() as u16; // pre exclusive borrow
            let mut decoder = BinDecoder::new(&binary);

            assert_eq!(
                RData::read(
                    &mut decoder,
                    record_type_from_rdata(&expect),
                    Restrict::new(length)
                )
                .unwrap(),
                expect
            );
        }
    }

    fn record_type_from_rdata(rdata: &RData) -> crate::rr::record_type::RecordType {
        match *rdata {
            RData::A(..) => RecordType::A,
            RData::AAAA(..) => RecordType::AAAA,
            RData::ANAME(..) => RecordType::ANAME,
            RData::CAA(..) => RecordType::CAA,
            RData::CNAME(..) => RecordType::CNAME,
            RData::MX(..) => RecordType::MX,
            RData::NAPTR(..) => RecordType::NAPTR,
            RData::NS(..) => RecordType::NS,
            RData::NULL(..) => RecordType::NULL,
            RData::OPENPGPKEY(..) => RecordType::OPENPGPKEY,
            RData::OPT(..) => RecordType::OPT,
            RData::PTR(..) => RecordType::PTR,
            RData::SOA(..) => RecordType::SOA,
            RData::SRV(..) => RecordType::SRV,
            RData::SSHFP(..) => RecordType::SSHFP,
            RData::TLSA(..) => RecordType::TLSA,
            RData::TXT(..) => RecordType::TXT,
            #[cfg(feature = "dnssec")]
            RData::DNSSEC(ref rdata) => RecordType::DNSSEC(rdata.to_record_type()),
            RData::Unknown { code, .. } => RecordType::Unknown(code),
            RData::ZERO => RecordType::ZERO,
        }
    }

    #[test]
    fn test_write_to() {
        test_emit_data_set(get_data(), |e, d| d.emit(e));
    }
}