Add DNS Stats widget

internal/feed/pihole.go

@@ -0,0 +1,109 @@
+package feed
+
+import (
+	"errors"
+	"net/http"
+	"sort"
+	"strings"
+)
+
+type piholeStatsResponse struct {
+	TotalQueries      int            `json:"dns_queries_today"`
+	QueriesSeries     map[int64]int  `json:"domains_over_time"`
+	BlockedQueries    int            `json:"ads_blocked_today"`
+	BlockedSeries     map[int64]int  `json:"ads_over_time"`
+	BlockedPercentage float64        `json:"ads_percentage_today"`
+	TopBlockedDomains map[string]int `json:"top_ads"`
+	DomainsBlocked    int            `json:"domains_being_blocked"`
+}
+
+func FetchPiholeStats(instanceURL, token string) (*DNSStats, error) {
+	if token == "" {
+		return nil, errors.New("missing API token")
+	}
+
+	requestURL := strings.TrimRight(instanceURL, "/") +
+		"/admin/api.php?summaryRaw&topItems&overTimeData10mins&auth=" + token
+
+	request, err := http.NewRequest("GET", requestURL, nil)
+
+	if err != nil {
+		return nil, err
+	}
+
+	responseJson, err := decodeJsonFromRequest[piholeStatsResponse](defaultClient, request)
+
+	if err != nil {
+		return nil, err
+	}
+
+	stats := &DNSStats{
+		TotalQueries:   responseJson.TotalQueries,
+		BlockedQueries: responseJson.BlockedQueries,
+		BlockedPercent: int(responseJson.BlockedPercentage),
+		DomainsBlocked: responseJson.DomainsBlocked,
+	}
+
+	if len(responseJson.TopBlockedDomains) > 0 {
+		domains := make([]DNSStatsBlockedDomain, 0, len(responseJson.TopBlockedDomains))
+
+		for domain, count := range responseJson.TopBlockedDomains {
+			domains = append(domains, DNSStatsBlockedDomain{
+				Domain:         domain,
+				PercentBlocked: int(float64(count) / float64(responseJson.BlockedQueries) * 100),
+			})
+		}
+
+		sort.Slice(domains, func(a, b int) bool {
+			return domains[a].PercentBlocked > domains[b].PercentBlocked
+		})
+
+		stats.TopBlockedDomains = domains[:min(len(domains), 5)]
+	}
+
+	// Pihole _should_ return data for the last 24 hours in a 10 minute interval, 6*24 = 144
+	if len(responseJson.QueriesSeries) != 144 || len(responseJson.BlockedSeries) != 144 {
+		return stats, nil
+	}
+
+	var lowestTimestamp int64 = 0
+
+	for timestamp := range responseJson.QueriesSeries {
+		if lowestTimestamp == 0 || timestamp < lowestTimestamp {
+			lowestTimestamp = timestamp
+		}
+	}
+
+	maxQueriesInSeries := 0
+
+	for i := 0; i < 8; i++ {
+		queries := 0
+		blocked := 0
+
+		for j := 0; j < 18; j++ {
+			index := lowestTimestamp + int64(i*10800+j*600)
+
+			queries += responseJson.QueriesSeries[index]
+			blocked += responseJson.BlockedSeries[index]
+		}
+
+		if queries > maxQueriesInSeries {
+			maxQueriesInSeries = queries
+		}
+
+		stats.Series[i] = DNSStatsSeries{
+			Queries: queries,
+			Blocked: blocked,
+		}
+
+		if queries > 0 {
+			stats.Series[i].PercentBlocked = int(float64(blocked) / float64(queries) * 100)
+		}
+	}
+
+	for i := 0; i < 8; i++ {
+		stats.Series[i].PercentTotal = int(float64(stats.Series[i].Queries) / float64(maxQueriesInSeries) * 100)
+	}
+
+	return stats, nil
+}