Add scripted trainer battle foundation and native move AI

src/game/scripts/interpreter.ts

@@ -154,7 +154,12 @@ export type ScriptEffect =
       selected: number;
     }
   /** startbattle: answered with wBattleResult. */
-  | { kind: "battle"; wild: { species: number; level: number } }
+  | {
+      kind: "battle";
+      wild?: { species: number; level: number };
+      trainer?: { classId: number; id: number; winText?: number; lossText?: number };
+      canLose?: boolean;
+    }
   /** newloadmap: the world enters this map after the script ends. */
   | { kind: "warp"; map: string; x: number; y: number };
 
@@ -266,6 +271,10 @@ export class ScriptRun {
       value = 0,
       battleResult = 0,
       spawn = 0;
+    let wild = this.options.wild;
+    let trainer: { classId: number; id: number } | undefined;
+    let winText: number | undefined, lossText: number | undefined;
+    let canLose = false;
     // One array for the whole run: specials append to and clear it in place.
     const pages: string[] = [];
     const byte = () => r.byte(p++);
@@ -463,18 +472,49 @@ export class ScriptRun {
           p = SYMBOLS.fruitTreeScript;
           break;
         }
+        case 0x1e: {
+          // Only VAR_BATTLETYPE's normal and CANLOSE modes are translated.
+          const variable = byte(), setting = byte();
+          if (variable !== 3 || (setting !== 0 && setting !== 1))
+            throw new UnsupportedScript(offset, opcode, " (battle type or variable)");
+          canLose = setting === 1;
+          break;
+        }
         case 0x5b:
+          trainer = undefined;
+          wild = this.options.wild;
           break; // randomwildmon clears wBattleScriptFlags.
+        case 0x5d:
+          wild = { species: byte(), level: byte() };
+          trainer = undefined;
+          break;
+        case 0x5e:
+          trainer = { classId: byte(), id: byte() };
+          wild = undefined;
+          break;
+        case 0x64: {
+          // Null pointers request the battle engine's default end text.
+          const bank = r.bank(p), won = word(), lost = word();
+          winText = won ? r.address(bank, won) : undefined;
+          lossText = lost ? r.address(bank, lost) : undefined;
+          break;
+        }
         case 0x5f: {
-          if (!this.options.wild) throw new UnsupportedScript(offset, opcode, " (trainer battle)");
-          const result = yield synchronous({ kind: "battle", wild: this.options.wild });
+          if (!wild && !trainer) throw new UnsupportedScript(offset, opcode, " (no opponent)");
+          yield* flush();
+          const result = yield synchronous({
+            kind: "battle", wild,
+            trainer: trainer && { ...trainer, winText, lossText }, canLose,
+          });
           if (typeof result !== "number") throw new Error("Invalid battle result.");
           battleResult = result;
+          value = result & 0x3f; // Script_startbattle also updates wScriptVar.
           break;
         }
         case 0x60:
           // Script_reloadmapafterbattle: a loss continues with the whiteout.
           if ((battleResult & 0x3f) === 1) p = SYMBOLS.battleWhiteoutScript;
+          canLose = false;
           break;
         case 0x8a: {
           byte(); // newloadmap MAPSETUP_WARP

src/game/scripts/text.ts

@@ -71,6 +71,7 @@ const CHARACTERS: Record<number, string> = {
 export interface TextContext {
   player: string;
   rival: string;
+  trainer?: string;
   mom: string;
   /** Native strings stored at the RAM addresses named by text_ram. */
   strings: Readonly<Record<number, string>>;
@@ -126,6 +127,7 @@ function character(code: number, context: TextContext): string | undefined {
   if (code === 0x5a) return battler(context, context.battle?.turn === 1);
   if (code === 0x52 || code === 0x14) return context.player;
   if (code === 0x53) return context.rival;
+  if (code === 0x3f) return context.trainer;
   if (code === 0x49) return context.mom;
   if (code >= 0x80 && code <= 0x99)
     return String.fromCharCode(65 + code - 0x80);