Implement integer source units and chunk payloads

internal/modules/input/seriatim/model.go

@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"strconv"
+	"strings"
 )
 
 type transcript struct {
@@ -13,7 +15,7 @@ type transcript struct {
 }
 
 type segment struct {
-	ID      string      `json:"id"`
+	ID      int         `json:"id"`
 	Start   json.Number `json:"start"`
 	End     json.Number `json:"end"`
 	Speaker string      `json:"speaker"`
@@ -78,7 +80,7 @@ func decodeSegment(raw []byte, index int) (segment, error) {
 
 	var decoded segment
 	if err := decodeOptionalSegmentID(fields, "id", &decoded.ID); err != nil {
-		return segment{}, fmt.Errorf("segment[%d] id must be a string or number: %w", index, err)
+		return segment{}, fmt.Errorf("segment[%d] id must be a positive integer string or number: %w", index, err)
 	}
 	if err := decodeOptionalNumber(fields, "start", &decoded.Start); err != nil {
 		return segment{}, fmt.Errorf("segment[%d] start must be a number: %w", index, err)
@@ -103,7 +105,7 @@ func decodeOptionalString(fields map[string]json.RawMessage, key string, out *st
 	return decodeJSON(raw, out)
 }
 
-func decodeOptionalSegmentID(fields map[string]json.RawMessage, key string, out *string) error {
+func decodeOptionalSegmentID(fields map[string]json.RawMessage, key string, out *int) error {
 	raw, ok := fields[key]
 	if !ok {
 		return nil
@@ -111,17 +113,46 @@ func decodeOptionalSegmentID(fields map[string]json.RawMessage, key string, out
 
 	var text string
 	if err := decodeJSON(raw, &text); err == nil {
-		*out = text
+		parsed, err := parsePositiveInt(text)
+		if err != nil {
+			return err
+		}
+		*out = parsed
 		return nil
 	}
 
 	var number json.Number
 	if err := decodeJSON(raw, &number); err == nil {
-		*out = number.String()
+		parsed, err := parsePositiveInt(number.String())
+		if err != nil {
+			return err
+		}
+		*out = parsed
 		return nil
 	}
 
-	return fmt.Errorf("must be a string or number")
+	return fmt.Errorf("must be a positive integer string or number")
+}
+
+func parsePositiveInt(value string) (int, error) {
+	trimmed := strings.TrimSpace(value)
+	if trimmed == "" {
+		return 0, fmt.Errorf("must not be empty")
+	}
+	if trimmed != value {
+		return 0, fmt.Errorf("must not contain leading or trailing whitespace")
+	}
+	parsed, err := strconv.Atoi(value)
+	if err != nil {
+		return 0, fmt.Errorf("must be an integer")
+	}
+	if parsed <= 0 {
+		return 0, fmt.Errorf("must be positive")
+	}
+	if strconv.Itoa(parsed) != value {
+		return 0, fmt.Errorf("must be a canonical positive integer")
+	}
+	return parsed, nil
 }
 
 func decodeOptionalNumber(fields map[string]json.RawMessage, key string, out *json.Number) error {