server: humidity record for each room

1 files changed, 60 insertions, 0 deletions

diff --git a/server/record.go b/server/record.go
new file mode 100644
index 0000000..9051146
--- /dev/null
+++ b/server/record.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"time"
+)
+
+type Record[T any] struct {
+	put       chan<- T
+	get       chan<- chan T
+	getRecent chan<- chan T
+}
+
+type entry[T any] struct {
+	t time.Time
+	v T
+}
+
+func newRecord[T any]() Record[T] {
+	put := make(chan T)
+	get := make(chan chan T)
+	getRecent := make(chan chan T)
+
+	go func() {
+		var entries []entry[T]
+
+		for {
+			select {
+			case v, ok := <-put:
+				if !ok {
+					return
+				}
+				entries = append(entries, entry[T]{time.Now(), v})
+			case c, ok := <-get:
+				if !ok {
+					return
+				}
+				for _, e := range entries {
+					c <- e.v
+				}
+				close(c)
+			case c, ok := <-getRecent:
+				if !ok {
+					return
+				}
+				if len(entries) > 0 {
+					c <- entries[len(entries)-1].v
+				}
+				close(c)
+			}
+		}
+	}()
+
+	return Record[T]{put, get, getRecent}
+}
+
+func (l Record[T]) Close() {
+	close(l.put)
+	close(l.get)
+	close(l.getRecent)
+}