Project restructure (#18)

* First pass at restructuring the project; untested but it does compile

* Restructure builds and runs 🎉

* Add the dist folder to the gitignore

* Update core/playlist/monitor.go

* golint and reorganize the monitor.go file

Co-authored-by: Gabe Kangas <gabek@real-ity.com>

core/ffmpeg/thumbnailGenerator.go

@@ -0,0 +1,93 @@
+package ffmpeg
+
+import (
+	"io/ioutil"
+	"os/exec"
+	"path"
+	"strings"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/gabek/owncast/config"
+)
+
+//StartThumbnailGenerator starts generating thumbnails
+func StartThumbnailGenerator(chunkPath string) {
+	// Every 20 seconds create a thumbnail from the most
+	// recent video segment.
+	ticker := time.NewTicker(20 * time.Second)
+	quit := make(chan struct{})
+
+	go func() {
+		for {
+			select {
+			case <-ticker.C:
+				if err := fireThumbnailGenerator(chunkPath); err != nil {
+					log.Errorln("Unable to generate thumbnail:", err)
+				}
+			case <-quit:
+				//TODO: evaluate if this is ever stopped
+				log.Println("thumbnail generator has stopped")
+				ticker.Stop()
+				return
+			}
+		}
+	}()
+}
+
+func fireThumbnailGenerator(chunkPath string) error {
+	// JPG takes less time to encode than PNG
+	outputFile := path.Join("webroot", "thumbnail.jpg")
+
+	framePath := path.Join(chunkPath, "0")
+	files, err := ioutil.ReadDir(framePath)
+	if err != nil {
+		return err
+	}
+
+	var modTime time.Time
+	var names []string
+	for _, fi := range files {
+		if path.Ext(fi.Name()) != ".ts" {
+			continue
+		}
+
+		if fi.Mode().IsRegular() {
+			if !fi.ModTime().Before(modTime) {
+				if fi.ModTime().After(modTime) {
+					modTime = fi.ModTime()
+					names = names[:0]
+				}
+				names = append(names, fi.Name())
+			}
+		}
+	}
+
+	if len(names) == 0 {
+		return nil
+	}
+
+	mostRecentFile := path.Join(framePath, names[0])
+
+	thumbnailCmdFlags := []string{
+		config.Config.FFMpegPath,
+		"-y",                 // Overwrite file
+		"-threads 1",         // Low priority processing
+		"-t 1",               // Pull from frame 1
+		"-i", mostRecentFile, // Input
+		"-f image2",  // format
+		"-vframes 1", // Single frame
+		outputFile,
+	}
+
+	ffmpegCmd := strings.Join(thumbnailCmdFlags, " ")
+
+	// fmt.Println(ffmpegCmd)
+
+	if _, err := exec.Command("sh", "-c", ffmpegCmd).Output(); err != nil {
+		return err
+	}
+
+	return nil
+}