haha

playlist/playlist.go

@@ -0,0 +1,181 @@
+package playlist
+
+import (
+	"fmt"
+	"time"
+	"errors"
+	"strconv"
+	"math/rand"
+	"encoding/json"
+	"../archive"
+	"../config"
+)
+
+var pln = fmt.Println
+
+type Playlist struct {
+	NAME 		string
+	CTRACK		config.Track_t	
+	CALBUM		config.Album_t
+	LIST		[]uint32
+	MAX			int
+}
+
+type PrettyPlaylist struct {
+	NAME 		string
+	CTRACK		config.Track_t	
+	CALBUM		config.Album_t
+	LIST		[]config.Track_t
+	MAX			int
+}
+
+
+func MakeRandom(name string, max int) (*Playlist, error) {
+	err := archive.Build()
+	if err != nil {
+		return nil, err
+	}
+
+	p := &Playlist{NAME: name, MAX: max}
+	p.LIST = make([]uint32, max)
+
+	for i := 0; i < max; i++ {
+		r, _ := Random()
+		p.LIST[i] = r			// might duplicate
+	}
+
+	return p, nil;
+}
+
+func (p *Playlist) Encode() string {
+
+	pp := p.Pretty()
+	res, _ := json.Marshal(pp)
+	return string(res)
+
+}
+
+func Decode(jsonstr string) (*Playlist, error) {
+
+	pp := &PrettyPlaylist{}
+
+	if err := json.Unmarshal([]byte(jsonstr), pp); err != nil {
+		return nil, err
+	}
+
+	p := pp.Unpretty()
+	return p, nil
+}
+
+func (p *Playlist) Pretty() *PrettyPlaylist {
+	pp := &PrettyPlaylist{NAME: p.NAME, CTRACK: p.CTRACK, CALBUM: p.CALBUM, MAX: p.MAX}
+	pp.LIST = make([]config.Track_t, len(p.LIST))
+	for i := 0; i < len(p.LIST); i++ {
+		pp.LIST[i] =  archive.Archive_map[p.LIST[i]]
+	}	
+	return pp
+}
+
+func (pp *PrettyPlaylist) Unpretty() *Playlist {
+	p := &Playlist{NAME: pp.NAME, CTRACK: pp.CTRACK, CALBUM: pp.CALBUM, MAX: pp.MAX}
+	p.LIST = make([]uint32, len(pp.LIST))
+	for i := 0; i < len(pp.LIST); i++ {
+		p.LIST = append(p.LIST, pp.LIST[i].ID)
+	}
+	return p	
+}
+
+// type PrettyPlaylist struct {
+// 	NAME 		string
+// 	CTRACK		config.Track_t	
+// 	CALBUM		config.Album_t
+// 	LIST		[]config.Track_t
+// 	MAX			int
+// }
+
+
+func (pp *PrettyPlaylist) Print() {
+
+	pln("Name: " + pp.NAME)
+	pln("CTRACK: " + pp.CTRACK.NAME)
+	pln("CALBUM: " + pp.CALBUM.NAME)
+	pln("Next:")
+	for i, r := range pp.LIST {
+		pln("	" + strconv.Itoa(i) + " - " + r.NAME)
+	}
+}
+
+// https://stackoverflow.com/questions/33834742/remove-and-adding-elements-to-array-in-go-lang
+
+func (p *Playlist) Pop() error {
+	if len(p.LIST) == 0 {
+		return errors.New("Playlist is empty")
+	} 
+
+	t := p.LIST[0]
+	if len(p.LIST) < 2 {	
+		p.LIST = make([]uint32, 0)
+	} else {
+		p.LIST = p.LIST[1:]
+	}
+
+	p.CTRACK = archive.Archive_map[t]
+	p.CALBUM = config.Xcfg.Archive.ALBUMS[p.CTRACK.AID]
+
+	return nil
+}
+
+func (p *Playlist) Push(track_id uint32) error {
+	if len(p.LIST) == p.MAX {
+		return errors.New("Playlist is full")
+	}
+	p.LIST = append(p.LIST, track_id)
+	return nil	
+}
+
+func (p *Playlist) PushFront(track_id uint32) error {
+	if len(p.LIST) == p.MAX {
+		return errors.New("Playlist is full")
+	}
+	p.LIST = append([]uint32{ track_id }, p.LIST...)		// don't forget '...''
+	return nil	
+}
+
+func (p *Playlist) Insert(track_id uint32, at_index int) error {
+	if at_index > p.MAX {
+		return errors.New("Invalid insert index")
+	}
+
+	p.LIST = append(p.LIST, 0)
+	copy(p.LIST[at_index+1:], p.LIST[at_index:])
+	p.LIST[at_index] = track_id
+
+	if len(p.LIST) > p.MAX {
+		p.LIST = p.LIST[:p.MAX]
+	}
+	
+	return nil	
+}
+
+func (p *Playlist) Delete(track_id uint32) error {
+
+	k := -1
+	for i := 0; i <= len(p.LIST); i++ {
+		if p.LIST[i] == track_id { k = i }
+	}
+
+	if k < 0 {
+		return errors.New("Invalid track ID")
+	}
+
+	p.LIST = append(p.LIST[:k-1], p.LIST[k+1:]...)
+	return nil
+
+}
+
+
+func Random() (uint32, string) {
+	rand.Seed(time.Now().UTC().UnixNano())
+	index := archive.Archive_map_keys[rand.Intn(len(archive.Archive_map_keys) - 1)]
+	return archive.Archive_map[index].ID, archive.Archive_map[index].NAME
+}