Add YouTube transcript processing with yt-dlp integration

Introduced a new tool for extracting YouTube video transcripts and leveraging them to answer questions. Updated `SearchAndRead` to support reading YouTube transcripts and regular pages distinctly. Included relevant dependencies for handling subtitles and video downloads.

pkg/agents/search.go

@@ -139,6 +139,11 @@ func (a Agent) SearchAndUseTools(ctx context.Context, searchQuery string, questi
 
 		slices.Sort(analyzed)
 		for j := len(analyzed) - 1; j >= 0; j-- {
+			v := analyzed[j]
+			if v < 0 || v >= len(searchResults) {
+				continue
+			}
+
 			searchResults = append(searchResults[:analyzed[j]], searchResults[analyzed[j]+1:]...)
 		}
 
@@ -181,7 +186,6 @@ Use appropriate tools to analyze the search results and determine if they answer
 		var learned []Knowledge
 		for _, r := range results.CallResults {
 			if r.Error != nil {
-				slog.Error("error executing search function", "error", err)
 				continue
 			}
 
@@ -208,9 +212,15 @@ Use appropriate tools to analyze the search results and determine if they answer
 func (a Agent) SearchAndRead(ctx context.Context, searchQuery string, questions []string, allowConcurrent bool, maxReads int) (Knowledge, error) {
 	return a.SearchAndUseTools(ctx, searchQuery, questions, 2, allowConcurrent, maxReads, []SearchTool{
 		{
-			Name:        "ReadPage",
+			Name:        "readpage",
 			Description: "Read the search result and see if it answers the question.  Try to avoid using this on low quality or spammy sites. You can use this function" + fmt.Sprint(maxReads) + " times, but do not call it multiple times on the same result.",
 			Function:    a.ReadPage,
 		},
-	})
+		{
+			Name:        "youtube",
+			Description: "Read the transcript to a youtube video and see if it answers the question.  Try to avoid using this on low quality or spammy links.  You can use this function" + fmt.Sprint(maxReads) + " times, but do not call it multiple times on the same result.",
+			Function:    a.ReadYouTubeTranscript,
+		},
+	},
+		gollm.Message{Role: gollm.RoleSystem, Text: "For youtube links, only use the youtube tool.  For other links, only use the readpage tool."})
 }

pkg/agents/youtube.go

@@ -0,0 +1,104 @@
+package agents
+
+import (
+	"context"
+	"fmt"
+	"github.com/asticode/go-astisub"
+	"github.com/lrstanley/go-ytdlp"
+	"io"
+	"log/slog"
+	"net/url"
+	"os"
+	"path/filepath"
+)
+
+func init() {
+	ytdlp.MustInstall(context.Background(), nil)
+}
+
+func (a Agent) ReadYouTubeTranscript(ctx context.Context, u *url.URL, questions []string) (Knowledge, error) {
+	dlp := ytdlp.New()
+
+	tmpDir, err := os.MkdirTemp("", "mort-ytdlp-")
+	if err != nil {
+		return Knowledge{}, fmt.Errorf("error creating temp dir: %w", err)
+	}
+
+	slog.Info("created temp dir", "path", tmpDir)
+	defer func(path string) {
+		err := os.RemoveAll(path)
+		if err != nil {
+			slog.Error("error removing temp file", "error", err)
+		}
+	}(tmpDir)
+
+	subFile := filepath.Join(tmpDir, "subs")
+	dlp.
+		SkipDownload().
+		WriteAutoSubs().
+		Output(subFile)
+
+	res, err := dlp.Run(ctx, u.String())
+	if err != nil {
+		return Knowledge{}, fmt.Errorf("error running yt-dlp: %w", err)
+	}
+
+	if res == nil {
+		return Knowledge{}, fmt.Errorf("yt-dlp returned nil")
+	}
+
+	if res.ExitCode != 0 {
+		return Knowledge{}, fmt.Errorf("yt-dlp exited with code %d", res.ExitCode)
+	}
+
+	// the transcript for this video now _should_ be at tmpDir/subs.en.vtt, however if it's not then just fine any
+	// vtt file in the directory
+	vttFile := filepath.Join(tmpDir, "subs.en.vtt")
+
+	_, err = os.Stat(vttFile)
+	if os.IsNotExist(err) {
+		vttFile = ""
+		files, err := os.ReadDir(tmpDir)
+		if err != nil {
+			return Knowledge{}, fmt.Errorf("error reading directory: %w", err)
+		}
+
+		for _, file := range files {
+			if filepath.Ext(file.Name()) == ".vtt" {
+				vttFile = filepath.Join(tmpDir, file.Name())
+				break
+			}
+		}
+	}
+
+	if vttFile == "" {
+		return Knowledge{}, fmt.Errorf("no vtt file found")
+	}
+
+	fp, err := os.Open(vttFile)
+	defer func(cl io.Closer) {
+		err := cl.Close()
+		if err != nil {
+			slog.Error("error closing file", "error", err)
+		}
+	}(fp)
+	if err != nil {
+		return Knowledge{}, fmt.Errorf("error opening vtt file: %w", err)
+	}
+
+	subs, err := astisub.ReadFromWebVTT(fp)
+	if err != nil {
+		return Knowledge{}, fmt.Errorf("error reading vtt file: %w", err)
+	}
+
+	if len(subs.Items) == 0 {
+		return Knowledge{}, fmt.Errorf("no subtitles found")
+	}
+
+	var ts string
+	for _, item := range subs.Items {
+		ts += item.String() + "\n"
+	}
+
+	return a.ExtractKnowledge(ctx, ts, u.String(), questions)
+}