Improve Tera Stellar handling (smogon#605)

Currently, Tera Stellar is shown in too many cases. When it's active, it is always shown, but this is misleading:

* When using a move other than tera blast, it only applies on the first time, otherwise it's identical to not being there at all
* It does nothing defensively, outside of giving a weakness to Stellar type attacks

Even in the case of Tera Blast, the first use has a different stab modifier, but both cases just display 'Tera Stellar' and 100 BP, which is incorrect --- the same description should ideally always yield the same numbers.

calc/src/desc.ts

@@ -23,6 +23,7 @@ export interface RawDesc {
   defenseEVs?: string;
   hits?: number;
   alliesFainted?: number;
+  isStellarFirstUse?: boolean;
   isBeadsOfRuin?: boolean;
   isSwordOfRuin?: boolean;
   isTabletsOfRuin?: boolean;
@@ -838,6 +839,11 @@ function buildDescription(description: RawDesc, attacker: Pokemon, defender: Pok
   if (description.attackerTera) {
     output += `Tera ${description.attackerTera} `;
   }
+
+  if (description.isStellarFirstUse) {
+    output += '(First Use) ';
+  }
+
   if (description.isBeadsOfRuin) {
     output += 'Beads of Ruin ';
   }

calc/src/mechanics/gen789.ts

@@ -99,14 +99,21 @@ export function calculateSMSSSV(
 
   const desc: RawDesc = {
     attackerName: attacker.name,
-    attackerTera: attacker.teraType,
     moveName: move.name,
     defenderName: defender.name,
-    defenderTera: defender.teraType,
     isDefenderDynamaxed: defender.isDynamaxed,
     isWonderRoom: field.isWonderRoom,
   };
 
+  // only display tera type if it applies
+  if (attacker.teraType !== 'Stellar' || move.name === 'Tera Blast' || move.isStellarFirstUse) {
+    // tera blast has special behavior with tera stellar
+    desc.isStellarFirstUse = attacker.name !== 'Terapagos-Stellar' && move.name === 'Tera Blast' &&
+      attacker.teraType === 'Stellar' && move.isStellarFirstUse;
+    desc.attackerTera = attacker.teraType;
+  }
+  if (defender.teraType !== 'Stellar') desc.defenderTera = defender.teraType;
+
   const result = new Result(gen, attacker, defender, move, field, 0, desc);
 
   if (move.category === 'Status' && !move.named('Nature Power')) {
@@ -360,6 +367,7 @@ export function calculateSMSSSV(
   }
 
   if (move.type === 'Stellar') {
+    desc.defenderTera = defender.teraType; // always show in this case
     typeEffectiveness = !defender.teraType ? 1 : 2;
   }
 

calc/src/test/calc.test.ts

@@ -1222,6 +1222,38 @@ describe('calc', () => {
           "0 Atk Weavile with an ally's Flower Gift Power Spot boosted switching boosted Pursuit (80 BP) vs. 0 HP / 0 Def Vulpix in Sun: 399-469 (183.8 - 216.1%) -- guaranteed OHKO"
         );
       });
+      describe('Tera Stellar', () => {
+        const terastal = Pokemon('Arceus', {teraType: 'Stellar'});
+        const control = Pokemon('Arceus');
+        test('should only be displayed on defender for Stellar attacks', () => {
+          expect(calculate(control, terastal, Move('Tera Blast'))
+            .rawDesc
+            .defenderTera).toBeUndefined();
+          expect(calculate(terastal, terastal, Move('Tera Blast'))
+            .rawDesc
+            .defenderTera).toBeDefined();
+          // make sure that it isn't caring about stellar first use
+          expect(calculate(terastal, terastal, Move('Tera Blast', {isStellarFirstUse: true}))
+            .rawDesc
+            .defenderTera).toBeDefined();
+          expect(calculate(control, terastal, Move('Tera Blast', {isStellarFirstUse: true}))
+            .rawDesc
+            .defenderTera).toBeUndefined();
+        });
+        test('should not be displayed for non-boosted attacks', () => expect(
+          calculate(terastal, control, Move('Judgment', {isStellarFirstUse: false}))
+            .rawDesc
+            .attackerTera
+        ).toBeUndefined());
+        test('should distinguish between first use for Tera Blast', () => {
+          // I don't exactly care what the difference is
+          const result = [true, false].map((isStellarFirstUse, ..._) =>
+            calculate(terastal, control, Move('Tera Blast', {isStellarFirstUse}))
+              .rawDesc
+              .isStellarFirstUse);
+          expect(result[0]).not.toEqual(result[1]);
+        });
+      });
     });
     describe('Descriptions', () => {
       inGen(9, ({gen, calculate, Pokemon, Move}) => {

src/js/shared_controls.js

@@ -1003,6 +1003,12 @@ function createPokemon(pokeInfo) {
 		var item = pokeInfo.find(".item").val();
 		var isDynamaxed = pokeInfo.find(".max").prop("checked");
 		var teraType = pokeInfo.find(".teraToggle").is(":checked") ? pokeInfo.find(".teraType").val() : undefined;
+		var opts = {
+			ability: ability,
+			item: item,
+			isDynamaxed: isDynamaxed,
+			teraType: teraType,
+		};
 		pokeInfo.isDynamaxed = isDynamaxed;
 		calcHP(pokeInfo);
 		var curHP = ~~pokeInfo.find(".current-hp").val();
@@ -1028,10 +1034,10 @@ function createPokemon(pokeInfo) {
 			status: CALC_STATUS[pokeInfo.find(".status").val()],
 			toxicCounter: status === 'Badly Poisoned' ? ~~pokeInfo.find(".toxic-counter").val() : 0,
 			moves: [
-				getMoveDetails(pokeInfo.find(".move1"), name, ability, item, isDynamaxed),
-				getMoveDetails(pokeInfo.find(".move2"), name, ability, item, isDynamaxed),
-				getMoveDetails(pokeInfo.find(".move3"), name, ability, item, isDynamaxed),
-				getMoveDetails(pokeInfo.find(".move4"), name, ability, item, isDynamaxed)
+				getMoveDetails(pokeInfo.find(".move1"), opts),
+				getMoveDetails(pokeInfo.find(".move2"), opts),
+				getMoveDetails(pokeInfo.find(".move3"), opts),
+				getMoveDetails(pokeInfo.find(".move4"), opts),
 			],
 			overrides: {
 				baseStats: baseStats,
@@ -1047,7 +1053,7 @@ function getGender(gender) {
 	return 'F';
 }
 
-function getMoveDetails(moveInfo, species, ability, item, useMax) {
+function getMoveDetails(moveInfo, opts) {
 	var moveName = moveInfo.find("select.move-selector").val();
 	var isZMove = gen > 6 && moveInfo.find("input.move-z").prop("checked");
 	var isCrit = moveInfo.find(".move-crit").prop("checked");
@@ -1059,11 +1065,22 @@ function getMoveDetails(moveInfo, species, ability, item, useMax) {
 		basePower: +moveInfo.find(".move-bp").val(),
 		type: moveInfo.find(".move-type").val()
 	};
+	if (moveName === 'Tera Blast') {
+		// custom logic for stellar type tera blast
+		var isStellar = opts.teraType === 'Stellar';
+		var statDrops = moveInfo.find('.stat-drops');
+		var dropsStats = statDrops.is(':visible');
+		if (isStellar !== dropsStats) {
+			// update stat drop dropdown here
+			if (isStellar) statDrops.show(); else statDrops.hide();
+		}
+		if (isStellar) overrides.self = {boosts: {atk: -1, spa: -1}};
+	}
 	if (gen >= 4) overrides.category = moveInfo.find(".move-cat").val();
 	return new calc.Move(gen, moveName, {
-		ability: ability, item: item, useZ: isZMove, species: species, isCrit: isCrit, hits: hits,
+		ability: opts.ability, item: opts.item, useZ: isZMove, species: opts.species, isCrit: isCrit, hits: hits,
 		isStellarFirstUse: isStellarFirstUse, timesUsed: timesUsed, timesUsedWithMetronome: timesUsedWithMetronome,
-		overrides: overrides, useMax: useMax
+		overrides: overrides, useMax: opts.useMax
 	});
 }