From 60f96104a26d1931cc66d670e7c0a73c676ced5d Mon Sep 17 00:00:00 2001
From: Simon Vieille <simon.vieille@trinaps.com>
Date: Sun, 27 Aug 2023 21:34:02 +0200
Subject: [PATCH] [wip] add audio controller

---
 audio_controller.go | 45 +++++++++++++++++++++++++++++++++++++++++++++
 go.mod              |  1 +
 go.sum              |  2 ++
 main.go             | 15 ++++++++++++---
 4 files changed, 60 insertions(+), 3 deletions(-)
 create mode 100644 audio_controller.go

diff --git a/audio_controller.go b/audio_controller.go
new file mode 100644
index 0000000..bca8220
--- /dev/null
+++ b/audio_controller.go
@@ -0,0 +1,45 @@
+package main
+
+import (
+	"encoding/binary"
+	"github.com/gordonklaus/portaudio"
+	"github.com/labstack/echo/v4"
+	"net/http"
+)
+
+func chk(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func audioController(c echo.Context) error {
+	if audioIsInitialized == false {
+		portaudio.Initialize()
+		defer portaudio.Terminate()
+		audioBuffer = make([]float32, audioSampleRate*audioSeconds)
+		stream, err := portaudio.OpenDefaultStream(1, 0, audioSampleRate, len(audioBuffer), func(in []float32) {
+			for i := range audioBuffer {
+				audioBuffer[i] = in[i]
+			}
+		})
+		chk(err)
+		chk(stream.Start())
+		defer stream.Close()
+	}
+
+	flusher, _ := c.Response().Writer.(http.Flusher)
+
+	c.Response().Header().Set("Connection", "Keep-Alive")
+	c.Response().Header().Set("Access-Control-Allow-Origin", "*")
+	c.Response().Header().Set("X-Content-Type-Options", "nosniff")
+	c.Response().Header().Set("Transfer-Encoding", "chunked")
+	c.Response().Header().Set("Content-Type", "audio/wave")
+
+	for true {
+		binary.Write(c.Response().Writer, binary.BigEndian, &audioBuffer)
+		flusher.Flush() // Trigger "chunked" encoding and send a chunk...
+	}
+
+	return nil
+}
diff --git a/go.mod b/go.mod
index a00f573..2675969 100644
--- a/go.mod
+++ b/go.mod
@@ -7,6 +7,7 @@ require (
 	github.com/daaku/go.zipexe v1.0.2 // indirect
 	github.com/gen2brain/shm v0.0.0-20230802011745-f2460f5984f7 // indirect
 	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
+	github.com/gordonklaus/portaudio v0.0.0-20230709114228-aafa478834f5 // indirect
 	github.com/gorilla/websocket v1.5.0 // indirect
 	github.com/jezek/xgb v1.1.0 // indirect
 	github.com/kbinani/screenshot v0.0.0-20230812210009-b87d31814237 // indirect
diff --git a/go.sum b/go.sum
index 55e33d8..3411f68 100644
--- a/go.sum
+++ b/go.sum
@@ -10,6 +10,8 @@ github.com/gen2brain/shm v0.0.0-20230802011745-f2460f5984f7 h1:VLEKvjGJYAMCXw0/3
 github.com/gen2brain/shm v0.0.0-20230802011745-f2460f5984f7/go.mod h1:uF6rMu/1nvu+5DpiRLwusA6xB8zlkNoGzKn8lmYONUo=
 github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
 github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
+github.com/gordonklaus/portaudio v0.0.0-20230709114228-aafa478834f5 h1:5AlozfqaVjGYGhms2OsdUyfdJME76E6rx5MdGpjzZpc=
+github.com/gordonklaus/portaudio v0.0.0-20230709114228-aafa478834f5/go.mod h1:WY8R6YKlI2ZI3UyzFk7P6yGSuS+hFwNtEzrexRyD7Es=
 github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
diff --git a/main.go b/main.go
index f210e5a..71a4631 100644
--- a/main.go
+++ b/main.go
@@ -12,14 +12,21 @@ import (
 	"os"
 )
 
+const (
+	audioSampleRate = 44100
+	audioSeconds    = 2
+)
+
 var (
 	templates map[string]*template.Template
 	//go:embed static
 	staticFiles embed.FS
 	//go:embed views/layout views/page
-	views   embed.FS
-	config  Config
-	actions Actions
+	views              embed.FS
+	config             Config
+	actions            Actions
+	audioBuffer        []float32
+	audioIsInitialized bool
 )
 
 func main() {
@@ -40,6 +47,7 @@ func main() {
 	}
 
 	config = value
+	audioIsInitialized = false
 	e.Use(middleware.BasicAuth(func(username, password string, c echo.Context) (bool, error) {
 		if config.Server.Auth.Username == "" && config.Server.Auth.Password == "" {
 			return true, nil
@@ -61,6 +69,7 @@ func main() {
 	e.GET("/static/*", echo.WrapHandler(http.StripPrefix("/static/", assetHandler)))
 	e.GET("/", homeController)
 	e.GET("/ws", wsController)
+	e.GET("/audio", audioController)
 
 	e.Logger.Fatal(e.Start(config.Server.Listen))
 }