v1.2.0: show the symbol paytable on the slots board

9 files changed, 73 insertions, 35 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 7de7c4f..85c7e16 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "zagan-bet"
-version = "1.1.0"
+version = "1.2.0"
 edition = "2024"
 
 [dependencies]
diff --git a/docs/SLOTS.md b/docs/SLOTS.md
index a64bdbf..a2e778d 100644
--- a/docs/SLOTS.md
+++ b/docs/SLOTS.md
@@ -66,17 +66,19 @@ The board is nine lines:
 
 ```
 === SLOTS ===
-Bet: 10 PLN   Lines: 5   Balance: 1000 PLN
+Bet: 10 PLN   Balance: 1000 PLN
 [ C ] [ L ] [ O ] [ G ] [ D ]
 [ S ] { C } { C } [ O ] [ G ]
 [ D ] [ S ] { C } [ L ] [ O ]
-
+Pays 3/4/5 x bet: C 2/5/15 L 3/7/20 O 3/8/25 G 4/12/40 D 6/18/70 S 9/30/150
 Won 20 PLN
 Winning lines: 2
 [+/-] Bet   [SPACE] Spin   [Q] Quit
 ```
 
-Winning cells use braces and are rendered yellow/bold in the terminal. The
-line list below the status names the paylines that won. Both come from the
-server's `win_lines` and `win_cells`, which are already carried through the
-client state for the animation pass.
+The line above the status is the compact paytable: for each symbol, the
+multipliers of the total bet for 3, 4 and 5 of a kind. Winning cells use
+braces and are rendered yellow/bold in the terminal. The line list below the
+status names the paylines that won. Both come from the server's `win_lines`
+and `win_cells`, which are already carried through the client state for the
+animation pass.
diff --git a/docs/TESTING.md b/docs/TESTING.md
index 8e35c5a..7f54798 100644
--- a/docs/TESTING.md
+++ b/docs/TESTING.md
@@ -36,7 +36,8 @@ Use an 80-column terminal because several output lines are width-sensitive.
    prompt, Ctrl+C exits and restores the terminal.
 4. `help` fits 80 columns. Tab completion wraps within 76 columns and the
    cursor stays visible.
-5. `play slots 50` shows a 5x3 grid, `Lines: 5`, and the fetched balance.
+5. `play slots 50` shows a 5x3 grid, the `Pays 3/4/5 x bet:` paytable line, and
+   the fetched balance.
 6. Space shows `Spinning...`, then the 3 rows, win text, winning-line list, and
    new balance inside the same 9-line board. Winning symbols appear as
    yellow/bold `{ X }` cells; the `Winning lines:` list matches. The controls
diff --git a/src/client/games/slots.rs b/src/client/games/slots.rs
index c367fcb..7e59919 100644
--- a/src/client/games/slots.rs
+++ b/src/client/games/slots.rs
@@ -1,10 +1,8 @@
 use super::traits::{Game, GamePhase, GameState};
+use crate::slots::{paytable_line, REELS, ROWS};
 
 /// Height of the game board. It must never depend on the spin result.
 pub const SLOT_BOARD_LINES: usize = 9;
-pub const LINES: usize = 5;
-pub const REELS: usize = 5;
-pub const ROWS: usize = 3;
 
 pub struct SlotsGame;
 
@@ -106,13 +104,13 @@ impl Game for SlotsGame {
         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",
+            "=== SLOTS ===\r\nBet: {} PLN   Balance: {} PLN\r\n{}\r\n{}\r\n{}\r\n{}\r\n{}\r\n{}\r\n[+/-] Bet   [SPACE] Spin   [Q] Quit",
             state.bet_amount,
-            LINES,
             balance,
             grid[0],
             grid[1],
             grid[2],
+            paytable_line(),
             self.render_status(state),
             self.render_win_lines(state)
         )
diff --git a/src/lib.rs b/src/lib.rs
index e700173..a261ab0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,4 +8,5 @@
 pub mod client;
 pub mod protocol;
 pub mod server;
+pub mod slots;
 pub mod tofu;
diff --git a/src/server/games/slots.rs b/src/server/games/slots.rs
index 1d71c9d..e9f58b1 100644
--- a/src/server/games/slots.rs
+++ b/src/server/games/slots.rs
@@ -1,19 +1,9 @@
 use super::traits::{Game, GameError, GamePhase, GameResult, GameState};
+use crate::slots::PAYTABLE;
 use rand::Rng;
 use std::collections::HashMap;
 
-pub const REELS: usize = 5;
-pub const ROWS: usize = 3;
-pub const SYMBOLS: [char; 6] = ['C', 'L', 'O', 'G', 'D', 'S'];
-
-/// Five paylines, each entry is the row used on reel 0..4.
-pub const PAYLINES: [[usize; REELS]; 5] = [
-    [0, 0, 0, 0, 0], // line 1: top
-    [1, 1, 1, 1, 1], // line 2: middle
-    [2, 2, 2, 2, 2], // line 3: bottom
-    [0, 1, 2, 1, 0], // line 4: V
-    [2, 1, 0, 1, 2], // line 5: inverted V
-];
+pub use crate::slots::{PAYLINES, REELS, ROWS, SYMBOLS};
 
 #[derive(Clone, Copy)]
 struct Payout {
@@ -37,15 +27,12 @@ pub struct SlotsGame {
 
 impl SlotsGame {
     pub fn new() -> Self {
-        let mut payouts = HashMap::new();
-
-        // RTP = 425/432 = 0.9838 (1.62% house edge) with five paylines.
-        payouts.insert('C', Payout { three: 2, four: 5, five: 15 });
-        payouts.insert('L', Payout { three: 3, four: 7, five: 20 });
-        payouts.insert('O', Payout { three: 3, four: 8, five: 25 });
-        payouts.insert('G', Payout { three: 4, four: 12, five: 40 });
-        payouts.insert('D', Payout { three: 6, four: 18, five: 70 });
-        payouts.insert('S', Payout { three: 9, four: 30, five: 150 });
+        let payouts = PAYTABLE
+            .iter()
+            .map(|&(symbol, three, four, five)| {
+                (symbol, Payout { three, four, five })
+            })
+            .collect();
 
         Self {
             payouts,
diff --git a/src/slots.rs b/src/slots.rs
new file mode 100644
index 0000000..561c449
--- /dev/null
+++ b/src/slots.rs
@@ -0,0 +1,33 @@
+//! Shared slots rules used by both the server engine and the client board.
+
+pub const REELS: usize = 5;
+pub const ROWS: usize = 3;
+pub const SYMBOLS: [char; 6] = ['C', 'L', 'O', 'G', 'D', 'S'];
+
+/// Five paylines, each entry is the row used on reel 0..4.
+pub const PAYLINES: [[usize; REELS]; 5] = [
+    [0, 0, 0, 0, 0], // line 1: top
+    [1, 1, 1, 1, 1], // line 2: middle
+    [2, 2, 2, 2, 2], // line 3: bottom
+    [0, 1, 2, 1, 0], // line 4: V
+    [2, 1, 0, 1, 2], // line 5: inverted V
+];
+
+/// (symbol, 3-of-a-kind, 4-of-a-kind, 5-of-a-kind) multipliers of total bet.
+pub const PAYTABLE: [(char, u64, u64, u64); 6] = [
+    ('C', 2, 5, 15),
+    ('L', 3, 7, 20),
+    ('O', 3, 8, 25),
+    ('G', 4, 12, 40),
+    ('D', 6, 18, 70),
+    ('S', 9, 30, 150),
+];
+
+/// One-line paytable rendered under the reels.
+pub fn paytable_line() -> String {
+    let entries: Vec<String> = PAYTABLE
+        .iter()
+        .map(|(symbol, three, four, five)| format!("{symbol} {three}/{four}/{five}"))
+        .collect();
+    format!("Pays 3/4/5 x bet: {}", entries.join(" "))
+}
diff --git a/tests/client_core.rs b/tests/client_core.rs
index 91ddcab..ea99d52 100644
--- a/tests/client_core.rs
+++ b/tests/client_core.rs
@@ -134,7 +134,9 @@ fn play_shows_a_nine_line_board_and_fetches_the_balance() {
 
     assert_eq!(h.board().len(), 9);
     assert!(h.board()[1].contains("Bet: 50 PLN"));
-    assert!(h.board()[1].contains("Lines: 5"));
+    assert!(!h.board()[1].contains("Lines:"));
+    assert!(h.board()[5].contains("Pays 3/4/5 x bet:"));
+    assert!(h.board()[5].contains("S 9/30/150"));
     assert!(h.sent.contains(&"INFO".to_string()));
 
     h.reply("INFO alice 1 1000");
diff --git a/tests/slots.rs b/tests/slots.rs
index 857e607..b7292b8 100644
--- a/tests/slots.rs
+++ b/tests/slots.rs
@@ -1,5 +1,6 @@
 //! Regression tests for the server-side 5x3 slots game.
 
+use zagan_bet::slots::{paytable_line, PAYTABLE};
 use zagan_bet::server::games::slots::{LineWin, SlotsGame, PAYLINES, REELS, ROWS};
 use zagan_bet::server::games::traits::{Game, GamePhase};
 
@@ -107,6 +108,19 @@ fn theoretical_rtp_is_just_under_one() {
 }
 
 #[test]
+fn the_paytable_line_lists_every_symbol_and_fits_80_columns() {
+    let line = paytable_line();
+
+    for (symbol, three, four, five) in PAYTABLE {
+        assert!(
+            line.contains(&format!("{symbol} {three}/{four}/{five}")),
+            "paytable is missing {symbol}"
+        );
+    }
+    assert!(line.len() <= 80, "paytable is too wide: {line:?}");
+}
+
+#[test]
 fn an_enormous_bet_saturates_instead_of_overflowing() {
     let (winnings, _) = payout(["SSSSS", "SSSSS", "SSSSS"], u64::MAX);