Harden item occurrence grounding

internal/modules/dnd/shared/matching.go

@@ -3,14 +3,12 @@ package shared
 import (
 	"strings"
 	"unicode"
-
-	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/npcs/identity"
 )
 
 // NormalizedTokens returns identity-normalized alphanumeric tokens from a
 // D&D value.
 func NormalizedTokens(value string) []string {
-	value = identity.ComparisonKey(value)
+	value = ComparisonKey(value)
 	if value == "" {
 		return nil
 	}

internal/modules/dnd/shared/matching_test.go

@@ -2,6 +2,32 @@ package shared
 
 import "testing"
 
+func TestComparisonKeyNormalizesDNDText(t *testing.T) {
+	if TextComparisonPolicy != "dnd.text_comparison.v1" {
+		t.Fatalf("TextComparisonPolicy = %q", TextComparisonPolicy)
+	}
+	for _, test := range []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{name: "case", input: "Captain Vale", want: "captain vale"},
+		{name: "compatibility", input: "Ａｌｌｙ", want: "ally"},
+		{name: "whitespace", input: "  Mira\u2003Thorn ", want: "mira thorn"},
+		{name: "apostrophes", input: "O’Rin and OʼRin", want: "o'rin and o'rin"},
+		{name: "unicode composition", input: "  Cafe\u0301\u2003d’Or ", want: "café d'or"},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			if got := ComparisonKey(test.input); got != test.want {
+				t.Fatalf("ComparisonKey(%q) = %q, want %q", test.input, got, test.want)
+			}
+		})
+	}
+	if ComparisonKey("Mira Thorn") == ComparisonKey("Mira Thorne") {
+		t.Fatal("different names received the same comparison key")
+	}
+}
+
 func TestContainsTokenSequence(t *testing.T) {
 	tests := []struct {
 		name  string

internal/modules/dnd/shared/text_comparison.go

@@ -0,0 +1,28 @@
+package shared
+
+import (
+	"strings"
+
+	"golang.org/x/text/cases"
+	"golang.org/x/text/unicode/norm"
+)
+
+// TextComparisonPolicy identifies the shared D&D text-comparison semantics.
+// A semantic change requires a new value and a review of every dependent
+// identity, mapping, normalization, and validator policy.
+const TextComparisonPolicy = "dnd.text_comparison.v1"
+
+// ComparisonKey returns the D&D Unicode- and case-insensitive comparison key.
+func ComparisonKey(value string) string {
+	value = norm.NFKC.String(value)
+	value = strings.Map(func(r rune) rune {
+		switch r {
+		case '\u2018', '\u2019', '\u02bc':
+			return '\''
+		default:
+			return r
+		}
+	}, value)
+	value = strings.Join(strings.Fields(value), " ")
+	return cases.Fold().String(value)
+}