import Toybox.Graphics;
import Toybox.Lang;
import Toybox.Math;
import Toybox.Time;
import Toybox.Timer;
import Toybox.WatchUi;

// Full-screen loading state shown while GpsService is acquiring a
// fix. Draws a circular progress bar along the display edge plus
// the German prompt "Standort wird bestimmt" in the center.
class LoadingView extends WatchUi.View {

    private var _eventType as String;
    private var _gps as GpsService or Null;
    private var _animTimer as Timer.Timer;
    private var _startMs as Number = 0;

    function initialize(eventType as String) {
        View.initialize();
        _eventType = eventType;
        _animTimer = new Timer.Timer();
    }

    function onShow() as Void {
        _startMs = _nowMs();
        _animTimer.start(method(:_tick), 50, true);
        _gps = new GpsService(method(:_onGpsResult));
        _gps.start();
    }

    function onHide() as Void {
        _animTimer.stop();
        if (_gps != null) {
            _gps.stop();
            _gps = null;
        }
    }

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

    function _onGpsResult(result as Dictionary or Null) as Void {
        _animTimer.stop();
        var now = Time.now().value();
        if (result != null) {
            var event = new Event(
                _eventType,
                now,
                result["lat"] as Float or Null,
                result["lon"] as Float or Null,
                result["acc"] as Float or Null
            );
            EventStore.add(event);
            WatchUi.switchToView(new SuccessView(), null, WatchUi.SLIDE_IMMEDIATE);
        } else {
            // No usable fix at all → save event with null coords (per
            // spec), but still surface an error screen so the user
            // knows GPS did not lock.
            var event = new Event(_eventType, now, null, null, null);
            EventStore.add(event);
            WatchUi.switchToView(new ErrorView(), null, WatchUi.SLIDE_IMMEDIATE);
        }
    }

    function onUpdate(dc as Dc) as Void {
        dc.setColor(Config.COLOR_FG, Config.COLOR_BG);
        dc.clear();

        var cx = LayoutMetrics.centerX(dc);
        var cy = LayoutMetrics.centerY(dc);
        var radius = LayoutMetrics.edgeArcRadius(dc);

        // Circular progress — white arc that grows with elapsed time.
        var elapsed = _nowMs() - _startMs;
        var progress = elapsed.toFloat() / Config.GPS_TIMEOUT_MS.toFloat();
        if (progress > 1.0) { progress = 1.0; }

        dc.setPenWidth(LayoutMetrics.edgeArcPenWidth(dc));
        dc.setColor(Config.COLOR_ACCENT, Config.COLOR_BG);
        var sweep = progress * 360.0;
        // drawArc uses degrees with 0° = 3 o'clock and counter-clockwise.
        // Start at 12 o'clock and sweep clockwise.
        var startDeg = 90;
        var endDeg = 90 - sweep;
        dc.drawArc(cx, cy, radius, Graphics.ARC_CLOCKWISE, startDeg, endDeg);

        dc.setColor(Config.COLOR_FG, Config.COLOR_BG);
        TextUtils.drawResourceCentered(dc, Rez.Strings.loading_gps, cx, cy, Graphics.FONT_TINY);
    }

    private function _nowMs() as Number {
        return System.getTimer();
    }
}