Closes #919, closes #982, closes #1003, closes #1012, closes #1022, closes #1028, closes #1033

src/link/LinkBattle.lua

@@ -9,15 +9,16 @@
 -- cable pull.
 --
 -- Cable rules: no experience, no money, no items; either side may RUN
--- (a draw); a fainted mon is auto-replaced by the next healthy party
--- member (the original prompts; documented divergence).  Badge stat
--- boosts don't apply on either side (divergence: Gen 1 famously kept
--- them in link battles).
+-- (a draw); a fainted mon is replaced from the party menu and the chosen
+-- slot rides the wire, the way ChooseNextMon hands it to
+-- LinkBattleExchangeData.  Badge stat boosts don't apply on either side
+-- (divergence: Gen 1 famously kept them in link battles).
 
 local Fingerprint = require("src.link.Fingerprint")
 local Font = require("src.render.Font")
 local Handshake = require("src.link.Handshake")
 local Logger = require("src.core.Logger")
+local Party = require("src.pokemon.Party")
 local Protocol = require("src.link.Protocol")
 local Runtime = require("src.mods.Runtime")
 local TurnOrder = require("src.battle.TurnOrder")
@@ -257,7 +258,9 @@ function LinkBattle.new(game, net, opts)
   self.enemyParty = theirParty
   self.playerParty = myParty -- intro ball row uses the clamped copies
   self.opponentName = theirName
-  self.introText = Strings("%s wants\nto battle!", theirName)
+  -- _TrainerWantsToFightText (data/text/text_2.asm:1257): wIsInBattle == 2
+  -- takes PrintBeginningBattleText's .trainerBattle arm, link included
+  self.introText = Strings("%s wants\nto fight!", theirName)
   self.remoteHashes = {}
   self.localHashes = {}
   self.remoteParts = {}
@@ -327,6 +330,68 @@ function LinkBattle.new(game, net, opts)
     end)
   end
 
+  -- ChooseNextMon (engine/battle/core.asm:1086-1103): the replacement after
+  -- a faint is a free party-menu pick in a link battle too -- DisplayPartyMenu
+  -- runs first, a fainted pick or a cancel goes back to it
+  -- (.goBackToPartyMenu), and only the chosen slot rides
+  -- LinkBattleExchangeData.
+  local function chooseReplacement(s)
+    s.linkReplacement = nil
+    s:uiNext(function()
+      return s:buildScreen("PartyMenu", {
+        battle = s,
+        party = myParty,
+        forceSwitch = true,
+        onSwitch = function(mon)
+          if mon.hp > 0 then s.linkReplacement = mon end
+        end,
+      })
+    end)
+    s:actNext(function()
+      local mon = s.linkReplacement
+      s.linkReplacement = nil
+      if s.result then return end
+      if not mon then
+        chooseReplacement(s)
+        return
+      end
+      for i, m in ipairs(myParty) do
+        if m == mon then send({ type = "replace", index = i }) break end
+      end
+      sendOutPlayer(s, mon)
+    end)
+  end
+
+  -- ReplaceFaintedEnemyMon (core.asm:892-905) reads the peer's slot back out
+  -- of the exchange, and EnemySendOutFirstMon (core.asm:1315-1320) decodes it
+  -- as wSerialExchangeNybbleReceiveData - 4.  HandlePlayerMonFainted
+  -- (core.asm:989-996) always runs ChooseNextMon BEFORE that read, so on a
+  -- double faint both machines commit their own slot before they block on the
+  -- peer's; our queue can reach the enemy's handler first, so the wait
+  -- pre-empts itself with the local pick rather than deadlocking on a message
+  -- neither side is going to send.
+  local function awaitReplacement(s)
+    s:actNext(function()
+      if s.result then return end
+      if s.player.mon.hp <= 0 and not s.linkChoiceQueued
+         and Party.firstHealthy(myParty) then
+        s.linkChoiceQueued = true
+        chooseReplacement(s)
+        awaitReplacement(s)
+        return
+      end
+      local idx = s.remoteReplace
+      if not idx then
+        awaitReplacement(s)
+        return
+      end
+      s.remoteReplace = nil
+      local mon = theirParty[idx]
+      if not mon or mon.hp <= 0 then mon = Party.firstHealthy(theirParty) end
+      sendOutEnemy(s, mon)
+    end)
+  end
+
   -- decode a remote action message against the enemy battler
   local function decodeTheirAction(s, msg)
     return decodeWireAction(s, msg, s.enemy)
@@ -540,12 +605,17 @@ function LinkBattle.new(game, net, opts)
     submit(s, { type = "action", kind = "run" }, nil)
   end
 
-  -- fainted mons auto-replace with the next healthy teammate, in party
-  -- order, identically on both machines
+  -- linkChoiceQueued: awaitReplacement already pre-empted itself with this
+  -- side's ChooseNextMon and put the slot on the wire, so the handler the
+  -- faint queued has nothing left to do but drop the flag
   self.playerMonFainted = function(s)
+    if s.linkChoiceQueued then
+      s.linkChoiceQueued = nil
+      return
+    end
     for _, mon in ipairs(myParty) do
       if mon.hp > 0 then
-        s:act(function() sendOutPlayer(s, mon) end)
+        if not s.result then chooseReplacement(s) end
         return
       end
     end
@@ -558,7 +628,7 @@ function LinkBattle.new(game, net, opts)
   self.enemyMonFainted = function(s)
     for _, mon in ipairs(theirParty) do
       if mon.hp > 0 then
-        s:act(function() sendOutEnemy(s, mon) end)
+        if not s.result then awaitReplacement(s) end
         return
       end
     end
@@ -579,6 +649,9 @@ function LinkBattle.new(game, net, opts)
         s.remoteHashes[msg.turn or 0] = msg.value
         s.remoteParts[msg.turn or 0] = msg.parts
         checkHashes(s)
+      elseif msg.type == "replace" then
+        local idx = math.floor(tonumber(msg.index) or 1)
+        s.remoteReplace = math.max(1, math.min(#theirParty, idx))
       elseif msg.type == "bye" then
         -- only a draw if our own simulation hasn't already decided
         -- (the winner's bye can arrive while we're still animating)
@@ -770,6 +843,34 @@ function LinkBattle.newSpectator(game, net, opts)
     end)
   end
 
+  local function awaitHostReplacement(s)
+    s:actNext(function()
+      if s.result then return end
+      local idx = table.remove(s.hostReplace, 1)
+      if not idx then
+        awaitHostReplacement(s)
+        return
+      end
+      local mon = hostParty[idx]
+      if not mon or mon.hp <= 0 then mon = Party.firstHealthy(hostParty) end
+      sendOutHost(s, mon)
+    end)
+  end
+
+  local function awaitGuestReplacement(s)
+    s:actNext(function()
+      if s.result then return end
+      local idx = table.remove(s.guestReplace, 1)
+      if not idx then
+        awaitGuestReplacement(s)
+        return
+      end
+      local mon = guestParty[idx]
+      if not mon or mon.hp <= 0 then mon = Party.firstHealthy(guestParty) end
+      sendOutGuest(s, mon)
+    end)
+  end
+
   local function resolveSpecTurn(s, hostMsg, guestMsg)
     if hostMsg.kind == "run" or guestMsg.kind == "run" then
       endSpectate(s, "The match ended.")
@@ -840,7 +941,7 @@ function LinkBattle.newSpectator(game, net, opts)
   self.playerMonFainted = function(s)
     for _, mon in ipairs(hostParty) do
       if mon.hp > 0 then
-        s:act(function() sendOutHost(s, mon) end)
+        if not s.result then awaitHostReplacement(s) end
         return
       end
     end
@@ -852,7 +953,7 @@ function LinkBattle.newSpectator(game, net, opts)
   self.enemyMonFainted = function(s)
     for _, mon in ipairs(guestParty) do
       if mon.hp > 0 then
-        s:act(function() sendOutGuest(s, mon) end)
+        if not s.result then awaitGuestReplacement(s) end
         return
       end
     end
@@ -862,6 +963,7 @@ function LinkBattle.newSpectator(game, net, opts)
   end
 
   self.hostMsg, self.guestMsg = nil, nil
+  self.hostReplace, self.guestReplace = {}, {}
   local baseUpdate = self.update
   self.update = function(s, dt)
     net:update()
@@ -875,6 +977,13 @@ function LinkBattle.newSpectator(game, net, opts)
             s.hostMsg, s.guestMsg = nil, nil
             resolveSpecTurn(s, h, g)
           end
+        elseif inner.type == "replace" then
+          local idx = math.floor(tonumber(inner.index) or 1)
+          if msg.side == "host" then
+            table.insert(s.hostReplace, math.max(1, math.min(#hostParty, idx)))
+          else
+            table.insert(s.guestReplace, math.max(1, math.min(#guestParty, idx)))
+          end
         elseif inner.type == "bye" or inner.type == "forfeit" then
           if not s.result then endSpectate(s, "The match ended.") end
         end

src/link/LinkState.lua

@@ -19,6 +19,7 @@ LinkState.__index = LinkState
 LinkState.isOpaque = true
 
 local CURSOR = 0xED
+local CURSOR_HOLLOW = 0xEC
 local ANY = "ANY" -- sentinel: a leading nil array entry breaks ipairs under
                   -- LuaJIT even though # still reports the full size, so
                   -- the level picker cycles this string instead of nil,
@@ -114,6 +115,7 @@ end
 function LinkState:exitWith(message, reason)
   DiscordPresence.setJoinCode(nil)
   self.game.linkSession = nil -- back to the player's own GAME SPEED
+  if self.game.linkNet == self.net then self.game.linkNet = nil end
   Runtime.emit("link.ended", { reason = reason or (message and "error" or "bye") })
   if self.net then self.net:close() end
   self.game.stack:pop()
@@ -519,6 +521,9 @@ function LinkState:startMode(mode, isHost)
     })
     self.net:send(self.trade:opening())
     self.index = 1
+    self.theirIndex = 1
+    self.side = "mine"
+    self.pickChoice = nil
   else
     self.stage = "battleWait"
     -- the host deals the shared RNG seed for the lockstep simulation
@@ -536,7 +541,14 @@ end
 -- trade flow
 -- -------------------------------------------------------------------
 
+function LinkState:openStats(mon)
+  if not mon then return end
+  self.game.linkNet = self.net
+  Screens.push(self.game, "SummaryMenu", mon)
+end
+
 function LinkState:updateTrade(input)
+  if self.game.linkNet == self.net then self.game.linkNet = nil end
   for _, msg in ipairs(self.net:poll()) do
     local reply = self.trade:handle(msg)
     if reply then self.net:send(reply) end
@@ -591,10 +603,51 @@ function LinkState:updateTrade(input)
     return
   end
 
-  if t.stage == "picking" and input:wasPressed("up") then
-    self.index = math.max(1, self.index - 1)
+  -- pokered engine/link/cable_club.asm TradeCenter_SelectMon: A on one of
+  -- your own mons opens the "STATS     TRADE" row (.displayStatsTradeMenu)
+  -- and only TRADE commits the pick, while the enemy list carries its own
+  -- cursor whose A shows that mon's status pages (.displayEnemyMonStats).
+  -- The cart's enemy path sets hl but never wMonDataLocation, the way the
+  -- battle menu's STATS (engine/battle/core.asm) does, so LoadMonData_ reads
+  -- the player's party and it draws YOUR mon at that slot -- an omission,
+  -- not behaviour, so we show the peer's mon.
+  if t.stage == "picking" and self.pickChoice then
+    if input:wasPressed("left") then
+      self.pickChoice = 1
+    elseif input:wasPressed("right") then
+      self.pickChoice = 2
+    elseif input:wasPressed("b") then
+      self.pickChoice = nil -- .cancelPlayerMonChoice: back to the list, not
+                            -- out of the trade
+    elseif input:wasPressed("a") then
+      if self.pickChoice == 1 then
+        self.pickChoice = nil
+        self:openStats(self.game.save.party[self.index])
+      elseif t:canPick(self.index) then
+        self.pickChoice = nil
+        self.side = "mine"
+        self.net:send(t:pick(self.index))
+      end
+    end
+  elseif t.stage == "picking" and input:wasPressed("up") then
+    if self.side == "theirs" then
+      self.theirIndex = math.max(1, self.theirIndex - 1)
+    else
+      self.index = math.max(1, self.index - 1)
+    end
   elseif t.stage == "picking" and input:wasPressed("down") then
-    self.index = math.min(#self.game.save.party, self.index + 1)
+    if self.side == "theirs" then
+      self.theirIndex = math.min(#(t.theirParty or {}), self.theirIndex + 1)
+    else
+      self.index = math.min(#self.game.save.party, self.index + 1)
+    end
+  elseif t.stage == "picking" and input:wasPressed("right") then
+    if t.theirParty and #t.theirParty > 0 then
+      self.side = "theirs"
+      self.theirIndex = math.min(self.theirIndex, #t.theirParty)
+    end
+  elseif t.stage == "picking" and input:wasPressed("left") then
+    self.side = "mine"
   elseif self.confirmed == nil and input:wasPressed("b") then
     -- once confirm=true has been sent to the peer, backing out here
     -- would desync the two sides (the peer may already be committing
@@ -603,8 +656,10 @@ function LinkState:updateTrade(input)
     self.net:send({ type = "bye" })
     self:exitWith(Strings("The trade was\ncancelled."))
   elseif t.stage == "picking" and input:wasPressed("a") then
-    if t:canPick(self.index) then
-      self.net:send(t:pick(self.index))
+    if self.side == "theirs" then
+      self:openStats((t.theirParty or {})[self.theirIndex])
+    else
+      self.pickChoice = 1
     end
   elseif t.stage == "confirming" and self.confirmed == nil then
     if input:wasPressed("a") then
@@ -738,25 +793,40 @@ function LinkState:draw()
       local label = (mon.nickname or def.name):sub(1, 8)
       if not t:canPick(i) then label = label .. "X" end
       Font.draw(label, 16, 20 + i * 12)
-      if i == self.index then Font.drawCode(CURSOR, 8, 20 + i * 12) end
+      if i == self.index and self.side ~= "theirs" then
+        Font.drawCode(CURSOR, 8, 20 + i * 12)
+      end
     end
     Font.draw(Strings("THEIRS"), 84, 20)
     for i, mon in ipairs(t.theirParty or {}) do
       local def = self.game.data.pokemon[mon.species]
       Font.draw((mon.nickname or def.name):sub(1, 8), 92, 20 + i * 12)
-      if t.theirPick == i then Font.drawCode(CURSOR, 84, 20 + i * 12) end
+      if self.side == "theirs" and i == self.theirIndex then
+        Font.drawCode(CURSOR, 84, 20 + i * 12)
+      elseif t.theirPick == i then
+        Font.drawCode(CURSOR_HOLLOW, 84, 20 + i * 12)
+      end
     end
-    local hint
-    if t.stage == "waitRecords" then hint = "Comparing games..."
-    elseif t.stage == "waitParty" then hint = "Exchanging data..."
-    elseif t.stage == "picking" then
-      hint = t:canPick(self.index) and "Pick one to trade"
-             or Strings("X: not on theirs")
-    elseif t.stage == "waitPick" then hint = "Waiting for them..."
-    elseif t.stage == "confirming" then
-      hint = self.confirmed and "Waiting..." or Strings("A: trade  B: cancel")
+    if self.pickChoice then
+      Font.draw(Strings("STATS"), 16, 128)
+      Font.draw(Strings("TRADE"), 96, 128)
+      Font.drawCode(CURSOR, self.pickChoice == 1 and 8 or 88, 128)
+    else
+      local hint
+      if t.stage == "waitRecords" then hint = "Comparing games..."
+      elseif t.stage == "waitParty" then hint = "Exchanging data..."
+      elseif t.stage == "picking" then
+        if self.side == "theirs" then hint = Strings("A: stats")
+        else
+          hint = t:canPick(self.index) and "Pick one to trade"
+                 or Strings("X: not on theirs")
+        end
+      elseif t.stage == "waitPick" then hint = "Waiting for them..."
+      elseif t.stage == "confirming" then
+        hint = self.confirmed and "Waiting..." or Strings("A: trade  B: cancel")
+      end
+      Font.draw(hint or "", 8, 132)
     end
-    Font.draw(hint or "", 8, 132)
 
   elseif self.stage == "battleWait" or self.stage == "battleRunning" then
     drawTitle("LINK BATTLE")