Save import: add Gen 1 and Gen 2

savedex.js now sniffs the file and parses whichever generation it is:

- Gen 1 (R/B/Y): 32 KB SRAM, fixed offsets — owned 0x25A3, seen 0x25B6
  (151 species), name 0x2598, one-byte complement checksum.
- Gen 2 (G/S/C): tries Gold/Silver offsets (0x2A4C/0x2A6C, checksum
  0x2D69) and Crystal (0x2A27/0x2A47, checksum 0x2D0D); the 16-bit
  checksum picks which, with a caught⊆seen / no-overflow sanity fallback.
- Gen 3: unchanged (parseGen3Dex kept as an alias).

parseSaveDex(buffer) is the new entry point; the Settings picker relabels
to "Import from a game save". Verified against synthetic Gen 1 / GS /
Crystal saves and end-to-end through the UI (a Gen 1 save merged
11 caught / 84 seen).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017Ve7HLspzeG2xDPtJQ8vmu

README.md

@@ -19,7 +19,12 @@ framework.
 - **Sprites** → cache-first with a capped LRU.
 
 Export / import of all local state (settings, tracking, team, form
-tracking, shiny hunts) as JSON lives in **Settings**.
+tracking, shiny hunts) as JSON lives in **Settings**, which also imports
+the Pokédex straight out of a **game save file** (`.sav` / `.srm`):
+Gen 1 (R/B/Y), Gen 2 (G/S/C) and Gen 3 (R/S/E, FR/LG). It reads the
+game's own seen/owned bitfields — checksum-picking Gold/Silver vs
+Crystal, resolving Gen 3's newer slot and rotated sections — and merges
+them in without removing anything.
 
 ## Scripts
 

src/components/GameSheet.js

@@ -7,6 +7,7 @@ import {
 } from '../data/pokedex-resolver.js';
 import { settings } from '../store/settings.js';
 import { gameColors } from '../data/game-colors.js';
+import { dragToClose } from '../lib/sheet-drag.js';
 
 let openInstance = null;
 
@@ -134,20 +135,18 @@ export async function openGameSheet() {
     }
   }
 
-  panel.append(
+  const head = el(
+    'div',
+    { class: 'gsheet__head' },
+    el('h2', {}, 'Choose your game'),
     el(
-      'div',
-      { class: 'gsheet__head' },
-      el('h2', {}, 'Choose your game'),
-      el(
-        'button',
-        { class: 'gsheet__close', type: 'button', 'aria-label': 'Close', onclick: close },
-        '✕',
-      ),
+      'button',
+      { class: 'gsheet__close', type: 'button', 'aria-label': 'Close', onclick: close },
+      '✕',
     ),
-    subdex,
-    list,
   );
+  dragToClose(panel, head, close);
+  panel.append(head, subdex, list);
   backdrop.append(panel);
   document.body.append(backdrop);
   document.addEventListener('keydown', onKey);

src/components/PokemonPicker.js

@@ -3,6 +3,7 @@ import { loadSnapshot } from '../data/snapshot.js';
 import { settings } from '../store/settings.js';
 import { Sprite } from './Sprite.js';
 import { TypeChip } from './TypeChip.js';
+import { dragToClose } from '../lib/sheet-drag.js';
 
 let openInstance = null;
 
@@ -83,16 +84,14 @@ export async function openPokemonPicker(onPick, { closeAfterPick = false } = {})
     }
   }
 
-  panel.append(
-    el(
-      'div',
-      { class: 'gsheet__head' },
-      el('h2', {}, 'Add a Pokémon'),
-      el('button', { class: 'gsheet__close', type: 'button', 'aria-label': 'Close', onclick: close }, '✕'),
-    ),
-    input,
-    results,
+  const head = el(
+    'div',
+    { class: 'gsheet__head' },
+    el('h2', {}, 'Add a Pokémon'),
+    el('button', { class: 'gsheet__close', type: 'button', 'aria-label': 'Close', onclick: close }, '✕'),
   );
+  dragToClose(panel, head, close);
+  panel.append(head, input, results);
   backdrop.append(panel);
   document.body.append(backdrop);
   document.addEventListener('keydown', onKey);

src/lib/anim.js

@@ -30,19 +30,28 @@ export function countUp(node, to, { from = 0, duration = 550, decimals = 0, pref
  * reduced-motion users just get an instant jump.
  */
 export function segThumb(seg, _count, active = 0) {
+  seg.classList.add('seg--thumbed');
   const thumb = document.createElement('div');
   thumb.className = 'seg__thumb';
   seg.prepend(thumb);
   let current = active;
-  const place = (i) => {
+  const place = (i, tries = 0) => {
     current = i;
     const b = seg.querySelectorAll('.seg__btn')[i];
-    if (!b || !b.offsetWidth) return;
-    thumb.style.width = `${b.offsetWidth}px`;
-    thumb.style.transform = `translateX(${b.offsetLeft - 3}px)`;
+    if (b && b.offsetWidth) {
+      thumb.style.width = `${b.offsetWidth}px`;
+      thumb.style.transform = `translateX(${b.offsetLeft - 3}px)`;
+    } else if (tries < 20) {
+      // Not laid out yet (hidden tab, webfont pending) — try again.
+      requestAnimationFrame(() => place(i, tries + 1));
+    }
   };
   requestAnimationFrame(() => place(active));
   if (document.fonts?.ready) document.fonts.ready.then(() => place(current));
+  if (typeof ResizeObserver !== 'undefined') {
+    const ro = new ResizeObserver(() => place(current));
+    ro.observe(seg);
+  }
   return place;
 }
 

src/lib/savedex.js

@@ -0,0 +1,233 @@
+/**
+ * Read the Pokédex (seen / owned) out of a Game Boy / GBA save file —
+ * Generations I, II and III, as dumped by emulators (`.sav`) or RetroArch
+ * (`.srm`). These read the game's own dex bitfields, not an approximation.
+ *
+ * Refs: Bulbapedia "Save data structure (Generation I / II / III)", and
+ * the pret disassemblies (pokered / pokecrystal / pokeemerald).
+ */
+
+/* ------------------------------------------------------------------ *
+ * Shared helpers
+ * ------------------------------------------------------------------ */
+
+const bitsToList = (bytes, start, count) => {
+  const list = [];
+  for (let n = 1; n <= count; n++) {
+    if (bytes[start + ((n - 1) >> 3)] & (1 << ((n - 1) & 7))) list.push(n);
+  }
+  return list;
+};
+
+// GB (Gen 1 & 2) in-game text -> ASCII, enough for trainer names.
+const GB_CHARS = (() => {
+  const t = { 0x7f: ' ', 0x50: '\0' };
+  const up = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
+  const lo = 'abcdefghijklmnopqrstuvwxyz';
+  for (let i = 0; i < 26; i++) {
+    t[0x80 + i] = up[i];
+    t[0xa0 + i] = lo[i];
+  }
+  for (let i = 0; i < 10; i++) t[0xf6 + i] = String(i);
+  Object.assign(t, { 0xe8: '.', 0xe3: '-', 0xf3: '/', 0xf4: ',', 0x9a: '(', 0x9b: ')', 0xe6: '?', 0xe7: '!' });
+  return t;
+})();
+
+// GBA (Gen 3) in-game text -> ASCII.
+const GBA_CHARS = (() => {
+  const t = { 0x00: ' ' };
+  for (let i = 0; i < 10; i++) t[0xa1 + i] = String(i);
+  const up = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
+  const lo = 'abcdefghijklmnopqrstuvwxyz';
+  for (let i = 0; i < 26; i++) {
+    t[0xbb + i] = up[i];
+    t[0xd5 + i] = lo[i];
+  }
+  Object.assign(t, {
+    0xad: '.', 0xae: '-', 0xba: '/', 0xac: ',', 0xb8: '&',
+  });
+  return t;
+})();
+
+function decodeName(bytes, table, terminator) {
+  let out = '';
+  for (const b of bytes) {
+    if (b === terminator) break;
+    const c = table[b];
+    if (c === '\0' || c === undefined) {
+      if (c === '\0') break;
+      continue;
+    }
+    out += c;
+  }
+  return out.trim();
+}
+
+const sumBytes = (bytes, from, to) => {
+  let s = 0;
+  for (let i = from; i <= to; i++) s = (s + bytes[i]) & 0xffffffff;
+  return s >>> 0;
+};
+
+/* ------------------------------------------------------------------ *
+ * Generation I  —  Red / Blue / Yellow (International, 32 KB SRAM)
+ * ------------------------------------------------------------------ */
+
+const G1 = { name: 0x2598, owned: 0x25a3, seen: 0x25b6, species: 151, ckByte: 0x3523, ckFrom: 0x2598, ckTo: 0x3522 };
+
+function tryGen1(bytes) {
+  if (bytes.length < 0x8000) return null;
+  const caught = bitsToList(bytes, G1.owned, G1.species);
+  const seen = bitsToList(bytes, G1.seen, G1.species);
+  const checksumOk = ((~sumBytes(bytes, G1.ckFrom, G1.ckTo)) & 0xff) === bytes[G1.ckByte];
+  if (!seen.length && !caught.length) return null;
+  return {
+    gen: 1,
+    game: 'Red / Blue / Yellow',
+    trainer: decodeName(bytes.subarray(G1.name, G1.name + 11), GB_CHARS, 0x50),
+    seen,
+    caught,
+    nationalUnlocked: true,
+    checksumOk,
+  };
+}
+
+/* ------------------------------------------------------------------ *
+ * Generation II  —  Gold / Silver / Crystal (International, 32 KB SRAM)
+ * ------------------------------------------------------------------ */
+
+const G2 = {
+  gs: { name: 0x200b, owned: 0x2a4c, seen: 0x2a6c, ck: 0x2d69, ckFrom: 0x2009, ckTo: 0x2d68, label: 'Gold / Silver' },
+  cr: { name: 0x2009, owned: 0x2a27, seen: 0x2a47, ck: 0x2d0d, ckFrom: 0x2009, ckTo: 0x2b82, label: 'Crystal' },
+};
+const G2_SPECIES = 251;
+
+function tryGen2Variant(bytes, v) {
+  const caught = bitsToList(bytes, v.owned, G2_SPECIES);
+  const seen = bitsToList(bytes, v.seen, G2_SPECIES);
+  if (!seen.length && !caught.length) return null;
+  // No species may be "caught" but not "seen", and the last used byte must
+  // not spill past species 251 — cheap sanity checks for the right offsets.
+  if (caught.some((n) => !seen.includes(n))) return null;
+  if (bytes[v.owned + 31] & 0xf8 || bytes[v.seen + 31] & 0xf8) return null;
+  const stored = bytes[v.ck] | (bytes[v.ck + 1] << 8);
+  const checksumOk = (sumBytes(bytes, v.ckFrom, v.ckTo) & 0xffff) === stored;
+  return {
+    gen: 2,
+    game: v.label,
+    trainer: decodeName(bytes.subarray(v.name, v.name + 11), GB_CHARS, 0x50),
+    seen,
+    caught,
+    nationalUnlocked: true,
+    checksumOk,
+  };
+}
+
+function tryGen2(bytes) {
+  if (bytes.length < 0x8000) return null;
+  const gs = tryGen2Variant(bytes, G2.gs);
+  const cr = tryGen2Variant(bytes, G2.cr);
+  if (gs?.checksumOk) return gs;
+  if (cr?.checksumOk) return cr;
+  return gs || cr || null;
+}
+
+/* ------------------------------------------------------------------ *
+ * Generation III  —  RSE / FRLG (128 KB, two slots, rotated sections)
+ * ------------------------------------------------------------------ */
+
+const SECTION_SIZE = 4096;
+const SECTIONS_PER_SLOT = 14;
+const SLOT_SIZE = SECTION_SIZE * SECTIONS_PER_SLOT; // 57344
+const SIGNATURE = 0x08012025;
+const SECTION_DATA_SIZE = [3884, 3968, 3968, 3968, 3848, 3968, 3968, 3968, 3968, 3968, 3968, 3968, 3968, 2000];
+const DEX_OFFSET = 0x18;
+const DEX_MAGIC = DEX_OFFSET + 2; // 0xDA = RSE national, 0xB9 = FRLG national
+const G3_OWNED = DEX_OFFSET + 16;
+const G3_SEEN = DEX_OFFSET + 68;
+const G3_SPECIES = 386;
+
+function readSlot(view, base) {
+  const sections = {};
+  let counter = -1;
+  let valid = 0;
+  for (let i = 0; i < SECTIONS_PER_SLOT; i++) {
+    const off = base + i * SECTION_SIZE;
+    if (view.getUint32(off + 0x0ffc, true) !== SIGNATURE) continue;
+    const id = view.getUint16(off + 0x0ff4, true);
+    if (id > 13) continue;
+    sections[id] = off;
+    counter = Math.max(counter, view.getUint32(off + 0x0ff8, true));
+    valid++;
+  }
+  return { sections, counter, valid };
+}
+
+function g3ChecksumOk(view, sectionOff, id) {
+  const size = SECTION_DATA_SIZE[id] ?? 3968;
+  let sum = 0;
+  for (let i = 0; i < size; i += 4) sum = (sum + view.getUint32(sectionOff + i, true)) >>> 0;
+  return (((sum >>> 16) + (sum & 0xffff)) & 0xffff) === view.getUint16(sectionOff + 0x0ff6, true);
+}
+
+function tryGen3(bytes) {
+  if (bytes.length < SLOT_SIZE + SECTION_SIZE) return null;
+  const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  const a = readSlot(view, 0);
+  const b = bytes.length >= 2 * SLOT_SIZE ? readSlot(view, SLOT_SIZE) : { sections: {}, counter: -1, valid: 0 };
+  if (a.valid < 3 && b.valid < 3) return null;
+  const slot = b.counter > a.counter ? b : a;
+  const s0 = slot.sections[0];
+  if (s0 == null) return null;
+
+  const magic = bytes[s0 + DEX_MAGIC];
+  const seen = bitsToList(bytes, s0 + G3_SEEN, G3_SPECIES);
+  const caught = bitsToList(bytes, s0 + G3_OWNED, G3_SPECIES);
+  if (!seen.length && !caught.length) return null;
+  return {
+    gen: 3,
+    game: magic === 0xb9 ? 'FireRed / LeafGreen' : 'Ruby / Sapphire / Emerald',
+    trainer: decodeName(bytes.subarray(s0, s0 + 7), GBA_CHARS, 0xff),
+    seen,
+    caught,
+    nationalUnlocked: magic === 0xda || magic === 0xb9,
+    checksumOk: g3ChecksumOk(view, s0, 0),
+  };
+}
+
+/* ------------------------------------------------------------------ *
+ * Public: sniff the file and parse whatever generation it is.
+ * ------------------------------------------------------------------ */
+
+/**
+ * @param {ArrayBuffer} buffer
+ * @returns {{ gen:number, game:string, trainer:string, seen:number[], caught:number[], nationalUnlocked:boolean }}
+ * @throws {Error} with a user-facing message if it can't be read.
+ */
+export function parseSaveDex(buffer) {
+  const bytes = new Uint8Array(buffer);
+  if (bytes.length < 0x8000) {
+    throw new Error('That file is too small to be a Pokémon save.');
+  }
+
+  // 128 KB → Gen 3. 32–64 KB → Gen 1 or 2 (checksum picks the winner).
+  const candidates =
+    bytes.length >= SLOT_SIZE + SECTION_SIZE
+      ? [tryGen3(bytes), tryGen2(bytes), tryGen1(bytes)]
+      : [tryGen2(bytes), tryGen1(bytes)];
+
+  const hits = candidates.filter(Boolean);
+  if (!hits.length) {
+    throw new Error(
+      "Couldn't find a Pokédex in that file — it may be a game this doesn't support yet, a corrupted save, or a Japanese cartridge.",
+    );
+  }
+  const best = hits.find((h) => h.checksumOk) || hits[0];
+  if (!best.checksumOk) {
+    console.warn('savedex: no checksum matched — importing the most likely reading anyway.');
+  }
+  return best;
+}
+
+// Back-compat: earlier code imported this name.
+export const parseGen3Dex = parseSaveDex;

src/lib/sheet-drag.js

@@ -0,0 +1,43 @@
+/**
+ * Drag a bottom sheet down by its handle to dismiss it. `panel` is the
+ * `.gsheet`, `handle` the grab area (its header), `close` the dismiss fn.
+ * Past ~110px (or a quick flick) it closes; otherwise it springs back.
+ */
+export function dragToClose(panel, handle, close) {
+  let y0 = 0;
+  let dy = 0;
+  let t0 = 0;
+  let dragging = false;
+
+  const start = (e) => {
+    if (e.touches.length !== 1) return;
+    y0 = e.touches[0].clientY;
+    dy = 0;
+    t0 = Date.now();
+    dragging = true;
+    panel.style.transition = 'none';
+  };
+
+  const move = (e) => {
+    if (!dragging) return;
+    dy = e.touches[0].clientY - y0;
+    // Rubber-band an upward pull; follow a downward one.
+    const shown = dy < 0 ? dy * 0.25 : dy;
+    panel.style.transform = `translateY(${shown}px)`;
+    if (dy > 0) e.preventDefault();
+  };
+
+  const end = () => {
+    if (!dragging) return;
+    dragging = false;
+    panel.style.transition = '';
+    panel.style.transform = '';
+    const flick = dy > 40 && Date.now() - t0 < 300;
+    if (dy > 110 || flick) close();
+  };
+
+  handle.addEventListener('touchstart', start, { passive: true });
+  handle.addEventListener('touchmove', move, { passive: false });
+  handle.addEventListener('touchend', end, { passive: true });
+  handle.addEventListener('touchcancel', end, { passive: true });
+}

src/lib/swipe.js

@@ -14,6 +14,24 @@ export function onSwipe(target, { onLeft, onRight, threshold = 60 } = {}) {
   let t0 = 0;
   let active = false;
   let claimed = false;
+  let startNode = null;
+
+  // Would a horizontal drag from `node` scroll a nested element instead of
+  // the page? (moves list, tab strip, coverage grid…) `dir` < 0 means the
+  // finger is moving left — that scrolls such an element to the right.
+  const scrollsInside = (node, dir) => {
+    for (let n = node; n && n !== document.body && n !== target.parentElement; n = n.parentElement) {
+      if (n.scrollWidth - n.clientWidth > 2) {
+        const ox = getComputedStyle(n).overflowX;
+        if (ox === 'auto' || ox === 'scroll') {
+          const max = n.scrollWidth - n.clientWidth;
+          if (dir < 0 && n.scrollLeft < max - 1) return true;
+          if (dir > 0 && n.scrollLeft > 1) return true;
+        }
+      }
+    }
+    return false;
+  };
 
   const start = (e) => {
     if (e.touches.length !== 1) {
@@ -25,6 +43,7 @@ export function onSwipe(target, { onLeft, onRight, threshold = 60 } = {}) {
     t0 = Date.now();
     active = true;
     claimed = false;
+    startNode = e.target;
   };
 
   const move = (e) => {
@@ -43,8 +62,15 @@ export function onSwipe(target, { onLeft, onRight, threshold = 60 } = {}) {
         active = false;
         return;
       }
-      // Only claim a horizontal page-swipe once the drag is unambiguous.
-      if (adx > 20 && adx > ady * 2) claimed = true;
+      // Only claim a horizontal page-swipe once the drag is unambiguous —
+      // and not when it should scroll something nested instead.
+      if (adx > 20 && adx > ady * 2) {
+        if (scrollsInside(startNode, dx)) {
+          active = false;
+          return;
+        }
+        claimed = true;
+      }
     }
     if (claimed) e.preventDefault();
   };

src/store/selection.js

@@ -46,6 +46,20 @@ export function setNote(id, note) {
   });
 }
 
+/** Merge in seen/caught species lists (e.g. from a save-file import). Never clears. */
+export function importFlags({ seen = [], caught = [] } = {}) {
+  selection.set((s) => {
+    const pokemon = { ...s.pokemon };
+    const stamp = new Date().toISOString();
+    const bump = (id, patch) => {
+      pokemon[id] = { ...(pokemon[id] || BLANK), ...patch, updatedAt: stamp };
+    };
+    for (const id of seen) bump(id, { seen: true });
+    for (const id of caught) bump(id, { seen: true, caught: true });
+    return { ...s, pokemon };
+  });
+}
+
 /** Aggregate seen/caught counts over an arbitrary list of national ids. */
 export function stats(speciesIds) {
   const p = selection.get().pokemon;

src/styles/layout.css

@@ -1725,6 +1725,11 @@
   justify-content: space-between;
   padding: 16px 0 8px;
   background: var(--surface);
+  cursor: grab;
+  touch-action: none;
+}
+.gsheet__head:active {
+  cursor: grabbing;
 }
 .gsheet__head::before {
   content: "";
@@ -3347,7 +3352,7 @@
   position: relative;
   z-index: 1;
 }
-.seg:has(.seg__thumb) .seg__btn.is-active {
+.seg--thumbed .seg__btn.is-active {
   background: none;
   box-shadow: none;
 }

src/views/SettingsView.js

@@ -1,9 +1,10 @@
 import { el, onTeardown } from '../lib/dom.js';
 import { settings, applyTheme } from '../store/settings.js';
-import { selection } from '../store/selection.js';
+import { selection, importFlags } from '../store/selection.js';
 import { team } from '../store/team.js';
 import { formTracking } from '../store/formTracking.js';
 import { shinyHunts } from '../store/shinyHunts.js';
+import { parseSaveDex } from '../lib/savedex.js';
 import { canInstall, onInstallChange, promptInstall } from '../lib/install.js';
 
 export async function SettingsView() {
@@ -122,6 +123,36 @@ export async function SettingsView() {
     storageNote.textContent = 'Storage estimate not available in this browser.';
   }
 
+  // Import the Pokédex out of a Gen 3 GBA save (.sav / .srm).
+  const saveNote = el('p', { class: 'settings__note' });
+  const saveInput = el('input', {
+    type: 'file',
+    accept: '.sav,.srm,.sa1,.fla,application/octet-stream',
+    style: 'display:none',
+    onchange: async (e) => {
+      const file = e.target.files[0];
+      if (!file) return;
+      saveNote.textContent = 'Reading…';
+      try {
+        const dex = parseSaveDex(await file.arrayBuffer());
+        const who = dex.trainer || dex.game;
+        if (
+          confirm(
+            `${dex.game}${dex.trainer ? ` — ${dex.trainer}` : ''}\n${dex.seen.length} seen, ${dex.caught.length} caught.\n\nMerge into your Pokédex? Nothing is removed.`,
+          )
+        ) {
+          importFlags({ seen: dex.seen, caught: dex.caught });
+          saveNote.textContent = `Merged ${dex.caught.length} caught / ${dex.seen.length} seen from ${who}.`;
+        } else {
+          saveNote.textContent = '';
+        }
+      } catch (err) {
+        saveNote.textContent = err.message || 'Could not read that save file.';
+      }
+      e.target.value = '';
+    },
+  });
+
   const importInput = el('input', {
     type: 'file',
     accept: 'application/json',
@@ -195,6 +226,14 @@ export async function SettingsView() {
       ' · ',
       el('a', { class: 'link', href: '#/shiny' }, 'Shiny hunts'),
     ),
+    el(
+      'p',
+      { class: 'settings__note' },
+      el('button', { class: 'button', type: 'button', onclick: () => saveInput.click() }, 'Import from a game save'),
+      ' — a .sav / .srm from Gen 1 (R/B/Y), Gen 2 (G/S/C) or Gen 3 (R/S/E, FR/LG). Reads the game’s own Pokédex; merges seen/caught, removes nothing.',
+    ),
+    saveInput,
+    saveNote,
     storageNote,
     el('div', { class: 'settings__actions' },
       el('button', {