// Author:  cirakg & claude ai
// Summary: PIN entry for unlocking, creating and changing the PIN: touch keypad or button digit selector, lockout display.
//
// README 13.1 and 13.4:
//   * A PIN has exactly 4 digits (KeyManager.PIN_DIGITS) and is submitted
//     as soon as the 4th is entered; there is no OK key.
//   * Touch screens get a keypad (1-9, then 0 and delete in the bottom row,
//     delete on the right as on phone keypads). The START button does
//     nothing there: a tap can also arrive as START, which used to submit a
//     PIN early. Watches without a touch screen get a digit selector:
//     UP/DOWN change the digit, START adds it, BACK deletes.
//   * A legacy PIN (4 to 10 digits, set before the 4-digit rule) is entered
//     the old way, with an OK key (and START on touch screens, "OK" in the
//     selector); after it unlocks, the screen asks for a new 4-digit PIN
//     and then continues to what was opened.
//   * Entered digits show as dots. A wrong PIN vibrates and shows any wait.
//   * Creating or changing the PIN asks twice.
//   * Key derivation (about 1 s) runs as a job on a timer, so the screen
//     shows "Checking..." and the watchdog never trips. So does the work
//     after a correct or new PIN (LockJob: pending entries are promoted,
//     waiting "Require PIN" changes applied); its lines go to the results.
// The typed digits are a ByteArray that is wiped after every attempt.

import Toybox.Attention;
import Toybox.Graphics;
import Toybox.Lang;
import Toybox.Timer;
import Toybox.WatchUi;

class PinView extends WatchUi.View {

    static const MODE_UNLOCK = 0;
    static const MODE_CREATE = 1;
    static const MODE_CHANGE = 2;

    // Selector positions 0-9 are digits; this one is "OK" (legacy PINs only).
    static const SELECT_OK = 10;
    // Keypad keys besides the digits (OK for legacy PINs only), and an
    // empty slot.
    static const KEY_DELETE = -1;
    static const KEY_OK = -2;
    static const KEY_NONE = -3;
    // Calibrate the PIN derivation to about this long on this watch.
    static const DERIVATION_TARGET_MS = 1000;
    static const CALIBRATION_SAMPLE = 200;

    var mode as Number;
    var busy as Boolean = false;
    // Unlocking a legacy PIN: 4 to 10 digits, submitted with OK.
    var legacy as Boolean = false;

    private var _onSuccess as Method() as Void or Null;
    private var _digits as ByteArray = []b;
    private var _first as ByteArray? = null; // first entry when creating
    private var _selector as Number = 0;
    private var _message as String? = null;
    private var _messageIsError as Boolean = false;
    private var _job as PinJob? = null;
    // The PIN copy the running derivation was given; wiped when it is done.
    private var _jobPin as ByteArray? = null;
    // The running derivation's timer driver (kept so it isn't collected).
    var runner as Jobs.JobRunner? = null;
    private var _lockJob as LockJob? = null;
    // A LockJob ran for this screen's PIN (a legacy PIN's new PIN runs a
    // second one, which adds to the first one's lines).
    private var _lockJobRan as Boolean = false;
    private var _ticker as Timer.Timer? = null;
    private var _keys as Array<Array<Number>> = [] as Array<Array<Number>>; // [x, y, w, h, key]
    private var _shownLogged as Boolean = false;

    // onSuccess runs after a correct or newly set PIN and must replace this
    // view (switchToView); without it the view just closes.
    function initialize(pinMode as Number, onSuccess as Method() as Void or Null) {
        View.initialize();
        mode = pinMode;
        _onSuccess = onSuccess;
        legacy = pinMode == MODE_UNLOCK && AppState.theVault().isLegacyPin();
    }

    function onShow() as Void {
        _shownLogged = false;
        var ticker = new Timer.Timer();
        ticker.start(method(:onTick), 1000, true);
        _ticker = ticker;
    }

    function onHide() as Void {
        if (_lockJobRan && _lockJob == null) {
            // Closed (or replaced): a "Confirm all" that follows has taken
            // the lock lines already; else they are in the results.
            ChangeQueue.takeLockLines();
        }
        var ticker = _ticker;
        if (ticker != null) {
            ticker.stop();
            _ticker = null;
        }
    }

    function onTick() as Void {
        WatchUi.requestUpdate();
    }

    // Seconds until another attempt is allowed (unlock mode only).
    function waitSeconds() as Number {
        return mode == MODE_UNLOCK ? AppState.theVault().lockout.remainingSeconds() : 0;
    }

    // ---- Input (called by PinDelegate) ----------------------------------

    // A keypad key: 0-9, KEY_DELETE or KEY_OK (legacy PINs only). The
    // PIN_DIGITS-th digit of a 4-digit PIN submits it.
    function press(key as Number) as Void {
        if (busy || waitSeconds() > 0) {
            return;
        }
        if (key == KEY_DELETE) {
            deleteDigit();
        } else if (key == KEY_OK) {
            if (legacy) {
                submit();
            }
        } else if (_digits.size() < (legacy ? KeyManager.MAX_PIN_DIGITS : KeyManager.PIN_DIGITS)) {
            _digits.add(0x30 + key);
            _message = null;
            if (!legacy && _digits.size() == KeyManager.PIN_DIGITS) {
                submit();
            }
        }
        WatchUi.requestUpdate();
    }

    // Selector: UP/DOWN, over the digits (and "OK" for a legacy PIN).
    function cycle(delta as Number) as Void {
        var positions = legacy ? SELECT_OK + 1 : SELECT_OK;
        _selector = ((_selector + delta) % positions + positions) % positions;
        WatchUi.requestUpdate();
    }

    // Selector: START.
    function choose() as Void {
        press(_selector == SELECT_OK ? KEY_OK : _selector);
    }

    // BACK: delete a digit; returns false when there was none (close).
    function back() as Boolean {
        if (busy) {
            return true;
        }
        if (_digits.size() == 0) {
            return false;
        }
        deleteDigit();
        WatchUi.requestUpdate();
        return true;
    }

    // The keypad key at a touch position, or null.
    function keyAt(x as Number, y as Number) as Number? {
        for (var i = 0; i < _keys.size(); i++) {
            var k = _keys[i];
            if (x >= k[0] && x < k[0] + k[2] && y >= k[1] && y < k[1] + k[3]) {
                return k[4];
            }
        }
        return null;
    }

    private function deleteDigit() as Void {
        if (_digits.size() > 0) {
            var shorter = _digits.slice(0, _digits.size() - 1);
            Bytes.wipe(_digits);
            _digits = shorter;
        }
    }

    // ---- Checking and setting the PIN ------------------------------------

    // A complete entry: check it (unlock) or keep it for the repeat (new PIN).
    private function submit() as Void {
        if (!(legacy ? KeyManager.isValidPin(_digits) : KeyManager.isValidNewPin(_digits))) {
            return; // a legacy OK with fewer than 4 digits
        }
        if (mode == MODE_UNLOCK) {
            startUnlock();
        } else if (_first == null) {
            _first = _digits;
            _digits = []b;
        } else if (Bytes.equal(_first as ByteArray, _digits)) {
            startSetPin();
        } else {
            Bytes.wipe(_first);
            _first = null;
            clearDigits();
            showMessage("PINs differ. Try again", true);
            buzz();
        }
    }

    private function startUnlock() as Void {
        var vault = AppState.theVault();
        _jobPin = Bytes.copy(_digits);
        try {
            _job = vault.beginUnlock(_jobPin as ByteArray);
        } catch (e instanceof VaultError) {
            Bytes.wipe(_jobPin);
            _jobPin = null;
            clearDigits();
            if (e.code == VaultError.NO_PIN) {
                mode = MODE_CREATE;
                legacy = false;
                showMessage("Set a PIN first", false);
            } else if (e.code != VaultError.LOCKED_OUT) {
                showMessage("PIN data damaged", true);
            }
            return;
        }
        clearDigits();
        startJob(method(:onUnlockDone));
    }

    private function startSetPin() as Void {
        var iterations = TestMode.ON ? Kdf.MIN_ITERATIONS : Kdf.calibrate(DERIVATION_TARGET_MS, CALIBRATION_SAMPLE);
        _jobPin = _first;
        _first = null;
        clearDigits();
        try {
            _job = AppState.theVault().beginSetPin(_jobPin as ByteArray, iterations);
        } catch (e instanceof VaultError) {
            Bytes.wipe(_jobPin);
            _jobPin = null;
            showMessage(e.code == VaultError.LOCKED ? "Unlock first" : KeyManager.PIN_DIGITS + " digits", true);
            return;
        }
        startJob(method(:onSetDone));
    }

    private function startJob(onDone as Method() as Void) as Void {
        busy = true;
        _message = null;
        var r = new Jobs.JobRunner(_job as PinJob, Kdf.ITERATIONS_PER_STEP, onDone);
        r.start();
        runner = r;
        WatchUi.requestUpdate();
    }

    function onUnlockDone() as Void {
        Bytes.wipe(_jobPin);
        _jobPin = null;
        var vault = AppState.theVault();
        if (vault.finishUnlock(_job as PinJob)) {
            _job = null;
            startLockJob();
            return;
        }
        busy = false;
        _shownLogged = false;
        _job = null;
        buzz();
        if (!vault.hasPin()) {
            // "Erase after 10 wrong PINs" just erased the locked entries.
            WatchUi.switchToView(new InfoView("PIN", ["10 wrong PINs: the locked entries were erased."], "erased"),
                new InfoDelegate(), WatchUi.SLIDE_IMMEDIATE);
            return;
        }
        showMessage("Wrong PIN", true);
    }

    function onSetDone() as Void {
        Bytes.wipe(_jobPin);
        _jobPin = null;
        AppState.theVault().finishSetPin(_job as PinJob);
        _job = null;
        startLockJob();
    }

    // Unlocked: promote the pending entries and apply waiting "Require
    // PIN" changes in steps, still showing the busy state (BACK waits).
    private function startLockJob() as Void {
        var job = new LockJob(AppState.theVault(), !_lockJobRan);
        _lockJobRan = true;
        _lockJob = job;
        var r = new Jobs.JobRunner(job, 1, method(:onLockJobDone));
        r.start();
        runner = r;
    }

    function onLockJobDone() as Void {
        busy = false;
        _shownLogged = false;
        var job = _lockJob as LockJob;
        _lockJob = null;
        if (job.lines.size() > 0) {
            Results.add(job.lines); // the list says "Results ready (menu)"
        }
        // "Encrypt names" can now reach locked entries, and a lock just
        // applied changes what the glance may show.
        AppState.processSettings();
        if (legacy) {
            askForNewPin();
            return;
        }
        succeed();
    }

    // After a legacy PIN unlocked: the same screen asks for a new 4-digit
    // PIN, and onSuccess runs once that is set. BACK leaves it unlocked
    // with the old PIN, which asks again at the next unlock.
    private function askForNewPin() as Void {
        AppState.activity();
        legacy = false;
        mode = MODE_CHANGE;
        if (_selector == SELECT_OK) {
            _selector = 0;
        }
        showMessage("Set a new " + KeyManager.PIN_DIGITS + "-digit PIN", false);
    }

    private function succeed() as Void {
        AppState.activity();
        var next = _onSuccess;
        if (next != null) {
            next.invoke();
        } else {
            WatchUi.popView(WatchUi.SLIDE_RIGHT);
        }
    }

    private function clearDigits() as Void {
        Bytes.wipe(_digits);
        _digits = []b;
    }

    private function showMessage(text as String, isError as Boolean) as Void {
        _message = text;
        _messageIsError = isError;
        _shownLogged = false;
        WatchUi.requestUpdate();
    }

    private function buzz() as Void {
        // Not in the UI-test build: the simulator shakes the drawing while
        // vibrating, which spoils screenshots.
        if (!TestMode.ON && Attention has :vibrate) {
            Attention.vibrate([new Attention.VibeProfile(50, 300)]);
        }
    }

    // ---- Drawing ------------------------------------------------------------

    function title() as String {
        if (busy) {
            return mode == MODE_UNLOCK ? "Checking…" : "Saving…";
        }
        if (mode == MODE_UNLOCK) {
            return "Enter PIN";
        }
        return _first == null ? "New PIN" : "Repeat PIN";
    }

    function onUpdate(dc as Graphics.Dc) as Void {
        Ui.clear(dc);
        var w = dc.getWidth();
        var h = dc.getHeight();
        var cx = w / 2;
        var wait = waitSeconds();

        var y = h * 9 / 100;
        dc.setColor(Ui.fg(), Graphics.COLOR_TRANSPARENT);
        dc.drawText(cx, y, Graphics.FONT_SMALL, Ui.fit(dc, wait > 0 ? "PIN locked" : title(), Graphics.FONT_SMALL,
            2 * Ui.halfWidthAt(dc, y)), Graphics.TEXT_JUSTIFY_CENTER);
        y += dc.getFontHeight(Graphics.FONT_SMALL) + 4;

        // Dots: entered digits filled, PIN_DIGITS slots (more for a long legacy PIN).
        var slots = _digits.size() > KeyManager.PIN_DIGITS ? _digits.size() : KeyManager.PIN_DIGITS;
        var r = h / 60 > 3 ? h / 60 : 3;
        var step = r * 3;
        var x = cx - (slots - 1) * step / 2;
        for (var i = 0; i < slots; i++) {
            dc.setColor(i < _digits.size() ? Ui.fg() : Ui.dim(), Graphics.COLOR_TRANSPARENT);
            if (i < _digits.size()) {
                dc.fillCircle(x, y + r, r);
            } else {
                dc.drawCircle(x, y + r, r);
            }
            x += step;
        }
        y += 2 * r + 4;

        var message = wait > 0 ? "Wrong PINs. Wait " + Ui.minutesSeconds(wait) : _message;
        if (message != null) {
            dc.setColor(_messageIsError || wait > 0 ? Ui.warn() : Ui.accent(), Graphics.COLOR_TRANSPARENT);
            dc.drawText(cx, y, Graphics.FONT_XTINY, Ui.fit(dc, message, Graphics.FONT_XTINY, 2 * Ui.halfWidthAt(dc, y)),
                Graphics.TEXT_JUSTIFY_CENTER);
        }
        y += dc.getFontHeight(Graphics.FONT_XTINY) + 2;

        if (Ui.isTouch()) {
            drawKeypad(dc, y, h - h / 20, wait > 0 || busy);
        } else {
            drawSelector(dc, y, h - h / 10, wait > 0 || busy);
        }

        if (!_shownLogged) {
            _shownLogged = true;
            // For UI scripts: the state the dots and the title show (never digits).
            Diag.data("pin_state", "mode=" + mode + " digits=" + _digits.size() + " repeat=" + (_first != null ? 1 : 0)
                + " busy=" + (busy ? 1 : 0));
            Diag.shown(wait > 0 ? "pin_wait" : (_message != null && _messageIsError ? "pin_error" : "pin"));
        }
    }

    // Logs the shown state again after a state change, for UI scripts.
    function markChanged() as Void {
        _shownLogged = false;
    }

    private function drawKeypad(dc as Graphics.Dc, top as Number, bottom as Number, disabled as Boolean) as Void {
        var w = dc.getWidth();
        var keyH = (bottom - top) / 4;
        var halfW = Ui.halfWidthBetween(dc, top, bottom);
        if (Ui.isRound()) {
            // The bottom row is narrowest; the keypad is as wide as it allows.
            halfW = Ui.halfWidthAt(dc, bottom - keyH / 2) + keyH / 2;
        }
        var keyW = 2 * halfW / 3;
        if (keyW > keyH * 2) {
            keyW = keyH * 2;
        }
        var left = w / 2 - 3 * keyW / 2;
        // A legacy PIN needs OK: delete, 0, OK. Otherwise the 4th digit
        // submits, and the bottom row is an empty slot, 0 and delete.
        var values = legacy ? [1, 2, 3, 4, 5, 6, 7, 8, 9, KEY_DELETE, 0, KEY_OK]
            : [1, 2, 3, 4, 5, 6, 7, 8, 9, KEY_NONE, 0, KEY_DELETE];
        var font = Graphics.FONT_MEDIUM;
        _keys = [] as Array<Array<Number>>;
        var log = "";
        for (var i = 0; i < 12; i++) {
            if (values[i] == KEY_NONE) {
                continue;
            }
            var kx = left + (i % 3) * keyW;
            var ky = top + (i / 3) * keyH;
            _keys.add([kx, ky, keyW, keyH, values[i] as Number]);
            var label = values[i] == KEY_OK ? "OK" : (values[i] as Number).toString();
            var isAction = (values[i] as Number) < 0;
            dc.setColor(disabled ? (Ui.dark() ? 0x444444 : Graphics.COLOR_LT_GRAY) : (isAction ? Ui.accent() : Ui.fg()),
                Graphics.COLOR_TRANSPARENT);
            if (values[i] == KEY_DELETE) {
                drawDeleteIcon(dc, kx + keyW / 2, ky + keyH / 2, dc.getFontHeight(Graphics.FONT_SMALL) / 2);
            } else {
                var f = isAction ? Graphics.FONT_SMALL : font;
                dc.drawText(kx + keyW / 2, ky + (keyH - dc.getFontHeight(f)) / 2, f, label, Graphics.TEXT_JUSTIFY_CENTER);
            }
            log += (log.length() > 0 ? ";" : "") + (values[i] as Number) + "=" + (kx + keyW / 2) + "," + (ky + keyH / 2);
        }
        if (!_shownLogged) {
            Diag.data("pin_keys", log);
        }
    }

    // A backspace key: an arrow-shaped outline with an x, `size` px high,
    // centred on (cx, cy). Fonts don't all have a backspace glyph.
    private function drawDeleteIcon(dc as Graphics.Dc, cx as Number, cy as Number, size as Number) as Void {
        var h = size / 2;
        var left = cx - size;
        var right = cx + size;
        dc.setPenWidth(2);
        dc.drawLine(left, cy, left + h, cy - h);
        dc.drawLine(left + h, cy - h, right, cy - h);
        dc.drawLine(right, cy - h, right, cy + h);
        dc.drawLine(right, cy + h, left + h, cy + h);
        dc.drawLine(left + h, cy + h, left, cy);
        var x = cx + h / 3;
        var a = h / 2;
        dc.drawLine(x - a, cy - a, x + a, cy + a);
        dc.drawLine(x - a, cy + a, x + a, cy - a);
        dc.setPenWidth(1);
    }

    private function drawSelector(dc as Graphics.Dc, top as Number, bottom as Number, disabled as Boolean) as Void {
        var cx = dc.getWidth() / 2;
        // Centred above the hint, so the lower arrow never touches it (it
        // did on the Forerunner 255S).
        var hintTop = bottom - dc.getFontHeight(Graphics.FONT_XTINY);
        var mid = (top + hintTop) / 2;
        var font = Graphics.FONT_NUMBER_MEDIUM;
        var label = _selector == SELECT_OK ? "OK" : _selector.toString();
        if (_selector == SELECT_OK) {
            font = Graphics.FONT_MEDIUM;
        }
        dc.setColor(disabled ? Ui.dim() : Ui.fg(), Graphics.COLOR_TRANSPARENT);
        dc.drawText(cx, mid - dc.getFontHeight(font) / 2, font, label, Graphics.TEXT_JUSTIFY_CENTER);
        dc.setColor(Ui.accent(), Graphics.COLOR_TRANSPARENT);
        var a = dc.getFontHeight(font) / 2 + 10;
        dc.fillPolygon([[cx - 8, mid - a], [cx + 8, mid - a], [cx, mid - a - 8]] as Array<Graphics.Point2D>);
        dc.fillPolygon([[cx - 8, mid + a], [cx + 8, mid + a], [cx, mid + a + 8]] as Array<Graphics.Point2D>);
        dc.setColor(Ui.dim(), Graphics.COLOR_TRANSPARENT);
        var hint = "START: add";
        dc.drawText(cx, hintTop, Graphics.FONT_XTINY,
            Ui.fit(dc, hint, Graphics.FONT_XTINY, 2 * Ui.halfWidthAt(dc, bottom)), Graphics.TEXT_JUSTIFY_CENTER);
    }
}

// Input on the PIN screen.
class PinDelegate extends WatchUi.BehaviorDelegate {

    function initialize() {
        BehaviorDelegate.initialize();
    }

    private function view() as PinView? {
        var current = WatchUi.getCurrentView()[0];
        return current instanceof PinView ? current : null;
    }

    function onTap(event as WatchUi.ClickEvent) as Boolean {
        var v = view();
        if (v == null) {
            return true;
        }
        var xy = event.getCoordinates();
        var key = v.keyAt(xy[0], xy[1]);
        if (key != null) {
            v.markChanged();
            v.press(key);
        }
        return true;
    }

    // On touch screens a tap also arrives as the select behaviour first;
    // returning false lets it through to onTap (the key under the finger),
    // and the START button comes through onKey.
    function onSelect() as Boolean {
        if (Ui.isTouch()) {
            return false;
        }
        var v = view();
        if (v != null) {
            v.markChanged();
            v.choose();
        }
        return true;
    }

    // START on a touch screen does nothing, in every mode: one tap can arrive
    // both here and in onTap, and submitting the digits typed so far was a
    // counted wrong PIN. A legacy PIN is submitted with the tappable OK key.
    function onKey(event as WatchUi.KeyEvent) as Boolean {
        if (Ui.isTouch() && event.getKey() == WatchUi.KEY_ENTER) {
            return true;
        }
        return false;
    }

    function onNextPage() as Boolean {
        var v = view();
        if (v != null && !Ui.isTouch()) {
            v.cycle(1);
        }
        return true;
    }

    function onPreviousPage() as Boolean {
        var v = view();
        if (v != null && !Ui.isTouch()) {
            v.cycle(-1);
        }
        return true;
    }

    function onBack() as Boolean {
        var v = view();
        if (v != null && v.back()) {
            return true;
        }
        WatchUi.popView(WatchUi.SLIDE_RIGHT);
        return true;
    }
}