package rr

import (
	"sort"

	"github.com/miekg/dns"
)

// TypeInfo describes a record type for the web UI and CLI.
type TypeInfo struct {
	Type        string `json:"type"`
	Code        uint16 `json:"code"`
	Common      bool   `json:"common"`
	Description string `json:"description"`
	Format      string `json:"format,omitempty"`
	Example     string `json:"example,omitempty"`
}

var described = []TypeInfo{
	{Type: "A", Common: true, Description: "IPv4 address", Format: "<IPv4 address>", Example: "192.0.2.10"},
	{Type: "AAAA", Common: true, Description: "IPv6 address", Format: "<IPv6 address>", Example: "2001:db8::10"},
	{Type: "CNAME", Common: true, Description: "Alias for another name (no other records may exist at the same name)", Format: "<target name>", Example: "www.example.com."},
	{Type: "MX", Common: true, Description: "Mail exchanger", Format: "<preference> <mail server host name>", Example: "10 mail.example.com."},
	{Type: "TXT", Common: true, Description: "Text. Plain text is quoted and split into 255-byte strings automatically; start with a quote to give presentation format.", Format: "<text> or \"string\" \"string\"", Example: "v=spf1 mx -all"},
	{Type: "NS", Common: true, Description: "Name server for the zone (at the apex) or a delegation (below it)", Format: "<name server host name>", Example: "ns1.example.com."},
	{Type: "PTR", Common: true, Description: "Reverse mapping (in in-addr.arpa / ip6.arpa zones)", Format: "<host name>", Example: "host.example.com."},
	{Type: "SRV", Common: true, Description: "Service location (owner _service._proto.name)", Format: "<priority> <weight> <port> <target>", Example: "0 5 5060 sip.example.com."},
	{Type: "CAA", Common: true, Description: "Certification authority authorization", Format: "<flags> <tag> <value>", Example: "0 issue \"letsencrypt.org\""},
	{Type: "HTTPS", Common: true, Description: "HTTPS service binding (RFC 9460)", Format: "<priority> <target> [params...]", Example: "1 . alpn=\"h2,h3\""},
	{Type: "SVCB", Description: "General service binding (RFC 9460)", Format: "<priority> <target> [params...]", Example: "1 svc.example.com. alpn=\"h2\" port=8443"},
	{Type: "SSHFP", Description: "SSH host key fingerprint", Format: "<algorithm> <fp type> <fingerprint hex>", Example: "4 2 9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08"},
	{Type: "TLSA", Description: "TLS certificate association, DANE (owner _port._proto.name)", Format: "<usage> <selector> <matching type> <data hex>", Example: "3 1 1 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"},
	{Type: "DS", Description: "Delegation signer for a signed child zone (at a delegation point)", Format: "<key tag> <algorithm> <digest type> <digest hex>", Example: "12345 13 2 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"},
	{Type: "DNAME", Description: "Redirects a whole subtree to another name", Format: "<target name>", Example: "other.example.net."},
	{Type: "NAPTR", Description: "Naming authority pointer", Format: "<order> <preference> \"<flags>\" \"<service>\" \"<regexp>\" <replacement>", Example: "100 10 \"u\" \"E2U+sip\" \"!^.*$!sip:info@example.com!\" ."},
	{Type: "LOC", Description: "Geographical location", Format: "<lat> <lon> <alt>m [size [hp [vp]]]", Example: "52 22 23.000 N 4 53 32.000 E -2.00m 0.00m 10000m 10m"},
	{Type: "HINFO", Description: "Host information", Format: "\"<cpu>\" \"<os>\"", Example: "\"PC\" \"Linux\""},
	{Type: "RP", Description: "Responsible person", Format: "<mailbox name> <TXT record name>", Example: "admin.example.com. ."},
	{Type: "URI", Description: "Uniform resource identifier", Format: "<priority> <weight> \"<uri>\"", Example: "10 1 \"https://example.com/\""},
	{Type: "OPENPGPKEY", Description: "OpenPGP public key (DANE)", Format: "<base64 key>"},
	{Type: "SMIMEA", Description: "S/MIME certificate association", Format: "<usage> <selector> <matching type> <data hex>"},
	{Type: "CERT", Description: "Certificate", Format: "<type> <key tag> <algorithm> <base64 certificate>"},
	{Type: "DHCID", Description: "DHCP identifier", Format: "<base64 data>"},
	{Type: "AFSDB", Description: "AFS database location", Format: "<subtype> <host name>", Example: "1 afs.example.com."},
	{Type: "APL", Description: "Address prefix list", Format: "[!]<family>:<prefix>/<len> ...", Example: "1:192.168.32.0/21"},
	{Type: "IPSECKEY", Description: "IPsec key", Format: "<precedence> <gateway type> <algorithm> <gateway> <base64 key>"},
	{Type: "KX", Description: "Key exchanger", Format: "<preference> <host name>", Example: "10 kx.example.com."},
	{Type: "KEY", Description: "Public key (SIG(0) and other legacy uses)", Format: "<flags> <protocol> <algorithm> <base64 key>"},
	{Type: "SPF", Description: "Deprecated SPF record type; publish SPF policies as TXT instead", Format: "\"v=spf1 ...\""},
	{Type: "CSYNC", Description: "Child-to-parent synchronization", Format: "<soa serial> <flags> <type list>", Example: "66 3 A NS AAAA"},
	{Type: "EUI48", Description: "48-bit MAC address", Format: "xx-xx-xx-xx-xx-xx", Example: "00-00-5e-00-53-2a"},
	{Type: "EUI64", Description: "64-bit EUI address", Format: "xx-xx-xx-xx-xx-xx-xx-xx", Example: "00-00-5e-ef-10-00-00-2a"},
	{Type: "RESINFO", Description: "Resolver information (RFC 9606)", Format: "key=value ...", Example: "qnamemin exterr=15,16,17"},
}

// Types returns information about every record type that can be managed,
// common types first.
func Types() []TypeInfo {
	seen := map[string]bool{}
	var out []TypeInfo
	for _, t := range described {
		code, ok := dns.StringToType[t.Type]
		if !ok {
			continue
		}
		t.Code = code
		out = append(out, t)
		seen[t.Type] = true
	}
	var rest []TypeInfo
	for code, name := range dns.TypeToString {
		if seen[name] {
			continue
		}
		if _, ok := dns.TypeToRR[code]; !ok {
			continue
		}
		if _, bad := forbidden[code]; bad {
			continue
		}
		rest = append(rest, TypeInfo{Type: name, Code: code, Description: name + " record (zone file format)"})
	}
	sort.Slice(rest, func(i, j int) bool { return rest[i].Type < rest[j].Type })
	return append(out, rest...)
}