just working with downloader

4 files changed, 260 insertions, 154 deletions

diff --git a/downloader/download_manager.go b/downloader/download_manager.go
index 004efc1..de028ab 100644
--- a/downloader/download_manager.go
+++ b/downloader/download_manager.go
@@ -1,89 +1,14 @@
 package downloader
 
-import (
-	"time"
-)
+import "github.com/bwmarrin/discordgo"
 
-// DownloadManager handles a download for a particular song.
 type DownloadManager struct {
-	Url string
-
-	Start    time.Duration
-	Duration time.Duration
-	End      time.Duration
-
-	pb chan (<-chan []byte)
-
-	info videoInfo
+	session *discordgo.Session
 }
 
-const clipTime = 10 * time.Second
-const preloadCount = 5
+func NewManager(s *discordgo.Session) *DownloadManager {
 
-func NewDownload(url string, startTime, dur time.Duration) (*DownloadManager, error) {
-	vInfo, err := info(url)
-	if err != nil {
-		return nil, err
+	return &DownloadManager{
+		session: s,
 	}
-
-	if dur == 0 {
-		dur = vInfo.Duration - startTime
-	}
-
-	dl := &DownloadManager{
-		Url: url,
-
-		Start:    startTime,
-		Duration: dur,
-		End:      startTime + dur,
-
-		pb:   make(chan (<-chan []byte), preloadCount),
-		info: *vInfo,
-	}
-
-	go dl.schedule()
-
-	return dl, nil
-}
-
-func (d *DownloadManager) SendOn(ch chan<- []byte) <-chan struct{} {
-	out := make(chan struct{}, 1)
-
-	go func() {
-		defer close(out)
-		for c := range d.pb {
-			for b := range c {
-				ch <- b
-			}
-		}
-	}()
-
-	return out
-}
-
-func (d *DownloadManager) schedule() {
-	go func() {
-		defer close(d.pb)
-		for i := 0; ; i++ {
-			clipStart := time.Duration(i)*clipTime + d.Start
-			clipEnd := time.Duration(i+1)*clipTime + d.Start
-
-			if clipStart >= d.End {
-				return
-			}
-
-			dur := clipTime
-			if clipEnd > d.End {
-				dur = d.End - clipStart
-			}
-
-			ch, err := d.download(clipStart, dur)
-			if err != nil {
-				log.Errorf("error setting up download: %q", err)
-				return
-			}
-
-			d.pb <- ch
-		}
-	}()
 }
diff --git a/downloader/downloader.go b/downloader/downloader.go
index 95c022f..cab561b 100644
--- a/downloader/downloader.go
+++ b/downloader/downloader.go
@@ -1,81 +1,130 @@
 package downloader
 
 import (
-	"net/url"
+	"io/ioutil"
+	"os"
 	"os/exec"
 	"strconv"
+	"sync"
 	"time"
 
-	"io/ioutil"
-	"os"
-
-	"encoding/json"
-
 	"github.com/mammothbane/thulani-go/wav"
-	"github.com/op/go-logging"
 )
 
-var log = logging.MustGetLogger("downloader")
+// Downloader handles a download for a particular song.
+type Downloader struct {
+	Url string
 
-// responsible for decoding from youtube
-type videoInfo struct {
-	Title       string        `json:"fulltitle"`
-	UrlStr      string        `json:"url"`
-	DurationSec int           `json:"duration"`
-	Url         *url.URL      `json:"-"`
-	Duration    time.Duration `json:"-"`
+	Start    time.Duration
+	Duration time.Duration
+	End      time.Duration
+
+	pause chan wav.State
+	once  sync.Once
+	done  chan struct{}
+	pb    chan *wavBundle
+
+	info videoInfo
 }
 
-func info(inUrl string) (*videoInfo, error) {
-	dl := exec.Command("youtube-dl", "-f", "bestaudio", "-x", "-j", inUrl)
+const clipTime = 10 * time.Second
+const preloadCount = 5
 
-	outpipe, err := dl.StdoutPipe()
+func NewDownload(url string, startTime, dur time.Duration) (*Downloader, error) {
+	vInfo, err := info(url)
 	if err != nil {
 		return nil, err
 	}
 
-	errpipe, err := dl.StderrPipe()
-	if err != nil {
-		return nil, err
+	if dur == 0 {
+		dur = vInfo.Duration - startTime
 	}
 
-	err = dl.Start()
-	if err != nil {
-		log.Errorf("starting youtube-dl failed")
-		return nil, err
-	}
+	dl := &Downloader{
+		Url: url,
 
-	o, ierr := ioutil.ReadAll(outpipe)
-	if ierr != nil {
-		log.Errorf("unable to read from output pipe")
-		return nil, err
-	}
+		Start:    startTime,
+		Duration: dur,
+		End:      startTime + dur,
 
-	e, ierr := ioutil.ReadAll(errpipe)
-	if ierr != nil {
-		log.Errorf("unable to read from error pipe")
-		return nil, err
+		pause: make(chan wav.State),
+		done:  make(chan struct{}, 1),
+		pb:    make(chan *wavBundle, preloadCount),
+		info:  *vInfo,
 	}
 
-	if err := dl.Wait(); err != nil {
-		log.Errorf("error:\n%v", string(e))
-		return nil, err
-	}
+	go dl.schedule()
 
-	v := videoInfo{}
-	if err := json.Unmarshal(o, &v); err != nil {
-		return nil, err
-	}
+	return dl, nil
+}
 
-	v.Duration = time.Duration(v.DurationSec) * time.Second
-	v.Url, err = url.Parse(v.UrlStr)
+func (d *Downloader) Stop() {
+	d.once.Do(func() {
+		close(d.done)
+	})
+}
+
+func (d *Downloader) Resume() {
+	d.pause <- wav.Resume
+}
 
-	//tgt, err := url.Parse(string(o))
-	//out := tgt.Scheme + "://" + tgt.Host + tgt.Path + "?" + tgt.Query().Encode()
-	return &v, err
+func (d *Downloader) Pause() {
+	d.pause <- wav.Pause
 }
 
-func (d *DownloadManager) download(startTime, duration time.Duration) (<-chan []byte, error) {
+func (d *Downloader) SendOn(ch chan<- []byte) <-chan struct{} {
+	out := make(chan struct{}, 1)
+
+	go func() {
+		defer close(out)
+		for wavB := range d.pb {
+			wavB.wav.Start(ch)
+
+			select {
+			case <-d.done:
+				wavB.wav.Stop()
+				wavB.cleanup()
+
+			case <-wavB.wav.Done:
+				break
+
+			case elem := <-d.pause:
+				wavB.wav.PlayState <- elem
+			}
+		}
+	}()
+
+	return out
+}
+
+func (d *Downloader) schedule() {
+	go func() {
+		defer close(d.pb)
+		for i := 0; ; i++ {
+			clipStart := time.Duration(i)*clipTime + d.Start
+			clipEnd := time.Duration(i+1)*clipTime + d.Start
+
+			if clipStart >= d.End {
+				return
+			}
+
+			dur := clipTime
+			if clipEnd > d.End {
+				dur = d.End - clipStart
+			}
+
+			wavb, err := d.download(clipStart, dur)
+			if err != nil {
+				log.Errorf("error setting up download: %q", err)
+				return
+			}
+
+			d.pb <- wavb
+		}
+	}()
+}
+
+func (d *Downloader) download(startTime, duration time.Duration) (*wavBundle, error) {
 	startSecond := int(startTime.Seconds())
 	args := []string{
 		"-ss", strconv.Itoa(startSecond),
@@ -117,17 +166,11 @@ func (d *DownloadManager) download(startTime, duration time.Duration) (<-chan []
 		return nil, err
 	}
 
-	ch := make(chan []byte, 1024*32)
-	done, err := wav.Load(file.Name(), ch)
+	wv, err := wav.New(file.Name())
 	if err != nil {
 		clearTemp()
 		return nil, err
 	}
 
-	go func() {
-		<-done
-		clearTemp()
-	}()
-
-	return ch, err
+	return &wavBundle{wav: wv, cleanup: clearTemp}, err
 }
diff --git a/downloader/util.go b/downloader/util.go
new file mode 100644
index 0000000..f744fad
--- /dev/null
+++ b/downloader/util.go
@@ -0,0 +1,77 @@
+package downloader
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/url"
+	"os/exec"
+	"time"
+
+	"github.com/mammothbane/thulani-go/wav"
+	"github.com/op/go-logging"
+)
+
+var log = logging.MustGetLogger("downloader")
+
+// responsible for decoding from youtube
+type videoInfo struct {
+	Title       string        `json:"fulltitle"`
+	UrlStr      string        `json:"url"`
+	DurationSec int           `json:"duration"`
+	Url         *url.URL      `json:"-"`
+	Duration    time.Duration `json:"-"`
+}
+
+func info(inUrl string) (*videoInfo, error) {
+	dl := exec.Command("youtube-dl", "-f", "bestaudio", "-x", "-j", inUrl)
+
+	outpipe, err := dl.StdoutPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	errpipe, err := dl.StderrPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	err = dl.Start()
+	if err != nil {
+		log.Errorf("starting youtube-dl failed")
+		return nil, err
+	}
+
+	o, ierr := ioutil.ReadAll(outpipe)
+	if ierr != nil {
+		log.Errorf("unable to read from output pipe")
+		return nil, err
+	}
+
+	e, ierr := ioutil.ReadAll(errpipe)
+	if ierr != nil {
+		log.Errorf("unable to read from error pipe")
+		return nil, err
+	}
+
+	if err := dl.Wait(); err != nil {
+		log.Errorf("error:\n%v", string(e))
+		return nil, err
+	}
+
+	v := videoInfo{}
+	if err := json.Unmarshal(o, &v); err != nil {
+		return nil, err
+	}
+
+	v.Duration = time.Duration(v.DurationSec) * time.Second
+	v.Url, err = url.Parse(v.UrlStr)
+
+	//tgt, err := url.Parse(string(o))
+	//out := tgt.Scheme + "://" + tgt.Host + tgt.Path + "?" + tgt.Query().Encode()
+	return &v, err
+}
+
+type wavBundle struct {
+	wav     *wav.Wav
+	cleanup func()
+}
diff --git a/wav/wav.go b/wav/wav.go
index 8556d60..c505a32 100644
--- a/wav/wav.go
+++ b/wav/wav.go
@@ -6,63 +6,126 @@ import "C"
 import (
 	"fmt"
 
+	"sync"
+
 	"github.com/op/go-logging"
 	"layeh.com/gopus"
 )
 
+type State int
+
+const (
+	Pause State = iota
+	Resume
+)
+
 // number of individual samples per channel per batch
 const samplesPerChannelPerBatch = 1920
 
 var log = logging.MustGetLogger("wav")
 
-func Load(filename string, ch chan<- []byte) (<-chan struct{}, error) {
+type Wav struct {
+	filename *C.char
+	enc      *gopus.Encoder
+	wav      *C.drwav
+
+	PlayState chan State
+	curState  State
+
+	once sync.Once
+	Done <-chan struct{}
+	done chan<- struct{}
+}
+
+func New(filename string) (*Wav, error) {
 	cfname := C.CString(filename)
 	wav := C.drwav_open_file(cfname)
 	if wav == nil {
-		close(ch)
+		C.drwav_close(wav)
 		return nil, fmt.Errorf("Unable to initialize drwav.")
 	}
 
 	if int(wav.channels) != 2 {
 		C.drwav_close(wav)
-		close(ch)
 		return nil, fmt.Errorf("Wrong number of channels!")
 	}
 
 	if int(wav.sampleRate) != 48000 {
 		C.drwav_close(wav)
-		close(ch)
 		return nil, fmt.Errorf("Wrong sample rate.")
 	}
 
 	enc, err := gopus.NewEncoder(int(wav.sampleRate), int(wav.channels), gopus.Audio)
 	if err != nil {
-		close(ch)
+		C.drwav_close(wav)
 		return nil, err
 	}
 
 	done := make(chan struct{}, 1)
-	go func(wav *C.drwav) {
-		defer close(done)
-		defer close(ch)
+	return &Wav{
+		filename: C.CString(filename),
+		enc:      enc,
+		wav:      wav,
+
+		PlayState: make(chan State),
+		curState:  Resume,
 
-		samplesPerBatch := samplesPerChannelPerBatch * int(wav.channels)
-		batchSize := samplesPerBatch * int(wav.bytesPerSample)
+		done: done,
+		Done: done,
+	}, nil
+}
+
+func (w *Wav) Stop() {
+	w.once.Do(func() {
+		close(w.done)
+	})
+}
+
+func (w *Wav) Start(ch chan<- []byte) {
+	go func() {
+		defer w.Stop()
+
+		samplesPerBatch := samplesPerChannelPerBatch * int(w.wav.channels)
+		batchSize := samplesPerBatch * int(w.wav.bytesPerSample)
 
 		buf := C.malloc(C.size_t(batchSize))
 		defer C.free(buf)
-		defer C.drwav_close(wav)
+		defer C.drwav_close(w.wav)
 
 		elems := make([]int16, samplesPerBatch)
 		idx := 0
 
-		for i := 0; i*samplesPerBatch <= int(wav.totalSampleCount); i += 1 {
-			readSamples := C.drwav_read_s16(wav, C.dr_uint64(samplesPerBatch), (*C.dr_int16)(buf))
+		for i := 0; i*samplesPerBatch <= int(w.wav.totalSampleCount); i += 1 {
+			readSamples := C.drwav_read_s16(w.wav, C.dr_uint64(samplesPerBatch), (*C.dr_int16)(buf))
 			slc := (*[1 << 30]int16)(buf)[:readSamples:readSamples]
 
 			readIdx := 0
 
+		inner:
 			for {
+				// check to see if we should die or pause
+				if w.curState == Pause { // if paused wait to die or get resumed
+					select {
+					case st := <-w.PlayState:
+						w.curState = st
+						continue inner
+
+					case <-w.Done:
+						return
+					}
+
+				} else {
+					select {
+					case st := <-w.PlayState:
+						w.curState = st
+						continue inner
+
+					case <-w.Done:
+						return
+					default:
+					}
+				}
+
 				batchSamplesToFill := samplesPerBatch - idx
 				readSamplesRemaining := int(readSamples) - readIdx
 
@@ -75,7 +138,7 @@ func Load(filename string, ch chan<- []byte) (<-chan struct{}, error) {
 				idx = 0
 				readIdx += batchSamplesToFill
 
-				b, err := processPCM(wav, enc, elems[:])
+				b, err := processPCM(w.wav, w.enc, elems[:])
 				if err != nil {
 					log.Errorf("error encoding pcm: %q", err)
 					continue
@@ -96,9 +159,7 @@ func Load(filename string, ch chan<- []byte) (<-chan struct{}, error) {
 				break
 			}
 		}
-	}(wav)
-
-	return done, nil
+	}()
 }
 
 func processPCM(wav *C.drwav, enc *gopus.Encoder, data []int16) ([]byte, error) {