From 296af1bdcda681286796ca955d476d59668bfef2 Mon Sep 17 00:00:00 2001
From: Gabe Cook <gabe565@gmail.com>
Date: Mon, 14 Aug 2023 23:23:04 -0500
Subject: [PATCH] feat: Add initial connection retry on fail

---
 cmd/cmd.go                 | 17 +---------
 internal/config/config.go  |  1 +
 internal/config/network.go |  7 ++--
 internal/device/dns.go     | 66 ++++++++++++++++++++++++++++++++++++++
 internal/device/watch.go   | 18 +++++++++--
 5 files changed, 88 insertions(+), 21 deletions(-)
 create mode 100644 internal/device/dns.go

diff --git a/cmd/cmd.go b/cmd/cmd.go
index 5cd7ddf..aaa99fd 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -3,7 +3,6 @@ package cmd
 import (
 	"context"
 	"log/slog"
-	"net"
 	"os"
 	"os/signal"
 	"sync"
@@ -12,8 +11,6 @@ import (
 	"github.com/gabe565/sponsorblockcast/internal/config"
 	"github.com/gabe565/sponsorblockcast/internal/device"
 	"github.com/spf13/cobra"
-	"github.com/spf13/viper"
-	castdns "github.com/vishen/go-chromecast/dns"
 )
 
 func NewCommand() *cobra.Command {
@@ -38,19 +35,7 @@ func run(cmd *cobra.Command, args []string) (err error) {
 	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
 	defer cancel()
 
-	var iface *net.Interface
-	interfaceName := viper.GetString(config.InterfaceKey)
-	if interfaceName != "" {
-		iface, err = net.InterfaceByName(interfaceName)
-		if err != nil {
-			return err
-		}
-		slog.Info("Searching for devices...", "interface", interfaceName)
-	} else {
-		slog.Info("Searching for devices...")
-	}
-
-	entries, err := castdns.DiscoverCastDNSEntries(ctx, iface)
+	entries, err := device.DiscoverCastDNSEntries(ctx)
 	if err != nil {
 		return err
 	}
diff --git a/internal/config/config.go b/internal/config/config.go
index bf41575..2f7e03f 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -5,5 +5,6 @@ import "github.com/spf13/viper"
 func Load() {
 	PausedIntervalValue = viper.GetDuration(PausedIntervalKey)
 	PlayingIntervalValue = viper.GetDuration(PlayingIntervalKey)
+	InterfaceValue = viper.GetString(InterfaceKey)
 	CategoriesValue = viper.GetStringSlice(CategoriesKey)
 }
diff --git a/internal/config/network.go b/internal/config/network.go
index d28d1d8..518d3cc 100644
--- a/internal/config/network.go
+++ b/internal/config/network.go
@@ -5,10 +5,13 @@ import (
 	"github.com/spf13/viper"
 )
 
-var InterfaceKey = "interface"
+var (
+	InterfaceKey   = "interface"
+	InterfaceValue string
+)
 
 func Interface(cmd *cobra.Command) {
-	cmd.PersistentFlags().StringP(InterfaceKey, "i", "", "Network interface to use for multicast dns discovery")
+	cmd.PersistentFlags().StringP(InterfaceKey, "i", InterfaceValue, "Network interface to use for multicast dns discovery")
 	if err := viper.BindPFlag(InterfaceKey, cmd.PersistentFlags().Lookup(InterfaceKey)); err != nil {
 		panic(err)
 	}
diff --git a/internal/device/dns.go b/internal/device/dns.go
new file mode 100644
index 0000000..f6c993f
--- /dev/null
+++ b/internal/device/dns.go
@@ -0,0 +1,66 @@
+package device
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net"
+	"time"
+
+	"github.com/gabe565/sponsorblockcast/internal/config"
+	castdns "github.com/vishen/go-chromecast/dns"
+)
+
+var ErrDeviceNotFound = errors.New("device not found")
+
+func DiscoverCastDNSEntryByUuid(ctx context.Context, uuid string) (castdns.CastEntry, error) {
+	var iface *net.Interface
+	if config.InterfaceValue != "" {
+		var err error
+		iface, err = net.InterfaceByName(config.InterfaceValue)
+		if err != nil {
+			return castdns.CastEntry{}, err
+		}
+	}
+
+	ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
+	defer cancel()
+
+	entries, err := castdns.DiscoverCastDNSEntries(ctx, iface)
+	if err != nil {
+		return castdns.CastEntry{}, err
+	}
+
+	for {
+		select {
+		case <-ctx.Done():
+			return castdns.CastEntry{}, fmt.Errorf("%w: %s", ErrDeviceNotFound, uuid)
+		case entry := <-entries:
+			if entry.UUID == uuid {
+				return entry, nil
+			}
+		}
+	}
+}
+
+func DiscoverCastDNSEntries(ctx context.Context) (<-chan castdns.CastEntry, error) {
+	var iface *net.Interface
+	if config.InterfaceValue != "" {
+		var err error
+		iface, err = net.InterfaceByName(config.InterfaceValue)
+		if err != nil {
+			return nil, err
+		}
+		slog.Info("Searching for devices...", "interface", config.InterfaceValue)
+	} else {
+		slog.Info("Searching for devices...")
+	}
+
+	entries, err := castdns.DiscoverCastDNSEntries(ctx, iface)
+	if err != nil {
+		return nil, err
+	}
+
+	return entries, nil
+}
diff --git a/internal/device/watch.go b/internal/device/watch.go
index c148a87..c396ec5 100644
--- a/internal/device/watch.go
+++ b/internal/device/watch.go
@@ -28,9 +28,21 @@ func Watch(ctx context.Context, entry castdns.CastEntry) {
 
 	app := application.NewApplication()
 
-	if err := app.Start(entry.GetAddr(), entry.GetPort()); err != nil {
-		logger.Warn("Failed to start application", "error", err.Error())
-		return
+	tries := 0
+	for {
+		if err := app.Start(entry.GetAddr(), entry.GetPort()); err == nil {
+			break
+		} else {
+			if tries == 0 {
+				logger.Warn("Failed to connect to device. Retrying")
+			}
+			tries += 1
+			entry, err = DiscoverCastDNSEntryByUuid(ctx, entry.UUID)
+			if err != nil && tries >= 10 {
+				logger.Warn("Failed to start application", "error", err.Error())
+				return
+			}
+		}
 	}
 	defer func() {
 		_ = app.Close(false)