1 files changed, 17 insertions, 0 deletions

diff --git a/src/client/ui.rs b/src/client/ui.rs
index 9d65087..6161166 100644
--- a/src/client/ui.rs
+++ b/src/client/ui.rs
@@ -244,6 +244,23 @@ pub fn first_contact_lines(addr: &str, fingerprint: &str) -> Vec<String> {
 
 /// Format remembered hosts so a 64-character fingerprint does not wrap on an
 /// 80-column terminal.
+/// Smallest terminal every game fits in. Roulette's felt is 12 lines and the
+/// controls are ~72 columns, so anything smaller would wrap or hide the board.
+pub const MIN_COLUMNS: u16 = 80;
+pub const MIN_ROWS: u16 = 24;
+
+/// Refuse to start when the terminal cannot show every game.
+pub fn terminal_too_small(columns: u16, rows: u16) -> Option<String> {
+    if columns >= MIN_COLUMNS && rows >= MIN_ROWS {
+        return None;
+    }
+    Some(format!(
+        "zagan.bet needs a terminal of at least {MIN_COLUMNS}x{MIN_ROWS} cells, \
+         but this one is {columns}x{rows}.\n\
+         Resize it and start again."
+    ))
+}
+
 /// Render remembered hosts.
 ///
 /// Two addresses that present the same certificate key are the same server, so