Can have intelligent strike after first hit

sea_battle_backend/src/data/boats_layout.rs

@@ -97,6 +97,26 @@ impl Coordinates {
             && self.y < rules.map_height as i32
     }
 
+    pub fn add_x<E>(&self, x: E) -> Self
+    where
+        E: Into<i32>,
+    {
+        Self {
+            x: self.x + x.into(),
+            y: self.y,
+        }
+    }
+
+    pub fn add_y<E>(&self, y: E) -> Self
+    where
+        E: Into<i32>,
+    {
+        Self {
+            x: self.x,
+            y: self.y + y.into(),
+        }
+    }
+
     pub fn human_print(&self) -> String {
         format!(
             "{}:{}",
@@ -111,9 +131,9 @@ impl Coordinates {
 
 #[derive(serde::Serialize, serde::Deserialize, Debug, Clone, Copy, Eq, PartialEq)]
 pub struct BoatPosition {
-    start: Coordinates,
-    len: usize,
-    direction: BoatDirection,
+    pub start: Coordinates,
+    pub len: usize,
+    pub direction: BoatDirection,
 }
 
 impl BoatPosition {
@@ -147,7 +167,7 @@ impl BoatPosition {
     }
 }
 
-#[derive(serde::Serialize, serde::Deserialize, Debug, Clone)]
+#[derive(serde::Serialize, serde::Deserialize, Debug, Clone, Default)]
 pub struct BoatsLayout(Vec<BoatPosition>);
 
 impl BoatsLayout {

sea_battle_backend/src/data/current_game_status.rs

@@ -4,7 +4,7 @@ use crate::data::{
     BoatPosition, BoatsLayout, Coordinates, GameRules, MapCellContent, PrintableMap,
 };
 
-#[derive(Debug, serde::Serialize, serde::Deserialize, Clone)]
+#[derive(Debug, serde::Serialize, serde::Deserialize, Clone, Default)]
 pub struct CurrentGameMapStatus {
     pub boats: BoatsLayout,
     pub successful_strikes: Vec<Coordinates>,
@@ -51,7 +51,7 @@ impl PrintableMap for PrintableCurrentGameMapStatus {
     }
 }
 
-#[derive(Debug, serde::Serialize, serde::Deserialize, Clone)]
+#[derive(Debug, serde::Serialize, serde::Deserialize, Clone, Default)]
 pub struct CurrentGameStatus {
     pub rules: GameRules,
     pub your_map: CurrentGameMapStatus,
@@ -93,6 +93,107 @@ impl CurrentGameStatus {
         panic!("Could not find fire location!")
     }
 
+    pub fn get_sunk_locations(&self) -> Vec<Coordinates> {
+        self.opponent_map
+            .sunk_boats
+            .iter()
+            .map(|f| f.all_coordinates())
+            .reduce(|mut a, mut b| {
+                a.append(&mut b);
+                a
+            })
+            .unwrap_or_default()
+    }
+
+    pub fn get_successful_but_un_sunk_locations(&self) -> Vec<Coordinates> {
+        let sunk_location = self.get_sunk_locations();
+
+        self.opponent_map
+            .successful_strikes
+            .iter()
+            .filter(|c| !sunk_location.contains(c))
+            .map(Coordinates::clone)
+            .collect()
+    }
+
+    fn test_attack_direction(
+        &self,
+        pos: &[Coordinates],
+        mut point: Coordinates,
+        add_x: i32,
+        add_y: i32,
+    ) -> Option<Coordinates> {
+        while pos.contains(&point) {
+            point = point.add_x(add_x).add_y(add_y);
+        }
+        if self.can_fire_at_location(point) {
+            return Some(point);
+        }
+
+        None
+    }
+
+    fn horizontal_attack_attempt(
+        &self,
+        pos: &[Coordinates],
+        left: Coordinates,
+        right: Coordinates,
+    ) -> Option<Coordinates> {
+        // Try right
+        if let Some(point) = self.test_attack_direction(pos, right, 1, 0) {
+            return Some(point);
+        }
+
+        // Try left
+        if let Some(point) = self.test_attack_direction(pos, left, -1, 0) {
+            return Some(point);
+        }
+
+        None
+    }
+
+    /// Attempt to continue an attack, if possible
+    pub fn continue_attack_boat(&self) -> Option<Coordinates> {
+        let pos = self.get_successful_but_un_sunk_locations();
+        if pos.is_empty() {
+            return None;
+        }
+
+        let start = pos[0];
+
+        let up = start.add_y(-1);
+        let down = start.add_y(1);
+        let left = start.add_x(-1);
+        let right = start.add_x(1);
+
+        // Try to do it horizontally
+        if !pos.contains(&up) && !pos.contains(&down) {
+            if let Some(c) = self.horizontal_attack_attempt(&pos, left, right) {
+                return Some(c);
+            }
+        }
+
+        // Try to do it vertically
+
+        // Try up
+        if let Some(point) = self.test_attack_direction(&pos, up, 0, -1) {
+            return Some(point);
+        }
+
+        // Try down
+        if let Some(point) = self.test_attack_direction(&pos, down, 0, 1) {
+            return Some(point);
+        }
+
+        // Try to do it horizontally again, but unconditionally
+        if let Some(c) = self.horizontal_attack_attempt(&pos, left, right) {
+            return Some(c);
+        }
+
+        // We could even panic here
+        None
+    }
+
     pub fn print_your_map(&self) {
         PrintableCurrentGameMapStatus(self.rules.clone(), self.your_map.clone()).print_map()
     }
@@ -101,3 +202,94 @@ impl CurrentGameStatus {
         PrintableCurrentGameMapStatus(self.rules.clone(), self.opponent_map.clone()).print_map()
     }
 }
+
+#[cfg(test)]
+mod test {
+    use crate::data::*;
+
+    #[test]
+    fn get_successful_but_un_sunk_locations() {
+        let unfinished = Coordinates::new(0, 0);
+        let sunk = Coordinates::new(3, 3);
+
+        let mut status = CurrentGameStatus::default();
+        status.opponent_map.successful_strikes.push(sunk);
+        status.opponent_map.successful_strikes.push(unfinished);
+
+        status.opponent_map.sunk_boats.push(BoatPosition {
+            start: sunk,
+            len: 1,
+            direction: BoatDirection::Left,
+        });
+
+        assert_eq!(status.get_sunk_locations(), vec![sunk]);
+        assert_eq!(
+            status.get_successful_but_un_sunk_locations(),
+            vec![unfinished]
+        );
+    }
+
+    #[test]
+    fn no_continue_attack() {
+        let status = CurrentGameStatus::default();
+        assert!(status.get_successful_but_un_sunk_locations().is_empty());
+        let next_fire = status.continue_attack_boat();
+        assert!(next_fire.is_none());
+    }
+
+    #[test]
+    fn continue_attack_unknown_direction() {
+        let unfinished = Coordinates::new(2, 2);
+        let possible_next_strikes = vec![
+            unfinished.add_x(-1),
+            unfinished.add_x(1),
+            unfinished.add_y(-1),
+            unfinished.add_y(1),
+        ];
+
+        let mut status = CurrentGameStatus::default();
+        status.opponent_map.successful_strikes.push(unfinished);
+
+        let next_fire = status.continue_attack_boat();
+
+        assert!(next_fire.is_some());
+        assert!(possible_next_strikes.contains(&next_fire.unwrap()))
+    }
+
+    #[test]
+    fn continue_attack_vertically_only() {
+        let unfinished = Coordinates::new(2, 2);
+        let possible_next_strikes = vec![unfinished.add_x(-1), unfinished.add_x(2)];
+
+        let mut status = CurrentGameStatus::default();
+        status.opponent_map.successful_strikes.push(unfinished);
+        status
+            .opponent_map
+            .successful_strikes
+            .push(unfinished.add_x(1));
+
+        let next_fire = status.continue_attack_boat();
+
+        assert!(next_fire.is_some());
+        assert!(possible_next_strikes.contains(&next_fire.unwrap()))
+    }
+
+    #[test]
+    fn continue_attack_vertically_after_horizontal_fail() {
+        let unfinished = Coordinates::new(2, 2);
+        let possible_next_strikes = vec![unfinished.add_y(-1), unfinished.add_y(1)];
+
+        let mut status = CurrentGameStatus::default();
+        status.opponent_map.successful_strikes.push(unfinished);
+        status.opponent_map.failed_strikes.push(unfinished.add_x(1));
+        status
+            .opponent_map
+            .failed_strikes
+            .push(unfinished.add_x(-1));
+
+        let next_fire = status.continue_attack_boat();
+
+        assert!(next_fire.is_some());
+        assert!(possible_next_strikes.contains(&next_fire.unwrap()))
+    }
+}

sea_battle_backend/src/data/game_rules.rs

@@ -11,6 +11,12 @@ pub struct GameRules {
     pub bot_type: BotType,
 }
 
+impl Default for GameRules {
+    fn default() -> Self {
+        Self::random_players_rules()
+    }
+}
+
 impl GameRules {
     pub fn random_players_rules() -> Self {
         Self {