Versus map size on the match page; the size sets the number of seats

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lobby.rs

@@ -673,6 +673,17 @@ fn teams_from(sides: &[u8], v: Option<&Value>) -> Vec<(u8, u8)> {
     sides.iter().copied().zip(teams).collect()
 }
 
+// versus map sizes and how many master seats each one has
+pub const MATCH_SIZES: [usize; 7] = [80, 96, 128, 160, 192, 224, 256];
+
+pub fn seats_for(size: usize) -> &'static [u8] {
+    match size {
+        0..=80 => &[0, 2],
+        81..=96 => &[0, 2, 3],
+        _ => &[0, 2, 3, 4],
+    }
+}
+
 fn seats_from(v: Option<&Value>) -> Vec<SeatInfo> {
     v.and_then(|x| x.as_array())
         .map(|arr| {

src/main.rs

@@ -358,7 +358,11 @@ fn account_action(a: MenuAction, cloud: &mut Cloud, menu: &mut Menu, app: &mut A
             }
         }
         MenuAction::MatchJoin(code) => app.client.join(&code),
-        MenuAction::MatchCreate => app.client.create_land(&[0, 2, 3, 4], app.settings.map_w, app.settings.map_h, app.settings.difficulty, app.settings.surface, app.settings.events),
+        MenuAction::MatchCreate => {
+            // the map size decides the number of master seats
+            let n = app.settings.match_size;
+            app.client.create_land(lobby::seats_for(n), n, n, app.settings.difficulty, app.settings.surface, app.settings.events)
+        }
         MenuAction::MatchCoopCreate(mission) => {
             let all = campaign::missions();
             if let Some(d) = all.get(mission) {

src/menu.rs

@@ -238,6 +238,7 @@ enum Btn {
     Tab(usize),
     Change(usize, i32),
     MapW(i32),
+    MatchSize(i32),
     Land,
     MapH(i32),
     Difficulty(i32),
@@ -437,6 +438,7 @@ pub struct Menu {
     pub error: Option<String>,   // message on the login and account pages
     pub match_ui: MatchUi,       // copied state of the multiplayer relay, shown on the Match page
     pub coop_mission: usize,     // co-op campaign mission selected on the Match page
+    match_size: usize,           // the versus map size (from the settings, for drawing)
     pub coop_editor: bool,       // the Match page offers a campaign document instead of the built-in missions
     pub coop_league: bool,       // ... and that document is the co-op campaign "League against the Lightwatch"
     league_doc: Option<CampaignDoc>, // the co-op campaign, built the first time it is chosen
@@ -497,6 +499,7 @@ impl Menu {
             error: None,
             match_ui: MatchUi::default(),
             coop_mission: crate::campaign::coop_mission_indexes().first().copied().unwrap_or(0),
+            match_size: 128,
             coop_editor: false,
             coop_league: false,
             league_doc: None,
@@ -682,6 +685,12 @@ impl Menu {
                 MenuAction::Consumed
             }
             Some(Btn::Start) => MenuAction::NewGame,
+            Some(Btn::MatchSize(d)) => {
+                let sizes = crate::lobby::MATCH_SIZES;
+                let k = sizes.iter().position(|&s| s >= settings.match_size).unwrap_or(2) as i32;
+                settings.match_size = sizes[(k + d).clamp(0, sizes.len() as i32 - 1) as usize];
+                MenuAction::SettingsChanged
+            }
             Some(Btn::MapW(d)) => {
                 settings.map_w = (settings.map_w as i32 + d * 32).clamp(MIN_SIZE as i32, MAX_SIZE as i32) as usize;
                 MenuAction::SettingsChanged
@@ -953,6 +962,7 @@ impl Menu {
         self.buttons.clear();
         self.lang_opts.clear();
         self.cur_lang = settings.language.clone();
+        self.match_size = settings.match_size;
         let Some(page) = self.page else {
             self.lang_open = None;
             return;
@@ -2053,6 +2063,19 @@ impl Menu {
                 }
             }
         }
+        // a new versus match: the map size and with it the number of seats
+        if !ui.started && !ui.room_open() {
+            let n = self.match_size;
+            let seats = crate::lobby::seats_for(n).len();
+            let r = Rect::new(ix, yy, 4.0 * CW(), CH() * 2.0);
+            button(gfx, r, "<", r.contains(vec2(mx, my)), FRAME);
+            self.buttons.push((r, Btn::MatchSize(-1)));
+            gfx.text(&trf("net.map_size", &[n.to_string(), n.to_string(), seats.to_string()]), ix + 5.0 * CW(), yy + CH() * 0.5, S(), TXT);
+            let r = Rect::new(ix + 30.0 * CW(), yy, 4.0 * CW(), CH() * 2.0);
+            button(gfx, r, ">", r.contains(vec2(mx, my)), FRAME);
+            self.buttons.push((r, Btn::MatchSize(1)));
+            yy += CH() * 2.4;
+        }
         self.field(gfx, ix, yy, w, &tr("net.join_hint"), 0, false);
         self.field(gfx, ix, yy + CH() * 2.4, w, &tr("net.chat"), 1, false);
         yy += CH() * 4.8;

src/settings.rs

@@ -163,6 +163,7 @@ pub struct Settings {
     pub hints: bool,
     pub difficulty: u8, // rival masters in free games: 0 easy, 1 medium, 2 hard
     pub map_w: usize, // size of new maps (64..256)
+    pub match_size: usize, // versus matches: the map is match_size x match_size (see lobby::seats_for)
     pub map_h: usize,
     pub surface: bool, // new free games: the eastern half lies above ground (forest)
     pub events: bool,  // random events in free games and versus matches
@@ -201,6 +202,7 @@ impl Default for Settings {
             hints: true,
             difficulty: 1,
             map_w: 64,
+            match_size: 128,
             map_h: 64,
             surface: false,
             events: true,