From 3205711bb1becb0653a56a97e596f345f22568ad Mon Sep 17 00:00:00 2001
From: marcobaobao <marco.piovanello@gmail.com>
Date: Tue, 20 Aug 2024 18:50:42 +0200
Subject: [PATCH] improved livestream waiting

---
 server/internal/livestream/livestream.go | 103 ++++++++++++++++-------
 1 file changed, 73 insertions(+), 30 deletions(-)

diff --git a/server/internal/livestream/livestream.go b/server/internal/livestream/livestream.go
index 9cbce4c..28472ac 100644
--- a/server/internal/livestream/livestream.go
+++ b/server/internal/livestream/livestream.go
@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"errors"
 	"io"
+	"log/slog"
 	"os"
 	"os/exec"
 	"strconv"
@@ -53,6 +54,7 @@ func (l *LiveStream) Start() error {
 		l.url,
 		"--wait-for-video", "10", // wait for the stream to be live and recheck every 10 secs
 		"--no-colors", // no ansi color fuzz
+		"--newline",
 		"--paths", config.Instance().DownloadPath,
 	)
 	l.proc = cmd.Process
@@ -72,7 +74,13 @@ func (l *LiveStream) Start() error {
 
 	// Start monitoring when the livestream is goin to be live.
 	// If already live do nothing.
-	go l.monitorStartTime(stdout)
+	doneWaiting := make(chan struct{})
+	go l.monitorStartTime(stdout, doneWaiting)
+
+	go func() {
+		<-doneWaiting
+		l.logFFMpeg(stdout)
+	}()
 
 	// Wait to the yt-dlp+ffmpeg process to finish.
 	cmd.Wait()
@@ -81,14 +89,18 @@ func (l *LiveStream) Start() error {
 	l.status = completed
 	l.done <- l
 
+	// cleanup
+	close(doneWaiting)
+
 	return nil
 }
 
-func (l *LiveStream) monitorStartTime(r io.Reader) error {
+func (l *LiveStream) monitorStartTime(r io.Reader, doneWait chan struct{}) {
 	// yt-dlp shows the time in the stdout
 	scanner := bufio.NewScanner(r)
 
 	defer func() {
+		doneWait <- struct{}{}
 		close(l.waitTimeChan)
 		close(l.errors)
 	}()
@@ -97,7 +109,7 @@ func (l *LiveStream) monitorStartTime(r io.Reader) error {
 	// use a custom split funciton to set the line separator to \r instead of \r\n or \n
 	scanner.Split(func(data []byte, atEOF bool) (advance int, token []byte, err error) {
 		for i := 0; i < len(data); i++ {
-			if data[i] == '\r' {
+			if data[i] == '\r' || data[i] == '\n' {
 				return i + 1, data[:i], nil
 			}
 		}
@@ -108,37 +120,60 @@ func (l *LiveStream) monitorStartTime(r io.Reader) error {
 		return 0, data, bufio.ErrFinalToken
 	})
 
-	// start scanning the stdout
-	for scanner.Scan() {
-		// l.log <- scanner.Bytes()
+	waitTimeScanner := func() {
+		for scanner.Scan() {
+			// l.log <- scanner.Bytes()
 
-		parts := strings.Split(scanner.Text(), ": ")
-		if len(parts) < 2 {
-			continue
+			// if this substring is in the current line the download is starting,
+			// no need to monitor the time to live.
+			//TODO: silly
+			if !strings.Contains(scanner.Text(), "Remaining time until next attempt") {
+				l.status = inProgress
+				return
+			}
+
+			parts := strings.Split(scanner.Text(), ": ")
+			if len(parts) < 2 {
+				continue
+			}
+
+			startsIn := parts[1]
+			parsed, err := parseTimeSpan(startsIn)
+			if err != nil {
+				continue
+			}
+
+			l.liveDate = parsed
+
+			//TODO: check if using channels is stupid or not
+			// l.waitTimeChan <- time.Until(start)
+			l.waitTime = time.Until(parsed)
 		}
-
-		// if this substring is in the current line the download is starting,
-		// no need to monitor the time to live.
-		//TODO: silly
-		if !strings.Contains(scanner.Text(), "Remaining time until next attempt") {
-			l.status = inProgress
-			return nil
-		}
-
-		startsIn := parts[1]
-		parsed, err := parseTimeSpan(startsIn)
-		if err != nil {
-			continue
-		}
-
-		l.liveDate = parsed
-
-		//TODO: check if using channels is stupid or not
-		// l.waitTimeChan <- time.Until(start)
-		l.waitTime = time.Until(parsed)
 	}
 
-	return nil
+	const TRIES = 5
+
+	/*
+		if it's waiting a livestream the 5th line will indicate the time to live
+		its a dumb and not robust method.
+
+		example:
+			[youtube] Extracting URL: https://www.youtube.com/watch?v=IQVbGfVVjgY
+			[youtube] IQVbGfVVjgY: Downloading webpage
+			[youtube] IQVbGfVVjgY: Downloading ios player API JSON
+			[youtube] IQVbGfVVjgY: Downloading web creator player API JSON
+			WARNING: [youtube] This live event will begin in 27 minutes.       <- STDERR, ignore
+			[wait] Waiting for 00:27:15 - Press Ctrl+C to try now              <- 5th line
+	*/
+
+	for range TRIES {
+		scanner.Scan()
+		line := scanner.Text()
+
+		if strings.Contains(line, "Waiting for") {
+			waitTimeScanner()
+		}
+	}
 }
 
 func (l *LiveStream) WaitTime() <-chan time.Duration {
@@ -191,3 +226,11 @@ func parseTimeSpan(timeStr string) (time.Time, error) {
 
 	return start, nil
 }
+
+func (l *LiveStream) logFFMpeg(r io.Reader) {
+	scanner := bufio.NewScanner(r)
+
+	for scanner.Scan() {
+		slog.Info("livestream ffmpeg output", slog.String("url", l.url), slog.String("stdout", scanner.Text()))
+	}
+}