From 640a61fe4853cc871252e682d7486b6558a995c6 Mon Sep 17 00:00:00 2001
From: szymon <szymon_jozef@proton.me>
Date: Wed, 12 Aug 2026 18:45:44 +0200
Subject: [PATCH] chore: add DeltaPosition

---
 nix/shell.nix      |  2 ++
 src/logic/board.rs |  6 +---
 src/logic/mod.rs   |  1 +
 src/logic/utils.rs | 75 +++++++++++++++++++++++++++++++++++-----------
 4 files changed, 62 insertions(+), 22 deletions(-)

diff --git a/nix/shell.nix b/nix/shell.nix
index 2b1722f..cb5683e 100644
--- a/nix/shell.nix
+++ b/nix/shell.nix
@@ -5,6 +5,8 @@
         rustfmt
       ];
 
+      RUST_LOG = "debug";
+
       inputsFrom = [
         (config.packages.default)
       ];
diff --git a/src/logic/board.rs b/src/logic/board.rs
index f667185..fd44e2e 100644
--- a/src/logic/board.rs
+++ b/src/logic/board.rs
@@ -1,8 +1,4 @@
-use crate::logic::{
-    pawn::{self, Pawn, PawnState},
-    player::Player,
-    utils::{Field, Position},
-};
+use crate::logic::{field::Field, pawn::Pawn, player::Player, utils::Position};
 use std::ops::{Index, IndexMut};
 
 use log::{debug, info, warn};
diff --git a/src/logic/mod.rs b/src/logic/mod.rs
index 2fe4b6d..81d0c3b 100644
--- a/src/logic/mod.rs
+++ b/src/logic/mod.rs
@@ -1,4 +1,5 @@
 mod board;
+mod field;
 mod pawn;
 mod player;
 mod utils;
diff --git a/src/logic/utils.rs b/src/logic/utils.rs
index 69490ed..590d4a2 100644
--- a/src/logic/utils.rs
+++ b/src/logic/utils.rs
@@ -1,6 +1,6 @@
 use core::fmt;
 
-use crate::logic::pawn::Pawn;
+use log::debug;
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub struct Position {
@@ -14,22 +14,63 @@ impl fmt::Display for Position {
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
-pub struct Field {
-    pub position: Position,
-    pub pawn: Option<Pawn>,
-}
+impl Position {
+    pub fn checked_add(&self, delta: &DeltaPosition) -> Option<Position> {
+        let new_row = self.row.checked_add_signed(delta.row as isize)?;
+        let new_column = self.column.checked_add_signed(delta.column as isize)?;
+        debug!("Adding row: {} + {} = {}", self.row, delta.row, new_row);
+        debug!(
+            "Adding column: {} + {} = {}",
+            self.column, delta.column, new_column
+        );
 
-impl fmt::Display for Field {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        if let Some(pawn) = &self.pawn {
-            write!(
-                f,
-                "Field at pos: {}. Pawn here owned by: {}",
-                self.position, pawn.owner
-            )
-        } else {
-            write!(f, "Field at pos: {}. No pawn here.", self.position)
-        }
+        Some(Position {
+            row: new_row,
+            column: new_column,
+        })
+    }
+}
+
+/// Vector for moving `Position`
+pub struct DeltaPosition {
+    pub row: i8,
+    pub column: i8,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn init_logger() {
+        let _ = env_logger::builder().is_test(true).try_init();
+    }
+
+    #[test]
+    fn test_adding_positions() {
+        init_logger();
+
+        let pos1: Position = Position { row: 1, column: 1 };
+        let delta_ok: DeltaPosition = DeltaPosition { row: 1, column: 1 };
+
+        let result1: Option<Position> = pos1.checked_add(&delta_ok);
+        assert!(result1.is_some());
+        assert_eq!(result1.unwrap(), Position { row: 2, column: 2 });
+
+        let delta_minus_ok: DeltaPosition = DeltaPosition {
+            row: -1,
+            column: -1,
+        };
+
+        let result1: Option<Position> = pos1.checked_add(&delta_minus_ok);
+        assert!(result1.is_some());
+        assert_eq!(result1.unwrap(), Position { row: 0, column: 0 });
+
+        let delta_not_ok: DeltaPosition = DeltaPosition {
+            row: -10,
+            column: -10,
+        };
+
+        let result3: Option<Position> = pos1.checked_add(&delta_not_ok);
+        assert!(result3.is_none());
     }
 }