Fix CGO type errors and improve GTK player

- Fix render.go CGO type assignments using plain uint32 casts
- Add video playlist tracking with unique IDs
- Improve drag-and-drop: assign to first available pane
- Add parseURIs with crash protection for drag data
- Improve mpv initialization handling
- Update .gitignore for build artifacts (.cache, gtkplayer binary)
- Improve GDK_BACKEND handling in run script

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitignore

@@ -1,6 +1,9 @@
 videotools.log
 .gocache/
 .gomodcache/
+.cache/
 VideoTools
 VTPlayer
 vt_player
+cmd/gtkplayer/gtkplayer
+test_*.sh

cmd/gtkplayer/main.go

@@ -4,8 +4,8 @@ import (
 	"fmt"
 	"log"
 	"path/filepath"
-	"time"
 	"strings"
+	"time"
 
 	"git.leaktechnologies.dev/stu/VT_Player/player/mpvembed"
 
@@ -40,10 +40,21 @@ type pane struct {
 	area *gtk.DrawingArea
 	mpv  *mpvembed.Client
 	path string
+	id   int
 }
 
 func (p *pane) hasVideo() bool { return p.path != "" }
 
+type videoEntry struct {
+	id   int
+	path string
+}
+
+var (
+	playlist    []videoEntry
+	nextVideoID = 1
+)
+
 func main() {
 	gtk.Init(nil)
 
@@ -70,7 +81,8 @@ func main() {
 	applyCSS()
 	preferDark()
 
-	setupDragDest(left, right, win)
+	setupDragDest(left, left, right)
+	setupDragDest(right, left, right)
 
 	win.Connect("destroy", func() {
 		if left.mpv != nil {
@@ -92,24 +104,31 @@ func newPane() *pane {
 	da.SetVExpand(true)
 	p := &pane{area: da}
 	da.Connect("realize", func() {
-		if p.mpv != nil {
-			return
-		}
-		mpv, err := mpvembed.New()
-		if err != nil {
-			log.Printf("mpv create: %v", err)
-			return
-		}
-		p.mpv = mpv
-
+		var xid uint64
 		if w, err := da.GetWindow(); err == nil && w != nil {
-			if xid := getWindowID(w); xid != 0 {
-				_ = mpv.SetWID(xid)
-			}
+			xid = getWindowID(w)
 		}
-		_ = mpv.SetOptionString("pause", "yes")
-		if err := mpv.Initialize(); err != nil {
-			log.Printf("mpv init: %v", err)
+
+		if p.mpv == nil {
+			mpv, err := mpvembed.New()
+			if err != nil {
+				log.Printf("mpv create: %v", err)
+				return
+			}
+			p.mpv = mpv
+			_ = p.mpv.SetOptionString("pause", "yes")
+			if xid != 0 {
+				_ = p.mpv.SetWID(xid)
+			}
+			if err := p.mpv.Initialize(); err != nil {
+				log.Printf("mpv init: %v", err)
+			}
+			return
+		}
+
+		// mpv already exists (created before realize); make sure WID is bound now
+		if xid != 0 {
+			_ = p.mpv.SetWID(xid)
 		}
 	})
 	return p
@@ -218,6 +237,7 @@ func loadIntoPane(p *pane, filename string) {
 		return
 	}
 	p.path = filename
+	p.id = getOrAddVideoID(filename)
 	if err := p.mpv.Command("loadfile", filename, "replace"); err != nil {
 		log.Printf("loadfile %s: %v", filename, err)
 	}
@@ -233,7 +253,11 @@ func metaSummary(a, b *pane) string {
 		pos, _ := p.mpv.GetPropertyDouble("time-pos")
 		w, _ := p.mpv.GetPropertyInt64("width")
 		h, _ := p.mpv.GetPropertyInt64("height")
-		return fmt.Sprintf("%s | %dx%d | %.1f/%.1fs", filepath.Base(p.path), w, h, pos, dur)
+		tag := ""
+		if p.id > 0 {
+			tag = fmt.Sprintf("#%d ", p.id)
+		}
+		return fmt.Sprintf("%s%s | %dx%d | %.1f/%.1fs", tag, filepath.Base(p.path), w, h, pos, dur)
 	}
 	return fmt.Sprintf("L: %s   |   R: %s", parts(a), parts(b))
 }
@@ -273,15 +297,15 @@ func preferDark() {
 	}
 }
 
-func setupDragDest(p *pane, win *gtk.Window) {
-	// Accept URI drops using a target list
-	target, err := gtk.TargetEntryNew("text/uri-list", gtk.TARGET_OTHER_APP, 0)
+func setupDragDest(targetPane *pane, left, right *pane) {
+	uriTarget, err := gtk.TargetEntryNew("text/uri-list", gtk.TARGET_OTHER_APP, 0)
 	if err != nil {
 		return
 	}
-	// DragDestSet requires at least one target; use the URI target.
-	p.area.DragDestSet(gtk.DEST_DEFAULT_ALL, []gtk.TargetEntry{*target}, gdk.ACTION_COPY)
-	p.area.Connect("drag-data-received", func(_ *gtk.DrawingArea, ctx *gdk.DragContext, x, y int, data *gtk.SelectionData, info uint, t uint32) {
+	targets := []gtk.TargetEntry{*uriTarget}
+	targetPane.area.DragDestSet(gtk.DEST_DEFAULT_ALL, targets, gdk.ACTION_COPY)
+
+	targetPane.area.Connect("drag-data-received", func(_ *gtk.DrawingArea, _ *gdk.DragContext, x, y int, data *gtk.SelectionData, _ uint, _ uint32) {
 		defer func() {
 			if r := recover(); r != nil {
 				log.Printf("drag handler panic: %v", r)
@@ -290,24 +314,13 @@ func setupDragDest(p *pane, win *gtk.Window) {
 		if data == nil {
 			return
 		}
-		raw := data.GetData()
-		if len(raw) == 0 {
-			// try text fallback
-			if txt := data.GetText(); txt != "" {
-				raw = []byte(txt)
-			}
-		}
-		if len(raw) == 0 {
-			return
-		}
-		// text/uri-list: newline or CRLF separated
-		lines := strings.Split(string(raw), "\n")
-		for _, ln := range lines {
-			ln = strings.TrimSpace(ln)
-			if ln == "" {
+
+		uris := parseURIs(data)
+		for _, u := range uris {
+			if u == "" {
 				continue
 			}
-			assignPathToPane(ln, p, nil)
+			assignPathToPane(u, left, right)
 			break
 		}
 	})
@@ -370,3 +383,56 @@ func uriToPath(u string) string {
 	}
 	return u
 }
+
+func getOrAddVideoID(path string) int {
+	if path == "" {
+		return 0
+	}
+	for _, e := range playlist {
+		if e.path == path {
+			return e.id
+		}
+	}
+	id := nextVideoID
+	nextVideoID++
+	playlist = append(playlist, videoEntry{id: id, path: path})
+	return id
+}
+
+// parseURIs tries to extract URIs from SelectionData while avoiding crashes on bad payloads.
+func parseURIs(data *gtk.SelectionData) []string {
+	if data == nil {
+		return nil
+	}
+
+	// try safe path using raw bytes first
+	raw := data.GetData()
+	if len(raw) == 0 {
+		if txt := data.GetText(); txt != "" {
+			raw = []byte(txt)
+		}
+	}
+	if len(raw) > 0 {
+		var out []string
+		for _, ln := range strings.Split(string(raw), "\n") {
+			ln = strings.TrimSpace(ln)
+			if ln != "" {
+				out = append(out, ln)
+			}
+		}
+		if len(out) > 0 {
+			return out
+		}
+	}
+
+	// fallback to GetURIs; guard with recover because upstream may panic on nil C arrays
+	defer func() {
+		if r := recover(); r != nil {
+			log.Printf("GetURIs panic: %v", r)
+		}
+	}()
+	if uris := data.GetURIs(); len(uris) > 0 {
+		return uris
+	}
+	return nil
+}

player/mpvembed/render.go

@@ -32,10 +32,10 @@ func NewRenderContext(c *Client, params []RenderParam) (*RenderContext, error) {
 	}
 	cparams := make([]C.mpv_render_param, len(params)+1)
 	for i, p := range params {
-		cparams[i]._type = C.int(p.Type)
+		cparams[i]._type = uint32(p.Type)
 		cparams[i].data = p.Data
 	}
-	cparams[len(params)]._type = C.MPV_RENDER_PARAM_INVALID
+	cparams[len(params)]._type = uint32(C.MPV_RENDER_PARAM_INVALID)
 
 	var rctx *C.mpv_render_context
 	if res := C.mpv_render_context_create(&rctx, c.handle, &cparams[0]); res < 0 {
@@ -70,10 +70,10 @@ func (r *RenderContext) Render(params []RenderParam) error {
 	}
 	cparams := make([]C.mpv_render_param, len(params)+1)
 	for i, p := range params {
-		cparams[i]._type = C.int(p.Type)
+		cparams[i]._type = uint32(p.Type)
 		cparams[i].data = p.Data
 	}
-	cparams[len(params)]._type = C.MPV_RENDER_PARAM_INVALID
+	cparams[len(params)]._type = uint32(C.MPV_RENDER_PARAM_INVALID)
 
 	if res := C.mpv_render_context_render(r.ctx, &cparams[0]); res < 0 {
 		return fmt.Errorf("mpv_render_context_render failed: %s", C.GoString(C.mpv_errstr_render(res)))

scripts/run.sh

@@ -16,7 +16,10 @@ if [ -d "$GTK_ENTRY" ]; then
     echo "🚀 Starting VT Player (GTK/mpv)..."
     echo "════════════════════════════════════════════════════════════════"
     echo ""
-    export GDK_BACKEND=x11
+    # Prefer an explicit backend only if the user hasn’t set one; default to X11 (works under XWayland).
+    if [ -z "$GDK_BACKEND" ]; then
+        export GDK_BACKEND=x11
+    fi
     export GOCACHE="$PROJECT_ROOT/.cache/go-build"
     export GOMODCACHE="$PROJECT_ROOT/.cache/go-mod"
     GOCACHE="$GOCACHE" GOMODCACHE="$GOMODCACHE" \