Save system: ceremonial PR (#42)

prototype for writing a save

Merge branch 'main' into savesystem

violently read player from file

oops, missed revisions in StateManager

create StateManager from file

autoformat the world

oops, forgot to save the split-up of save.ts

Save on end-of-day, or after endgame.

Putting it here avoids a circular reference problem

Merge branch 'main' into savesystem

Integrate save system

Deal with save corruption correctly

Co-authored-by: Kistaro Windrider <kistaro@gmail.com>
Reviewed-on: #42
Co-authored-by: Nyeogmi <economicsbat@gmail.com>
Co-committed-by: Nyeogmi <economicsbat@gmail.com>

src/main.ts

@@ -2,5 +2,5 @@ import { hostGame } from "./engine/internal/host.ts";
 import { game } from "./game.ts";
 import { getStateManager } from "./statemanager.ts";
 
-getStateManager().startFirstGame();
+getStateManager().startOrLoadFirstGame();
 hostGame(game);

src/playerprogress.ts

@@ -1,6 +1,12 @@
 import { ALL_STATS, Skill, Stat, SuccessorOption, Wish } from "./datatypes.ts";
 import { getSkills } from "./skills.ts";
 import { getThralls, ItemStage, LifeStage, Thrall } from "./thralls.ts";
+import { SaveFileV1, mustBeSaveFileV1 } from "./saveformat.ts";
+
+interface NewRoundConfig {
+  asSuccessor: SuccessorOption;
+  withWish: Wish | null;
+}
 
 export class PlayerProgress {
   #name: string;
@@ -20,25 +26,65 @@ export class PlayerProgress {
   #thrallsObtainedItem: number[];
   #thrallsDeliveredItem: number[];
 
-  constructor(asSuccessor: SuccessorOption, withWish: Wish | null) {
-    this.#name = asSuccessor.name;
-    this.#thrallTemplate = asSuccessor.template.id;
-    this.#nImprovements = asSuccessor.nImprovements;
-    this.#stats = { ...asSuccessor.stats };
-    this.#talents = { ...asSuccessor.talents };
-    this.#isInPenance = asSuccessor.inPenance;
-    this.#wish = withWish;
-    this.#exp = 0;
-    this.#blood = 0;
-    this.#itemsPurloined = 0;
-    this.#skillsLearned = [];
-    this.#untrimmedSkillsAvailable = [];
-    this.#thrallsUnlocked = [];
-    this.#thrallDamage = {};
-    this.#thrallsObtainedItem = [];
-    this.#thrallsDeliveredItem = [];
+  constructor(args: NewRoundConfig | SaveFileV1) {
+    if ("asSuccessor" in args) {
+      //asSuccessor: SuccessorOption, withWish: Wish | null) {
+      const config = args as NewRoundConfig;
+      const asSuccessor = config.asSuccessor;
+      this.#name = asSuccessor.name;
+      this.#thrallTemplate = asSuccessor.template.id;
+      this.#nImprovements = asSuccessor.nImprovements;
+      this.#stats = { ...asSuccessor.stats };
+      this.#talents = { ...asSuccessor.talents };
+      this.#isInPenance = asSuccessor.inPenance;
+      this.#wish = config.withWish;
+      this.#exp = 0;
+      this.#blood = 0;
+      this.#itemsPurloined = 0;
+      this.#skillsLearned = [];
+      this.#untrimmedSkillsAvailable = [];
+      this.#thrallsUnlocked = [];
+      this.#thrallDamage = {};
+      this.#thrallsObtainedItem = [];
+      this.#thrallsDeliveredItem = [];
 
-    this.refill();
+      this.refill();
+    } else {
+      const file = mustBeSaveFileV1(args);
+      this.#name = file.name;
+      this.#thrallTemplate = file.thrallTemplateId;
+      this.#nImprovements = file.nImprovements;
+      this.#stats = {
+        AGI: file.stats.agi,
+        INT: file.stats.int,
+        CHA: file.stats.cha,
+        PSI: file.stats.psi,
+      };
+      this.#talents = {
+        AGI: file.talents.agi,
+        INT: file.talents.int,
+        CHA: file.talents.cha,
+        PSI: file.talents.psi,
+      };
+      (this.#isInPenance = file.isInPenance),
+        (this.#wish = file.wishId >= 0 ? { id: file.wishId } : null);
+      this.#exp = file.exp;
+      this.#blood = file.blood;
+      this.#itemsPurloined = file.itemsPurloined;
+      this.#skillsLearned = file.skillsLearned;
+      this.#untrimmedSkillsAvailable = file.untrimmedSkillsAvailableIds.map(
+        (id) => {
+          return { id: id };
+        },
+      );
+      this.#thrallsUnlocked = file.thrallsUnlocked;
+      this.#thrallDamage = {};
+      for (let i = 0; i < file.thrallDamage.length; ++i) {
+        this.#thrallDamage[i] = file.thrallDamage[i];
+      }
+      this.#thrallsObtainedItem = file.thrallsObtainedItem;
+      this.#thrallsDeliveredItem = file.thrallsDeliveredItem;
+    }
   }
 
   applyEndOfTurn() {
@@ -206,7 +252,11 @@ export class PlayerProgress {
     return skillsAvailable.slice(0, 6);
   }
 
-  getLearnedSkills() {
+  getUntrimmedAvailableSkillIds(): number[] {
+    return this.#untrimmedSkillsAvailable.map((s) => s.id);
+  }
+
+  getLearnedSkills(): Skill[] {
     let learnedSkills = [];
     for (let s of this.#skillsLearned.values()) {
       learnedSkills.push({ id: s });
@@ -214,6 +264,10 @@ export class PlayerProgress {
     return learnedSkills;
   }
 
+  getRawLearnedSkills(): number[] {
+    return [...this.#skillsLearned];
+  }
+
   getStats() {
     return { ...this.#stats };
   }
@@ -233,6 +287,10 @@ export class PlayerProgress {
     return this.#thrallsUnlocked.indexOf(thrall.id) != -1;
   }
 
+  getUnlockedThrallIds(): number[] {
+    return [...this.#thrallsUnlocked];
+  }
+
   damageThrall(thrall: Thrall, amount: number) {
     if (amount <= 0.0) {
       throw new Error(`damage must be some positive amount, not ${amount}`);
@@ -246,6 +304,10 @@ export class PlayerProgress {
       (this.#thrallDamage[thrall.id] ?? 0.0) + amount;
   }
 
+  getThrallDamage(thrall: Thrall): number {
+    return this.#thrallDamage[thrall.id] ?? 0.0;
+  }
+
   getThrallLifeStage(thrall: Thrall): LifeStage {
     let damage = this.#thrallDamage[thrall.id] ?? 0;
     if (damage < 0.5) {
@@ -270,6 +332,10 @@ export class PlayerProgress {
     this.#thrallsObtainedItem.push(thrall.id);
   }
 
+  getThrallObtainedItemIds(): number[] {
+    return [...this.#thrallsObtainedItem];
+  }
+
   deliverThrallItem(thrall: Thrall) {
     if (this.#thrallsDeliveredItem.indexOf(thrall.id) != -1) {
       return;
@@ -277,6 +343,10 @@ export class PlayerProgress {
     this.#thrallsDeliveredItem.push(thrall.id);
   }
 
+  getThrallDeliveredItemIds(): number[] {
+    return [...this.#thrallsDeliveredItem];
+  }
+
   getThrallItemStage(thrall: Thrall): ItemStage {
     if (this.#thrallsDeliveredItem.indexOf(thrall.id) != -1) {
       return ItemStage.Delivered;
@@ -308,7 +378,11 @@ export function initPlayerProgress(
   asSuccessor: SuccessorOption,
   withWish: Wish | null,
 ) {
-  active = new PlayerProgress(asSuccessor, withWish);
+  active = new PlayerProgress({ asSuccessor: asSuccessor, withWish: withWish });
+}
+
+export function rehydratePlayerProgress(savefile: SaveFileV1) {
+  active = new PlayerProgress(savefile);
 }
 
 export function getPlayerProgress(): PlayerProgress {

src/save.ts

@@ -0,0 +1,147 @@
+import { getPlayerProgress } from "./playerprogress";
+import { getStateManager } from "./statemanager";
+import { getThralls } from "./thralls";
+import { SaveFileV1, mustBeSaveFileV1 } from "./saveformat";
+import { getHuntMode } from "./huntmode.ts";
+
+export interface SaveFile {
+  version: string;
+  revision: number;
+}
+
+type SaveSlot = "FLEDGLING_SLOT_1" | "FLEDGLING_SLOT_2";
+
+/// The result of attempting to load a V1 save file.
+interface SaveFileV1LoadResult {
+  // If present and valid, the loaded file.
+  file: SaveFileV1 | null;
+
+  /// A file loading error, if any. If `file` is present, this refers
+  /// to an error reading from the *other* slot.
+  error: string | null;
+
+  /// The slot this file was loaded from, or that a load attempt failed from.
+  /// If multiple load attempts failed and none succeeded, this refers to
+  /// any one attempted slot.
+  slot: SaveSlot;
+}
+
+function readFromSlot(slot: SaveSlot): SaveFileV1LoadResult {
+  var serialized = localStorage.getItem(slot);
+  if (serialized === null) {
+    return {
+      file: null,
+      error: null,
+      slot: slot,
+    };
+  }
+  try {
+    return {
+      file: mustBeSaveFileV1(JSON.parse(serialized)),
+      error: null,
+      slot: slot,
+    };
+  } catch (e) {
+    let message = "unidentifiable error";
+    if (e instanceof Error) {
+      message = e.message;
+    }
+    return {
+      file: null,
+      error: message,
+      slot: slot,
+    };
+  }
+}
+
+/// Reads the more recent valid save file, if either is valid. If no save files
+/// are present, `file` and `error` will both be absent. If an invalid save
+/// file is discovered, `error` will refer to the issue(s) detected.
+export function readBestSave(): SaveFileV1LoadResult {
+  const from1 = readFromSlot("FLEDGLING_SLOT_1");
+  const from2 = readFromSlot("FLEDGLING_SLOT_2");
+  if (from1.file && from2.file) {
+    return from1.file.revision > from2.file.revision ? from1 : from2;
+  }
+
+  var errors: string[] = [];
+  if (from1.error) {
+    errors = ["slot 1 error: " + from1.error];
+  }
+  if (from2.error) {
+    errors.push("slot 2 error: " + from2.error);
+  }
+  var msg: string | null = errors.length > 0 ? errors.join("\n") : null;
+  if (from1.file) {
+    return {
+      file: from1.file,
+      error: msg,
+      slot: "FLEDGLING_SLOT_1",
+    };
+  }
+  return {
+    file: from2.file,
+    error: msg,
+    slot: "FLEDGLING_SLOT_2",
+  };
+}
+
+export function saveGame() {
+  const targetSlot: SaveSlot =
+    readBestSave().slot === "FLEDGLING_SLOT_1"
+      ? "FLEDGLING_SLOT_2"
+      : "FLEDGLING_SLOT_1";
+  return saveIntoSlot(targetSlot);
+}
+
+function extractCurrentState(): SaveFileV1 {
+  const progress = getPlayerProgress();
+  const stateManager = getStateManager();
+  const huntMode = getHuntMode();
+  var thrallDamage: number[] = [];
+  const nThralls = getThralls().length;
+  for (let i = 0; i < nThralls; ++i) {
+    thrallDamage.push(progress.getThrallDamage({ id: i }));
+  }
+  return {
+    version: "fledgling_save_v1",
+    revision: stateManager.nextRevision(),
+    turn: stateManager.getTurn(),
+    name: progress.name,
+    thrallTemplateId: progress.template.id,
+    nImprovements: progress.nImprovements,
+    stats: {
+      agi: progress.getStat("AGI"),
+      int: progress.getStat("INT"),
+      cha: progress.getStat("CHA"),
+      psi: progress.getStat("PSI"),
+    },
+    talents: {
+      agi: progress.getTalent("AGI"),
+      int: progress.getTalent("INT"),
+      cha: progress.getTalent("CHA"),
+      psi: progress.getTalent("PSI"),
+    },
+    isInPenance: progress.isInPenance,
+    wishId: progress.getWish()?.id ?? -1,
+    exp: progress.getExperience(),
+    blood: progress.getBlood(),
+    itemsPurloined: progress.getItemsPurloined(),
+    skillsLearned: progress.getRawLearnedSkills(),
+    untrimmedSkillsAvailableIds: progress.getUntrimmedAvailableSkillIds(),
+    thrallsUnlocked: progress.getUnlockedThrallIds(),
+    thrallDamage: thrallDamage,
+    thrallsObtainedItem: progress.getThrallObtainedItemIds(),
+    thrallsDeliveredItem: progress.getThrallDeliveredItemIds(),
+    depth: huntMode.getDepth(),
+  };
+}
+
+function saveIntoSlot(slot: SaveSlot) {
+  localStorage.setItem(slot, JSON.stringify(extractCurrentState()));
+}
+
+export function wipeSaves() {
+  localStorage.removeItem("FLEDGLING_SLOT_1");
+  localStorage.removeItem("FLEDGLING_SLOT_2");
+}

src/saveformat.ts

@@ -0,0 +1,185 @@
+export interface StatCounterV1 {
+  agi: number;
+  int: number;
+  cha: number;
+  psi: number;
+}
+
+export interface SaveFileV1 {
+  version: "fledgling_save_v1";
+  revision: number;
+
+  turn: number;
+
+  name: string;
+  thrallTemplateId: number;
+  nImprovements: number;
+  stats: StatCounterV1;
+  talents: StatCounterV1;
+  isInPenance: boolean;
+  wishId: number; // negative: Wish is absent
+  exp: number;
+  blood: number;
+  itemsPurloined: number;
+  skillsLearned: number[];
+  untrimmedSkillsAvailableIds: number[];
+  thrallsUnlocked: number[];
+  thrallDamage: number[]; // 0: thrall is absent or undamaged
+  thrallsObtainedItem: number[];
+  thrallsDeliveredItem: number[];
+  depth: number;
+}
+
+/// Checks whether obj is a valid save file, as far as we can tell, and returns
+/// it unchanged if it is, or throws an error if it's not valid.
+export function mustBeSaveFileV1(obj: unknown): SaveFileV1 {
+  if (obj === undefined || obj === null) {
+    throw new Error("nonexistent");
+  }
+  if (typeof obj !== "object") {
+    throw new Error(`not an object; was ${typeof obj}`);
+  }
+
+  if (!("version" in obj)) {
+    throw new Error("no magic number");
+  }
+  if (obj.version !== "fledgling_save_v1") {
+    throw new Error(`bad magic number: ${obj.version}`);
+  }
+
+  return {
+    version: "fledgling_save_v1",
+    revision: mustGetNumber(obj, "revision"),
+    turn: mustGetNumber(obj, "turn"),
+    name: mustGetString(obj, "name"),
+    thrallTemplateId: mustGetNumber(obj, "thrallTemplateId"),
+    nImprovements: mustGetNumber(obj, "nImprovements"),
+    stats: mustGetStatCounterV1(obj, "stats"),
+    talents: mustGetStatCounterV1(obj, "talents"),
+    isInPenance: mustGetBoolean(obj, "isInPenance"),
+    wishId: mustGetNumber(obj, "wishId"),
+    exp: mustGetNumber(obj, "exp"),
+    blood: mustGetNumber(obj, "blood"),
+    itemsPurloined: mustGetNumber(obj, "itemsPurloined"),
+    skillsLearned: mustGetNumberArray(obj, "skillsLearned"),
+    untrimmedSkillsAvailableIds: mustGetNumberArray(
+      obj,
+      "untrimmedSkillsAvailableIds",
+    ),
+    thrallsUnlocked: mustGetNumberArray(obj, "thrallsUnlocked"),
+    thrallDamage: mustGetNumberArray(obj, "thrallDamage"),
+    thrallsObtainedItem: mustGetNumberArray(obj, "thrallsObtainedItem"),
+    thrallsDeliveredItem: mustGetNumberArray(obj, "thrallsDeliveredItem"),
+    depth: mustGetNumber(obj, "depth"),
+  };
+}
+
+function mustGetNumber(obj: object, key: string): number {
+  if (obj === null || obj === undefined) {
+    throw new Error("container absent");
+  }
+  if (typeof obj !== "object") {
+    throw new Error(`container was not an object; was ${typeof obj}`);
+  }
+  if (!(key in obj)) {
+    throw new Error(`missing number: ${key}`);
+  }
+  const dict = obj as { [key: string]: any };
+  const val = dict[key];
+  if (typeof val !== "number") {
+    throw new Error(`not a number: ${key}: ${val}`);
+  }
+  return val;
+}
+
+function mustGetString(obj: object, key: string): string {
+  if (obj === null || obj === undefined) {
+    throw new Error("container absent");
+  }
+  if (typeof obj !== "object") {
+    throw new Error(`container was not an object; was ${typeof obj}`);
+  }
+  if (!(key in obj)) {
+    throw new Error(`missing number: ${key}`);
+  }
+  const dict = obj as { [key: string]: any };
+  const val = dict[key];
+  if (typeof val !== "string") {
+    throw new Error(`not a string: ${key}: ${val}`);
+  }
+  return val;
+}
+
+function mustGetStatCounterV1(obj: object, key: string): StatCounterV1 {
+  if (obj === null || obj === undefined) {
+    throw new Error("container absent");
+  }
+  if (typeof obj !== "object") {
+    throw new Error(`container was not an object; was ${typeof obj}`);
+  }
+  if (!(key in obj)) {
+    throw new Error(`missing number: ${key}`);
+  }
+  const dict = obj as { [key: string]: any };
+  const val = dict[key];
+  if (typeof val !== "object") {
+    throw new Error(`not an object: ${key}: ${val}`);
+  }
+
+  try {
+    return {
+      agi: mustGetNumber(val, "agi"),
+      int: mustGetNumber(val, "int"),
+      cha: mustGetNumber(val, "cha"),
+      psi: mustGetNumber(val, "psi"),
+    };
+  } catch (e) {
+    let message = "unrecognizable error";
+    if (e instanceof Error) {
+      message = e.message;
+    }
+    throw new Error(`reading ${key}: ${message}`);
+  }
+}
+
+function mustGetBoolean(obj: object, key: string): boolean {
+  if (obj === null || obj === undefined) {
+    throw new Error("container absent");
+  }
+  if (typeof obj !== "object") {
+    throw new Error(`container was not an object; was ${typeof obj}`);
+  }
+  if (!(key in obj)) {
+    throw new Error(`missing number: ${key}`);
+  }
+  const dict = obj as { [key: string]: any };
+  const val = dict[key];
+  if (typeof val !== "boolean") {
+    throw new Error(`not boolean: ${key}: ${val}`);
+  }
+  return val;
+}
+
+function mustGetNumberArray(obj: object, key: string): number[] {
+  if (obj === null || obj === undefined) {
+    throw new Error("container absent");
+  }
+  if (typeof obj !== "object") {
+    throw new Error(`container was not an object; was ${typeof obj}`);
+  }
+  if (!(key in obj)) {
+    throw new Error(`missing number: ${key}`);
+  }
+  const dict = obj as { [key: string]: any };
+  const val = dict[key];
+  if (typeof val !== "object") {
+    throw new Error(`not an object: ${key}: ${val}`);
+  }
+
+  for (const x of val) {
+    if (typeof x !== "number") {
+      throw new Error(`contained non-number item in ${key}: ${val}`);
+    }
+  }
+  return val;
+}

src/statemanager.ts

@@ -1,4 +1,8 @@
-import { getPlayerProgress, initPlayerProgress } from "./playerprogress.ts";
+import {
+  getPlayerProgress,
+  initPlayerProgress,
+  rehydratePlayerProgress,
+} from "./playerprogress.ts";
 import { getHuntMode, HuntMode, initHuntMode } from "./huntmode.ts";
 import { getVNModal } from "./vnmodal.ts";
 import { getScorer } from "./scorer.ts";
@@ -10,20 +14,46 @@ import { openingScene } from "./openingscene.ts";
 import { generateName } from "./namegen.ts";
 import { photogenicThralls } from "./thralls.ts";
 import { choose } from "./utils.ts";
+import { SaveFileV1 } from "./saveformat.ts";
+import { readBestSave, saveGame } from "./save.ts";
 
 const N_TURNS: number = 9;
 
 export class StateManager {
   #turn: number;
+  #revision: number;
 
-  constructor() {
-    this.#turn = 1;
+  constructor(file?: SaveFileV1) {
+    this.#turn = file?.turn ?? 1;
+    this.#revision = file?.revision ?? 1;
   }
 
   getTurn(): number {
     return this.#turn;
   }
 
+  nextRevision(): number {
+    this.#revision++;
+    return this.#revision;
+  }
+
+  startOrLoadFirstGame() {
+    let save = readBestSave();
+    if (save.file != null || save.error != null) {
+      const file = save.file;
+      const error = save.error;
+      getVNModal().play([
+        {
+          type: "saveGameScreen",
+          file: file,
+          error: error,
+        },
+      ]);
+      return;
+    }
+
+    this.startFirstGame();
+  }
   startFirstGame() {
     getVNModal().play([
       ...openingScene,
@@ -57,7 +87,17 @@ export class StateManager {
     sndSleep.play({ bgm: true });
   }
 
+  resumeGame(saveFile: SaveFileV1) {
+    // hack: prepare depth which advance() uses
+    this.#turn = saveFile.turn;
+    this.#revision = saveFile.revision;
+    rehydratePlayerProgress(saveFile);
+    initHuntMode(new HuntMode(saveFile.depth, generateManor()));
+    this.advance();
+  }
+
   advance() {
+    saveGame();
     if (this.#turn + 1 <= N_TURNS) {
       this.#turn += 1;
       getPlayerProgress().applyEndOfTurn();

src/thralls.ts

@@ -52,6 +52,10 @@ class ThrallsTable {
     }
     return thralls;
   }
+
+  get length(): number {
+    return this.#thralls.length;
+  }
 }
 export type ThrallData = {
   label: string;

src/vnmodal.ts

@@ -1,8 +1,13 @@
 import { D, I } from "./engine/public.ts";
-import { AlignX, AlignY, Point } from "./engine/datatypes.ts";
+import { AlignX, AlignY, Point, Rect, Size } from "./engine/datatypes.ts";
 import { withCamera } from "./layout.ts";
 import { VNScene, VNSceneMessage, VNScenePart } from "./vnscene.ts";
 import { C } from "./colors.ts";
+import { DrawPile } from "./drawpile.ts";
+import { wipeSaves } from "./save.ts";
+import { SaveFileV1 } from "./saveformat.ts";
+import { addButton } from "./button.ts";
+import { getStateManager } from "./statemanager.ts";
 
 const WIDTH = 384;
 const HEIGHT = 384;
@@ -90,6 +95,8 @@ function createCathexis(part: VNScenePart): SceneCathexis {
     case "callback":
       part?.callback();
       return new SkipCathexis();
+    case "saveGameScreen":
+      return new SaveGameCathexis(part.file, part.error);
   }
 }
 
@@ -112,7 +119,6 @@ class SceneMessageCathexis {
     let firstFrame = !this.#gotOneFrame;
     this.#gotOneFrame = true;
 
-    // TODO: SFX
     if (!firstFrame && I.isMouseClicked("leftMouse")) {
       this.#done = true;
     }
@@ -152,3 +158,88 @@ class SkipCathexis {
     throw new Error("shouldn't ever be drawn");
   }
 }
+
+class SaveGameCathexis {
+  #drawpile: DrawPile;
+  #file: SaveFileV1 | null;
+  #error: string | null;
+  #done: boolean;
+
+  constructor(file: SaveFileV1 | null, error: string | null) {
+    this.#drawpile = new DrawPile();
+    this.#file = file;
+    this.#error = error;
+    this.#done = false;
+  }
+
+  isDone() {
+    return this.#done;
+  }
+
+  update() {
+    let name = this.#file?.name;
+    let turn = this.#file?.turn ?? 0;
+    let turnText = turn < 9 ? `${name}, Turn ${turn + 1}` : "Sentence of Fate";
+    this.#drawpile.clear();
+    this.#drawpile.add(0, () => {
+      D.drawText(
+        this.#error && this.#file
+          ? `A save was invalid. Continue from an alternate save?
+
+${this.#error}`
+          : this.#error
+            ? `Your save was invalid:
+
+${this.#error}`
+          : "Resume from save?",
+        new Point(WIDTH / 2, HEIGHT / 2),
+        C.FG_BOLD,
+        {
+          alignX: AlignX.Center,
+          alignY: AlignY.Middle,
+          forceWidth: WIDTH,
+        },
+      );
+    });
+
+    addButton(
+      this.#drawpile,
+      "Clear Save",
+      new Rect(new Point(0, HEIGHT - 32), new Size(128, 32)),
+      this.#file != null,
+      () => {
+        wipeSaves();
+        this.#file = null;
+      },
+    );
+    if (this.#file) {
+      let file = this.#file;
+      addButton(
+        this.#drawpile,
+        `Continue (${turnText})`,
+        new Rect(new Point(128, HEIGHT - 32), new Size(WIDTH - 128, 32)),
+        true,
+        () => {
+          getStateManager().resumeGame(file);
+          this.#done = true;
+        },
+      );
+    } else {
+      addButton(
+        this.#drawpile,
+        `Start New Game`,
+        new Rect(new Point(128, HEIGHT - 32), new Size(WIDTH - 128, 32)),
+        true,
+        () => {
+          getStateManager().startFirstGame();
+          this.#done = true;
+        },
+      );
+    }
+    this.#drawpile.executeOnClick();
+  }
+
+  draw() {
+    this.#drawpile.draw();
+  }
+}

src/vnscene.ts

@@ -1,4 +1,5 @@
 import { Sound } from "./sound.ts";
+import { SaveFileV1 } from "./saveformat.ts";
 
 export type VNSceneMessage = {
   type: "message";
@@ -11,9 +12,18 @@ export type VNSceneCallback = {
   callback: () => void;
 };
 
+export type VNSceneSaveGameScreen = {
+  type: "saveGameScreen";
+  file: SaveFileV1 | null;
+  error: string | null;
+};
+
 export type VNSceneBasisPart = string | VNSceneMessage | VNSceneCallback;
 export type VNSceneBasis = VNSceneBasisPart[];
-export type VNScenePart = VNSceneMessage | VNSceneCallback;
+export type VNScenePart =
+  | VNSceneMessage
+  | VNSceneCallback
+  | VNSceneSaveGameScreen;
 export type VNScene = VNScenePart[];
 
 export function compile(basis: VNSceneBasis): VNScene {