Implement integer source units and chunk payloads

internal/modules/sharedassets/dnd/unit_refs.go

@@ -11,9 +11,8 @@ import (
 )
 
 type UnitRef struct {
-	value      string
+	value      int
 	fromNumber bool
-	number     int
 }
 
 type SourceRefResponse struct {
@@ -23,19 +22,22 @@ type SourceRefResponse struct {
 }
 
 func UnitRefFromString(value string) UnitRef {
-	return UnitRef{value: value}
+	parsed, _ := parseUnitRefNumber(value)
+	return UnitRef{value: parsed}
 }
 
 func UnitRefFromInt(value int) UnitRef {
 	return UnitRef{
-		value:      strconv.Itoa(value),
+		value:      value,
 		fromNumber: true,
-		number:     value,
 	}
 }
 
 func (ref UnitRef) String() string {
-	return ref.value
+	if ref.value == 0 {
+		return ""
+	}
+	return strconv.Itoa(ref.value)
 }
 
 func (ref *UnitRef) UnmarshalJSON(raw []byte) error {
@@ -48,13 +50,17 @@ func (ref *UnitRef) UnmarshalJSON(raw []byte) error {
 		if err := json.Unmarshal(raw, &value); err != nil {
 			return err
 		}
-		*ref = UnitRefFromString(value)
+		number, err := parseUnitRefNumber(value)
+		if err != nil {
+			return err
+		}
+		*ref = UnitRef{value: number}
 		return nil
 	}
 
-	number, err := strconv.Atoi(string(raw))
+	number, err := parseUnitRefNumber(string(raw))
 	if err != nil {
-		return fmt.Errorf("unit ref must be a string or integer")
+		return err
 	}
 	*ref = UnitRefFromInt(number)
 	return nil
@@ -62,72 +68,47 @@ func (ref *UnitRef) UnmarshalJSON(raw []byte) error {
 
 func (ref UnitRef) MarshalJSON() ([]byte, error) {
 	if ref.fromNumber {
-		return []byte(strconv.Itoa(ref.number)), nil
+		return []byte(strconv.Itoa(ref.value)), nil
 	}
-	return json.Marshal(ref.value)
+	return json.Marshal(ref.String())
 }
 
-func ResolveUnitID(doc *source.SourceDocument, field string, ref UnitRef) (string, error) {
-	value := strings.TrimSpace(ref.value)
-	if value == "" {
-		return "", fmt.Errorf("%s must not be empty", field)
+func ResolveUnitID(doc *source.SourceDocument, field string, ref UnitRef) (int, error) {
+	if ref.value <= 0 {
+		return 0, fmt.Errorf("%s must be positive", field)
 	}
-	if id, ok := canonicalUnitID(doc, value); ok {
-		return id, nil
+	if _, ok := source.UnitIndex(doc, ref.value); !ok {
+		return 0, fmt.Errorf("%s %d was not found", field, ref.value)
 	}
-	if number, ok := unitNumber(value); ok {
-		if id, ok := unitIDByNumber(doc, number); ok {
-			return id, nil
-		}
-		return "", fmt.Errorf("%s %d was not found as a source-unit ID or 1-based unit number", field, number)
-	}
-	return "", fmt.Errorf("%s %q was not found", field, value)
+	return ref.value, nil
 }
 
 func SourceRefCandidate(doc *source.SourceDocument, ref SourceRefResponse) source.SourceRef {
 	return source.SourceRef{
 		SourceID:    strings.TrimSpace(ref.SourceID),
-		StartUnitID: unitIDCandidate(doc, ref.StartUnitID),
-		EndUnitID:   unitIDCandidate(doc, ref.EndUnitID),
+		StartUnitID: unitIDCandidate(ref.StartUnitID),
+		EndUnitID:   unitIDCandidate(ref.EndUnitID),
 	}
 }
 
-func unitIDCandidate(doc *source.SourceDocument, ref UnitRef) string {
-	value := strings.TrimSpace(ref.value)
-	if id, ok := canonicalUnitID(doc, value); ok {
-		return id
-	}
-	if number, ok := unitNumber(value); ok {
-		if id, ok := unitIDByNumber(doc, number); ok {
-			return id
-		}
-	}
-	return value
+func unitIDCandidate(ref UnitRef) int {
+	return ref.value
 }
 
-func canonicalUnitID(doc *source.SourceDocument, value string) (string, bool) {
-	if doc == nil {
-		return "", false
+func parseUnitRefNumber(value string) (int, error) {
+	trimmed := strings.TrimSpace(value)
+	if trimmed == "" {
+		return 0, fmt.Errorf("unit ref must not be empty")
 	}
-	for _, unit := range doc.Units {
-		if unit.ID == value {
-			return unit.ID, true
-		}
+	if trimmed != value {
+		return 0, fmt.Errorf("unit ref must not contain leading or trailing whitespace")
 	}
-	return "", false
-}
-
-func unitIDByNumber(doc *source.SourceDocument, number int) (string, bool) {
-	if doc == nil || number < 1 || number > len(doc.Units) {
-		return "", false
-	}
-	return doc.Units[number-1].ID, true
-}
-
-func unitNumber(value string) (int, bool) {
 	number, err := strconv.Atoi(value)
 	if err != nil {
-		return 0, false
+		return 0, fmt.Errorf("unit ref must be an integer")
 	}
-	return number, true
+	if number <= 0 {
+		return 0, fmt.Errorf("unit ref must be positive")
+	}
+	return number, nil
 }