CLOSES #1091, CLOSES #1097, CLOSES #1100, CLOSES #1104, CLOSES #1135, CLOSES #1155, CLOSES #1157, CLOSES #1158, CLOSES #1159, CLOSES #1160, CLOSES #1167, CLOSES #1208

src/ui/gen2/BattleState.lua

@@ -106,6 +106,10 @@ local TEXT_ASK_FORGET_SLOT = Strings.source("Which move should\nbe forgotten?")
 local TEXT_CANT_FORGET_HM = Strings.source("HM moves can't be\nforgotten now.")
 local TEXT_STOP_LEARNING = Strings.source("Stop learning\n%s?")
 
+-- BattleText_EnemyIsAboutToUseWillPlayerChangeMon (data/text/battle.asm:222-231).
+local TEXT_ENEMY_ABOUT_TO_USE = Strings.source(
+  "%s\nis about to use\v%s.\fWill %s\nchange POKéMON?")
+
 -- _AskForgetMoveText, all three paragraphs (data/text/common_3.asm:141-165).
 local TEXT_ASK_FORGET_MOVE = Strings.source(
   "%s is\ntrying to learn\v%s.\fBut %s\ncan't learn more\vthan four moves."
@@ -548,6 +552,14 @@ BattleState.PLAYER_PIC_TILES = 6
 -- box's own bottom centre.
 local PIC_RESIZE_TILES = { [0] = 6, [1] = 4, [2] = 2, [3] = 7, [4] = 5, [5] = 3 }
 
+-- SUBSTATUS_UNDERGROUND / SUBSTATUS_FLYING, which BattleCommand_Charge sets on
+-- FLY and DIG only (engine/battle/effect_commands.asm:5478-5485); the port
+-- carries both as the volatile `vanished` flag.
+function BattleState.isVanished(mon)
+  local volatiles = mon and mon.volatile
+  return (volatiles and volatiles.vanished) and true or false
+end
+
 function BattleState:drawPic(mon, back)
   -- During the intro slide the player-side pic belongs to presentSlide's
   -- backpic overlay, not to the baked bands (see BattleAnimView).
@@ -571,6 +583,13 @@ function BattleState:drawPic(mon, back)
   -- The box is empty either because the animation running right now has
   -- cleared it, or because the last one ENDED with it cleared (picHidden).
   if (anim and anim.hidden) or self.picHidden[side] then return end
+  -- Mid FLY / DIG the box is empty: DisappearUser ClearBoxes it
+  -- (engine/battle/misc.asm:1-13), AppearUserRaiseSub puts it back on the
+  -- stored attack (engine/battle/effect_commands.asm:2113-2117).
+  if not (trainerBack or enemyTrainer) and BattleState.isVanished(mon)
+     and not (self.vanishAnim and self.vanishAnim == self.anim) then
+    return
+  end
   local G = love.graphics
   local w, h = image:getDimensions()
   local px, py
@@ -582,10 +601,12 @@ function BattleState:drawPic(mon, back)
     py = BattleState.PLAYER_PIC_TILE_Y * 8 + (box - h)
     boxTiles = BattleState.PLAYER_PIC_TILES
   else
-    -- Bottom-aligned and horizontally centred inside the 7x7 box.
+    -- PadFrontpic pads a short pic and never a long one
+    -- (engine/gfx/load_pics.asm:342-386), so an oversized mod pic pins to the
+    -- box's own corner at hlcoord 12, 0 rather than to a negative offset.
     local box = BattleState.ENEMY_PIC_TILES * 8
-    px = BattleState.ENEMY_PIC_TILE_X * 8 + math.floor((box - w) / 2)
-    py = BattleState.ENEMY_PIC_TILE_Y * 8 + (box - h)
+    px = BattleState.ENEMY_PIC_TILE_X * 8 + math.max(0, math.floor((box - w) / 2))
+    py = BattleState.ENEMY_PIC_TILE_Y * 8 + math.max(0, box - h)
     boxTiles = BattleState.ENEMY_PIC_TILES
   end
   -- One tile per two frames to the right, SlideBattlePicOut's own step.
@@ -903,11 +924,12 @@ function BattleState:startAnim(key, opts)
     param = opts.param or 0,
     sfxOrder = audio.sfxOrder,
     ballPalette = opts.ballPalette,
+    -- BGEffect_CheckFlyDigStatus reads wPlayerSubStatus3 / wEnemySubStatus3
+    -- (engine/battle_anims/bg_effects.asm:2838-2851); the port keeps that bit
+    -- on the mon's volatile table, not on the mon itself.
     flying = {
-      player = self.battle and self.battle.player
-        and self.battle.player.vanished or false,
-      enemy = self.battle and self.battle.enemy
-        and self.battle.enemy.vanished or false,
+      player = BattleState.isVanished(self.battle and self.battle.player),
+      enemy = BattleState.isVanished(self.battle and self.battle.enemy),
     },
     hooks = {
       -- anim_sound (engine/battle_anims/anim_commands.asm:1105) calls
@@ -1365,6 +1387,13 @@ function BattleState:advanceQueue()
         end
       end
     end
+    -- BattleCommand_Charge runs LoadMoveAnim BEFORE DisappearUser
+    -- (engine/battle/effect_commands.asm:5459-5470), so FLY / DIG still draw
+    -- the take-off or the burrow on the turn the substatus goes up; the box
+    -- only empties once THIS animation is done with.
+    if BattleState.isVanished(self:activeMon(event.side)) then
+      self.vanishAnim = self.anim
+    end
   elseif event.kind == "damage" and event.side then
     -- ANIM_x_DAMAGE is the MOVE's after-anim (effect_commands.asm:1963-1972),
     -- so only a move hit gets it; `animMove` is HandleWrap's (core.asm:1198-1203).
@@ -1864,6 +1893,20 @@ function BattleState:update(_dt)
     return
   end
 
+  -- The prompt's earlier pages: PlaceYesNoBox only follows the LAST one
+  -- (engine/battle/core.asm:3302-3305), so the mon is named and read first.
+  if self.phase == "shift-intro" then
+    if self.messageTimer > 0 then
+      if input:wasPressed("a") or input:wasPressed("b") then
+        self.messageTimer = 0
+      end
+      return
+    end
+    self:nextPage()
+    if not self.messagePages then self.phase = "ask-shift" end
+    return
+  end
+
   -- OfferSwitch's YesNoBox: YES opens PickSwitchMonInBattle, NO (and B) falls
   -- straight through to the enemy's send-out (engine/battle/core.asm:3305-3310).
   if self.phase == "ask-shift" then
@@ -2464,13 +2507,13 @@ end
 -- (engine/battle/core.asm:3298-3304, data/text/battle.asm:222-231).
 function BattleState:offerShiftSwitch(mon)
   self.shiftIndex = 1
-  self.phase = "ask-shift"
   local trainer = (self.battle.trainer and self.battle.trainer.name) or "Foe"
   local player = (self.save and self.save.player and self.save.player.name)
     or "GOLD"
-  self.message = trainer .. " is about to use " .. self:name(mon)
-    .. ". Will " .. player .. " change POKéMON?"
-  self.messageTimer = MESSAGE_FRAMES
+  -- The `para` splits this in two (data/text/battle.asm:222-231): the incoming
+  -- mon is NAMED on its own page, and only the second carries the yes/no box.
+  self:showPages(Strings(TEXT_ENEMY_ABOUT_TO_USE, trainer, self:name(mon), player))
+  self.phase = self.messagePages and "shift-intro" or "ask-shift"
 end
 
 function BattleState:answerUseNextMon(yes)