Update D&D schemas to require integer unit_id values

internal/modules/sharedassets/dnd/unit_refs.go

@@ -0,0 +1,133 @@
+package dnd
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+)
+
+type UnitRef struct {
+	value      string
+	fromNumber bool
+	number     int
+}
+
+type SourceRefResponse struct {
+	SourceID    string  `json:"source_id"`
+	StartUnitID UnitRef `json:"start_unit_id"`
+	EndUnitID   UnitRef `json:"end_unit_id"`
+}
+
+func UnitRefFromString(value string) UnitRef {
+	return UnitRef{value: value}
+}
+
+func UnitRefFromInt(value int) UnitRef {
+	return UnitRef{
+		value:      strconv.Itoa(value),
+		fromNumber: true,
+		number:     value,
+	}
+}
+
+func (ref UnitRef) String() string {
+	return ref.value
+}
+
+func (ref *UnitRef) UnmarshalJSON(raw []byte) error {
+	raw = bytes.TrimSpace(raw)
+	if len(raw) == 0 {
+		return fmt.Errorf("unit ref must be a string or integer")
+	}
+	if raw[0] == '"' {
+		var value string
+		if err := json.Unmarshal(raw, &value); err != nil {
+			return err
+		}
+		*ref = UnitRefFromString(value)
+		return nil
+	}
+
+	number, err := strconv.Atoi(string(raw))
+	if err != nil {
+		return fmt.Errorf("unit ref must be a string or integer")
+	}
+	*ref = UnitRefFromInt(number)
+	return nil
+}
+
+func (ref UnitRef) MarshalJSON() ([]byte, error) {
+	if ref.fromNumber {
+		return []byte(strconv.Itoa(ref.number)), nil
+	}
+	return json.Marshal(ref.value)
+}
+
+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)
+	}
+	if id, ok := canonicalUnitID(doc, value); ok {
+		return id, nil
+	}
+	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)
+}
+
+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),
+	}
+}
+
+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 canonicalUnitID(doc *source.SourceDocument, value string) (string, bool) {
+	if doc == nil {
+		return "", false
+	}
+	for _, unit := range doc.Units {
+		if unit.ID == value {
+			return unit.ID, true
+		}
+	}
+	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 number, true
+}