Switch to single-instance Widget model

And make widget() functions return pointers to widgets instead of just
widgets

Signed-off-by: AnErrupTion <anerruption@disroot.org>

ly-ui/src/components/BigLabel.zig

@@ -44,6 +44,7 @@ pub const BigLabelLocale = enum {
     fa,
 };
 
+instance: ?Widget = null,
 allocator: ?Allocator = null,
 buffer: *TerminalBuffer,
 text: []const u8,
@@ -67,6 +68,7 @@ pub fn init(
     calculate_timeout_fn: ?*const fn (*BigLabel, *anyopaque) anyerror!?usize,
 ) BigLabel {
     return .{
+        .instance = null,
         .allocator = null,
         .buffer = buffer,
         .text = text,
@@ -85,8 +87,9 @@ pub fn deinit(self: *BigLabel) void {
     if (self.allocator) |allocator| allocator.free(self.text);
 }
 
-pub fn widget(self: *BigLabel) Widget {
-    return Widget.init(
+pub fn widget(self: *BigLabel) *Widget {
+    if (self.instance) |*instance| return instance;
+    self.instance = Widget.init(
         "BigLabel",
         null,
         self,
@@ -97,6 +100,7 @@ pub fn widget(self: *BigLabel) Widget {
         null,
         calculateTimeout,
     );
+    return &self.instance.?;
 }
 
 pub fn setTextAlloc(

ly-ui/src/components/CenteredBox.zig

@@ -7,6 +7,7 @@ const Widget = @import("../Widget.zig");
 
 const CenteredBox = @This();
 
+instance: ?Widget = null,
 buffer: *TerminalBuffer,
 horizontal_margin: usize,
 vertical_margin: usize,
@@ -40,6 +41,7 @@ pub fn init(
     update_fn: ?*const fn (*CenteredBox, *anyopaque) anyerror!void,
 ) CenteredBox {
     return .{
+        .instance = null,
         .buffer = buffer,
         .horizontal_margin = horizontal_margin,
         .vertical_margin = vertical_margin,
@@ -59,8 +61,9 @@ pub fn init(
     };
 }
 
-pub fn widget(self: *CenteredBox) Widget {
-    return Widget.init(
+pub fn widget(self: *CenteredBox) *Widget {
+    if (self.instance) |*instance| return instance;
+    self.instance = Widget.init(
         "CenteredBox",
         null,
         self,
@@ -71,6 +74,7 @@ pub fn widget(self: *CenteredBox) Widget {
         null,
         null,
     );
+    return &self.instance.?;
 }
 
 pub fn positionXY(self: *CenteredBox, original_pos: Position) void {

ly-ui/src/components/Label.zig

@@ -8,6 +8,7 @@ const Position = @import("../Position.zig");
 const TerminalBuffer = @import("../TerminalBuffer.zig");
 const Widget = @import("../Widget.zig");
 
+instance: ?Widget,
 allocator: ?Allocator,
 text: []const u8,
 max_width: ?usize,
@@ -27,6 +28,7 @@ pub fn init(
     calculate_timeout_fn: ?*const fn (*Label, *anyopaque) anyerror!?usize,
 ) Label {
     return .{
+        .instance = null,
         .allocator = null,
         .text = text,
         .max_width = max_width,
@@ -43,8 +45,9 @@ pub fn deinit(self: *Label) void {
     if (self.allocator) |allocator| allocator.free(self.text);
 }
 
-pub fn widget(self: *Label) Widget {
-    return Widget.init(
+pub fn widget(self: *Label) *Widget {
+    if (self.instance) |*instance| return instance;
+    self.instance = Widget.init(
         "Label",
         null,
         self,
@@ -55,6 +58,7 @@ pub fn widget(self: *Label) Widget {
         null,
         calculateTimeout,
     );
+    return &self.instance.?;
 }
 
 pub fn setTextAlloc(

ly-ui/src/components/Text.zig

@@ -10,6 +10,7 @@ const DynamicString = std.ArrayListUnmanaged(u8);
 
 const Text = @This();
 
+instance: ?Widget,
 allocator: Allocator,
 buffer: *TerminalBuffer,
 text: DynamicString,
@@ -38,6 +39,7 @@ pub fn init(
 ) !*Text {
     var self = try allocator.create(Text);
     self.* = Text{
+        .instance = null,
         .allocator = allocator,
         .buffer = buffer,
         .text = .empty,
@@ -70,8 +72,9 @@ pub fn deinit(self: *Text) void {
     self.allocator.destroy(self);
 }
 
-pub fn widget(self: *Text) Widget {
-    return Widget.init(
+pub fn widget(self: *Text) *Widget {
+    if (self.instance) |*instance| return instance;
+    self.instance = Widget.init(
         "Text",
         self.keybinds,
         self,
@@ -82,6 +85,7 @@ pub fn widget(self: *Text) Widget {
         handle,
         null,
     );
+    return &self.instance.?;
 }
 
 pub fn positionX(self: *Text, original_pos: Position) void {