Vendor ratatui temporarily (#835)

* Vendor ratatui temporarily

Once https://github.com/tui-rs-revival/ratatui/pull/114 has been merged,
we can undo this! But otherwise we can't publish to crates.io with a git
dependency.

* make tests pass

* Shush.

* these literally just fail in nix, nowhere else

idk how to work with nix properly, and they're also not our tests

1 files changed, 129 insertions, 0 deletions

diff --git a/src/ratatui/widgets/tabs.rs b/src/ratatui/widgets/tabs.rs
new file mode 100644
index 00000000..9b5f5469
--- /dev/null
+++ b/src/ratatui/widgets/tabs.rs
@@ -0,0 +1,129 @@
+use crate::ratatui::{
+    buffer::Buffer,
+    layout::Rect,
+    style::Style,
+    symbols,
+    text::{Span, Spans},
+    widgets::{Block, Widget},
+};
+
+/// A widget to display available tabs in a multiple panels context.
+///
+/// # Examples
+///
+/// ```
+/// # use ratatui::widgets::{Block, Borders, Tabs};
+/// # use ratatui::style::{Style, Color};
+/// # use ratatui::text::{Spans};
+/// # use ratatui::symbols::{DOT};
+/// let titles = ["Tab1", "Tab2", "Tab3", "Tab4"].iter().cloned().map(Spans::from).collect();
+/// Tabs::new(titles)
+///     .block(Block::default().title("Tabs").borders(Borders::ALL))
+///     .style(Style::default().fg(Color::White))
+///     .highlight_style(Style::default().fg(Color::Yellow))
+///     .divider(DOT);
+/// ```
+#[derive(Debug, Clone)]
+pub struct Tabs<'a> {
+    /// A block to wrap this widget in if necessary
+    block: Option<Block<'a>>,
+    /// One title for each tab
+    titles: Vec<Spans<'a>>,
+    /// The index of the selected tabs
+    selected: usize,
+    /// The style used to draw the text
+    style: Style,
+    /// Style to apply to the selected item
+    highlight_style: Style,
+    /// Tab divider
+    divider: Span<'a>,
+}
+
+impl<'a> Tabs<'a> {
+    pub fn new(titles: Vec<Spans<'a>>) -> Tabs<'a> {
+        Tabs {
+            block: None,
+            titles,
+            selected: 0,
+            style: Default::default(),
+            highlight_style: Default::default(),
+            divider: Span::raw(symbols::line::VERTICAL),
+        }
+    }
+
+    pub fn block(mut self, block: Block<'a>) -> Tabs<'a> {
+        self.block = Some(block);
+        self
+    }
+
+    pub fn select(mut self, selected: usize) -> Tabs<'a> {
+        self.selected = selected;
+        self
+    }
+
+    pub fn style(mut self, style: Style) -> Tabs<'a> {
+        self.style = style;
+        self
+    }
+
+    pub fn highlight_style(mut self, style: Style) -> Tabs<'a> {
+        self.highlight_style = style;
+        self
+    }
+
+    pub fn divider<T>(mut self, divider: T) -> Tabs<'a>
+    where
+        T: Into<Span<'a>>,
+    {
+        self.divider = divider.into();
+        self
+    }
+}
+
+impl<'a> Widget for Tabs<'a> {
+    fn render(mut self, area: Rect, buf: &mut Buffer) {
+        buf.set_style(area, self.style);
+        let tabs_area = match self.block.take() {
+            Some(b) => {
+                let inner_area = b.inner(area);
+                b.render(area, buf);
+                inner_area
+            }
+            None => area,
+        };
+
+        if tabs_area.height < 1 {
+            return;
+        }
+
+        let mut x = tabs_area.left();
+        let titles_length = self.titles.len();
+        for (i, title) in self.titles.into_iter().enumerate() {
+            let last_title = titles_length - 1 == i;
+            x = x.saturating_add(1);
+            let remaining_width = tabs_area.right().saturating_sub(x);
+            if remaining_width == 0 {
+                break;
+            }
+            let pos = buf.set_spans(x, tabs_area.top(), &title, remaining_width);
+            if i == self.selected {
+                buf.set_style(
+                    Rect {
+                        x,
+                        y: tabs_area.top(),
+                        width: pos.0.saturating_sub(x),
+                        height: 1,
+                    },
+                    self.highlight_style,
+                );
+            }
+            x = pos.0.saturating_add(1);
+            let remaining_width = tabs_area.right().saturating_sub(x);
+            if remaining_width == 0 || last_title {
+                break;
+            }
+            let pos = buf.set_span(x, tabs_area.top(), &self.divider, remaining_width);
+            x = pos.0;
+        }
+    }
+}