A ton of bug fixes

src/views/help_view.rs

@@ -1,9 +1,10 @@
 use minimad::{Composite, CompositeStyle, Compound, Line};
 use ratatui::layout::{Constraint, Layout, Rect};
-use ratatui::style::{Color, Modifier, Style};
+use ratatui::style::{Color, Modifier, Style, Stylize};
 use ratatui::text::{Line as RLine, Span};
 use ratatui::widgets::{Block, Borders, List, ListItem, Padding, Paragraph, Wrap};
 use ratatui::Frame;
+use tui_big_text::{BigText, PixelSize};
 
 use crate::app::App;
 use crate::views::highlight;
@@ -11,8 +12,10 @@ use crate::views::highlight;
 // To add a new help topic: drop a .md file in docs/ and add one line here.
 const DOCS: &[(&str, &str)] = &[
     ("Welcome", include_str!("../../docs/welcome.md")),
+    ("Audio Engine", include_str!("../../docs/audio_engine.md")),
     ("Keybindings", include_str!("../../docs/keybindings.md")),
     ("Sequencer", include_str!("../../docs/sequencer.md")),
+    ("About", include_str!("../../docs/about.md")),
 ];
 
 pub fn topic_count() -> usize {
@@ -47,8 +50,36 @@ fn render_topics(frame: &mut Frame, app: &App, area: Rect) {
     frame.render_widget(list, area);
 }
 
+const WELCOME_TOPIC: usize = 0;
+const BIG_TITLE_HEIGHT: u16 = 6;
+
 fn render_content(frame: &mut Frame, app: &App, area: Rect) {
-    let (name, md) = DOCS[app.ui.help_topic];
+    let (_, md) = DOCS[app.ui.help_topic];
+
+    let is_welcome = app.ui.help_topic == WELCOME_TOPIC;
+    let md_area = if is_welcome {
+        let [title_area, rest] =
+            Layout::vertical([Constraint::Length(BIG_TITLE_HEIGHT), Constraint::Fill(1)])
+                .areas(area);
+        let big_title = BigText::builder()
+            .pixel_size(PixelSize::Quadrant)
+            .style(Style::new().cyan().bold())
+            .lines(vec!["CAGIRE".into()])
+            .centered()
+            .build();
+        let subtitle = Paragraph::new(RLine::from(Span::styled(
+            "A Forth Sequencer",
+            Style::new().fg(Color::White),
+        )))
+        .alignment(ratatui::layout::Alignment::Center);
+        let [big_area, subtitle_area] =
+            Layout::vertical([Constraint::Length(4), Constraint::Length(2)]).areas(title_area);
+        frame.render_widget(big_title, big_area);
+        frame.render_widget(subtitle, subtitle_area);
+        rest
+    } else {
+        area
+    };
     let query = &app.ui.help_search_query;
     let has_query = !query.is_empty();
     let query_lower = query.to_lowercase();
@@ -57,7 +88,7 @@ fn render_content(frame: &mut Frame, app: &App, area: Rect) {
 
     let has_search_bar = app.ui.help_search_active || has_query;
     let search_bar_height: u16 = u16::from(has_search_bar);
-    let visible_height = area.height.saturating_sub(6 + search_bar_height) as usize;
+    let visible_height = md_area.height.saturating_sub(6 + search_bar_height) as usize;
     let max_scroll = lines.len().saturating_sub(visible_height);
     let scroll = app.ui.help_scroll().min(max_scroll);
 
@@ -76,18 +107,17 @@ fn render_content(frame: &mut Frame, app: &App, area: Rect) {
 
     let content_area = if has_search_bar {
         let [content, search] =
-            Layout::vertical([Constraint::Fill(1), Constraint::Length(1)]).areas(area);
+            Layout::vertical([Constraint::Fill(1), Constraint::Length(1)]).areas(md_area);
         render_search_bar(frame, app, search);
         content
     } else {
-        area
+        md_area
     };
 
     let para = Paragraph::new(visible)
         .block(
             Block::default()
                 .borders(Borders::ALL)
-                .title(name)
                 .padding(Padding::new(2, 2, 2, 2)),
         )
         .wrap(Wrap { trim: false });
@@ -158,8 +188,52 @@ fn code_border_style() -> Style {
     Style::new().fg(Color::Rgb(60, 60, 70))
 }
 
+fn preprocess_underscores(md: &str) -> String {
+    let mut out = String::with_capacity(md.len());
+    for line in md.lines() {
+        let mut result = String::with_capacity(line.len());
+        let mut chars = line.char_indices().peekable();
+        let bytes = line.as_bytes();
+        while let Some((i, c)) = chars.next() {
+            if c == '`' {
+                result.push(c);
+                for (_, ch) in chars.by_ref() {
+                    result.push(ch);
+                    if ch == '`' {
+                        break;
+                    }
+                }
+                continue;
+            }
+            if c == '_' {
+                let before_is_space = i == 0 || bytes[i - 1] == b' ';
+                if before_is_space {
+                    if let Some(end) = line[i + 1..].find('_') {
+                        let inner = &line[i + 1..i + 1 + end];
+                        if !inner.is_empty() {
+                            result.push('*');
+                            result.push_str(inner);
+                            result.push('*');
+                            for _ in 0..end {
+                                chars.next();
+                            }
+                            chars.next(); // skip closing _
+                            continue;
+                        }
+                    }
+                }
+            }
+            result.push(c);
+        }
+        out.push_str(&result);
+        out.push('\n');
+    }
+    out
+}
+
 fn parse_markdown(md: &str) -> Vec<RLine<'static>> {
-    let text = minimad::Text::from(md);
+    let processed = preprocess_underscores(md);
+    let text = minimad::Text::from(processed.as_str());
     let mut lines = Vec::new();
 
     let mut code_line_nr: usize = 0;
@@ -218,13 +292,13 @@ fn composite_to_line(composite: Composite) -> RLine<'static> {
     }
 
     for compound in composite.compounds {
-        spans.push(compound_to_span(compound, base_style));
+        compound_to_spans(compound, base_style, &mut spans);
     }
 
     RLine::from(spans)
 }
 
-fn compound_to_span(compound: Compound, base: Style) -> Span<'static> {
+fn compound_to_spans(compound: Compound, base: Style, out: &mut Vec<Span<'static>>) {
     let mut style = base;
 
     if compound.bold {
@@ -240,5 +314,39 @@ fn compound_to_span(compound: Compound, base: Style) -> Span<'static> {
         style = style.add_modifier(Modifier::CROSSED_OUT);
     }
 
-    Span::styled(compound.src.to_string(), style)
+    let src = compound.src.to_string();
+    let link_style = Style::new()
+        .fg(Color::Rgb(120, 200, 180))
+        .add_modifier(Modifier::UNDERLINED);
+
+    let mut rest = src.as_str();
+    while let Some(start) = rest.find('[') {
+        let after_bracket = &rest[start + 1..];
+        if let Some(text_end) = after_bracket.find("](") {
+            let url_start = start + 1 + text_end + 2;
+            if let Some(url_end) = rest[url_start..].find(')') {
+                if start > 0 {
+                    out.push(Span::styled(rest[..start].to_string(), style));
+                }
+                let text = &rest[start + 1..start + 1 + text_end];
+                let url = &rest[url_start..url_start + url_end];
+                if text == url {
+                    out.push(Span::styled(url.to_string(), link_style));
+                } else {
+                    out.push(Span::styled(text.to_string(), link_style));
+                    out.push(Span::styled(
+                        format!(" ({url})"),
+                        Style::new().fg(Color::Rgb(100, 100, 100)),
+                    ));
+                }
+                rest = &rest[url_start + url_end + 1..];
+                continue;
+            }
+        }
+        out.push(Span::styled(rest[..start + 1].to_string(), style));
+        rest = &rest[start + 1..];
+    }
+    if !rest.is_empty() {
+        out.push(Span::styled(rest.to_string(), style));
+    }
 }