v1.1.0: highlight winning symbols on the slots board

6 files changed, 125 insertions, 20 deletions

diff --git a/src/bin/client/repl.rs b/src/bin/client/repl.rs
index 033fb1a..58cb541 100644
--- a/src/bin/client/repl.rs
+++ b/src/bin/client/repl.rs
@@ -240,8 +240,12 @@ impl ClientState {
             .map(|line| {
                 if line.starts_with("===") {
                     line.as_str().bold().cyan().to_string()
-                } else if line.contains("JACKPOT") || line.contains("Two of a kind") {
+                } else if line.contains('{') {
+                    style_winning_cells(line)
+                } else if line.contains("WIN!") || line.starts_with("Won ") {
                     line.as_str().bold().green().to_string()
+                } else if line.starts_with("Winning lines:") {
+                    line.as_str().yellow().to_string()
                 } else if line.starts_with("ERROR:") {
                     line.as_str().red().to_string()
                 } else {
@@ -436,6 +440,31 @@ impl ClientState {
     }
 }
 
+fn style_winning_cells(line: &str) -> String {
+    let chars: Vec<char> = line.chars().collect();
+    let mut out = String::new();
+    let mut index = 0;
+
+    while index < chars.len() {
+        if chars[index] == '{' {
+            let start = index;
+            while index < chars.len() && chars[index] != '}' {
+                index += 1;
+            }
+            if index < chars.len() {
+                index += 1;
+            }
+            let cell: String = chars[start..index].iter().collect();
+            out.push_str(&cell.as_str().bold().yellow().to_string());
+        } else {
+            out.push(chars[index]);
+            index += 1;
+        }
+    }
+
+    out
+}
+
 fn map_key(key: crossterm::event::KeyEvent) -> Option<Key> {
     if key.modifiers.contains(KeyModifiers::CONTROL) {
         match key.code {
diff --git a/src/client/games/manager.rs b/src/client/games/manager.rs
index 8436142..168c49d 100644
--- a/src/client/games/manager.rs
+++ b/src/client/games/manager.rs
@@ -76,6 +76,7 @@ impl GameManager {
         session.data.remove("reels");
         session.data.remove("win_type");
         session.data.remove("win_lines");
+        session.data.remove("win_cells");
         session.data.remove("winnings");
         Ok(())
     }
@@ -101,6 +102,15 @@ impl GameManager {
                 .collect::<Vec<_>>()
                 .join(","),
         );
+        session.data.insert(
+            "win_cells".to_string(),
+            result
+                .win_cells
+                .iter()
+                .map(usize::to_string)
+                .collect::<Vec<_>>()
+                .join(","),
+        );
         session
             .data
             .insert("winnings".to_string(), result.winnings.to_string());
@@ -118,6 +128,7 @@ impl GameManager {
         session.data.remove("reels");
         session.data.remove("win_type");
         session.data.remove("win_lines");
+        session.data.remove("win_cells");
         session.data.remove("winnings");
         session.data.insert("error".to_string(), message.into());
     }
diff --git a/src/client/games/response.rs b/src/client/games/response.rs
index de22a75..d7f9d45 100644
--- a/src/client/games/response.rs
+++ b/src/client/games/response.rs
@@ -7,6 +7,7 @@ pub struct SpinResult {
     pub reels: String,
     pub win_type: String,
     pub win_lines: Vec<usize>,
+    pub win_cells: Vec<usize>,
 }
 
 /// Parse one server reply to `PLAY_START`.
@@ -52,11 +53,11 @@ pub fn parse_spin_response(response: &str) -> Result<SpinResult, String> {
 
     let win_lines = parts
         .get(7)
-        .map(|raw| {
-            raw.split(',')
-                .filter_map(|value| value.trim().parse::<usize>().ok())
-                .collect()
-        })
+        .map(|raw| parse_indices(raw))
+        .unwrap_or_default();
+    let win_cells = parts
+        .get(8)
+        .map(|raw| parse_indices(raw))
         .unwrap_or_default();
 
     Ok(SpinResult {
@@ -67,5 +68,12 @@ pub fn parse_spin_response(response: &str) -> Result<SpinResult, String> {
         reels: parts[5].to_string(),
         win_type: parts[6].to_string(),
         win_lines,
+        win_cells,
     })
 }
+
+fn parse_indices(raw: &str) -> Vec<usize> {
+    raw.split(',')
+        .filter_map(|value| value.trim().parse::<usize>().ok())
+        .collect()
+}
diff --git a/src/client/games/slots.rs b/src/client/games/slots.rs
index 39c43b2..c367fcb 100644
--- a/src/client/games/slots.rs
+++ b/src/client/games/slots.rs
@@ -13,22 +13,40 @@ impl SlotsGame {
         Self
     }
 
-    fn cell(chars: &[char], row: usize, col: usize) -> char {
-        if chars.len() == REELS * ROWS {
+    fn cell(chars: &[char], row: usize, col: usize, winning: &[usize]) -> String {
+        let symbol = if chars.len() == REELS * ROWS {
             chars.get(col * ROWS + row).copied().unwrap_or('?')
         } else if chars.len() == 3 && row == 0 {
             // Legacy 3-symbol server: degrade to the first row.
             chars.get(col).copied().unwrap_or('?')
         } else {
             '?'
+        };
+
+        if winning.contains(&(col * ROWS + row)) {
+            format!("{{ {} }}", symbol)
+        } else {
+            format!("[ {} ]", symbol)
         }
     }
 
-    fn render_grid(&self, reels: &str) -> [String; ROWS] {
+    fn highlighted_cells(state: &GameState) -> Vec<usize> {
+        state
+            .data
+            .get("win_cells")
+            .map(|raw| {
+                raw.split(',')
+                    .filter_map(|value| value.trim().parse::<usize>().ok())
+                    .collect()
+            })
+            .unwrap_or_default()
+    }
+
+    fn render_grid(&self, reels: &str, winning: &[usize]) -> [String; ROWS] {
         let chars: Vec<char> = reels.chars().collect();
         std::array::from_fn(|row| {
             (0..REELS)
-                .map(|col| format!("[ {} ]", Self::cell(&chars, row, col)))
+                .map(|col| Self::cell(&chars, row, col, winning))
                 .collect::<Vec<_>>()
                 .join(" ")
         })
@@ -84,7 +102,8 @@ impl Game for SlotsGame {
             .get("balance")
             .map(String::as_str)
             .unwrap_or("?");
-        let grid = self.render_grid(&reels);
+        let winning = Self::highlighted_cells(state);
+        let grid = self.render_grid(&reels, &winning);
 
         format!(
             "=== SLOTS ===\r\nBet: {} PLN   Lines: {}   Balance: {} PLN\r\n{}\r\n{}\r\n{}\r\n\r\n{}\r\n{}\r\n[+/-] Bet   [SPACE] Spin   [Q] Quit",
diff --git a/src/server/core.rs b/src/server/core.rs
index 33cafbf..350fe18 100644
--- a/src/server/core.rs
+++ b/src/server/core.rs
@@ -254,6 +254,11 @@ impl ServerCore {
             .get("win_lines")
             .cloned()
             .unwrap_or_else(|| "-".to_string());
+        let win_cells = result
+            .result_data
+            .get("win_cells")
+            .cloned()
+            .unwrap_or_else(|| "-".to_string());
 
         match database::apply_spin(
             &mut self.conn,
@@ -268,7 +273,7 @@ impl ServerCore {
             Ok(new_balance) => {
                 let _ = self.sessions.remove_session(&session_id);
                 format!(
-                    "GAME_RESULT {session_id} {winnings} {bet_amount} {new_balance} {reels} {win_type} {win_lines}"
+                    "GAME_RESULT {session_id} {winnings} {bet_amount} {new_balance} {reels} {win_type} {win_lines} {win_cells}"
                 )
             }
             Err(error) => {
diff --git a/src/server/games/slots.rs b/src/server/games/slots.rs
index 2ef1b46..1d71c9d 100644
--- a/src/server/games/slots.rs
+++ b/src/server/games/slots.rs
@@ -22,6 +22,13 @@ struct Payout {
     five: u64,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct LineWin {
+    pub line: usize,
+    /// Column-major cell indices of the matched symbols.
+    pub cells: Vec<usize>,
+}
+
 pub struct SlotsGame {
     payouts: HashMap<char, Payout>,
     /// Deterministic grid for tests and demos, in column-major order.
@@ -65,10 +72,11 @@ impl SlotsGame {
             .collect()
     }
 
-    /// Evaluate one spin. Returns the total win and the 1-based winning lines.
-    pub fn calculate_payout(&self, grid: &[char], bet: u64) -> (u64, Vec<usize>) {
+    /// Evaluate one spin. Returns the total win and the winning lines with
+    /// the column-major cells that should be highlighted.
+    pub fn calculate_payout(&self, grid: &[char], bet: u64) -> (u64, Vec<LineWin>) {
         let mut total = 0u64;
-        let mut winning_lines = Vec::new();
+        let mut wins = Vec::new();
 
         for (index, pattern) in PAYLINES.iter().enumerate() {
             let Some(&first) = grid.get(pattern[0]) else {
@@ -99,10 +107,19 @@ impl SlotsGame {
             };
 
             total = total.saturating_add(bet.saturating_mul(multiplier));
-            winning_lines.push(index + 1);
+            let cells = pattern
+                .iter()
+                .enumerate()
+                .take(run)
+                .map(|(col, row)| col * ROWS + row)
+                .collect();
+            wins.push(LineWin {
+                line: index + 1,
+                cells,
+            });
         }
 
-        (total, winning_lines)
+        (total, wins)
     }
 
     /// Exact theoretical return to player for the current paytable.
@@ -213,12 +230,27 @@ impl Game for SlotsGame {
             )));
         }
 
-        let (winnings, winning_lines) = self.calculate_payout(&grid, state.bet_amount);
+        let (winnings, wins) = self.calculate_payout(&grid, state.bet_amount);
         let win_type = classify_win(winnings, state.bet_amount);
-        let win_lines = if winning_lines.is_empty() {
+        let win_lines = if wins.is_empty() {
+            "-".to_string()
+        } else {
+            wins.iter()
+                .map(|win| win.line.to_string())
+                .collect::<Vec<_>>()
+                .join(",")
+        };
+
+        let mut cells: Vec<usize> = wins
+            .iter()
+            .flat_map(|win| win.cells.iter().copied())
+            .collect();
+        cells.sort_unstable();
+        cells.dedup();
+        let win_cells = if cells.is_empty() {
             "-".to_string()
         } else {
-            winning_lines
+            cells
                 .iter()
                 .map(usize::to_string)
                 .collect::<Vec<_>>()
@@ -229,6 +261,7 @@ impl Game for SlotsGame {
         result_data.insert("reels".to_string(), reel_string.clone());
         result_data.insert("win_type".to_string(), win_type.to_string());
         result_data.insert("win_lines".to_string(), win_lines);
+        result_data.insert("win_cells".to_string(), win_cells);
 
         Ok(GameResult {
             session_id: state.session_id.clone(),