From 8e6959a3cb4fa0ac69393d274e9418d0954eca7d Mon Sep 17 00:00:00 2001
From: Eduardo Flores <edfloreshz@gmail.com>
Date: Sat, 15 Oct 2022 15:08:44 -0700
Subject: [PATCH] View Switcher Widget

---
 examples/cosmic/src/window.rs |  4 +-
 src/widget/view_switcher.rs   | 89 +++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 src/widget/view_switcher.rs

diff --git a/examples/cosmic/src/window.rs b/examples/cosmic/src/window.rs
index 0d4cfc37..41f46aa4 100644
--- a/examples/cosmic/src/window.rs
+++ b/examples/cosmic/src/window.rs
@@ -9,7 +9,7 @@ use cosmic::{
     iced_lazy::responsive,
     iced_winit::window::{drag, toggle_maximize, minimize},
     theme::{self, Theme},
-    widget::{button, nav_button, nav_bar, nav_bar_page, nav_bar_section, header_bar, settings, scrollable, toggler},
+    widget::{button, nav_button, nav_bar, header_bar, settings, scrollable, toggler},
     Element,
     ElementExt,
 };
@@ -62,6 +62,7 @@ pub enum Message {
     TogglerToggled(bool),
     PickListSelected(&'static str),
     RowSelected(usize),
+    ViewChanged(usize),
     Close,
     ToggleSidebar,
     Drag,
@@ -110,6 +111,7 @@ impl Application for Window {
             Message::Minimize => return minimize(true),
             Message::Maximize => return toggle_maximize(),
             Message::RowSelected(row) => println!("Selected row {row}"),
+            Message::ViewChanged(view) => println!("Selected view {view}"),
         }
 
         Command::none()
diff --git a/src/widget/view_switcher.rs b/src/widget/view_switcher.rs
new file mode 100644
index 00000000..7cfe240e
--- /dev/null
+++ b/src/widget/view_switcher.rs
@@ -0,0 +1,89 @@
+use derive_setters::Setters;
+use iced::{
+    alignment::{Horizontal, Vertical},
+    theme,
+    widget::{button, container, text, Row},
+    Background, Element, Length, Renderer, Theme, Alignment,
+};
+use iced_lazy::Component;
+
+#[derive(Setters)]
+pub struct ViewSwitcher<'a, Message> {
+    options: Vec<&'a str>,
+    #[setters(strip_option)]
+    on_view_changed: Option<Box<dyn Fn(usize) -> Message + 'a>>
+}
+
+pub fn view_switcher<'a, Message>() -> ViewSwitcher<'a, Message> {
+    ViewSwitcher { options: vec![], on_view_changed: None }
+}
+
+#[derive(Clone)]
+pub enum ViewSwitcherEvent {
+    ViewSelected(usize),
+}
+
+#[derive(Default)]
+pub struct ViewSwitcherState {
+    selected_view: usize,
+}
+
+impl<'a, Message> Component<Message, Renderer> for ViewSwitcher<'a, Message> {
+    type State = ViewSwitcherState;
+
+    type Event = ViewSwitcherEvent;
+
+    fn update(&mut self, state: &mut Self::State, event: Self::Event) -> Option<Message> {
+        match event {
+            ViewSwitcherEvent::ViewSelected(index) => state.selected_view = index,
+        }
+        self.on_view_changed.as_ref().map(|on_view_changed| (on_view_changed)(state.selected_view))
+    }
+
+    fn view(&self, state: &Self::State) -> Element<'_, Self::Event, Renderer> {
+        let mut options: Vec<Element<'a, Self::Event, Renderer>> = vec![];
+
+        for (index, option) in self.options.iter().enumerate() {
+            options.push(
+                button(
+                    container(text(option))
+                        .width(Length::Fill)
+                        .height(Length::Fill)
+                        .align_x(Horizontal::Center)
+                        .align_y(Vertical::Center),
+                )
+                .width(Length::Fill)
+                .height(Length::Units(32))
+                .style(if state.selected_view == index {
+                    theme::Button::Secondary.into()
+                } else {
+                    theme::Button::Primary.into()
+                })
+                .on_press(ViewSwitcherEvent::ViewSelected(index))
+                .into(),
+            );
+        }
+        container(Row::with_children(options).align_items(Alignment::Fill))
+            .width(Length::Fill)
+            .padding(2)
+            .style(theme::Container::Custom(view_switcher_container_style))
+            .into()
+    }
+}
+
+pub fn view_switcher_container_style(theme: &Theme) -> iced_style::container::Appearance {
+    let accent = &theme.cosmic().accent;
+    iced_style::container::Appearance {
+        text_color: Default::default(),
+        background: Some(Background::Color(accent.base.into())),
+        border_radius: 24.0,
+        border_width: 2.0,
+        border_color: accent.base.into(),
+    }
+}
+
+impl<'a, Message: 'a> From<ViewSwitcher<'a, Message>> for Element<'a, Message> {
+    fn from(view_switcher: ViewSwitcher<'a, Message>) -> Self {
+        iced_lazy::component(view_switcher)
+    }
+}