From bf1512cf0a528c171e667596f1d54b3612afa75c Mon Sep 17 00:00:00 2001
From: Pierre-Olivier Mercier <nemunaire@nemunai.re>
Date: Sun, 4 Dec 2022 10:54:23 +0100
Subject: [PATCH] New parameter to fetch and send the grid frequency

---
 frequency.go    | 96 +++++++++++++++++++++++++++++++++++++++++++++++++
 main.go         | 27 +++++++++++++-
 measurements.go |  1 +
 3 files changed, 123 insertions(+), 1 deletion(-)
 create mode 100644 frequency.go

diff --git a/frequency.go b/frequency.go
new file mode 100644
index 0000000..17be790
--- /dev/null
+++ b/frequency.go
@@ -0,0 +1,96 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const SwissGridAPI = "https://www.swissgrid.ch/bin/services/apicache?path=/content/swissgrid/fr/home/operation/grid-data/current-data/jcr:content/parsys/livedatawidget_10292"
+
+type SwissGridItem struct {
+	Id           string `json:"id"`
+	Label        string `json:"label"`
+	Value        string `json:"value"`
+	MergeColumns bool   `json:"mergeColumns"`
+	IsLabelBold  bool   `json:"isLabelBold"`
+	IsValueBold  bool   `json:"isValueBold"`
+}
+type SwissGridMaker struct {
+	Id              string  `json:"id"`
+	X               float64 `json:"x"`
+	Y               float64 `json:"y"`
+	Text1           string  `json:"text1"`
+	Text2           string  `json:"text2"`
+	TextColor       string  `json:"textColor"`
+	BackgroundColor string  `json:"backgroundColor"`
+	BorderColor     string  `json:"borderColor"`
+	Type            string  `json:"type"`
+	Direction       string  `json:"direction"`
+	Rotation        *string `json:"rotation"`
+	Opacity         float64 `json:"opacity"`
+	FontSizeDesktop string  `json:"fontSizeDesktop"`
+	FontSizeTablet  string  `json:"fontSizeTablet"`
+	FontSizePhone   string  `json:"fontSizePhone"`
+}
+
+type SwissGridData struct {
+	Data struct {
+		Table  []SwissGridItem `json:"table"`
+		Marker []SwissGridItem `json:"marker"`
+	} `json:"data"`
+}
+
+func FetchFrequency() (*SwissGridData, error) {
+	res, err := http.Get(SwissGridAPI)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode > 299 {
+		return nil, fmt.Errorf("Response failed with status code: %d", res.StatusCode)
+	}
+
+	dec := json.NewDecoder(res.Body)
+	var data SwissGridData
+	err = dec.Decode(&data)
+	if err != nil {
+		return nil, err
+	}
+
+	return &data, err
+}
+
+func WriteFrequency(writer TICWriter, freq *SwissGridData) error {
+	for _, i := range freq.Data.Table {
+		if i.Id == "FreqAct" {
+			f, err := strconv.ParseFloat(strings.Fields(i.Value)[0], 64)
+			if err != nil {
+				return err
+			}
+
+			point := Point{
+				Data: []byte(fmt.Sprintf("%.0f", f*1000)),
+			}
+
+			err = writer.AddPoints(
+				map[string]Point{
+					"FREQ": point,
+				},
+				time.Now(),
+			)
+			if err != nil {
+				log.Println("Unable to write frequency point:", err)
+			}
+
+			break
+		}
+	}
+
+	return nil
+}
diff --git a/main.go b/main.go
index 5178b1d..c68cfbc 100644
--- a/main.go
+++ b/main.go
@@ -175,6 +175,7 @@ type TICWriter interface {
 
 func main() {
 	var legacyMode = flag.Bool("legacy-mode", false, "Assume teleinformation in legacy mode")
+	var pushFrequency = flag.Bool("push-frequency", false, "Also fetch data about the grid frequency")
 	flag.Parse()
 
 	if len(flag.Args()) < 1 {
@@ -217,7 +218,31 @@ func main() {
 
 	interrupt := make(chan os.Signal, 1)
 	signal.Notify(interrupt, os.Interrupt, syscall.SIGTERM)
-	<-interrupt
+	if *pushFrequency {
+		ticker := time.NewTicker(25 * time.Second)
+		defer ticker.Stop()
+
+	frequencyloop:
+		for {
+			select {
+			case <-ticker.C:
+				freq, err := FetchFrequency()
+				if err != nil {
+					log.Println("An error occurs during FetchFrequency: ", err.Error())
+					continue frequencyloop
+				}
+
+				err = WriteFrequency(writer, freq)
+				if err != nil {
+					log.Println("An error occurs during WriteFrequency: ", err.Error())
+				}
+			case <-interrupt:
+				break frequencyloop
+			}
+		}
+	} else {
+		<-interrupt
+	}
 
 	writer.Close()
 }
diff --git a/measurements.go b/measurements.go
index 0048fae..8571ae6 100644
--- a/measurements.go
+++ b/measurements.go
@@ -51,6 +51,7 @@ var (
 	}
 
 	MeasurementUnits = map[string]string{
+		"FREQ":   "mHz",
 		"EAST":   "Wh",
 		"EASF01": "Wh",
 		"EASF02": "Wh",