bgclock/README.md

# Backgammon Clock

A two-player match clock with **simple delay you can actually see**. Reserve time
plus a fixed number of free seconds each turn that never carry over — the
Backgammon Galaxy control. Defaults to 3:00 + 12s.

Plain HTML, CSS and JavaScript. No frameworks, no fonts, no images, no network.

## Getting it onto your phone

Chrome will only offer a real install over HTTPS, so the file needs a host.
GitHub Pages is free and takes about two minutes:

1. Create a new public repository, e.g. `bgclock`.
2. Upload all six files from `public_html/` to the root: `index.html`,
   `manifest.webmanifest`, `sw.js`, `icon-192.png`, `icon-512.png`,
   `icon-maskable-512.png`.
3. **Settings → Pages → Source: Deploy from a branch → `main` / `(root)` → Save.**
4. Wait a minute, then open `https://<you>.github.io/bgclock/` on your phone.
5. **Android, Chrome:** menu (⋮) → **Add to Home screen** → **Install**.
   **iOS, Safari:** Share (□↑) → **Add to Home Screen** → **Add**. It has to be
   Safari — Chrome and Firefox on iOS can't install a web app.

Open it from the home-screen icon and it runs fullscreen with no browser
chrome, offline, with the screen kept awake while a game is on.

On iOS a few things behave differently, none of them fatal:

- **Install from Safari, and play from the home-screen icon.** In a Safari tab
  you lose a strip of the screen to the toolbar, and iOS clears the saved
  settings of a site you haven't visited for a week. The installed app keeps
  its own storage and doesn't get pruned that way.
- **The ringer switch doesn't mute the clock.** The page claims a playback
  audio session so you can hear the delay tick with the phone silenced, which
  in exchange pauses any music you had going. If you'd rather keep the music,
  delete the `navigator.audioSession` line in `index.html`.
- **Screen wake needs iOS 16.4 or newer.** Below that the screen dims on its
  usual schedule mid-game.

If you're using a different path than `/bgclock/`, edit the `"id"` field in
`manifest.webmanifest` to match, or just delete that line.

To try it before hosting, open `public_html/index.html` in any browser —
everything works except installation and the service worker.

## Using it

- **Tap your own half** to end your turn and start your opponent's clock.
  At the start, whoever taps first sets the *other* player going.
- The waiting player's taps are ignored, so a stray hand won't stop the clock.
- A tap counts when you **lift** your finger, and only if it didn't move. A swipe
  does nothing, so Android's swipe-up-from-the-bottom and the status-bar pull-down
  work over either half without costing anyone their turn — and a hand dragged
  across the panel won't change it either.
- Your clock runs until you lift. Holding a finger on the panel costs you the
  time you can see counting off, and holding it past zero flags you, exactly as
  if you hadn't touched it at all.
- The bar under the big time is the delay draining. When it empties you get a
  soft tick and your reserve starts moving. That's the moment worth hearing.
- **Reset** starts a whole new match: clocks back to full *and* the score back to
  0–0. It takes two taps: the first arms the button — it lights up and a ring
  unwinds around it — and a second tap within those two seconds does it. One
  stray thumb can't wipe a live match. It's absent on a fresh match, where there
  is nothing yet to wipe.
- **Pause** freezes mid-turn and resumes exactly where it stopped, delay
  included. Opening either sheet pauses automatically. The settings sheet leaves
  it paused — everything in there resets the clocks anyway — while the score
  sheet picks the turn back up when you close it, so glancing at the score
  doesn't cost you a tap on play. It's absent before each game's first tap, with
  no clock running to freeze.

Both buttons keep their space in the bar while they're away, so nothing shifts
under your thumb — the same as the gear.
- **Settings are only reachable before a match starts.** Every control in that
  sheet resets both clocks, so the gear disappears the moment the first tap
  starts the clock and comes back after a reset. Its space in the bar is kept
  empty, so nothing else shifts. That means a mistake in the time or delay can
  only be fixed by resetting and starting the match again — deliberately, since
  the alternative is wiping two live clocks by accident. Correcting a clock
  mid-match is what the score sheet is for.

Backgammon clocks pause between games, and after a cocked die the delay is
normally restarted — use pause and reset for those.

## Matches

Set **Match** in the settings to the number of points you're playing to — 1, 3,
5 and up to 29. The time you set is *per point*, so a 5-point match at 2:00 a
point puts 10:00 on each clock, and the settings sheet shows you that sum.

Each half reads the state from that player's own side of the board:

```
You:   1 out of 5
Them:  3
Moves: 7
```

So "You" always means whoever is sitting at that end — both players read their
own score on the top line, and the two halves show mirrored numbers.

At **1 point** there's no match to keep score of, so the score lines and the
score-sheet icon all disappear and you get the plain single-game clock with just
its move count. Set the match to 3 or more and they come back.

The score sheet is the middle icon in the bar. It's filled in from the phone
holder's side: **You** is the bottom half, **Them** the far end.

Nothing in that sheet takes effect until you press **Done**:

- **Done with nothing changed** leaves everything exactly as it was — same turn,
  same delay part-spent, same move counts — and the clock picks up where it left
  off. Tapping outside the sheet is the same as changing nothing, so a stray tap
  can't restart a game. A pause you set yourself before opening the sheet
  survives; only the sheet's own pause is undone.
- **Change a score** and the game restarts when you press Done: move counters
  back to zero and the turn back to the first tap, waiting on whoever rolls the
  lower die. The clocks keep whatever they were showing.
- **Change only a clock** — the sheet also lets you correct either player's time
  to the second — and the game carries on undisturbed and running: same turn,
  same delay position, same moves.

Shortening the match to fewer points than someone has already won pulls their
score down to fit.

## Settings

Under **Delay** are three presets — **2m / 12s**, **3m / 12s** and **3m / 15s**.
Tapping one jumps both timers there and lights it up. Change the time or delay by
hand and the highlight goes out; land back on a preset's numbers and it comes
back on.

| Setting | Range | Default |
| --- | --- | --- |
| Match | 1 – 29 points, odd | 1 |
| Time | 0:15 – 99:00 per point | 3:00 |
| Delay | 0 – 60 s | 12 s |
| Colour | Sage, Brass, Slate, Teal, Plum | Sage |
| Sound | on / off | on |

Brass is the colour in the chess.com app, if you want the exact original look.
Changing match, time or delay resets the clocks — the score is left alone, so you
can fix the delay mid-match without losing where you are.

Settings **and the match in progress** are kept in `localStorage`, so they
survive closing the tab, force-quitting the installed app and rebooting the
phone — the app also asks for persistent storage so they aren't evicted when the
device runs low on space (Chrome honours that request; Safari ignores it).
Reopening restores the score, both clocks, the move counts, whose turn it is and
how much delay was left. The one thing it can't restore is time passing while
the app was closed, so it comes back paused rather than charging anyone for the
gap: a crash shouldn't decide a game.

## Sounds

All three are generated with the Web Audio API, so there are no audio files to
download and nothing to attribute.

- **Turn change** — a soft rising fifth with an octave partial, marimba-like.
- **Delay expiry** — a single quiet 300 Hz tick, deliberately easy to miss unless
  you're listening for it.
- **Time out** — a falling triad, loud and unambiguous.

## Licence

Do whatever you like with it.