Add input validation to Go to line popup

Add a context struct for the go to line popup to keep the max line
number allowed

Add support for negative values for the go to line popup input (go to
the -n-th to last line)

Make the go to line input box red when invalid values are provided

Add an error message to the Go to line popup when invalid values are
used

Allow arbitrarily large values in the Go to line input box

src/app.rs

@@ -675,8 +675,8 @@ impl App {
 			StackablePopupOpen::CompareCommits(param) => {
 				self.compare_commits_popup.open(param)?;
 			}
-			StackablePopupOpen::GotoLine => {
-				self.goto_line_popup.open();
+			StackablePopupOpen::GotoLine(param) => {
+				self.goto_line_popup.open(param);
 			}
 		}
 

src/popups/blame_file.rs

@@ -30,6 +30,8 @@ use ratatui::{
 };
 use std::path::Path;
 
+use super::{goto_line::GotoLineContext, GotoLineOpen};
+
 static NO_COMMIT_ID: &str = "0000000";
 static NO_AUTHOR: &str = "<no author>";
 static MIN_AUTHOR_WIDTH: usize = 3;
@@ -333,7 +335,11 @@ impl Component for BlameFilePopup {
 					self.hide_stacked(true);
 					self.visible = true;
 					self.queue.push(InternalEvent::OpenPopup(
-						StackablePopupOpen::GotoLine,
+						StackablePopupOpen::GotoLine(GotoLineOpen {
+							context: GotoLineContext {
+								max_line: self.get_max_line_number(),
+							},
+						}),
 					));
 				}
 

src/popups/goto_line.rs

@@ -11,6 +11,7 @@ use crate::{
 
 use ratatui::{
 	layout::Rect,
+	style::{Color, Style},
 	widgets::{Block, Clear, Paragraph},
 	Frame,
 };
@@ -19,27 +20,44 @@ use anyhow::Result;
 
 use crossterm::event::{Event, KeyCode};
 
+#[derive(Debug)]
+pub struct GotoLineContext {
+	pub max_line: usize,
+}
+
+#[derive(Debug)]
+pub struct GotoLineOpen {
+	pub context: GotoLineContext,
+}
+
 pub struct GotoLinePopup {
 	visible: bool,
-	line: String,
+	input: String,
+	line_number: usize,
 	key_config: SharedKeyConfig,
 	queue: Queue,
 	theme: SharedTheme,
+	invalid_input: bool,
+	context: GotoLineContext,
 }
 
 impl GotoLinePopup {
 	pub fn new(env: &Environment) -> Self {
 		Self {
 			visible: false,
-			line: String::new(),
+			input: String::new(),
 			key_config: env.key_config.clone(),
 			queue: env.queue.clone(),
 			theme: env.theme.clone(),
+			invalid_input: false,
+			context: GotoLineContext { max_line: 0 },
+			line_number: 0,
 		}
 	}
 
-	pub fn open(&mut self) {
+	pub fn open(&mut self, open: GotoLineOpen) {
 		self.visible = true;
+		self.context = open.context;
 	}
 }
 
@@ -63,41 +81,67 @@ impl Component for GotoLinePopup {
 			if let Event::Key(key) = event {
 				if key_match(key, self.key_config.keys.exit_popup) {
 					self.visible = false;
-					self.line.clear();
+					self.input.clear();
 					self.queue.push(InternalEvent::PopupStackPop);
 				} else if let KeyCode::Char(c) = key.code {
-					if c.is_ascii_digit() {
-						// I'd assume it's unusual for people to blame
-						// files with milions of lines
-						if self.line.len() < 6 {
-							self.line.push(c);
-						}
+					if c.is_ascii_digit() || c == '-' {
+						self.input.push(c);
 					}
 				} else if key.code == KeyCode::Backspace {
-					self.line.pop();
+					self.input.pop();
 				} else if key_match(key, self.key_config.keys.enter) {
 					self.visible = false;
-					if !self.line.is_empty() {
+					if self.invalid_input {
+						self.queue.push(InternalEvent::ShowErrorMsg(
+                            format!("Invalid input: only numbers between -{0} and {0} (included) are allowed",self.context.max_line))
+                            ,
+                        );
+					} else if !self.input.is_empty() {
 						self.queue.push(InternalEvent::GotoLine(
-							self.line.parse::<usize>()?,
+							self.line_number,
 						));
 					}
 					self.queue.push(InternalEvent::PopupStackPop);
-					self.line.clear();
+					self.input.clear();
+					self.invalid_input = false;
+				}
+			}
+			match self.input.parse::<isize>() {
+				Ok(input) => {
+					if input.unsigned_abs() > self.context.max_line {
+						self.invalid_input = true;
+					} else {
+						self.invalid_input = false;
+						self.line_number = if input > 0 {
+							input.unsigned_abs()
+						} else {
+							self.context.max_line
+								- input.unsigned_abs()
+						}
+					}
+				}
+				Err(_) => {
+					if !self.input.is_empty() {
+						self.invalid_input = true;
+					}
 				}
-				return Ok(EventState::Consumed);
 			}
+			return Ok(EventState::Consumed);
 		}
-
 		Ok(EventState::NotConsumed)
 	}
 }
 
 impl DrawableComponent for GotoLinePopup {
 	fn draw(&self, f: &mut Frame, area: Rect) -> Result<()> {
 		if self.is_visible() {
-			let input = Paragraph::new(self.line.as_str())
-				.style(self.theme.text(true, false))
+			let style = if self.invalid_input {
+				Style::default().fg(Color::Red)
+			} else {
+				self.theme.text(true, false)
+			};
+			let input = Paragraph::new(self.input.as_str())
+				.style(style)
 				.block(Block::bordered().title("Go to Line"));
 
 			let input_area = ui::centered_rect_absolute(15, 3, area);

src/popups/mod.rs

@@ -35,7 +35,7 @@ pub use externaleditor::ExternalEditorPopup;
 pub use fetch::FetchPopup;
 pub use file_revlog::{FileRevOpen, FileRevlogPopup};
 pub use fuzzy_find::FuzzyFindPopup;
-pub use goto_line::GotoLinePopup;
+pub use goto_line::{GotoLineOpen, GotoLinePopup};
 pub use help::HelpPopup;
 pub use inspect_commit::{InspectCommitOpen, InspectCommitPopup};
 pub use log_search::LogSearchPopupPopup;

src/queue.rs

@@ -2,7 +2,7 @@ use crate::{
 	components::FuzzyFinderTarget,
 	popups::{
 		AppOption, BlameFileOpen, FileRevOpen, FileTreeOpen,
-		InspectCommitOpen,
+		GotoLineOpen, InspectCommitOpen,
 	},
 	tabs::StashingOptions,
 };
@@ -69,7 +69,7 @@ pub enum StackablePopupOpen {
 	///
 	CompareCommits(InspectCommitOpen),
 	///
-	GotoLine,
+	GotoLine(GotoLineOpen),
 }
 
 pub enum AppTabs {