From 37463f46c3426eceafd96c77edbde742ade09fa6 Mon Sep 17 00:00:00 2001
From: Rushmore75 <oliveratkinsoneng@gmail.com>
Date: Wed, 12 Nov 2025 08:39:25 -0700
Subject: [PATCH] add grid_max

---
 src/app/app.rs        | 10 ++++++--
 src/app/logic/calc.rs | 57 +++++++++++++++++++++++++++++++++++++++----
 src/app/mode.rs       |  6 ++---
 3 files changed, 63 insertions(+), 10 deletions(-)

diff --git a/src/app/app.rs b/src/app/app.rs
index 9923763..e0b8cda 100644
--- a/src/app/app.rs
+++ b/src/app/app.rs
@@ -246,10 +246,16 @@ impl App {
                     event::KeyCode::Enter => {
                         let v = editor.as_string();
 
+                        // try to insert as a float
                         if let Ok(v) = v.parse::<f64>() {
-                            self.grid.set_cell_raw(self.grid.selected_cell, v);
+                            self.grid.set_cell_raw(self.grid.selected_cell, Some(v));
                         } else {
-                            self.grid.set_cell_raw(self.grid.selected_cell, v);
+                            // if you can't, then insert as a string
+                            if !v.is_empty() {
+                                self.grid.set_cell_raw(self.grid.selected_cell, Some(v));
+                            } else {
+                                self.grid.set_cell_raw::<CellType>(self.grid.selected_cell, None);
+                            }
                         }
 
                         self.mode = Mode::Normal;
diff --git a/src/app/logic/calc.rs b/src/app/logic/calc.rs
index 7f11501..fb1fed1 100644
--- a/src/app/logic/calc.rs
+++ b/src/app/logic/calc.rs
@@ -1,6 +1,7 @@
 use std::fmt::Display;
 
 use evalexpr::*;
+use ratatui::buffer::Cell;
 
 use crate::app::logic::ctx;
 
@@ -27,6 +28,30 @@ impl std::fmt::Debug for Grid {
 }
 
 impl Grid {
+
+    /// Iterate over the entire grid and see where
+    /// the farthest modified cell is.
+    #[must_use]
+    pub fn max(&self) -> (usize, usize) {
+        let mut max_x = 0;
+        let mut max_y = 0;
+
+        for (xi, x) in self.cells.iter().enumerate() {
+            for (yi, cell) in x.iter().enumerate() {
+                if cell.is_some() {
+                    if yi > max_y {
+                        max_y = yi
+                    }
+                    if xi > max_x {
+                        max_x = xi
+                    }
+                }
+            }
+        }
+
+        (max_x, max_y)
+    }
+
     pub fn new() -> Self {
         let mut a = Vec::with_capacity(LEN);
         for _ in 0..LEN {
@@ -110,15 +135,17 @@ impl Grid {
 
     }
 
-    pub fn set_cell<T: Into<CellType>>(&mut self, cell_id: &str, val: T) {
+    /// Helper for tests
+    #[cfg(test)]
+    fn set_cell<T: Into<CellType>>(&mut self, cell_id: &str, val: T) {
         if let Some(loc) = Self::parse_to_idx(cell_id) {
-            self.set_cell_raw(loc, val);
+            self.set_cell_raw(loc, Some(val));
         }
     }
 
-    pub fn set_cell_raw<T: Into<CellType>>(&mut self, (x,y): (usize, usize), val: T) {
+    pub fn set_cell_raw<T: Into<CellType>>(&mut self, (x,y): (usize, usize), val: Option<T>) {
         // TODO check oob
-        self.cells[x][y] = Some(val.into());
+        self.cells[x][y] = val.map(|v| v.into());
     }
 
     /// Get cells via text like:
@@ -332,4 +359,24 @@ fn invalid_equations() {
     assert!(res.is_some());
     assert!(res.is_some_and(|v| v == 10.));
     
-}
\ No newline at end of file
+}
+
+#[test]
+fn grid_max() {
+    let mut grid = Grid::new();
+
+    grid.set_cell("A0", 1.);
+    let (mx, my) = grid.max();
+    assert_eq!(mx, 0);
+    assert_eq!(my, 0);
+
+    grid.set_cell("B0", 1.);
+    let (mx, my) = grid.max();
+    assert_eq!(mx, 1);
+    assert_eq!(my, 0);
+
+    grid.set_cell("B5", 1.);
+    let (mx, my) = grid.max();
+    assert_eq!(mx, 1);
+    assert_eq!(my, 5);
+}
diff --git a/src/app/mode.rs b/src/app/mode.rs
index 6fcda5e..601a95f 100644
--- a/src/app/mode.rs
+++ b/src/app/mode.rs
@@ -7,7 +7,7 @@ use ratatui::{
     prelude, style::{Color, Style}, widgets::{Paragraph, Widget}
 };
 
-use crate::app::{app::App, logic::calc::LEN, error_msg::ErrorMessage};
+use crate::app::{app::App, error_msg::ErrorMessage, logic::calc::{CellType, LEN}};
 
 pub enum Mode {
     Insert(Chord),
@@ -142,7 +142,7 @@ impl Mode {
                     if key == 'd' {
                         for x in low_x..=hi_x {
                             for y in low_y..=hi_y {
-                                app.grid.set_cell_raw((x, y), String::new());
+                                app.grid.set_cell_raw::<CellType>((x, y), None);
                             }
                         }
                         app.mode = Mode::Normal
@@ -179,7 +179,7 @@ impl Mode {
                     Err(_) => match chord.as_string().as_str() {
                         "d " | "dw" => {
                             let loc = app.grid.selected_cell;
-                            app.grid.set_cell_raw(loc, String::new());
+                            app.grid.set_cell_raw::<CellType>(loc, None);
                             app.mode = Mode::Normal;
                         }
                         "gg" => {