scrolling part 2

Kacperacy · May 14, 2024 · 8b8d9da · 8b8d9da
1 parent 5740316
commit 8b8d9da
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Showing 4 changed files with 178 additions and 36 deletions.
diff --git a/] b/]
@@ -0,0 +1,121 @@
+use std::error;
+
+use ratatui::layout::Rect;
+
+pub type AppResult<T> = std::result::Result<T, Box<dyn error::Error>>;
+
+#[derive(Debug)]
+pub struct Direction {
+    pub x: i8,
+    pub y: i8,
+}
+
+#[derive(Debug)]
+pub struct Position {
+    pub x: usize,
+    pub y: usize,
+}
+
+#[derive(Debug)]
+pub struct App {
+    pub running: bool,
+    pub content: Vec<String>,
+    pub cursor_position: Position,
+    pub cursor_offset: Position,
+    pub opened_filename: String,
+    pub window_size: Rect,
+}
+
+impl Default for App {
+    fn default() -> Self {
+        Self {
+            running: true,
+            content: Vec::new(),
+            cursor_position: Position { x: 0, y: 0 },
+            cursor_offset: Position { x: 0, y: 0 },
+            opened_filename: String::new(),
+            window_size: Rect::new(0, 0, 0, 0),
+        }
+    }
+}
+
+impl App {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn tick(&self) {}
+
+    pub fn quit(&mut self) {
+        self.running = false;
+    }
+
+    pub fn insert_char(&mut self, c: char) {
+        while self.cursor_position.y >= self.content.len() {
+            self.content.push(String::new());
+        }
+        self.content[self.cursor_position.y + self.cursor_offset.y]
+            .insert(self.cursor_position.x + self.cursor_offset.x, c);
+        self.move_cursor(Direction { x: 1, y: 0 });
+    }
+
+    pub fn add_new_line(&mut self) {
+        self.content.insert(
+            self.cursor_position.y + self.cursor_offset.y + 1,
+            String::new(),
+        );
+        self.move_cursor(Direction { x: 0, y: -1 })
+    }
+
+    pub fn pop_char(&mut self) {
+        self.content[self.cursor_position.y].pop();
+
+        if self.cursor_position.x > 0 {
+            self.cursor_position.x -= 1;
+        }
+    }
+
+    pub fn move_cursor(&mut self, direction: Direction) {
+        if direction.x < 0 && self.cursor_position.x + self.cursor_offset.x > 0 {
+            if self.cursor_position.x == 0 {
+                self.cursor_offset.x -= 1;
+            } else {
+                self.cursor_position.x -= 1;
+            }
+        } else if direction.x > 0 {
+            if let Some(line) = self.content.get(self.cursor_position.y) {
+                if line.len() > self.cursor_position.x + self.cursor_offset.x {
+                    if self.window_size.width.saturating_sub(1) > self.cursor_position.x as u16 {
+                        self.cursor_position.x += 1;
+                    } else {
+                        self.cursor_offset.x += 1;
+                    }
+                }
+            }
+        }
+
+        if direction.y > 0 && self.cursor_position.y + self.cursor_offset.y > 0 {
+            if self.cursor_position.y == 0 {
+                self.cursor_offset.y -= 1;
+            } else {
+                self.cursor_position.y -= 1;
+            }
+
+            if self.cursor_position.x > self.content[self.cursor_position.y].len() {
+                self.cursor_position.x = self.content[self.cursor_position.y].len();
+            }
+        } else if direction.y < 0
+            && self.cursor_position.y + self.cursor_offset.y < self.content.len().saturating_sub(1)
+        {
+            if self.window_size.height.saturating_sub(4) > self.cursor_position.y as u16 {
+                self.cursor_position.y += 1;
+            } else {
+                self.cursor_offset.y += 1;
+            }
+
+            if self.cursor_position.x > self.content[self.cursor_position.y].len() {
+                self.cursor_position.x = self.content[self.cursor_position.y].len();
+            }
+        }
+    }
+}
diff --git a/src/app.rs b/src/app.rs
@@ -54,23 +54,39 @@ impl App {
         while self.cursor_position.y >= self.content.len() {
             self.content.push(String::new());
         }
+
         self.content[self.cursor_position.y + self.cursor_offset.y]
             .insert(self.cursor_position.x + self.cursor_offset.x, c);
-        self.cursor_position.x += 1;
+        self.move_cursor(Direction { x: 1, y: 0 });
     }
 
     pub fn add_new_line(&mut self) {
-        self.content
-            .insert(self.cursor_position.y + self.cursor_offset.y, String::new());
-        self.cursor_position.y += 1;
-        self.cursor_position.x = 0;
+        while self.cursor_position.y >= self.content.len() {
+            self.content.push(String::new());
+        }
+
+        self.content.insert(
+            self.cursor_position.y + self.cursor_offset.y + 1,
+            String::new(),
+        );
+        self.move_cursor(Direction { x: 0, y: -1 });
     }
 
     pub fn pop_char(&mut self) {
-        self.content[self.cursor_position.y].pop();
+        if self.content.len() == 0 {
+            return;
+        }
+
+        if self.content[self.cursor_position.y + self.cursor_offset.y].len() == 0 {
+            self.content
+                .remove(self.cursor_position.y + self.cursor_offset.y);
+
+            self.move_cursor(Direction { x: 0, y: 1 });
+        } else {
+            self.content[self.cursor_position.y + self.cursor_offset.y]
+                .remove(self.cursor_position.x + self.cursor_offset.x - 1);
 
-        if self.cursor_position.x > 0 {
-            self.cursor_position.x -= 1;
+            self.move_cursor(Direction { x: -1, y: 0 });
         }
     }
 
@@ -102,6 +118,7 @@ impl App {
 
             if self.cursor_position.x > self.content[self.cursor_position.y].len() {
                 self.cursor_position.x = self.content[self.cursor_position.y].len();
+                self.cursor_offset.x = 0;
             }
         } else if direction.y < 0
             && self.cursor_position.y + self.cursor_offset.y < self.content.len().saturating_sub(1)
@@ -114,6 +131,7 @@ impl App {
 
             if self.cursor_position.x > self.content[self.cursor_position.y].len() {
                 self.cursor_position.x = self.content[self.cursor_position.y].len();
+                self.cursor_offset.x = 0;
             }
         }
     }

diff --git a/src/handler.rs b/src/handler.rs
@@ -2,35 +2,38 @@ use crate::app::{App, AppResult, Direction};
 use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
 
 pub fn handle_key_events(key_event: KeyEvent, app: &mut App) -> AppResult<()> {
-    match key_event.code {
-        KeyCode::Char('c') | KeyCode::Char('C') => {
-            if key_event.modifiers == KeyModifiers::CONTROL {
+    match key_event.modifiers {
+        KeyModifiers::CONTROL => {
+            if key_event.code == KeyCode::Char('c') || key_event.code == KeyCode::Char('C') {
                 app.quit();
             }
         }
-        KeyCode::Enter => {
-            app.add_new_line();
-        }
-        KeyCode::Backspace => {
-            app.pop_char();
-        }
-        KeyCode::Left => {
-            app.move_cursor(Direction { x: -1, y: 0 });
-        }
-        KeyCode::Right => {
-            app.move_cursor(Direction { x: 1, y: 0 });
-        }
-        KeyCode::Up => {
-            app.move_cursor(Direction { x: 0, y: 1 });
-        }
-        KeyCode::Down => {
-            app.move_cursor(Direction { x: 0, y: -1 });
-        }
-        _ => {
-            if let KeyCode::Char(c) = key_event.code {
-                app.insert_char(c)
+        _ => match key_event.code {
+            KeyCode::Enter => {
+                app.add_new_line();
             }
-        }
-    }
+            KeyCode::Backspace => {
+                app.pop_char();
+            }
+            KeyCode::Left => {
+                app.move_cursor(Direction { x: -1, y: 0 });
+            }
+            KeyCode::Right => {
+                app.move_cursor(Direction { x: 1, y: 0 });
+            }
+            KeyCode::Up => {
+                app.move_cursor(Direction { x: 0, y: 1 });
+            }
+            KeyCode::Down => {
+                app.move_cursor(Direction { x: 0, y: -1 });
+            }
+            _ => {
+                if let KeyCode::Char(c) = key_event.code {
+                    app.insert_char(c)
+                }
+            }
+        },
+    };
+
     Ok(())
 }
diff --git a/src/ui.rs b/src/ui.rs
@@ -17,8 +17,8 @@ pub fn render(app: &mut App, frame: &mut Frame) {
 
     let cursor_position_status = Line::from(format!(
         " {:>2}:{:<2} ",
-        app.cursor_position.y + 1,
-        app.cursor_position.x + 1,
+        app.cursor_position.y + app.cursor_offset.y + 1,
+        app.cursor_position.x + app.cursor_offset.x + 1,
     ))
     .right_aligned()
     .style(Style::default().bg(Color::Rgb(128, 192, 255)).bold());