From d68e088500e5a4959f198c6d18d58b709257f505 Mon Sep 17 00:00:00 2001
From: Savanni D'Gerinel <savanni@luminescent-dreams.com>
Date: Wed, 3 May 2023 20:49:20 -0400
Subject: [PATCH] Implement the self-capture rule

---
 kifu/kifu-core/src/board.rs | 100 ++++++++----------------------------
 kifu/kifu-gtk/Makefile      |   2 +-
 2 files changed, 23 insertions(+), 79 deletions(-)

diff --git a/kifu/kifu-core/src/board.rs b/kifu/kifu-core/src/board.rs
index bd89291..4390c53 100644
--- a/kifu/kifu-core/src/board.rs
+++ b/kifu/kifu-core/src/board.rs
@@ -2,9 +2,10 @@ use crate::{Color, Size};
 use grid::Grid;
 use std::collections::HashSet;
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 pub enum Error {
     InvalidPosition,
+    SelfCapture,
 }
 
 #[derive(Clone, Debug)]
@@ -69,6 +70,8 @@ impl Board {
             return Err(Error::InvalidPosition);
         }
 
+        let old_groups = self.groups.clone();
+
         let mut friendly_group = self
             .adjacencies(&coordinate)
             .into_iter()
@@ -95,6 +98,11 @@ impl Board {
             }
         }
 
+        if self.liberties(&friendly_group) == 0 {
+            self.groups = old_groups;
+            return Err(Error::SelfCapture);
+        }
+
         Ok(())
     }
 
@@ -117,13 +125,11 @@ impl Board {
 
     pub fn adjacent_groups(&self, group: &Group) -> Vec<Group> {
         let adjacent_spaces = self.group_halo(group).into_iter();
-        println!("adjacent spaces: {:?}", adjacent_spaces);
         let mut grps: Vec<Group> = Vec::new();
 
         adjacent_spaces.for_each(|coord| match self.group(&coord) {
             None => return,
             Some(adj) => {
-                println!("group found: {:?}", adj.color);
                 if group.color == adj.color {
                     return;
                 }
@@ -151,32 +157,6 @@ impl Board {
             .into_iter()
             .filter(|c| self.stone(&c) == None)
             .count()
-
-        // let adjacencies: HashSet<Coordinate> = self.adjacencies(group.coordinates.iter()).collect();
-        /*
-        println!("adjacencies: {:?}", adjacencies);
-        let opposing_spaces = adjacencies
-            .iter()
-            .filter(|coord| match self.grid.get(coord.row, coord.column) {
-                None => true,
-                Some(&None) => false,
-                Some(&Some(c)) => c != group.color,
-            })
-            .cloned()
-            .collect::<HashSet<Coordinate>>();
-        println!("opposition: {:?}", opposing_spaces);
-
-        adjacencies.len() - opposing_spaces.len()
-        */
-
-        /*
-        group
-            .adjacencies(self.size.width as u8 - 1, self.size.height as u8 - 1)
-            .into_iter()
-            .filter(|coordinate| self.stone(*coordinate).is_none())
-            .collect::<Vec<Coordinate>>()
-            .len()
-            */
     }
 
     pub fn adjacencies(&self, coordinate: &Coordinate) -> Vec<Coordinate> {
@@ -204,41 +184,6 @@ impl Board {
         v.into_iter().filter(|c| self.within_board(c)).collect()
     }
 
-    /*
-    pub fn adjacencies<'a>(
-        &'a self,
-        coordinates: impl Iterator<Item = &'a Coordinate> + 'a,
-    ) -> impl Iterator<Item = Coordinate> + 'a {
-        coordinates
-            .map(|coordinate| {
-                let mut v = Vec::new();
-                if coordinate.column > 0 {
-                    v.push(Coordinate {
-                        column: coordinate.column - 1,
-                        row: coordinate.row,
-                    });
-                }
-                if coordinate.row > 0 {
-                    v.push(Coordinate {
-                        column: coordinate.column,
-                        row: coordinate.row - 1,
-                    });
-                }
-                v.push(Coordinate {
-                    column: coordinate.column + 1,
-                    row: coordinate.row,
-                });
-                v.push(Coordinate {
-                    column: coordinate.column,
-                    row: coordinate.row + 1,
-                });
-                v
-            })
-            .flatten()
-            .filter(|coordinate| self.within_board(coordinate))
-    }
-    */
-
     pub fn within_board(&self, coordinate: &Coordinate) -> bool {
         coordinate.column < self.size.width && coordinate.row < self.size.height
     }
@@ -256,18 +201,6 @@ impl Group {
     }
 }
 
-/*
-impl Group {
-    pub fn adjacencies(&self, max_column: usize, max_row: usize) -> HashSet<Coordinate> {
-        self.coordinates
-            .iter()
-            .map(|stone| stone.adjacencies(max_column, max_row))
-            .flatten()
-            .collect()
-    }
-}
-*/
-
 #[cfg(test)]
 mod test {
     use super::*;
@@ -329,6 +262,10 @@ mod test {
                 (Coordinate { column: 6, row: 16 }, Color::White),
                 (Coordinate { column: 7, row: 17 }, Color::White),
                 (Coordinate { column: 7, row: 18 }, Color::White),
+                /* */
+                (Coordinate { column: 17, row: 0 }, Color::White),
+                (Coordinate { column: 17, row: 1 }, Color::White),
+                (Coordinate { column: 18, row: 1 }, Color::White),
             ]
             .into_iter(),
         );
@@ -594,8 +531,15 @@ mod test {
         });
     }
 
-    fn suicide_is_forbidden() {
-        assert!(false);
+    #[test]
+    fn self_capture_is_forbidden() {
+        with_example_board(|mut board| {
+            let res = board.place_stone(Coordinate { column: 18, row: 0 }, Color::Black);
+            assert_eq!(res, Err(Error::SelfCapture));
+
+            let res = board.place_stone(Coordinate { column: 5, row: 18 }, Color::Black);
+            assert_eq!(res, Err(Error::SelfCapture));
+        });
     }
 
     fn captures_preceed_self_capture() {
diff --git a/kifu/kifu-gtk/Makefile b/kifu/kifu-gtk/Makefile
index 08b2bcb..2297add 100644
--- a/kifu/kifu-gtk/Makefile
+++ b/kifu/kifu-gtk/Makefile
@@ -2,4 +2,4 @@ release:
 	cargo build --release
 
 dev:
-	cargo watch -x run
+	cargo watch -x 'run --bin kifu-gtk'