From bc516bce7ddf45440791daacd60048e5d520c063 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Simonsen?= <rss@knowhowdata.dk>
Date: Wed, 3 Jan 2024 15:08:21 +0100
Subject: [PATCH] Adds automatic extention of nest stream before it expires.

---
 pkg/nest/api.go    | 62 ++++++++++++++++++++++++++++++++++++++++------
 pkg/nest/client.go | 39 ++++++++++++++++++++++++++---
 2 files changed, 91 insertions(+), 10 deletions(-)

diff --git a/pkg/nest/api.go b/pkg/nest/api.go
index 9c7f4546..e260799e 100644
--- a/pkg/nest/api.go
+++ b/pkg/nest/api.go
@@ -121,7 +121,7 @@ func (a *API) GetDevices(projectID string) (map[string]string, error) {
 	return devices, nil
 }
 
-func (a *API) ExchangeSDP(projectID, deviceID, offer string) (string, error) {
+func (a *API) ExchangeSDP(projectID, deviceID, offer string) (string, string, time.Time, error) {
 	var reqv struct {
 		Command string `json:"command"`
 		Params  struct {
@@ -133,14 +133,14 @@ func (a *API) ExchangeSDP(projectID, deviceID, offer string) (string, error) {
 
 	b, err := json.Marshal(reqv)
 	if err != nil {
-		return "", err
+		return "", "", time.Time{}, err
 	}
 
 	uri := "https://smartdevicemanagement.googleapis.com/v1/enterprises/" +
 		projectID + "/devices/" + deviceID + ":executeCommand"
 	req, err := http.NewRequest("POST", uri, bytes.NewReader(b))
 	if err != nil {
-		return "", err
+		return "", "", time.Time{}, err
 	}
 
 	req.Header.Set("Authorization", "Bearer "+a.Token)
@@ -148,11 +148,11 @@ func (a *API) ExchangeSDP(projectID, deviceID, offer string) (string, error) {
 	client := &http.Client{Timeout: time.Second * 5000}
 	res, err := client.Do(req)
 	if err != nil {
-		return "", err
+		return "", "", time.Time{}, err
 	}
 
 	if res.StatusCode != 200 {
-		return "", errors.New("nest: wrong status: " + res.Status)
+		return "", "", time.Time{}, errors.New("nest: wrong status: " + res.Status)
 	}
 
 	var resv struct {
@@ -164,10 +164,58 @@ func (a *API) ExchangeSDP(projectID, deviceID, offer string) (string, error) {
 	}
 
 	if err = json.NewDecoder(res.Body).Decode(&resv); err != nil {
-		return "", err
+		return "", "", time.Time{}, err
 	}
 
-	return resv.Results.Answer, nil
+	return resv.Results.Answer, resv.Results.MediaSessionId, resv.Results.ExpiresAt, nil
+}
+
+func (a *API) ExtendStream(projectID, deviceID, mediaSessionID string) (string, time.Time, error) {
+	var reqv struct {
+		Command string `json:"command"`
+		Params  struct {
+			MediaSessionID string `json:"mediaSessionId"`
+		} `json:"params"`
+	}
+	reqv.Command = "sdm.devices.commands.CameraLiveStream.ExtendWebRtcStream"
+	reqv.Params.MediaSessionID = mediaSessionID
+
+	b, err := json.Marshal(reqv)
+	if err != nil {
+		return "", time.Time{}, err
+	}
+
+	uri := "https://smartdevicemanagement.googleapis.com/v1/enterprises/" +
+		projectID + "/devices/" + deviceID + ":executeCommand"
+	req, err := http.NewRequest("POST", uri, bytes.NewReader(b))
+	if err != nil {
+		return "", time.Time{}, err
+	}
+
+	req.Header.Set("Authorization", "Bearer "+a.Token)
+
+	client := &http.Client{Timeout: time.Second * 5000}
+	res, err := client.Do(req)
+	if err != nil {
+		return "", time.Time{}, err
+	}
+
+	if res.StatusCode != 200 {
+		return "", time.Time{}, errors.New("nest: wrong status: " + res.Status)
+	}
+
+	var resv struct {
+		Results struct {
+			ExpiresAt      time.Time `json:"expiresAt"`
+			MediaSessionId string    `json:"mediaSessionId"`
+		} `json:"results"`
+	}
+
+	if err = json.NewDecoder(res.Body).Decode(&resv); err != nil {
+		return "", time.Time{}, err
+	}
+
+	return resv.Results.MediaSessionId, resv.Results.ExpiresAt, nil
 }
 
 type Device struct {
diff --git a/pkg/nest/client.go b/pkg/nest/client.go
index b2b0c964..6beabd81 100644
--- a/pkg/nest/client.go
+++ b/pkg/nest/client.go
@@ -4,13 +4,21 @@ import (
 	"errors"
 	"net/url"
 
+	"time"
+
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/webrtc"
 	pion "github.com/pion/webrtc/v3"
 )
 
 type Client struct {
-	conn *webrtc.Conn
+	conn            *webrtc.Conn
+	projectId       string
+	deviceId        string
+	mediaSessionId  string
+	streamExpiresAt time.Time
+	nestApi         *API
+	timer           *time.Timer
 }
 
 func NewClient(rawURL string) (*Client, error) {
@@ -64,7 +72,7 @@ func NewClient(rawURL string) (*Client, error) {
 	}
 
 	// 4. Exchange SDP via Hass
-	answer, err := nestAPI.ExchangeSDP(projectID, deviceID, offer)
+	answer, mediaSessionId, expiresAt, err := nestAPI.ExchangeSDP(projectID, deviceID, offer)
 	if err != nil {
 		return nil, err
 	}
@@ -74,7 +82,7 @@ func NewClient(rawURL string) (*Client, error) {
 		return nil, err
 	}
 
-	return &Client{conn: conn}, nil
+	return &Client{conn: conn, deviceId: deviceID, projectId: projectID, mediaSessionId: mediaSessionId, streamExpiresAt: expiresAt, nestApi: nestAPI}, nil
 }
 
 func (c *Client) GetMedias() []*core.Media {
@@ -90,10 +98,35 @@ func (c *Client) AddTrack(media *core.Media, codec *core.Codec, track *core.Rece
 }
 
 func (c *Client) Start() error {
+	c.StartExtendStreamTimer()
+
 	return c.conn.Start()
 }
 
+func (c *Client) StartExtendStreamTimer() {
+	ontimer := func() {
+		c.ExtendStream()
+		c.StartExtendStreamTimer()
+	}
+	// Calculate the duration until 30 seconds before the stream expires
+	duration := time.Until(c.streamExpiresAt.Add(-30 * time.Second))
+
+	// Start the timer
+	c.timer = time.AfterFunc(duration, ontimer)
+}
+
+func (c *Client) ExtendStream() error {
+	mediaSessionId, expiresAt, err := c.nestApi.ExtendStream(c.projectId, c.deviceId, c.mediaSessionId)
+	if err != nil {
+		return err
+	}
+	c.mediaSessionId = mediaSessionId
+	c.streamExpiresAt = expiresAt
+	return nil
+}
+
 func (c *Client) Stop() error {
+	c.timer.Stop()
 	return c.conn.Stop()
 }