1 files changed, 55 insertions, 0 deletions
diff --git a/server/chart.go b/server/chart.go
new file mode 100644
index 0000000..1f20d3c
--- /dev/null
+++ b/server/chart.go
@@ -0,0 +1,55 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"fmt"
+	"time"
+	"github.com/wcharczuk/go-chart/v2"
+)
+
+type ChartHandler struct {
+	building Building
+}
+
+func (h ChartHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	log.Println(r.Method, r.URL)
+
+	if r.Method != http.MethodGet {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		fmt.Fprintf(w, "invalid method: '%s'", r.Method)
+		return
+	}
+
+	var series []chart.Series
+	for room, record := range h.building {
+		var x []time.Time
+		var y []float64
+		c := make(chan Entry[Humidity])
+		record.get <- c
+		for e := range c {
+			x = append(x, e.t)
+			y = append(y, float64(e.v))
+		}
+		series = append(series, chart.TimeSeries{
+			Name: string(room),
+			XValues: x,
+			YValues: y,
+		})
+	}
+
+	graph := chart.Chart{
+		Background: chart.Style{
+			Padding: chart.Box{Top: 20, Left: 20},
+		},
+		Series: series,
+	}
+	graph.Elements = []chart.Renderable{
+		chart.Legend(&graph),
+	}
+
+	w.Header().Set("Content-Type", "image/png")
+	if err := graph.Render(chart.PNG, w); err != nil {
+		log.Println(err)
+	}
+}