feat: word list cache + word filtering

src/modules/ui/app.rs

@@ -1,16 +1,16 @@
-use crate::modules::source::{FileDatabase, WordSource};
+use crate::modules::source::{FileDatabase, Word, WordSource};
 use crossterm::event::{
     self,
-    Event::{self, Key},
+    Event::{self},
 };
 use ratatui::{
     DefaultTerminal, Frame,
     layout::{Constraint, Direction, Flex, Layout},
     style::{Color, Style},
     text::Text,
-    widgets::{Block, Borders, Padding, Paragraph},
+    widgets::{Block, Borders, Paragraph},
 };
-use std::{io, ops::Index};
+use std::io;
 
 #[derive(PartialEq)]
 pub enum UiState {
@@ -26,6 +26,7 @@ pub struct App {
     state: UiState,
     file_database: FileDatabase,
     scroll_position: usize,
+    word_list: Vec<Word>,
     word_filter: Option<String>,
     lang_filter: Option<String>,
     exit: bool,
@@ -33,10 +34,13 @@ pub struct App {
 
 impl App {
     pub fn new(db: FileDatabase) -> Self {
+        let wl = db.get_all_words();
+
         Self {
             state: UiState::LIST,
             file_database: db,
             scroll_position: 0,
+            word_list: wl,
             word_filter: None,
             lang_filter: None,
             exit: false,
@@ -105,25 +109,13 @@ impl App {
             filters_layout[1],
         );
 
-        // FIXME: this is wrong, the list must reside in memory and only be updated when required,
-        // this makes a new call every frame, insane
-        let word_list = {
-            if let Some(w_filter) = &self.word_filter
-                && let Some(l_filter) = &self.lang_filter
-            {
-                self.file_database
-                    .find_by_word_and_lang(&word_filter, &l_filter)
-            } else if let Some(l_filter) = &self.lang_filter {
-                self.file_database.find_by_lang(&l_filter)
-            } else {
-                self.file_database.get_all_words()
-            }
-        };
         frame.render_widget(
             Paragraph::new("Word list").block(Block::new().borders(Borders::ALL).title("Entries")),
             words_layout[0],
         );
-        let selected_word = word_list.into_iter().nth(self.scroll_position);
+
+        // PERF: do not clone
+        let selected_word = self.word_list.clone().into_iter().nth(self.scroll_position);
         if let Some(w) = selected_word {
             frame.render_widget(
                 Paragraph::new(w.description).block(Block::new().borders(Borders::ALL)),
@@ -141,6 +133,25 @@ impl App {
         frame.render_widget(help_text, help_area);
     }
 
+    fn update_word_list(&mut self) {
+        let word_list = {
+            if let Some(w_filter) = &self.word_filter
+                && let Some(l_filter) = &self.lang_filter
+            {
+                self.file_database
+                    .find_by_word_and_lang(&w_filter, &l_filter)
+            } else if let Some(w_filter) = &self.word_filter {
+                self.file_database.find_by_word(&w_filter)
+            } else if let Some(l_filter) = &self.lang_filter {
+                self.file_database.find_by_lang(&l_filter)
+            } else {
+                self.file_database.get_all_words()
+            }
+        };
+        self.scroll_position = 0;
+        self.word_list = word_list;
+    }
+
     fn handle_events(&mut self) -> io::Result<()> {
         if let Event::Key(key) = event::read()? {
             match key.code {
@@ -153,6 +164,7 @@ impl App {
                             } else {
                                 self.word_filter = Some(c.to_string());
                             }
+                            self.update_word_list();
                         }
                         UiState::FILTERLANG => {
                             if let Some(mut prev_lang) = self.lang_filter.clone() {
@@ -161,6 +173,7 @@ impl App {
                             } else {
                                 self.lang_filter = Some(c.to_string());
                             }
+                            self.update_word_list();
                         }
                         _ => {
                             // Quit
@@ -185,14 +198,34 @@ impl App {
                             }
                             // Movement
                             if c == 'j' {
+                                if self.scroll_position > 0 {
                                     self.scroll_position -= 1;
                                 }
+                            }
                             if c == 'k' {
+                                if self.scroll_position < self.word_list.len() - 1 {
                                     self.scroll_position += 1;
                                 }
                             }
                         }
                     }
+                }
+                event::KeyCode::Backspace => match self.state {
+                    UiState::FILTERWORD => {
+                        if let Some(w) = &self.word_filter {
+                            if w.len() <= 1 {
+                                self.word_filter = None;
+                            } else {
+                                let mut new_w = w.clone();
+                                new_w.pop();
+                                self.word_filter = Some(new_w);
+                            }
+                            self.update_word_list();
+                        }
+                    }
+                    UiState::FILTERLANG => {}
+                    _ => {}
+                },
                 event::KeyCode::Esc => {
                     self.state = UiState::LIST;
                 }