feat(model): нейтральная модель Record с нормализацией и Equal

internal/model/record.go

@@ -0,0 +1,105 @@
+package model
+
+import (
+	"sort"
+	"strings"
+)
+
+type RecordType string
+
+const (
+	A     RecordType = "A"
+	AAAA  RecordType = "AAAA"
+	CNAME RecordType = "CNAME"
+	MX    RecordType = "MX"
+	TXT   RecordType = "TXT"
+	SRV   RecordType = "SRV"
+	NS    RecordType = "NS"
+	SOA   RecordType = "SOA"
+)
+
+// Managed reports whether the type participates in diff+apply.
+// NS and SOA are read-only.
+func (t RecordType) Managed() bool {
+	switch t {
+	case A, AAAA, CNAME, MX, TXT, SRV:
+		return true
+	default:
+		return false
+	}
+}
+
+// Record is the provider-neutral representation of a DNS RRset.
+// For MX the value is "<priority> <target>"; for SRV it is
+// "<priority> <weight> <port> <target>". Values is an unordered set.
+type Record struct {
+	Type   RecordType
+	Name   string
+	TTL    int
+	Values []string
+}
+
+// Key uniquely identifies an RRset within a zone.
+func (r Record) Key() string {
+	return string(r.Type) + " " + normalizeName(r.Name)
+}
+
+func normalizeName(name string) string {
+	n := strings.ToLower(strings.TrimSpace(name))
+	if n != "" && !strings.HasSuffix(n, ".") {
+		n += "."
+	}
+	return n
+}
+
+// normalizeValue canonicalizes a single RR value for comparison.
+func normalizeValue(t RecordType, content string) string {
+	c := strings.Join(strings.Fields(content), " ") // collapse whitespace
+	switch t {
+	case TXT:
+		return c // case-sensitive — keep as is
+	case MX:
+		parts := strings.SplitN(c, " ", 2)
+		if len(parts) == 2 {
+			return parts[0] + " " + normalizeName(parts[1])
+		}
+		return c
+	case SRV:
+		f := strings.Fields(c)
+		if len(f) == 4 {
+			return f[0] + " " + f[1] + " " + f[2] + " " + normalizeName(f[3])
+		}
+		return c
+	case CNAME, NS:
+		return normalizeName(c)
+	default: // A, AAAA, SOA
+		return strings.ToLower(c)
+	}
+}
+
+// NormalizedValues returns sorted, normalized values.
+func (r Record) NormalizedValues() []string {
+	out := make([]string, len(r.Values))
+	for i, v := range r.Values {
+		out[i] = normalizeValue(r.Type, v)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// Equal reports whether two records have the same TTL and value set.
+func (r Record) Equal(o Record) bool {
+	if r.TTL != o.TTL {
+		return false
+	}
+	a, b := r.NormalizedValues(), o.NormalizedValues()
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}