feat(tui2): copy tui crate and normalize snapshots (#7833)

Introduce a full codex-tui source snapshot under the new codex-tui2
crate so viewport work can be replayed in isolation.

This change copies the entire codex-rs/tui/src tree into
codex-rs/tui2/src in one atomic step, rather than piecemeal, to keep
future diffs vs the original viewport bookmark easy to reason about.

The goal is for codex-tui2 to render identically to the existing TUI
behind the `features.tui2` flag while we gradually port the
viewport/history commits from the joshka/viewport bookmark onto this
forked tree.

While on this baseline change, we also ran the codex-tui2 snapshot test
suite and accepted all insta snapshots for the new crate, so the
snapshot files now use the codex-tui2 naming scheme and encode the
unmodified legacy TUI behavior. This keeps later viewport commits
focused on intentional behavior changes (and their snapshots) rather
than on mechanical snapshot renames.

codex-rs/tui2/src/insert_history.rs

@@ -0,0 +1,530 @@
+use std::fmt;
+use std::io;
+use std::io::Write;
+
+use crate::wrapping::word_wrap_lines_borrowed;
+use crossterm::Command;
+use crossterm::cursor::MoveTo;
+use crossterm::queue;
+use crossterm::style::Color as CColor;
+use crossterm::style::Colors;
+use crossterm::style::Print;
+use crossterm::style::SetAttribute;
+use crossterm::style::SetBackgroundColor;
+use crossterm::style::SetColors;
+use crossterm::style::SetForegroundColor;
+use crossterm::terminal::Clear;
+use crossterm::terminal::ClearType;
+use ratatui::layout::Size;
+use ratatui::prelude::Backend;
+use ratatui::style::Color;
+use ratatui::style::Modifier;
+use ratatui::text::Line;
+use ratatui::text::Span;
+
+/// Insert `lines` above the viewport using the terminal's backend writer
+/// (avoids direct stdout references).
+pub fn insert_history_lines<B>(
+    terminal: &mut crate::custom_terminal::Terminal<B>,
+    lines: Vec<Line>,
+) -> io::Result<()>
+where
+    B: Backend + Write,
+{
+    let screen_size = terminal.backend().size().unwrap_or(Size::new(0, 0));
+
+    let mut area = terminal.viewport_area;
+    let mut should_update_area = false;
+    let last_cursor_pos = terminal.last_known_cursor_pos;
+    let writer = terminal.backend_mut();
+
+    // Pre-wrap lines using word-aware wrapping so terminal scrollback sees the same
+    // formatting as the TUI. This avoids character-level hard wrapping by the terminal.
+    let wrapped = word_wrap_lines_borrowed(&lines, area.width.max(1) as usize);
+    let wrapped_lines = wrapped.len() as u16;
+    let cursor_top = if area.bottom() < screen_size.height {
+        // If the viewport is not at the bottom of the screen, scroll it down to make room.
+        // Don't scroll it past the bottom of the screen.
+        let scroll_amount = wrapped_lines.min(screen_size.height - area.bottom());
+
+        // Emit ANSI to scroll the lower region (from the top of the viewport to the bottom
+        // of the screen) downward by `scroll_amount` lines. We do this by:
+        //   1) Limiting the scroll region to [area.top()+1 .. screen_height] (1-based bounds)
+        //   2) Placing the cursor at the top margin of that region
+        //   3) Emitting Reverse Index (RI, ESC M) `scroll_amount` times
+        //   4) Resetting the scroll region back to full screen
+        let top_1based = area.top() + 1; // Convert 0-based row to 1-based for DECSTBM
+        queue!(writer, SetScrollRegion(top_1based..screen_size.height))?;
+        queue!(writer, MoveTo(0, area.top()))?;
+        for _ in 0..scroll_amount {
+            // Reverse Index (RI): ESC M
+            queue!(writer, Print("\x1bM"))?;
+        }
+        queue!(writer, ResetScrollRegion)?;
+
+        let cursor_top = area.top().saturating_sub(1);
+        area.y += scroll_amount;
+        should_update_area = true;
+        cursor_top
+    } else {
+        area.top().saturating_sub(1)
+    };
+
+    // Limit the scroll region to the lines from the top of the screen to the
+    // top of the viewport. With this in place, when we add lines inside this
+    // area, only the lines in this area will be scrolled. We place the cursor
+    // at the end of the scroll region, and add lines starting there.
+    //
+    // ┌─Screen───────────────────────┐
+    // │┌╌Scroll region╌╌╌╌╌╌╌╌╌╌╌╌╌╌┐│
+    // │┆                            ┆│
+    // │┆                            ┆│
+    // │┆                            ┆│
+    // │█╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┘│
+    // │╭─Viewport───────────────────╮│
+    // ││                            ││
+    // │╰────────────────────────────╯│
+    // └──────────────────────────────┘
+    queue!(writer, SetScrollRegion(1..area.top()))?;
+
+    // NB: we are using MoveTo instead of set_cursor_position here to avoid messing with the
+    // terminal's last_known_cursor_position, which hopefully will still be accurate after we
+    // fetch/restore the cursor position. insert_history_lines should be cursor-position-neutral :)
+    queue!(writer, MoveTo(0, cursor_top))?;
+
+    for line in wrapped {
+        queue!(writer, Print("\r\n"))?;
+        queue!(
+            writer,
+            SetColors(Colors::new(
+                line.style
+                    .fg
+                    .map(std::convert::Into::into)
+                    .unwrap_or(CColor::Reset),
+                line.style
+                    .bg
+                    .map(std::convert::Into::into)
+                    .unwrap_or(CColor::Reset)
+            ))
+        )?;
+        queue!(writer, Clear(ClearType::UntilNewLine))?;
+        // Merge line-level style into each span so that ANSI colors reflect
+        // line styles (e.g., blockquotes with green fg).
+        let merged_spans: Vec<Span> = line
+            .spans
+            .iter()
+            .map(|s| Span {
+                style: s.style.patch(line.style),
+                content: s.content.clone(),
+            })
+            .collect();
+        write_spans(writer, merged_spans.iter())?;
+    }
+
+    queue!(writer, ResetScrollRegion)?;
+
+    // Restore the cursor position to where it was before we started.
+    queue!(writer, MoveTo(last_cursor_pos.x, last_cursor_pos.y))?;
+
+    let _ = writer;
+    if should_update_area {
+        terminal.set_viewport_area(area);
+    }
+
+    Ok(())
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SetScrollRegion(pub std::ops::Range<u16>);
+
+impl Command for SetScrollRegion {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "\x1b[{};{}r", self.0.start, self.0.end)
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> std::io::Result<()> {
+        panic!("tried to execute SetScrollRegion command using WinAPI, use ANSI instead");
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        // TODO(nornagon): is this supported on Windows?
+        true
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct ResetScrollRegion;
+
+impl Command for ResetScrollRegion {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        write!(f, "\x1b[r")
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> std::io::Result<()> {
+        panic!("tried to execute ResetScrollRegion command using WinAPI, use ANSI instead");
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        // TODO(nornagon): is this supported on Windows?
+        true
+    }
+}
+
+struct ModifierDiff {
+    pub from: Modifier,
+    pub to: Modifier,
+}
+
+impl ModifierDiff {
+    fn queue<W>(self, mut w: W) -> io::Result<()>
+    where
+        W: io::Write,
+    {
+        use crossterm::style::Attribute as CAttribute;
+        let removed = self.from - self.to;
+        if removed.contains(Modifier::REVERSED) {
+            queue!(w, SetAttribute(CAttribute::NoReverse))?;
+        }
+        if removed.contains(Modifier::BOLD) {
+            queue!(w, SetAttribute(CAttribute::NormalIntensity))?;
+            if self.to.contains(Modifier::DIM) {
+                queue!(w, SetAttribute(CAttribute::Dim))?;
+            }
+        }
+        if removed.contains(Modifier::ITALIC) {
+            queue!(w, SetAttribute(CAttribute::NoItalic))?;
+        }
+        if removed.contains(Modifier::UNDERLINED) {
+            queue!(w, SetAttribute(CAttribute::NoUnderline))?;
+        }
+        if removed.contains(Modifier::DIM) {
+            queue!(w, SetAttribute(CAttribute::NormalIntensity))?;
+        }
+        if removed.contains(Modifier::CROSSED_OUT) {
+            queue!(w, SetAttribute(CAttribute::NotCrossedOut))?;
+        }
+        if removed.contains(Modifier::SLOW_BLINK) || removed.contains(Modifier::RAPID_BLINK) {
+            queue!(w, SetAttribute(CAttribute::NoBlink))?;
+        }
+
+        let added = self.to - self.from;
+        if added.contains(Modifier::REVERSED) {
+            queue!(w, SetAttribute(CAttribute::Reverse))?;
+        }
+        if added.contains(Modifier::BOLD) {
+            queue!(w, SetAttribute(CAttribute::Bold))?;
+        }
+        if added.contains(Modifier::ITALIC) {
+            queue!(w, SetAttribute(CAttribute::Italic))?;
+        }
+        if added.contains(Modifier::UNDERLINED) {
+            queue!(w, SetAttribute(CAttribute::Underlined))?;
+        }
+        if added.contains(Modifier::DIM) {
+            queue!(w, SetAttribute(CAttribute::Dim))?;
+        }
+        if added.contains(Modifier::CROSSED_OUT) {
+            queue!(w, SetAttribute(CAttribute::CrossedOut))?;
+        }
+        if added.contains(Modifier::SLOW_BLINK) {
+            queue!(w, SetAttribute(CAttribute::SlowBlink))?;
+        }
+        if added.contains(Modifier::RAPID_BLINK) {
+            queue!(w, SetAttribute(CAttribute::RapidBlink))?;
+        }
+
+        Ok(())
+    }
+}
+
+fn write_spans<'a, I>(mut writer: &mut impl Write, content: I) -> io::Result<()>
+where
+    I: IntoIterator<Item = &'a Span<'a>>,
+{
+    let mut fg = Color::Reset;
+    let mut bg = Color::Reset;
+    let mut last_modifier = Modifier::empty();
+    for span in content {
+        let mut modifier = Modifier::empty();
+        modifier.insert(span.style.add_modifier);
+        modifier.remove(span.style.sub_modifier);
+        if modifier != last_modifier {
+            let diff = ModifierDiff {
+                from: last_modifier,
+                to: modifier,
+            };
+            diff.queue(&mut writer)?;
+            last_modifier = modifier;
+        }
+        let next_fg = span.style.fg.unwrap_or(Color::Reset);
+        let next_bg = span.style.bg.unwrap_or(Color::Reset);
+        if next_fg != fg || next_bg != bg {
+            queue!(
+                writer,
+                SetColors(Colors::new(next_fg.into(), next_bg.into()))
+            )?;
+            fg = next_fg;
+            bg = next_bg;
+        }
+
+        queue!(writer, Print(span.content.clone()))?;
+    }
+
+    queue!(
+        writer,
+        SetForegroundColor(CColor::Reset),
+        SetBackgroundColor(CColor::Reset),
+        SetAttribute(crossterm::style::Attribute::Reset),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::markdown_render::render_markdown_text;
+    use crate::test_backend::VT100Backend;
+    use ratatui::layout::Rect;
+    use ratatui::style::Color;
+
+    #[test]
+    fn writes_bold_then_regular_spans() {
+        use ratatui::style::Stylize;
+
+        let spans = ["A".bold(), "B".into()];
+
+        let mut actual: Vec<u8> = Vec::new();
+        write_spans(&mut actual, spans.iter()).unwrap();
+
+        let mut expected: Vec<u8> = Vec::new();
+        queue!(
+            expected,
+            SetAttribute(crossterm::style::Attribute::Bold),
+            Print("A"),
+            SetAttribute(crossterm::style::Attribute::NormalIntensity),
+            Print("B"),
+            SetForegroundColor(CColor::Reset),
+            SetBackgroundColor(CColor::Reset),
+            SetAttribute(crossterm::style::Attribute::Reset),
+        )
+        .unwrap();
+
+        assert_eq!(
+            String::from_utf8(actual).unwrap(),
+            String::from_utf8(expected).unwrap()
+        );
+    }
+
+    #[test]
+    fn vt100_blockquote_line_emits_green_fg() {
+        // Set up a small off-screen terminal
+        let width: u16 = 40;
+        let height: u16 = 10;
+        let backend = VT100Backend::new(width, height);
+        let mut term = crate::custom_terminal::Terminal::with_options(backend).expect("terminal");
+        // Place viewport on the last line so history inserts scroll upward
+        let viewport = Rect::new(0, height - 1, width, 1);
+        term.set_viewport_area(viewport);
+
+        // Build a blockquote-like line: apply line-level green style and prefix "> "
+        let mut line: Line<'static> = Line::from(vec!["> ".into(), "Hello world".into()]);
+        line = line.style(Color::Green);
+        insert_history_lines(&mut term, vec![line])
+            .expect("Failed to insert history lines in test");
+
+        let mut saw_colored = false;
+        'outer: for row in 0..height {
+            for col in 0..width {
+                if let Some(cell) = term.backend().vt100().screen().cell(row, col)
+                    && cell.has_contents()
+                    && cell.fgcolor() != vt100::Color::Default
+                {
+                    saw_colored = true;
+                    break 'outer;
+                }
+            }
+        }
+        assert!(
+            saw_colored,
+            "expected at least one colored cell in vt100 output"
+        );
+    }
+
+    #[test]
+    fn vt100_blockquote_wrap_preserves_color_on_all_wrapped_lines() {
+        // Force wrapping by using a narrow viewport width and a long blockquote line.
+        let width: u16 = 20;
+        let height: u16 = 8;
+        let backend = VT100Backend::new(width, height);
+        let mut term = crate::custom_terminal::Terminal::with_options(backend).expect("terminal");
+        // Viewport is the last line so history goes directly above it.
+        let viewport = Rect::new(0, height - 1, width, 1);
+        term.set_viewport_area(viewport);
+
+        // Create a long blockquote with a distinct prefix and enough text to wrap.
+        let mut line: Line<'static> = Line::from(vec![
+            "> ".into(),
+            "This is a long quoted line that should wrap".into(),
+        ]);
+        line = line.style(Color::Green);
+
+        insert_history_lines(&mut term, vec![line])
+            .expect("Failed to insert history lines in test");
+
+        // Parse and inspect the final screen buffer.
+        let screen = term.backend().vt100().screen();
+
+        // Collect rows that are non-empty; these should correspond to our wrapped lines.
+        let mut non_empty_rows: Vec<u16> = Vec::new();
+        for row in 0..height {
+            let mut any = false;
+            for col in 0..width {
+                if let Some(cell) = screen.cell(row, col)
+                    && cell.has_contents()
+                    && cell.contents() != "\0"
+                    && cell.contents() != " "
+                {
+                    any = true;
+                    break;
+                }
+            }
+            if any {
+                non_empty_rows.push(row);
+            }
+        }
+
+        // Expect at least two rows due to wrapping.
+        assert!(
+            non_empty_rows.len() >= 2,
+            "expected wrapped output to span >=2 rows, got {non_empty_rows:?}",
+        );
+
+        // For each non-empty row, ensure all non-space cells are using a non-default fg color.
+        for row in non_empty_rows {
+            for col in 0..width {
+                if let Some(cell) = screen.cell(row, col) {
+                    let contents = cell.contents();
+                    if !contents.is_empty() && contents != " " {
+                        assert!(
+                            cell.fgcolor() != vt100::Color::Default,
+                            "expected non-default fg on row {row} col {col}, got {:?}",
+                            cell.fgcolor()
+                        );
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn vt100_colored_prefix_then_plain_text_resets_color() {
+        let width: u16 = 40;
+        let height: u16 = 6;
+        let backend = VT100Backend::new(width, height);
+        let mut term = crate::custom_terminal::Terminal::with_options(backend).expect("terminal");
+        let viewport = Rect::new(0, height - 1, width, 1);
+        term.set_viewport_area(viewport);
+
+        // First span colored, rest plain.
+        let line: Line<'static> = Line::from(vec![
+            Span::styled("1. ", ratatui::style::Style::default().fg(Color::LightBlue)),
+            Span::raw("Hello world"),
+        ]);
+
+        insert_history_lines(&mut term, vec![line])
+            .expect("Failed to insert history lines in test");
+
+        let screen = term.backend().vt100().screen();
+
+        // Find the first non-empty row; verify first three cells are colored, following cells default.
+        'rows: for row in 0..height {
+            let mut has_text = false;
+            for col in 0..width {
+                if let Some(cell) = screen.cell(row, col)
+                    && cell.has_contents()
+                    && cell.contents() != " "
+                {
+                    has_text = true;
+                    break;
+                }
+            }
+            if !has_text {
+                continue;
+            }
+
+            // Expect "1. Hello world" starting at col 0.
+            for col in 0..3 {
+                let cell = screen.cell(row, col).unwrap();
+                assert!(
+                    cell.fgcolor() != vt100::Color::Default,
+                    "expected colored prefix at col {col}, got {:?}",
+                    cell.fgcolor()
+                );
+            }
+            for col in 3..(3 + "Hello world".len() as u16) {
+                let cell = screen.cell(row, col).unwrap();
+                assert_eq!(
+                    cell.fgcolor(),
+                    vt100::Color::Default,
+                    "expected default color for plain text at col {col}, got {:?}",
+                    cell.fgcolor()
+                );
+            }
+            break 'rows;
+        }
+    }
+
+    #[test]
+    fn vt100_deep_nested_mixed_list_third_level_marker_is_colored() {
+        // Markdown with five levels (ordered → unordered → ordered → unordered → unordered).
+        let md = "1. First\n   - Second level\n     1. Third level (ordered)\n        - Fourth level (bullet)\n          - Fifth level to test indent consistency\n";
+        let text = render_markdown_text(md);
+        let lines: Vec<Line<'static>> = text.lines.clone();
+
+        let width: u16 = 60;
+        let height: u16 = 12;
+        let backend = VT100Backend::new(width, height);
+        let mut term = crate::custom_terminal::Terminal::with_options(backend).expect("terminal");
+        let viewport = ratatui::layout::Rect::new(0, height - 1, width, 1);
+        term.set_viewport_area(viewport);
+
+        insert_history_lines(&mut term, lines).expect("Failed to insert history lines in test");
+
+        let screen = term.backend().vt100().screen();
+
+        // Reconstruct screen rows as strings to locate the 3rd level line.
+        let rows: Vec<String> = screen.rows(0, width).collect();
+
+        let needle = "1. Third level (ordered)";
+        let row_idx = rows
+            .iter()
+            .position(|r| r.contains(needle))
+            .unwrap_or_else(|| {
+                panic!("expected to find row containing {needle:?}, have rows: {rows:?}")
+            });
+        let col_start = rows[row_idx].find(needle).unwrap() as u16; // column where '1' starts
+
+        // Verify that the numeric marker ("1.") at the third level is colored
+        // (non-default fg) and the content after the following space resets to default.
+        for c in [col_start, col_start + 1] {
+            let cell = screen.cell(row_idx as u16, c).unwrap();
+            assert!(
+                cell.fgcolor() != vt100::Color::Default,
+                "expected colored 3rd-level marker at row {row_idx} col {c}, got {:?}",
+                cell.fgcolor()
+            );
+        }
+        let content_col = col_start + 3; // skip '1', '.', and the space
+        if let Some(cell) = screen.cell(row_idx as u16, content_col) {
+            assert_eq!(
+                cell.fgcolor(),
+                vt100::Color::Default,
+                "expected default color for 3rd-level content at row {row_idx} col {content_col}, got {:?}",
+                cell.fgcolor()
+            );
+        }
+    }
+}