new new

playlist/playlist.go

@@ -1,7 +1,7 @@
 package playlist
 
 import (
-	"fmt"
+	"log"
 	"time"
 	"errors"
 	"strconv"
@@ -11,7 +11,7 @@ import (
 	"../config"
 )
 
-var pln = fmt.Println
+var pln = log.Println
 
 type Playlist struct {
 	NAME 		string
@@ -105,6 +105,14 @@ func (pp *PrettyPlaylist) Print() {
 	}
 }
 
+func print(slice []uint32) {
+	for i, r := range slice {
+		pln("	" + strconv.Itoa(i) + " - " + archive.Archive_map[r].NAME)
+	}
+
+}
+
+// https://github.com/golang/go/wiki/SliceTricks
 // https://stackoverflow.com/questions/33834742/remove-and-adding-elements-to-array-in-go-lang
 
 func (p *Playlist) Pop() error {
@@ -157,20 +165,54 @@ func (p *Playlist) Insert(track_id uint32, at_index int) error {
 	return nil	
 }
 
-func (p *Playlist) Delete(track_id uint32) error {
-
+func (p *Playlist) index(track_id uint32) int {
 	k := -1
-	for i := 0; i <= len(p.LIST); i++ {
+	for i := 0; i < len(p.LIST); i++ {
 		if p.LIST[i] == track_id { k = i }
 	}
+	return k	
+}
 
+func (p *Playlist) Delete(track_id uint32) error {
+	k := p.index(track_id);
+	if k < 0 {
+		return errors.New("Invalid track ID")
+	}
+	p.LIST = append(p.LIST[:k-1], p.LIST[k+1:]...)
+	return nil
+}
+
+func (p *Playlist) Move(track_id uint32, at_index int) error {
+	if at_index > p.MAX {
+		return errors.New("Invalid insert index")
+	}
+	k := p.index(track_id);
 	if k < 0 {
 		return errors.New("Invalid track ID")
 	}
 
-	p.LIST = append(p.LIST[:k-1], p.LIST[k+1:]...)
-	return nil
+	slice_head := p.LIST[:k]
+	slice_move := p.LIST[k+1:at_index+1]
+	slice_tail := make([]uint32, len(p.LIST[at_index+1:]))
+	copy(slice_tail, p.LIST[at_index+1:])
 
+	// slice_move = append(slice_move, track_id)
+
+	pln("from_index: " + strconv.Itoa(k))
+	pln("at_index: " + strconv.Itoa(at_index))
+	pln("------")
+	pln("slice head: ")
+	print(slice_head)
+	pln("slice move: ")
+	print(slice_move)
+	pln("** ")
+	pln("slice tail: ")
+	print(slice_tail)
+	pln("...........................")
+
+	p.LIST = append(slice_head, append(append(slice_move, track_id), slice_tail...)...)
+
+	return nil
 }