From b50e1ee84d3b03d20b7c54585548558efef9d912 Mon Sep 17 00:00:00 2001
From: Oleg Pykhalov <go.wigust@gmail.com>
Date: Sun, 4 Feb 2024 08:30:09 +0300
Subject: Allow to switch monitor inputs.

HDMI-1, HDMI-2, DP-1.
---
 README.md | 19 +++++++++++++++++++
 main.go   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/README.md b/README.md
index 6d97db7..4509509 100644
--- a/README.md
+++ b/README.md
@@ -48,3 +48,22 @@ Toggle brightness between current and minimal values:
 ```shell
 curl --request POST 127.0.0.1:49281/toggle
 ```
+
+Switch to HDMI-1:
+```shell
+curl -d '{"value": "x0090"}' -XPOST 127.0.0.1:49281/set-input
+```
+
+Switch to HDMI-2:
+```shell
+curl -d '{"value": "x0091"}' -XPOST 127.0.0.1:49281/set-input
+```
+
+Switch to DP-1:
+```shell
+curl -d '{"value": "x00d0"}' -XPOST 127.0.0.1:49281/set-input
+```
+
+# Thanks
+
+- [LG 29UM69G fails switching input · Issue #100 · rockowitz/ddcutil](https://github.com/rockowitz/ddcutil/issues/100)
diff --git a/main.go b/main.go
index 60de258..69e2f58 100644
--- a/main.go
+++ b/main.go
@@ -27,7 +27,13 @@ type Brightness struct {
 	ToggledValue int
 }
 
+type Input struct {
+	Lock  bool
+	Value string
+}
+
 var currentBrightness Brightness
+var currentInput Input
 
 func update() {
 	if currentBrightness.Lock == false {
@@ -79,6 +85,49 @@ func ddcutilSetBrightness(brightness Brightness) {
 	}
 }
 
+func ddcutilSetInput(input Input) {
+	if currentInput.Lock == false {
+		currentInput.Lock = true
+		cmd := exec.Command("ddcutil", "setvcp", "xF4",
+			input.Value,
+			"--i2c-source-addr=x50",
+			"--noverify")
+		log.Println(cmd.String())
+		_, err := cmd.CombinedOutput()
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		currentInput.Value = input.Value
+		currentInput.Lock = false
+	} else {
+		log.Println("Active lock, no operation performed")
+		return
+	}
+}
+
+func setInput(w http.ResponseWriter, r *http.Request) {
+	if r.Method == "POST" {
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		var input Input
+		json.Unmarshal([]byte(body), &input)
+		newValue := Input{Value: input.Value}
+		if newValue.Value == currentInput.Value {
+			log.Println("Input is the same")
+		} else {
+			ddcutilSetInput(newValue)
+			log.Println("Current input is", currentInput.Value)
+		}
+	} else {
+		log.Println("Active lock, no operation performed")
+		return
+	}
+}
+
 func set(w http.ResponseWriter, r *http.Request) {
 	if r.Method == "POST" {
 		body, err := io.ReadAll(r.Body)
@@ -172,5 +221,6 @@ func main() {
 	http.HandleFunc("/decrease", decrease)
 	http.HandleFunc("/increase", increase)
 	http.HandleFunc("/toggle", toggle)
+	http.HandleFunc("/set-input", setInput)
 	log.Fatal(http.ListenAndServe(configuration.Listen, nil))
 }
-- 
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