Share D&D cited source traversal

internal/modules/dnd/shared/matching.go

@@ -0,0 +1,43 @@
+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)
+	if value == "" {
+		return nil
+	}
+	return strings.FieldsFunc(value, func(r rune) bool {
+		return !unicode.IsLetter(r) && !unicode.IsDigit(r)
+	})
+}
+
+// ContainsTokenSequence reports whether value contains the complete normalized
+// query token sequence as consecutive tokens.
+func ContainsTokenSequence(value string, query string) bool {
+	valueTokens := NormalizedTokens(value)
+	queryTokens := NormalizedTokens(query)
+	if len(queryTokens) == 0 || len(queryTokens) > len(valueTokens) {
+		return false
+	}
+	for start := 0; start <= len(valueTokens)-len(queryTokens); start++ {
+		matches := true
+		for offset, token := range queryTokens {
+			if valueTokens[start+offset] != token {
+				matches = false
+				break
+			}
+		}
+		if matches {
+			return true
+		}
+	}
+	return false
+}