From db25ac11f2f12c2c31ca74b11a6c0eca5b2c0a14 Mon Sep 17 00:00:00 2001
From: Alex Hamlin <alex@alexhamlin.co>
Date: Sat, 7 Sep 2024 12:49:00 -0700
Subject: [PATCH] Play with an iterator for channel names

If I were writing this today for the first time, this is probably how
I'd do it.

In fact, this made me notice that I never updated my GitHub test
workflow to Go 1.23 (or Node.js 22 for that matter).
---
 .github/workflows/main-tests.yml |  4 +--
 go.mod                           |  2 +-
 internal/api/api.go              |  3 ++-
 internal/atsc/tuner/tuner.go     | 44 +++++++++++++-------------------
 4 files changed, 23 insertions(+), 30 deletions(-)

diff --git a/.github/workflows/main-tests.yml b/.github/workflows/main-tests.yml
index a8ed260..1f12d91 100644
--- a/.github/workflows/main-tests.yml
+++ b/.github/workflows/main-tests.yml
@@ -12,7 +12,7 @@ jobs:
     - name: Install Go
       uses: actions/setup-go@v5
       with:
-        go-version: "1.22"
+        go-version: "1.23"
     - name: Install libgstreamer1.0-dev
       run: |
         sudo apt-get install -y libunwind-dev
@@ -27,7 +27,7 @@ jobs:
     - name: Install Node
       uses: actions/setup-node@v4
       with:
-        node-version: 20.x
+        node-version: 22.x
     - name: Install Packages
       run: cd client && yarn install --frozen-lockfile
     - name: Build Client
diff --git a/go.mod b/go.mod
index bf8210c..ca81643 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/ahamlinman/hypcast
 
-go 1.22
+go 1.23.0
 
 require (
 	github.com/google/go-cmp v0.6.0
diff --git a/internal/api/api.go b/internal/api/api.go
index afb68da..6accd1c 100644
--- a/internal/api/api.go
+++ b/internal/api/api.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"log/slog"
 	"net/http"
+	"slices"
 
 	"github.com/gorilla/websocket"
 
@@ -50,7 +51,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 func (h *Handler) handleConfigChannels(w http.ResponseWriter, r *http.Request) {
 	w.Header().Add("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(h.tuner.ChannelNames())
+	json.NewEncoder(w).Encode(slices.Collect(h.tuner.ChannelNames()))
 }
 
 func (h *Handler) rpcStop(r *http.Request, _ struct{}) (code int, body any) {
diff --git a/internal/atsc/tuner/tuner.go b/internal/atsc/tuner/tuner.go
index 201fdde..1ae855c 100644
--- a/internal/atsc/tuner/tuner.go
+++ b/internal/atsc/tuner/tuner.go
@@ -5,6 +5,7 @@ package tuner
 import (
 	"errors"
 	"fmt"
+	"iter"
 	"log/slog"
 	"strings"
 	"sync"
@@ -111,21 +112,23 @@ func NewTuner(channels []atsc.Channel, videoPipeline VideoPipeline) *Tuner {
 }
 
 func makeChannelMap(channels []atsc.Channel) map[string]atsc.Channel {
-	m := make(map[string]atsc.Channel)
-	for _, c := range channels {
-		m[c.Name] = c
+	m := make(map[string]atsc.Channel, len(channels))
+	for _, ch := range channels {
+		m[ch.Name] = ch
 	}
 	return m
 }
 
-// ChannelNames returns the names of channels that are known to this tuner and
-// may be passed to Tune.
-func (t *Tuner) ChannelNames() []string {
-	channelNames := make([]string, len(t.channels))
-	for i, ch := range t.channels {
-		channelNames[i] = ch.Name
+// ChannelNames returns an iterator over the names of channels that may be
+// passed to [Tuner.Tune].
+func (t *Tuner) ChannelNames() iter.Seq[string] {
+	return func(yield func(string) bool) {
+		for _, ch := range t.channels {
+			if !yield(ch.Name) {
+				break
+			}
+		}
 	}
-	return channelNames
 }
 
 // WatchStatus sets up a handler function to continuously receive the status of
@@ -201,14 +204,8 @@ func (t *Tuner) Tune(channelName string) (err error) {
 	}
 	slog.Info("Started transcode pipeline")
 
-	t.status.Set(Status{
-		State:       StatePlaying,
-		ChannelName: channelName,
-	})
-	t.tracks.Set(Tracks{
-		Video: vt,
-		Audio: at,
-	})
+	t.status.Set(Status{State: StatePlaying, ChannelName: channelName})
+	t.tracks.Set(Tracks{Video: vt, Audio: at})
 	return nil
 }
 
@@ -296,7 +293,6 @@ func (t *Tuner) destroyAnyRunningPipeline() error {
 	if t.pipeline == nil {
 		return nil
 	}
-
 	err := t.pipeline.Close()
 	t.pipeline = nil
 	slog.Info("Destroyed transcode pipeline", "error", err)
@@ -335,13 +331,9 @@ var (
 
 func (t *Tuner) createTrackPair() (video, audio *webrtc.TrackLocalStaticSample, err error) {
 	streamID := fmt.Sprintf("Tuner(%p)", t)
-
-	video, err = webrtc.NewTrackLocalStaticSample(VideoCodecCapability, streamID, streamID)
-	if err != nil {
-		return
-	}
-
-	audio, err = webrtc.NewTrackLocalStaticSample(AudioCodecCapability, streamID, streamID)
+	video, verr := webrtc.NewTrackLocalStaticSample(VideoCodecCapability, streamID, streamID)
+	audio, aerr := webrtc.NewTrackLocalStaticSample(AudioCodecCapability, streamID, streamID)
+	err = errors.Join(verr, aerr)
 	return
 }