feat(zone): add Cloudflare-style traffic overview charts

Expose Zone stats API with multi-host access-log aggregates and time
series, and render unique visitors, requests and data served on the
Zone overview with 24h/7d/30d range controls.

internal/apps/openflare/zone/stats.go

@@ -0,0 +1,199 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package zone
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"time"
+
+	"github.com/Rain-kl/Wavelet/internal/db"
+	"github.com/Rain-kl/Wavelet/internal/model"
+	"gorm.io/gorm"
+)
+
+// StatsRange is a supported traffic window for Zone analytics.
+type StatsRange string
+
+const (
+	StatsRange24h StatsRange = "24h"
+	StatsRange7d  StatsRange = "7d"
+	StatsRange30d StatsRange = "30d"
+)
+
+// StatsPoint is one bucket on a Zone traffic chart.
+type StatsPoint struct {
+	BucketStartedAt time.Time `json:"bucket_started_at"`
+	RequestCount    int64     `json:"request_count"`
+	UniqueVisitors  int64     `json:"unique_visitors"`
+	BytesSent       int64     `json:"bytes_sent"`
+}
+
+// Stats summarizes edge traffic for all domains under a Zone.
+type Stats struct {
+	Range           StatsRange   `json:"range"`
+	RangeHours      int          `json:"range_hours"`
+	WindowStartedAt time.Time    `json:"window_started_at"`
+	WindowEndedAt   time.Time    `json:"window_ended_at"`
+	BucketMinutes   int          `json:"bucket_minutes"`
+	UniqueVisitors  int64        `json:"unique_visitors"`
+	RequestCount    int64        `json:"request_count"`
+	BytesSent       int64        `json:"bytes_sent"`
+	DomainCount     int          `json:"domain_count"`
+	Available       bool         `json:"available"`
+	Series          []StatsPoint `json:"series"`
+}
+
+func parseStatsRange(raw string) (StatsRange, time.Duration, int, error) {
+	switch StatsRange(strings.TrimSpace(raw)) {
+	case "", StatsRange24h:
+		return StatsRange24h, 24 * time.Hour, 60, nil
+	case StatsRange7d:
+		return StatsRange7d, 7 * 24 * time.Hour, 6 * 60, nil
+	case StatsRange30d:
+		return StatsRange30d, 30 * 24 * time.Hour, 24 * 60, nil
+	default:
+		return "", 0, 0, errors.New(errStatsRangeInvalid)
+	}
+}
+
+// GetStats aggregates access-log traffic for a Zone over a time range.
+func GetStats(ctx context.Context, id uint, rangeRaw string) (*Stats, error) {
+	statsRange, window, bucketMinutes, err := parseStatsRange(rangeRaw)
+	if err != nil {
+		return nil, err
+	}
+
+	var zone model.Zone
+	if err := db.DB(ctx).First(&zone, id).Error; err != nil {
+		return nil, err
+	}
+
+	var domains []model.ZoneDomain
+	if err := db.DB(ctx).Where("zone_id = ?", id).Order("domain asc").Find(&domains).Error; err != nil {
+		return nil, err
+	}
+
+	now := time.Now().UTC().Truncate(time.Minute)
+	since := now.Add(-window)
+	// Align chart window start to bucket boundary for cleaner x-axis labels.
+	bucket := time.Duration(bucketMinutes) * time.Minute
+	since = since.Truncate(bucket)
+
+	result := &Stats{
+		Range:           statsRange,
+		RangeHours:      int(window / time.Hour),
+		WindowStartedAt: since,
+		WindowEndedAt:   now,
+		BucketMinutes:   bucketMinutes,
+		DomainCount:     len(domains),
+		Available:       true,
+		Series:          emptyStatsSeries(since, now, bucketMinutes),
+	}
+	if len(domains) == 0 {
+		return result, nil
+	}
+
+	hosts := make([]string, 0, len(domains))
+	for _, domain := range domains {
+		if host := strings.TrimSpace(domain.Domain); host != "" {
+			hosts = append(hosts, host)
+		}
+	}
+	if len(hosts) == 0 {
+		return result, nil
+	}
+
+	requestCount, uniqueVisitors, err := model.CountOpenFlareAccessLogs(ctx, model.OpenFlareAccessLogQuery{
+		Hosts: hosts,
+		Since: since,
+		Until: now,
+	})
+	if err != nil {
+		if isAnalyticsUnavailable(err) {
+			result.Available = false
+			return result, nil
+		}
+		return nil, err
+	}
+	result.RequestCount = requestCount
+	result.UniqueVisitors = uniqueVisitors
+	// Bytes are not yet persisted on edge access logs; keep the field for UI compatibility.
+	result.BytesSent = 0
+
+	buckets, err := model.ListOpenFlareAccessLogBuckets(ctx, model.OpenFlareAccessLogBucketQuery{
+		Hosts:       hosts,
+		Since:       since,
+		Until:       now,
+		FoldMinutes: bucketMinutes,
+		SortBy:      "logged_at",
+		SortOrder:   "asc",
+	})
+	if err != nil {
+		if isAnalyticsUnavailable(err) {
+			result.Available = false
+			return result, nil
+		}
+		return nil, err
+	}
+
+	byEpoch := make(map[int64]model.OpenFlareAccessLogBucketRow, len(buckets))
+	for _, bucketRow := range buckets {
+		if bucketRow == nil {
+			continue
+		}
+		byEpoch[bucketRow.BucketEpoch] = *bucketRow
+	}
+	series := emptyStatsSeries(since, now, bucketMinutes)
+	for index := range series {
+		epoch := series[index].BucketStartedAt.Unix()
+		if row, ok := byEpoch[epoch]; ok {
+			series[index].RequestCount = row.RequestCount
+			series[index].UniqueVisitors = row.UniqueIPCount
+			series[index].BytesSent = 0
+		}
+	}
+	result.Series = series
+	return result, nil
+}
+
+func emptyStatsSeries(since, until time.Time, bucketMinutes int) []StatsPoint {
+	if bucketMinutes <= 0 {
+		bucketMinutes = 60
+	}
+	bucket := time.Duration(bucketMinutes) * time.Minute
+	start := since.UTC().Truncate(bucket)
+	end := until.UTC()
+	if !end.After(start) {
+		return []StatsPoint{{BucketStartedAt: start}}
+	}
+	// Cap points to keep chart readable.
+	maxPoints := 120
+	capacity := int(end.Sub(start)/bucket) + 1
+	if capacity > maxPoints {
+		capacity = maxPoints
+	}
+	points := make([]StatsPoint, 0, capacity)
+	for cursor := start; !cursor.After(end) && len(points) < maxPoints; cursor = cursor.Add(bucket) {
+		points = append(points, StatsPoint{BucketStartedAt: cursor})
+	}
+	if len(points) == 0 {
+		points = append(points, StatsPoint{BucketStartedAt: start})
+	}
+	return points
+}
+
+func isAnalyticsUnavailable(err error) bool {
+	if err == nil {
+		return false
+	}
+	if errors.Is(err, gorm.ErrInvalidDB) {
+		return true
+	}
+	msg := strings.ToLower(err.Error())
+	return strings.Contains(msg, "clickhouse connection is not initialized") ||
+		strings.Contains(msg, "clickhouse is not") ||
+		strings.Contains(msg, "database is not initialized")
+}