Code refactor and clean part II (#75)

## Brief description of changes

- moved UI initialization codes from `main.rs` to `view::mod.rs`
- updated application's logging level
- renamed functions, added more comments/code documentations
- added some code cleanups

12 files changed, 295 insertions, 202 deletions

diff --git a/hackernews_tui/src/client/mod.rs b/hackernews_tui/src/client/mod.rs
index 5d4ad4d..d7d7e98 100644
--- a/hackernews_tui/src/client/mod.rs
+++ b/hackernews_tui/src/client/mod.rs
@@ -29,6 +29,7 @@ pub struct HNClient {
     client: ureq::Agent,
 }
 
+/// A macro to log the runtime of an expression
 macro_rules! log {
     ($e:expr, $desc:expr) => {{
         let time = std::time::SystemTime::now();
@@ -81,8 +82,6 @@ impl HNClient {
 
         // loads first 5 comments to ensure the corresponding `CommentView` has data to render
         self.load_comments(&sender, &mut ids, 5)?;
-        // used to test loading bar
-        // std::thread::sleep(std::time::Duration::from_secs(1000));
         std::thread::spawn({
             let client = self.clone();
             let sleep_dur = std::time::Duration::from_millis(1000);
diff --git a/hackernews_tui/src/client/parser.rs b/hackernews_tui/src/client/parser.rs
index 0756ee4..fb76276 100644
--- a/hackernews_tui/src/client/parser.rs
+++ b/hackernews_tui/src/client/parser.rs
@@ -147,12 +147,13 @@ pub struct HnText {
     pub level: usize,
     pub state: CollapseState,
     pub text: StyledString,
+    /// The minimized version of the text used to display the text component when it's partially collapsed.
     pub minimized_text: StyledString,
     pub links: Vec<String>,
 }
 
 #[derive(Debug, Clone)]
-/// The collapse state of a text component
+/// The collapse state of a HN text component
 pub enum CollapseState {
     Collapsed,
     PartiallyCollapsed,
diff --git a/hackernews_tui/src/client/query.rs b/hackernews_tui/src/client/query.rs
index 26071b7..072b4e2 100644
--- a/hackernews_tui/src/client/query.rs
+++ b/hackernews_tui/src/client/query.rs
@@ -7,15 +7,15 @@ pub struct FilterInterval<T> {
     end: Option<T>,
 }
 
-impl<T: std::fmt::Display + Copy> FilterInterval<T> {
+impl<T: std::fmt::Display> FilterInterval<T> {
     pub fn query(&self, field: &str) -> String {
         format!(
             "{}{}",
-            match self.start {
+            match self.start.as_ref() {
                 Some(x) => format!(",{}>={}", field, x),
                 None => "".to_string(),
             },
-            match self.end {
+            match self.end.as_ref() {
                 Some(x) => format!(",{}<{}", field, x),
                 None => "".to_string(),
             },
@@ -26,11 +26,11 @@ impl<T: std::fmt::Display + Copy> FilterInterval<T> {
         format!(
             "{}: [{}:{}]",
             field,
-            match self.start {
+            match self.start.as_ref() {
                 Some(x) => x.to_string(),
                 None => "".to_string(),
             },
-            match self.end {
+            match self.end.as_ref() {
                 Some(x) => x.to_string(),
                 None => "".to_string(),
             }
@@ -93,3 +93,9 @@ impl StoryNumericFilters {
         }
     }
 }
+
+impl std::fmt::Display for StoryNumericFilters {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.desc())
+    }
+}
diff --git a/hackernews_tui/src/config/mod.rs b/hackernews_tui/src/config/mod.rs
index 0235749..b23f6ca 100644
--- a/hackernews_tui/src/config/mod.rs
+++ b/hackernews_tui/src/config/mod.rs
@@ -80,10 +80,8 @@ pub fn load_config(config_file_str: &str) {
     let config = match Config::from_config_file(&config_file) {
         Err(err) => {
             tracing::error!(
-                "failed to load configurations from the file {}: {} \
-                     \n...Use the default configurations instead",
-                config_file_str,
-                err
+                "failed to load configurations from the file {config_file_str}: {err:#}\
+                 \nUse the default configurations instead",
             );
             Config::default()
         }
diff --git a/hackernews_tui/src/main.rs b/hackernews_tui/src/main.rs
index 73e40e3..10a43b5 100644
--- a/hackernews_tui/src/main.rs
+++ b/hackernews_tui/src/main.rs
@@ -10,112 +10,16 @@ const DEFAULT_LOG_FILE: &str = "hn-tui.log";
 
 use clap::*;
 use prelude::*;
-use view::help_view::HasHelpView;
-
-macro_rules! set_up_switch_view_shortcut {
-    ($key:expr,$tag:expr,$s:expr,$client:expr) => {
-        $s.set_on_post_event($key, move |s| {
-            view::story_view::add_story_view_layer(
-                s,
-                $client,
-                $tag,
-                true,
-                0,
-                client::StoryNumericFilters::default(),
-                false,
-            );
-        });
-    };
-}
-
-fn set_up_global_callbacks(s: &mut Cursive, client: &'static client::HNClient) {
-    s.clear_global_callbacks(Event::CtrlChar('c'));
-
-    let global_keymap = config::get_global_keymap().clone();
-
-    // .............................................................
-    // global shortcuts for switching between different Story Views
-    // .............................................................
-
-    set_up_switch_view_shortcut!(global_keymap.goto_front_page_view, "front_page", s, client);
-    set_up_switch_view_shortcut!(global_keymap.goto_all_stories_view, "story", s, client);
-    set_up_switch_view_shortcut!(global_keymap.goto_ask_hn_view, "ask_hn", s, client);
-    set_up_switch_view_shortcut!(global_keymap.goto_show_hn_view, "show_hn", s, client);
-    set_up_switch_view_shortcut!(global_keymap.goto_jobs_view, "job", s, client);
-
-    // custom navigation shortcuts
-    config::get_config()
-        .keymap
-        .custom_keymaps
-        .iter()
-        .for_each(|data| {
-            s.set_on_post_event(data.key.clone(), move |s| {
-                view::story_view::add_story_view_layer(
-                    s,
-                    client,
-                    &data.tag,
-                    data.by_date,
-                    0,
-                    data.numeric_filters,
-                    false,
-                );
-            });
-        });
-
-    // ............................................
-    // end of navigation shortcuts for Story Views
-    // ............................................
-
-    s.set_on_post_event(global_keymap.goto_previous_view, |s| {
-        if s.screen_mut().len() > 1 {
-            s.pop_layer();
-        }
-    });
-
-    s.set_on_post_event(global_keymap.goto_search_view, move |s| {
-        view::search_view::add_search_view_layer(s, client);
-    });
-
-    s.set_on_post_event(global_keymap.open_help_dialog, |s| {
-        s.add_layer(view::help_view::DefaultHelpView::construct_on_event_help_view())
-    });
-
-    s.set_on_post_event(global_keymap.quit, |s| s.quit());
-}
 
 fn run() {
-    let mut s = cursive::default();
-
-    let theme = config::get_config_theme();
-    s.update_theme(|t| {
-        t.palette.set_color("view", theme.palette.background.into());
-        t.palette
-            .set_color("primary", theme.palette.foreground.into());
-        t.palette
-            .set_color("title_primary", theme.palette.foreground.into());
-        t.palette
-            .set_color("highlight", theme.palette.selection_background.into());
-        t.palette
-            .set_color("highlight_text", theme.palette.selection_foreground.into());
-    });
-
     // setup HN Client
     let client = client::init_client();
-    set_up_global_callbacks(&mut s, client);
-
-    // render `front_page` story view as the application's default view
-    view::story_view::add_story_view_layer(
-        &mut s,
-        client,
-        "front_page",
-        false,
-        0,
-        client::StoryNumericFilters::default(),
-        false,
-    );
 
-    // use `cursive_buffered_backend` to fix the flickering issue
-    // when using `cursive` with `crossterm_backend` (https://github.com/gyscos/Cursive/issues/142)
+    // setup the application's UI
+    let s = view::init_ui(client);
+
+    // use `cursive_buffered_backend` crate to fix the flickering issue
+    // when using `cursive` with `crossterm_backend` (See https://github.com/gyscos/Cursive/issues/142)
     let crossterm_backend = backends::crossterm::Backend::init().unwrap();
     let buffered_backend = Box::new(cursive_buffered_backend::BufferedBackend::new(
         crossterm_backend,
@@ -128,7 +32,7 @@ fn run() {
 /// initialize application logging
 fn init_logging(log_dir_str: &str) {
     if std::env::var("RUST_LOG").is_err() {
-        std::env::set_var("RUST_LOG", "info")
+        std::env::set_var("RUST_LOG", "hackernews_tui=info")
     }
 
     let log_dir = std::path::PathBuf::from(log_dir_str);
diff --git a/hackernews_tui/src/view/article_view.rs b/hackernews_tui/src/view/article_view.rs
index 22b4339..79a3ca7 100644
--- a/hackernews_tui/src/view/article_view.rs
+++ b/hackernews_tui/src/view/article_view.rs
@@ -98,7 +98,7 @@ impl ScrollViewContainer for ArticleView {
     }
 }
 
-pub fn get_article_main_view(article: client::Article) -> OnEventView<ArticleView> {
+fn construct_article_main_view(article: client::Article) -> OnEventView<ArticleView> {
     let is_suffix_key = |c: &Event| -> bool {
         let article_view_keymap = config::get_article_view_keymap();
         article_view_keymap.open_link_in_browser.has_event(c)
@@ -158,9 +158,11 @@ pub fn get_article_main_view(article: client::Article) -> OnEventView<ArticleVie
         .on_scroll_events()
 }
 
-pub fn get_article_view(article: client::Article) -> impl View {
+/// Construct an article view of an article
+pub fn construct_article_view(article: client::Article) -> impl View {
     let desc = format!("Article View - {}", article.title);
-    let main_view = get_article_main_view(article).full_height();
+    let main_view = construct_article_main_view(article).full_height();
+
     let mut view = LinearLayout::vertical()
         .child(utils::construct_view_title_bar(&desc))
         .child(main_view)
@@ -171,7 +173,8 @@ pub fn get_article_view(article: client::Article) -> impl View {
     view
 }
 
-pub fn add_article_view_layer(s: &mut Cursive, url: &str) {
-    let async_view = async_view::get_article_view_async(s, url);
+/// Retrieve an article from a given `url` and construct an article view of that article
+pub fn construct_and_add_new_article_view(s: &mut Cursive, url: &str) {
+    let async_view = async_view::construct_article_view_async(s, url);
     s.screen_mut().add_transparent_layer(Layer::new(async_view))
 }
diff --git a/hackernews_tui/src/view/async_view.rs b/hackernews_tui/src/view/async_view.rs
index 4d9c680..709d950 100644
--- a/hackernews_tui/src/view/async_view.rs
+++ b/hackernews_tui/src/view/async_view.rs
@@ -4,7 +4,7 @@ use anyhow::Context;
 use cursive_aligned_view::Alignable;
 use cursive_async_view::AsyncView;
 
-pub fn get_comment_view_async(
+pub fn construct_comment_view_async(
     siv: &mut Cursive,
     client: &'static client::HNClient,
     story: &client::Story,
@@ -16,7 +16,7 @@ pub fn get_comment_view_async(
         move |result: Result<_>| {
             ResultView::new(
                 result.with_context(|| format!("failed to load comments from story (id={})", id)),
-                |receiver| comment_view::get_comment_view(&story, receiver),
+                |receiver| comment_view::construct_comment_view(&story, receiver),
             )
         }
     })
@@ -25,7 +25,7 @@ pub fn get_comment_view_async(
     .full_screen()
 }
 
-pub fn get_story_view_async(
+pub fn construct_story_view_async(
     siv: &mut Cursive,
     client: &'static client::HNClient,
     tag: &'static str,
@@ -40,12 +40,12 @@ pub fn get_story_view_async(
             ResultView::new(
                 result.with_context(|| {
                     format!(
-                        "failed to get stories (tag={}, by_date={}, page={}, numeric_filters={:#?}):",
+                        "failed to get stories (tag={}, by_date={}, page={}, numeric_filters={{{}}})",
                         tag, by_date, page, numeric_filters,
                     )
                 }),
                 |stories| {
-                    story_view::get_story_view(stories, client, tag, by_date, page, numeric_filters)
+                    story_view::construct_story_view(stories, client, tag, by_date, page, numeric_filters)
                 },
             )
         },
@@ -55,7 +55,7 @@ pub fn get_story_view_async(
     .full_screen()
 }
 
-pub fn get_article_view_async(siv: &mut Cursive, article_url: &str) -> impl View {
+pub fn construct_article_view_async(siv: &mut Cursive, article_url: &str) -> impl View {
     let err_context = format!(
         "Failed to execute the command:\n\
          `{} {}`.\n\n\
@@ -73,7 +73,7 @@ pub fn get_article_view_async(siv: &mut Cursive, article_url: &str) -> impl View
         move |result| {
             let err_context = err_context.clone();
             ResultView::new(result.with_context(|| err_context), |article| {
-                article_view::get_article_view(article)
+                article_view::construct_article_view(article)
             })
         },
     )
diff --git a/hackernews_tui/src/view/comment_view.rs b/hackernews_tui/src/view/comment_view.rs
index 8e59448..925fa67 100644
--- a/hackernews_tui/src/view/comment_view.rs
+++ b/hackernews_tui/src/view/comment_view.rs
@@ -13,12 +13,16 @@ pub struct CommentView {
     raw_command: String,
 }
 
+pub enum NavigationDirection {
+    Next,
+    Previous,
+}
+
 impl ViewWrapper for CommentView {
     wrap_impl!(self.view: ScrollView<LinearLayout>);
 }
 
 impl CommentView {
-    /// Return a new CommentView given a comment list and the discussed story url
     pub fn new(story_text: client::HnText, receiver: client::CommentReceiver) -> Self {
         let mut view = CommentView {
             view: LinearLayout::vertical()
@@ -39,7 +43,7 @@ impl CommentView {
         view
     }
 
-    /// Check the `CommentReceiver` channel if there are new comments loaded
+    /// Check the comment receiver channel if there are new comments loaded
     /// then update the internal comment data accordingly.
     pub fn try_update_comments(&mut self) {
         let mut new_comments = vec![];
@@ -94,33 +98,31 @@ impl CommentView {
         &self,
         start_id: usize,
         max_level: usize,
-        direction: bool,
+        direction: NavigationDirection,
     ) -> usize {
-        if direction {
-            // ->
-            (start_id + 1..self.len())
+        match direction {
+            NavigationDirection::Next => (start_id + 1..self.len())
                 .find(|&id| self.comments[id].level <= max_level)
-                .unwrap_or_else(|| self.len())
-        } else {
-            // <-
-            (0..start_id)
+                .unwrap_or_else(|| self.len()),
+            NavigationDirection::Previous => (0..start_id)
                 .rfind(|&id| self.comments[id].level <= max_level)
-                .unwrap_or(start_id)
+                .unwrap_or(start_id),
         }
     }
 
-    /// Return the id of the next visible comment
-    pub fn find_next_visible_comment(&self, start_id: usize, direction: bool) -> usize {
-        if direction {
-            // ->
-            (start_id + 1..self.len())
+    /// Return the id of the next visible comment (`direction` dependent)
+    pub fn find_next_visible_comment(
+        &self,
+        start_id: usize,
+        direction: NavigationDirection,
+    ) -> usize {
+        match direction {
+            NavigationDirection::Next => (start_id + 1..self.len())
                 .find(|&id| self.get_comment_component(id).is_visible())
-                .unwrap_or_else(|| self.len())
-        } else {
-            // <-
-            (0..start_id)
+                .unwrap_or_else(|| self.len()),
+            NavigationDirection::Previous => (0..start_id)
                 .rfind(|&id| self.get_comment_component(id).is_visible())
-                .unwrap_or(start_id)
+                .unwrap_or(start_id),
         }
     }
 
@@ -138,27 +140,29 @@ impl CommentView {
             .unwrap()
     }
 
-    /// Toggle the collapsing state of comments whose height is greater
-    /// than the `min_height`.
-    /// **Note** `PartiallyCollapsed` comment's state is unchanged, only toggle its visibility.
-    /// Also, the state and visibility of such comment's children are unaffected.
-    fn toggle_comment_collapse_state(&mut self, i: usize, min_height: usize) {
-        if i == self.len() || self.comments[i].level <= min_height {
+    /// Toggle the collapsing state of comments whose level is greater than the `min_level`.
+    fn toggle_comment_collapse_state(&mut self, start_id: usize, min_level: usize) {
+        // This function will be called recursively until it's unable to find any comments.
+        //
+        // **Note**: `PartiallyCollapsed` comment's state is unchanged, we only toggle its visibility.
+        // Also, the state and visibility of such comment's children are unaffected as they should already
+        // be in a collapsed state.
+        if start_id == self.len() || self.comments[start_id].level <= min_level {
             return;
         }
-        match self.comments[i].state {
+        match self.comments[start_id].state {
             client::CollapseState::Collapsed => {
-                self.comments[i].state = client::CollapseState::Normal;
-                self.get_comment_component_mut(i).unhide();
-                self.toggle_comment_collapse_state(i + 1, min_height)
+                self.comments[start_id].state = client::CollapseState::Normal;
+                self.get_comment_component_mut(start_id).unhide();
+                self.toggle_comment_collapse_state(start_id + 1, min_level)
             }
             client::CollapseState::Normal => {
-                self.comments[i].state = client::CollapseState::Collapsed;
-                self.get_comment_component_mut(i).hide();
-                self.toggle_comment_collapse_state(i + 1, min_height)
+                self.comments[start_id].state = client::CollapseState::Collapsed;
+                self.get_comment_component_mut(start_id).hide();
+                self.toggle_comment_collapse_state(start_id + 1, min_level)
             }
             client::CollapseState::PartiallyCollapsed => {
-                let component = self.get_comment_component_mut(i);
+                let component = self.get_comment_component_mut(start_id);
                 if component.is_visible() {
                     component.hide();
                 } else {
@@ -166,8 +170,12 @@ impl CommentView {
                 }
 
                 // skip toggling all child comments of the current comment
-                let next_id = self.find_comment_id_by_max_level(i, self.comments[i].level, true);
-                self.toggle_comment_collapse_state(next_id, min_height)
+                let next_id = self.find_comment_id_by_max_level(
+                    start_id,
+                    self.comments[start_id].level,
+                    NavigationDirection::Next,
+                );
+                self.toggle_comment_collapse_state(next_id, min_level)
             }
         };
     }
@@ -179,7 +187,7 @@ impl CommentView {
         match comment.state {
             client::CollapseState::Collapsed => {
                 panic!(
-                    "invalid comment state `Collapsed` when calling `toggle_collapse_focused_comment`"
+                    "invalid collapse state `Collapsed` when calling `toggle_collapse_focused_comment`"
                 );
             }
             client::CollapseState::PartiallyCollapsed => {
@@ -233,7 +241,10 @@ impl ScrollViewContainer for CommentView {
     }
 }
 
-fn get_comment_main_view(story: &client::Story, receiver: client::CommentReceiver) -> impl View {
+fn construct_comment_main_view(
+    story: &client::Story,
+    receiver: client::CommentReceiver,
+) -> impl View {
     let is_suffix_key = |c: &Event| -> bool {
         let comment_view_keymap = config::get_comment_view_keymap();
         comment_view_keymap.open_link_in_browser.has_event(c)
@@ -263,36 +274,48 @@ fn get_comment_main_view(story: &client::Story, receiver: client::CommentReceive
         })
         // comment navigation shortcuts
         .on_pre_event_inner(comment_view_keymap.prev_comment, |s, _| {
-            s.set_focus_index(s.find_next_visible_comment(s.get_focus_index(), false))
+            s.set_focus_index(
+                s.find_next_visible_comment(s.get_focus_index(), NavigationDirection::Previous),
+            )
         })
         .on_pre_event_inner(comment_view_keymap.next_comment, |s, _| {
-            let next_id = s.find_next_visible_comment(s.get_focus_index(), true);
+            let next_id =
+                s.find_next_visible_comment(s.get_focus_index(), NavigationDirection::Next);
             s.set_focus_index(next_id)
         })
         .on_pre_event_inner(comment_view_keymap.next_leq_level_comment, move |s, _| {
             let id = s.get_focus_index();
-            let next_id = s.find_comment_id_by_max_level(id, s.comments[id].level, true);
+            let next_id =
+                s.find_comment_id_by_max_level(id, s.comments[id].level, NavigationDirection::Next);
             s.set_focus_index(next_id)
         })
         .on_pre_event_inner(comment_view_keymap.prev_leq_level_comment, move |s, _| {
             let id = s.get_focus_index();
-            let next_id = s.find_comment_id_by_max_level(id, s.comments[id].level, false);
+            let next_id = s.find_comment_id_by_max_level(
+                id,
+                s.comments[id].level,
+                NavigationDirection::Previous,
+            );
             s.set_focus_index(next_id)
         })
         .on_pre_event_inner(comment_view_keymap.next_top_level_comment, move |s, _| {
             let id = s.get_focus_index();
-            let next_id = s.find_comment_id_by_max_level(id, 0, true);
+            let next_id = s.find_comment_id_by_max_level(id, 0, NavigationDirection::Next);
             s.set_focus_index(next_id)
         })
         .on_pre_event_inner(comment_view_keymap.prev_top_level_comment, move |s, _| {
             let id = s.get_focus_index();
-            let next_id = s.find_comment_id_by_max_level(id, 0, false);
+            let next_id = s.find_comment_id_by_max_level(id, 0, NavigationDirection::Previous);
             s.set_focus_index(next_id)
         })
         .on_pre_event_inner(comment_view_keymap.parent_comment, move |s, _| {
             let id = s.get_focus_index();
             if s.comments[id].level > 0 {
-                let next_id = s.find_comment_id_by_max_level(id, s.comments[id].level - 1, false);
+                let next_id = s.find_comment_id_by_max_level(
+                    id,
+                    s.comments[id].level - 1,
+                    NavigationDirection::Previous,
+                );
                 s.set_focus_index(next_id)
             } else {
                 Some(EventResult::Consumed(None))
@@ -342,7 +365,7 @@ fn get_comment_main_view(story: &client::Story, receiver: client::CommentReceive
             let url = story.url.clone();
             move |s| {
                 if !url.is_empty() {
-                    article_view::add_article_view_layer(s, &url)
+                    article_view::construct_and_add_new_article_view(s, &url)
                 }
             }
         })
@@ -359,14 +382,22 @@ fn get_comment_main_view(story: &client::Story, receiver: client::CommentReceive
         .full_height()
 }
 
-pub fn get_comment_view(story: &client::Story, receiver: client::CommentReceiver) -> impl View {
-    let status_bar =
-        utils::construct_view_title_bar(&format!("Comment View - {}", story.title.source()));
-
-    let main_view = get_comment_main_view(story, receiver);
+/// Construct a comment view of a given story.
+///
+/// # Arguments:
+/// * `story`: a Hacker News story
+/// * `receiver`: a "subscriber" channel that gets comments asynchronously from another thread
+pub fn construct_comment_view(
+    story: &client::Story,
+    receiver: client::CommentReceiver,
+) -> impl View {
+    let main_view = construct_comment_main_view(story, receiver);
 
     let mut view = LinearLayout::vertical()
-        .child(status_bar)
+        .child(utils::construct_view_title_bar(&format!(
+            "Comment View - {}",
+            story.title.source()
+        )))
         .child(main_view)
         .child(utils::construct_footer_view::<CommentView>());
     view.set_focus_index(1)
@@ -375,13 +406,14 @@ pub fn get_comment_view(story: &client::Story, receiver: client::CommentReceiver
     view
 }
 
-pub fn add_comment_view_layer(
+/// Retrieve comments of a story and construct a comment view of that story
+pub fn construct_and_add_new_comment_view(
     s: &mut Cursive,
     client: &'static client::HNClient,
     story: &client::Story,
     pop_layer: bool,
 ) {
-    let async_view = async_view::get_comment_view_async(s, client, story);
+    let async_view = async_view::construct_comment_view_async(s, client, story);
     if pop_layer {
         s.pop_layer();
     }
diff --git a/hackernews_tui/src/view/mod.rs b/hackernews_tui/src/view/mod.rs
index cf3c66c..a41934d 100644
--- a/hackernews_tui/src/view/mod.rs
+++ b/hackernews_tui/src/view/mod.rs
@@ -11,3 +11,128 @@ pub mod comment_view;
 pub mod help_view;
 pub mod search_view;
 pub mod story_view;
+
+use crate::view::help_view::HasHelpView;
+
+use super::prelude::*;
+
+fn set_up_switch_story_view_shortcut(
+    keys: config::Keys,
+    tag: &'static str,
+    s: &mut Cursive,
+    client: &'static client::HNClient,
+    numeric_filters: Option<client::StoryNumericFilters>,
+) {
+    s.set_on_post_event(keys, move |s| {
+        story_view::construct_and_add_new_story_view(
+            s,
+            client,
+            tag,
+            true,
+            0,
+            numeric_filters.unwrap_or_default(),
+            false,
+        );
+    });
+}
+
+fn set_up_global_callbacks(s: &mut Cursive, client: &'static client::HNClient) {
+    s.clear_global_callbacks(Event::CtrlChar('c'));
+
+    let global_keymap = config::get_global_keymap().clone();
+
+    // .............................................................
+    // global shortcuts for switching between different Story Views
+    // .............................................................
+
+    set_up_switch_story_view_shortcut(
+        global_keymap.goto_front_page_view,
+        "front_page",
+        s,
+        client,
+        None,
+    );
+    set_up_switch_story_view_shortcut(
+        global_keymap.goto_all_stories_view,
+        "story",
+        s,
+        client,
+        None,
+    );
+    set_up_switch_story_view_shortcut(global_keymap.goto_ask_hn_view, "ask_hn", s, client, None);
+    set_up_switch_story_view_shortcut(global_keymap.goto_show_hn_view, "show_hn", s, client, None);
+    set_up_switch_story_view_shortcut(global_keymap.goto_jobs_view, "job", s, client, None);
+
+    // custom navigation shortcuts
+    config::get_config()
+        .keymap
+        .custom_keymaps
+        .iter()
+        .for_each(|data| {
+            s.set_on_post_event(data.key.clone(), move |s| {
+                story_view::construct_and_add_new_story_view(
+                    s,
+                    client,
+                    &data.tag,
+                    data.by_date,
+                    0,
+                    data.numeric_filters,
+                    false,
+                );
+            });
+        });
+
+    // ............................................
+    // end of navigation shortcuts for Story Views
+    // ............................................
+
+    s.set_on_post_event(global_keymap.goto_previous_view, |s| {
+        if s.screen_mut().len() > 1 {
+            s.pop_layer();
+        }
+    });
+
+    s.set_on_post_event(global_keymap.goto_search_view, move |s| {
+        search_view::construct_and_add_new_search_view(s, client);
+    });
+
+    s.set_on_post_event(global_keymap.open_help_dialog, |s| {
+        s.add_layer(help_view::DefaultHelpView::construct_on_event_help_view())
+    });
+
+    s.set_on_post_event(global_keymap.quit, |s| s.quit());
+}
+
+/// Initialize the application's UI
+pub fn init_ui(client: &'static client::HNClient) -> cursive::CursiveRunnable {
+    let mut s = cursive::default();
+
+    // initialize `cursive` color palette which is determined by the application's theme
+    let theme = config::get_config_theme();
+    s.update_theme(|t| {
+        t.palette.set_color("view", theme.palette.background.into());
+        t.palette
+            .set_color("primary", theme.palette.foreground.into());
+        t.palette
+            .set_color("title_primary", theme.palette.foreground.into());
+        t.palette
+            .set_color("highlight", theme.palette.selection_background.into());
+        t.palette
+            .set_color("highlight_text", theme.palette.selection_foreground.into());
+    });
+
+    set_up_global_callbacks(&mut s, client);
+
+    // render `front_page` story view as the application's startup view
+    story_view::construct_and_add_new_story_view(
+        &mut s,
+        client,
+        "front_page",
+        false,
+        0,
+        client::StoryNumericFilters::default(),
+        false,
+    );
+
+    s
+}
diff --git a/hackernews_tui/src/view/search_view.rs b/hackernews_tui/src/view/search_view.rs
index 3086919..7c21940 100644
--- a/hackernews_tui/src/view/search_view.rs
+++ b/hackernews_tui/src/view/search_view.rs
@@ -44,7 +44,7 @@ impl SearchView {
                     )))
                     .child(EditableTextView::new()),
             )
-            .child(story_view::get_story_main_view(vec![], client, 0).full_height());
+            .child(story_view::construct_story_main_view(vec![], client, 0).full_height());
 
         Self {
             mode: SearchViewMode::Search,
@@ -131,7 +131,7 @@ impl SearchView {
         self.view.remove_child(1);
         let starting_id = client::SEARCH_LIMIT * self.page;
         self.view.add_child(
-            story_view::get_story_main_view(stories, self.client, starting_id).full_height(),
+            story_view::construct_story_main_view(stories, self.client, starting_id).full_height(),
         );
         // the old Story View is deleted hence losing the current focus,
         // we need to place the focus back to the new Story View
@@ -155,7 +155,7 @@ impl ViewWrapper for SearchView {
     }
 }
 
-fn get_search_main_view(client: &'static client::HNClient, cb_sink: CbSink) -> impl View {
+fn construct_search_main_view(client: &'static client::HNClient, cb_sink: CbSink) -> impl View {
     let story_view_keymap = config::get_story_view_keymap().clone();
     let search_view_keymap = config::get_search_view_keymap().clone();
 
@@ -211,7 +211,8 @@ fn get_search_main_view(client: &'static client::HNClient, cb_sink: CbSink) -> i
                 Some(EventResult::Consumed(None))
             }
         })
-        // paging/filtering while in NavigationMode
+        // paging/filtering commands while in NavigationMode
+        // Those commands need to be handled differently from the story view.
         .on_pre_event_inner(story_view_keymap.toggle_sort_by_date, |s, _| match s.mode {
             SearchViewMode::Navigation => {
                 s.page = 0;
@@ -244,20 +245,22 @@ fn get_search_main_view(client: &'static client::HNClient, cb_sink: CbSink) -> i
         })
 }
 
-pub fn get_search_view(client: &'static client::HNClient, cb_sink: CbSink) -> impl View {
-    let main_view = get_search_main_view(client, cb_sink);
+fn construct_search_view(client: &'static client::HNClient, cb_sink: CbSink) -> impl View {
+    let main_view = construct_search_main_view(client, cb_sink);
+
     let mut view = LinearLayout::vertical()
         .child(utils::construct_view_title_bar("Search View"))
         .child(main_view)
         .child(utils::construct_footer_view::<SearchView>());
+
     view.set_focus_index(1)
         .unwrap_or(EventResult::Consumed(None));
 
     view
 }
 
-pub fn add_search_view_layer(s: &mut Cursive, client: &'static client::HNClient) {
+pub fn construct_and_add_new_search_view(s: &mut Cursive, client: &'static client::HNClient) {
     let cb_sink = s.cb_sink().clone();
     s.screen_mut()
-        .add_transparent_layer(Layer::new(get_search_view(client, cb_sink)));
+        .add_transparent_layer(Layer::new(construct_search_view(client, cb_sink)));
 }
diff --git a/hackernews_tui/src/view/story_view.rs b/hackernews_tui/src/view/story_view.rs
index b70b71f..393fd87 100644
--- a/hackernews_tui/src/view/story_view.rs
+++ b/hackernews_tui/src/view/story_view.rs
@@ -125,7 +125,7 @@ impl ScrollViewContainer for StoryView {
     }
 }
 
-pub fn get_story_main_view(
+pub fn construct_story_main_view(
     stories: Vec<client::Story>,
     client: &'static client::HNClient,
     starting_id: usize,
@@ -172,7 +172,7 @@ pub fn get_story_main_view(
             // so it can be cloned without greatly affecting performance