fix(agent): handle vnstat 1.x JSON format to prevent frontend crash

internal/agent/bandwidth.go

@@ -52,6 +52,13 @@ func (a *Agent) handleHistoricalExport(c *gin.Context) {
 		return
 	}
 
+	// Normalize vnstat 1.x JSON format to 2.x format
+	// vnstat 1.x uses "hours"/"days"/"months" (plural) and lacks "time" fields
+	// vnstat 2.x uses "hour"/"day"/"month" (singular) with "time" fields
+	if jsonVer, ok := bandwidthData["jsonversion"].(string); ok && jsonVer == "1" {
+		normalizeVnstatV1(bandwidthData)
+	}
+
 	// Add server time information for timezone handling
 	now := time.Now()
 	bandwidthData["server_time"] = now.Format(time.RFC3339)
@@ -160,6 +167,65 @@ func (a *Agent) handlePeakStats(c *gin.Context) {
 	c.JSON(http.StatusOK, stats)
 }
 
+// normalizeVnstatV1 converts vnstat JSON version 1 format to version 2 format.
+// v1 uses plural keys ("hours", "days", "months") and hour entries lack "time" fields.
+// v2 uses singular keys ("hour", "day", "month") and hour entries include "time" with hour/minute.
+func normalizeVnstatV1(data map[string]any) {
+	data["jsonversion"] = "2"
+
+	interfaces, ok := data["interfaces"].([]any)
+	if !ok {
+		return
+	}
+
+	for _, iface := range interfaces {
+		ifaceMap, ok := iface.(map[string]any)
+		if !ok {
+			continue
+		}
+
+		traffic, ok := ifaceMap["traffic"].(map[string]any)
+		if !ok {
+			continue
+		}
+
+		// Rename plural keys to singular and synthesize "time" for hour entries
+		if hours, ok := traffic["hours"].([]any); ok {
+			for _, entry := range hours {
+				hourMap, ok := entry.(map[string]any)
+				if !ok {
+					continue
+				}
+				// v1 stores hour-of-day in "id" field (0-23)
+				if id, ok := hourMap["id"].(float64); ok {
+					hourMap["time"] = map[string]any{
+						"hour":   int(id),
+						"minute": 0,
+					}
+				}
+				// v1 hour entries may lack "day" in date
+				if dateMap, ok := hourMap["date"].(map[string]any); ok {
+					if _, hasDay := dateMap["day"]; !hasDay {
+						dateMap["day"] = float64(time.Now().Day())
+					}
+				}
+			}
+			traffic["hour"] = hours
+			delete(traffic, "hours")
+		}
+
+		if days, ok := traffic["days"].([]any); ok {
+			traffic["day"] = days
+			delete(traffic, "days")
+		}
+
+		if months, ok := traffic["months"].([]any); ok {
+			traffic["month"] = months
+			delete(traffic, "months")
+		}
+	}
+}
+
 // formatBytesPerSecond formats bytes per second to human readable string
 func formatBytesPerSecond(bytes int) string {
 	if bytes == 0 {

internal/agent/bandwidth_test.go

@@ -0,0 +1,162 @@
+// Copyright (c) 2024-2025, s0up and the autobrr contributors.
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package agent
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNormalizeVnstatV1(t *testing.T) {
+	// Simulated vnstat 1.18 JSON output
+	v1JSON := `{
+		"vnstatversion": "1.18",
+		"jsonversion": "1",
+		"interfaces": [{
+			"id": "eth0",
+			"nick": "",
+			"traffic": {
+				"total": {"rx": 1000000, "tx": 500000},
+				"hours": [
+					{"id": 0, "date": {"year": 2025, "month": 1, "day": 6}, "rx": 100, "tx": 50},
+					{"id": 14, "date": {"year": 2025, "month": 1, "day": 6}, "rx": 200, "tx": 100}
+				],
+				"days": [
+					{"id": 0, "date": {"year": 2025, "month": 1, "day": 6}, "rx": 5000, "tx": 2500}
+				],
+				"months": [
+					{"id": 0, "date": {"year": 2025, "month": 1}, "rx": 100000, "tx": 50000}
+				]
+			}
+		}]
+	}`
+
+	var data map[string]any
+	require.NoError(t, json.Unmarshal([]byte(v1JSON), &data))
+
+	normalizeVnstatV1(data)
+
+	// jsonversion should be updated to "2"
+	assert.Equal(t, "2", data["jsonversion"])
+
+	interfaces := data["interfaces"].([]any)
+	iface := interfaces[0].(map[string]any)
+	traffic := iface["traffic"].(map[string]any)
+
+	// "hours" should be renamed to "hour"
+	assert.Nil(t, traffic["hours"], "old 'hours' key should be removed")
+	hourData, ok := traffic["hour"].([]any)
+	require.True(t, ok, "should have 'hour' key")
+	assert.Len(t, hourData, 2)
+
+	// Hour entries should have "time" field added
+	firstHour := hourData[0].(map[string]any)
+	timeField, ok := firstHour["time"].(map[string]any)
+	require.True(t, ok, "hour entry should have 'time' field")
+	assert.Equal(t, 0, timeField["hour"].(int))
+	assert.Equal(t, 0, timeField["minute"].(int))
+
+	secondHour := hourData[1].(map[string]any)
+	timeField2 := secondHour["time"].(map[string]any)
+	assert.Equal(t, 14, timeField2["hour"].(int))
+
+	// "days" should be renamed to "day"
+	assert.Nil(t, traffic["days"], "old 'days' key should be removed")
+	dayData, ok := traffic["day"].([]any)
+	require.True(t, ok, "should have 'day' key")
+	assert.Len(t, dayData, 1)
+
+	// "months" should be renamed to "month"
+	assert.Nil(t, traffic["months"], "old 'months' key should be removed")
+	monthData, ok := traffic["month"].([]any)
+	require.True(t, ok, "should have 'month' key")
+	assert.Len(t, monthData, 1)
+}
+
+func TestNormalizeVnstatV1_HourWithoutDay(t *testing.T) {
+	// vnstat 1.18 may omit "day" from hour entries
+	v1JSON := `{
+		"vnstatversion": "1.18",
+		"jsonversion": "1",
+		"interfaces": [{
+			"id": "eth0",
+			"nick": "",
+			"traffic": {
+				"total": {"rx": 1000, "tx": 500},
+				"hours": [
+					{"id": 10, "date": {"year": 2025, "month": 1}, "rx": 100, "tx": 50}
+				]
+			}
+		}]
+	}`
+
+	var data map[string]any
+	require.NoError(t, json.Unmarshal([]byte(v1JSON), &data))
+
+	normalizeVnstatV1(data)
+
+	interfaces := data["interfaces"].([]any)
+	iface := interfaces[0].(map[string]any)
+	traffic := iface["traffic"].(map[string]any)
+	hourData := traffic["hour"].([]any)
+	firstHour := hourData[0].(map[string]any)
+
+	timeField := firstHour["time"].(map[string]any)
+	assert.Equal(t, 10, timeField["hour"].(int))
+
+	// Should have day added to date
+	dateField := firstHour["date"].(map[string]any)
+	assert.NotNil(t, dateField["day"], "day should be added to date when missing")
+}
+
+func TestNormalizeVnstatV1_NoInterfaces(t *testing.T) {
+	data := map[string]any{
+		"vnstatversion": "1.18",
+		"jsonversion":   "1",
+	}
+
+	// Should not panic
+	normalizeVnstatV1(data)
+	assert.Equal(t, "2", data["jsonversion"])
+}
+
+func TestNormalizeVnstatV1_EmptyTraffic(t *testing.T) {
+	data := map[string]any{
+		"vnstatversion": "1.18",
+		"jsonversion":   "1",
+		"interfaces": []any{
+			map[string]any{
+				"id":      "eth0",
+				"traffic": map[string]any{},
+			},
+		},
+	}
+
+	// Should not panic
+	normalizeVnstatV1(data)
+	assert.Equal(t, "2", data["jsonversion"])
+}
+
+func TestFormatBytesPerSecond(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    int
+		expected string
+	}{
+		{"zero", 0, "0 B/s"},
+		{"bytes", 512, "512.00 B/s"},
+		{"kibibytes", 1024, "1.00 KiB/s"},
+		{"mebibytes", 1048576, "1.00 MiB/s"},
+		{"gibibytes", 1073741824, "1.00 GiB/s"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.expected, formatBytesPerSecond(tt.input))
+		})
+	}
+}