Feat: collapsible help

src/input/help_page.rs

@@ -3,6 +3,8 @@ use std::sync::atomic::Ordering;
 
 use super::{InputContext, InputResult};
 use crate::commands::AppCommand;
+use crate::model::categories;
+use crate::model::docs;
 use crate::state::{ConfirmAction, DictFocus, FlashKind, HelpFocus, Modal};
 
 pub(super) fn handle_help_page(ctx: &mut InputContext, key: KeyEvent) -> InputResult {
@@ -30,6 +32,12 @@ pub(super) fn handle_help_page(ctx: &mut InputContext, key: KeyEvent) -> InputRe
             ctx.app.ui.help_focused_block = None;
         }
         KeyCode::Tab => ctx.dispatch(AppCommand::HelpToggleFocus),
+        KeyCode::Left if ctx.app.ui.help_focus == HelpFocus::Topics => {
+            collapse_help_section(ctx);
+        }
+        KeyCode::Right if ctx.app.ui.help_focus == HelpFocus::Topics => {
+            expand_help_section(ctx);
+        }
         KeyCode::Char('n') if ctx.app.ui.help_focus == HelpFocus::Content => {
             navigate_code_block(ctx, true);
         }
@@ -130,6 +138,66 @@ fn execute_focused_block(ctx: &mut InputContext) {
     }
 }
 
+fn collapse_help_section(ctx: &mut InputContext) {
+    if let Some(s) = ctx.app.ui.help_on_section {
+        if ctx.app.ui.help_collapsed.get(s).copied().unwrap_or(false) {
+            return;
+        }
+    }
+    let section = match ctx.app.ui.help_on_section {
+        Some(s) => s,
+        None => docs::section_index_for_topic(ctx.app.ui.help_topic),
+    };
+    if let Some(v) = ctx.app.ui.help_collapsed.get_mut(section) {
+        *v = true;
+    }
+    ctx.app.ui.help_on_section = Some(section);
+    ctx.app.ui.help_focused_block = None;
+}
+
+fn expand_help_section(ctx: &mut InputContext) {
+    let Some(section) = ctx.app.ui.help_on_section else {
+        return;
+    };
+    if let Some(v) = ctx.app.ui.help_collapsed.get_mut(section) {
+        *v = false;
+    }
+    ctx.app.ui.help_on_section = None;
+    if let Some(first) = docs::first_topic_in_section(section) {
+        ctx.app.ui.help_topic = first;
+    }
+    ctx.app.ui.help_focused_block = None;
+}
+
+fn collapse_dict_section(ctx: &mut InputContext) {
+    if let Some(s) = ctx.app.ui.dict_on_section {
+        if ctx.app.ui.dict_collapsed.get(s).copied().unwrap_or(false) {
+            return;
+        }
+    }
+    let section = match ctx.app.ui.dict_on_section {
+        Some(s) => s,
+        None => categories::section_index_for_category(ctx.app.ui.dict_category),
+    };
+    if let Some(v) = ctx.app.ui.dict_collapsed.get_mut(section) {
+        *v = true;
+    }
+    ctx.app.ui.dict_on_section = Some(section);
+}
+
+fn expand_dict_section(ctx: &mut InputContext) {
+    let Some(section) = ctx.app.ui.dict_on_section else {
+        return;
+    };
+    if let Some(v) = ctx.app.ui.dict_collapsed.get_mut(section) {
+        *v = false;
+    }
+    ctx.app.ui.dict_on_section = None;
+    if let Some(first) = categories::first_category_in_section(section) {
+        ctx.app.ui.dict_category = first;
+    }
+}
+
 pub(super) fn handle_dict_page(ctx: &mut InputContext, key: KeyEvent) -> InputResult {
     let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
 
@@ -152,6 +220,12 @@ pub(super) fn handle_dict_page(ctx: &mut InputContext, key: KeyEvent) -> InputRe
             ctx.dispatch(AppCommand::DictClearSearch);
         }
         KeyCode::Tab => ctx.dispatch(AppCommand::DictToggleFocus),
+        KeyCode::Left if ctx.app.ui.dict_focus == DictFocus::Categories => {
+            collapse_dict_section(ctx);
+        }
+        KeyCode::Right if ctx.app.ui.dict_focus == DictFocus::Categories => {
+            expand_dict_section(ctx);
+        }
         KeyCode::Char('j') | KeyCode::Down => match ctx.app.ui.dict_focus {
             DictFocus::Categories => ctx.dispatch(AppCommand::DictNextCategory),
             DictFocus::Words => ctx.dispatch(AppCommand::DictScrollDown(1)),