DRY: typed AppPrefs facade — one owner for the critical/warning key + default (#162)

app/src/main/java/com/almothafar/simplebatterynotifier/model/LevelThresholds.java

@@ -0,0 +1,16 @@
+package com.almothafar.simplebatterynotifier.model;
+
+/**
+ * The two battery-level alert thresholds as one value, so critical and warning travel together instead
+ * of as a loose {@code (int, int)} pair callers must keep in the right order (#162). Critical is the
+ * lower, more urgent level; warning the higher.
+ * <p>
+ * No ordering invariant is enforced here: the range slider structurally keeps critical below warning,
+ * and any persisted or corrupt pair is reconciled by
+ * {@code BatteryRangeSliderHelper.clampPair(LevelThresholds, int, int, int)} before it is shown.
+ *
+ * @param critical the critical level in percent — turns the gauge red and fires the critical alert
+ * @param warning  the warning level in percent — turns the gauge amber and fires the warning alert
+ */
+public record LevelThresholds(int critical, int warning) {
+}

app/src/main/java/com/almothafar/simplebatterynotifier/receiver/BatteryLevelReceiver.java

@@ -15,6 +15,7 @@
 import com.almothafar.simplebatterynotifier.service.NotificationService;
 import com.almothafar.simplebatterynotifier.service.SlowChargeDetector;
 import com.almothafar.simplebatterynotifier.service.SystemService;
+import com.almothafar.simplebatterynotifier.util.AppPrefs;
 import com.almothafar.simplebatterynotifier.util.TemperatureUtils;
 
 import static java.util.Objects.isNull;
@@ -104,8 +105,8 @@ public void onReceive(final Context context, final Intent intent) {
 
 		final SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(context);
 		final LevelAlertConfig config = new LevelAlertConfig(
-				sharedPref.getInt(context.getString(R.string._pref_key_critical_battery_level), 20),
-				sharedPref.getInt(context.getString(R.string._pref_key_warn_battery_level), 40),
+				AppPrefs.criticalLevel(context),
+				AppPrefs.warningLevel(context),
 				sharedPref.getBoolean(context.getString(R.string._pref_key_notify_for_warning_level), true),
 				sharedPref.getBoolean(context.getString(R.string._pref_key_notify_for_full_level), true),
 				sharedPref.getBoolean(context.getString(R.string._pref_key_notify_every_tick), false));

app/src/main/java/com/almothafar/simplebatterynotifier/service/BatteryRateTracker.java

@@ -65,12 +65,6 @@ public final class BatteryRateTracker {
 	// Above this the derived %/h is garbage (e.g. a wrong-unit current); reject rather than display it.
 	static final int MAX_PLAUSIBLE_RATE_PPH = 500;
 
-	// The "red / high drain" limit shared with the fast-drain alert (#109): default and accepted range.
-	// MIN/MAX must match the slider bounds (android:min/android:max) in pref_alerts.xml; they are
-	// enforced when the preference is read, so an out-of-range stored value can't skew the red line.
-	public static final int DEFAULT_DRAIN_LIMIT_PPH = 20;
-	public static final int MIN_DRAIN_LIMIT_PPH = 5;
-	public static final int MAX_DRAIN_LIMIT_PPH = 60;
 	// Amber sits just below the red limit; 0.75x keeps colour reserved for genuinely high drain (#108).
 	private static final float AMBER_RATIO = 0.75f;
 
@@ -386,33 +380,6 @@ static int signedCurrentMilliAmps(final int microAmps, final boolean charging) {
 		return charging ? magnitude : -magnitude;
 	}
 
-	/**
-	 * The user's shared "high drain" limit in %/h — the red line in the details table (#108) and the
-	 * fast-drain alert trigger (#109). Defaults to {@link #DEFAULT_DRAIN_LIMIT_PPH}.
-	 *
-	 * @param context Application context
-	 *
-	 * @return the configured limit in %/h
-	 */
-	public static int getDrainLimitPercentPerHour(final Context context) {
-		final int stored = PreferenceManager.getDefaultSharedPreferences(context)
-		                                    .getInt(context.getString(R.string._pref_key_fast_drain_limit), DEFAULT_DRAIN_LIMIT_PPH);
-		return clampDrainLimit(stored);
-	}
-
-	/**
-	 * Clamps a stored drain limit to the accepted range, so a corrupt or out-of-range preference value
-	 * can't skew the red line here or the fast-drain trigger in #109. The bounds mirror the slider's
-	 * {@code android:min}/{@code android:max} in {@code pref_alerts.xml}. Pure so it is unit-testable.
-	 *
-	 * @param stored the raw persisted limit in %/h
-	 *
-	 * @return the limit clamped to [{@link #MIN_DRAIN_LIMIT_PPH}, {@link #MAX_DRAIN_LIMIT_PPH}]
-	 */
-	static int clampDrainLimit(final int stored) {
-		return Math.max(MIN_DRAIN_LIMIT_PPH, Math.min(MAX_DRAIN_LIMIT_PPH, stored));
-	}
-
 	/**
 	 * The amber threshold derived just below a given red limit (#108). Pure so it is unit-testable.
 	 *

app/src/main/java/com/almothafar/simplebatterynotifier/service/FastDrainDetector.java

@@ -10,6 +10,7 @@
 import com.almothafar.simplebatterynotifier.service.SustainedConditionTracker.Outcome;
 import com.almothafar.simplebatterynotifier.service.SustainedConditionTracker.Streak;
 import com.almothafar.simplebatterynotifier.service.SustainedConditionTracker.StreakStore;
+import com.almothafar.simplebatterynotifier.util.AppPrefs;
 
 import static java.util.Objects.isNull;
 
@@ -80,7 +81,7 @@ public static void evaluate(Context context, BatteryDO batteryDO, BatteryRate ra
 			return;
 		}
 
-		final int limit = BatteryRateTracker.getDrainLimitPercentPerHour(context);
+		final int limit = AppPrefs.drainLimitPph(context);
 		final long sustainedMs = minutesPref(prefs, context, R.string._pref_key_fast_drain_sustained_minutes,
 				DEFAULT_SUSTAINED_MINUTES, MIN_SUSTAINED_MINUTES, MAX_SUSTAINED_MINUTES);
 		final long reminderGapMs = minutesPref(prefs, context, R.string._pref_key_fast_drain_reminder_minutes,
@@ -143,7 +144,7 @@ private static long minutesPref(SharedPreferences prefs,
 
 	/**
 	 * Clamps a stored minutes preference to its slider range and converts to millis. Mirrors
-	 * {@link BatteryRateTracker#clampDrainLimit}: the slider constrains UI input, but a corrupt or
+	 * {@link AppPrefs#clampDrainLimit}: the slider constrains UI input, but a corrupt or
 	 * out-of-range stored value (e.g. 0 sustained minutes) would otherwise defeat the sustained-window
 	 * requirement and fire on a momentary spike. Pure so it is unit-testable.
 	 *

app/src/main/java/com/almothafar/simplebatterynotifier/service/NotificationService.java

@@ -31,6 +31,7 @@
 import com.almothafar.simplebatterynotifier.model.ChargeSpeed;
 import com.almothafar.simplebatterynotifier.model.ChargeSpeedTier;
 import com.almothafar.simplebatterynotifier.ui.MainActivity;
+import com.almothafar.simplebatterynotifier.util.AppPrefs;
 import com.almothafar.simplebatterynotifier.util.BatteryPercentFormatter;
 import com.almothafar.simplebatterynotifier.util.GeneralHelper;
 import com.almothafar.simplebatterynotifier.util.TemperatureUtils;
@@ -1407,8 +1408,8 @@ private static class NotificationConfig {
 			this.type = type;
 
 			// Load common preferences
-			final int warningLevel = prefs.getInt(context.getString(R.string._pref_key_warn_battery_level), 40);
-			final int criticalLevel = prefs.getInt(context.getString(R.string._pref_key_critical_battery_level), 20);
+			final int warningLevel = AppPrefs.warningLevel(context);
+			final int criticalLevel = AppPrefs.criticalLevel(context);
 
 			this.stickyNotification = prefs.getBoolean(context.getString(R.string._pref_key_notifications_sticky), false);
 			final boolean withinWindow = isWithinNotificationWindow(context, prefs);

app/src/main/java/com/almothafar/simplebatterynotifier/ui/MainActivity.java

@@ -3,7 +3,6 @@
 import android.Manifest;
 import android.content.ActivityNotFoundException;
 import android.content.Intent;
-import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.BatteryManager;
@@ -28,13 +27,14 @@
 import androidx.annotation.NonNull;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.content.ContextCompat;
-import androidx.preference.PreferenceManager;
 import com.almothafar.simplebatterynotifier.R;
 import com.almothafar.simplebatterynotifier.model.BatteryDO;
+import com.almothafar.simplebatterynotifier.model.LevelThresholds;
 import com.almothafar.simplebatterynotifier.service.BatteryHealthTracker;
 import com.almothafar.simplebatterynotifier.service.PowerConnectionService;
 import com.almothafar.simplebatterynotifier.service.SystemService;
 import com.almothafar.simplebatterynotifier.ui.widget.HorseshoeProgressBar;
+import com.almothafar.simplebatterynotifier.util.AppPrefs;
 import com.almothafar.simplebatterynotifier.util.BatteryPercentFormatter;
 
 import java.util.List;
@@ -305,10 +305,9 @@ private static HorseshoeProgressBar.Flow flowOf(final int batteryStatus) {
 	 */
 	private void initializeFirstValues() {
 		fillBatteryInfo();
-		final SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
 
-		batteryGauge.setThresholds(sharedPref.getInt(getString(R.string._pref_key_critical_battery_level), 20),
-				sharedPref.getInt(getString(R.string._pref_key_warn_battery_level), 40));
+		final LevelThresholds levels = AppPrefs.batteryLevels(this);
+		batteryGauge.setThresholds(levels.critical(), levels.warning());
 
 		// Keep the in-fly slider in sync with values that may have changed in Settings.
 		syncThresholdSlider();
@@ -356,15 +355,11 @@ public void onStartTrackingTouch(@NonNull final RangeSlider slider) {
 			@Override
 			public void onStopTrackingTouch(@NonNull final RangeSlider slider) {
 				final List<Float> values = slider.getValues();
-				final int critical = Math.round(values.get(0));
-				final int warning = Math.round(values.get(1));
+				final LevelThresholds levels = new LevelThresholds(Math.round(values.get(0)), Math.round(values.get(1)));
 
-				PreferenceManager.getDefaultSharedPreferences(MainActivity.this).edit()
-						.putInt(getString(R.string._pref_key_critical_battery_level), critical)
-						.putInt(getString(R.string._pref_key_warn_battery_level), warning)
-						.apply();
+				AppPrefs.setBatteryLevels(MainActivity.this, levels);
 
-				batteryGauge.setThresholds(critical, warning);
+				batteryGauge.setThresholds(levels.critical(), levels.warning());
 			}
 		});
 
@@ -379,18 +374,13 @@ private void syncThresholdSlider() {
 		if (isNull(thresholdSlider)) {
 			return;
 		}
-		final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
-		final int critical = prefs.getInt(getString(R.string._pref_key_critical_battery_level),
-				BatteryRangeSliderHelper.DEFAULT_CRITICAL);
-		final int warning = prefs.getInt(getString(R.string._pref_key_warn_battery_level),
-				BatteryRangeSliderHelper.DEFAULT_WARNING);
-		final int[] pair = BatteryRangeSliderHelper.clampPair(critical, warning,
+		final LevelThresholds pair = BatteryRangeSliderHelper.clampPair(AppPrefs.batteryLevels(this),
 				BatteryRangeSliderHelper.LEVEL_FROM, BatteryRangeSliderHelper.LEVEL_TO,
 				BatteryRangeSliderHelper.MIN_SEPARATION);
 
-		thresholdSlider.setValues((float) pair[0], (float) pair[1]);
+		thresholdSlider.setValues((float) pair.critical(), (float) pair.warning());
 		updateThresholdCaptions(findViewById(R.id.thresholdCriticalCaption),
-				findViewById(R.id.thresholdWarningCaption), pair[0], pair[1]);
+				findViewById(R.id.thresholdWarningCaption), pair.critical(), pair.warning());
 	}
 
 	private void updateThresholdCaptions(final TextView criticalCaption, final TextView warningCaption,

app/src/main/java/com/almothafar/simplebatterynotifier/ui/fragment/BatteryDetailsFragment.java

@@ -28,6 +28,7 @@
 import com.almothafar.simplebatterynotifier.service.BatteryHealthTracker;
 import com.almothafar.simplebatterynotifier.service.BatteryRateTracker;
 import com.almothafar.simplebatterynotifier.service.SystemService;
+import com.almothafar.simplebatterynotifier.util.AppPrefs;
 import com.almothafar.simplebatterynotifier.util.GeneralHelper;
 import com.almothafar.simplebatterynotifier.util.TemperatureUtils;
 import com.google.android.material.dialog.MaterialAlertDialogBuilder;
@@ -632,7 +633,7 @@ private int rateColor(final Context context, final BatteryRateTracker.BatteryRat
 		if (rate.charging()) {
 			return 0;
 		}
-		final int limit = BatteryRateTracker.getDrainLimitPercentPerHour(context);
+		final int limit = AppPrefs.drainLimitPph(context);
 		if (rate.percentPerHour() >= limit) {
 			return GeneralHelper.getColor(getResources(), R.color.battery_rate_high);
 		}

app/src/main/java/com/almothafar/simplebatterynotifier/ui/preference/BatteryRangeSliderHelper.java

@@ -1,6 +1,7 @@
 package com.almothafar.simplebatterynotifier.ui.preference;
 
 import com.almothafar.simplebatterynotifier.R;
+import com.almothafar.simplebatterynotifier.model.LevelThresholds;
 import com.google.android.material.slider.RangeSlider;
 
 /**
@@ -20,10 +21,6 @@ public final class BatteryRangeSliderHelper {
 	public static final int LEVEL_TO = 50;
 	/** Minimum gap kept between the critical and warning thumbs, in percent. */
 	public static final int MIN_SEPARATION = 5;
-	/** Default critical level, matching the historical {@code SeekBarPreference} default. */
-	public static final int DEFAULT_CRITICAL = 20;
-	/** Default warning level, matching the historical {@code SeekBarPreference} default. */
-	public static final int DEFAULT_WARNING = 40;
 
 	private BatteryRangeSliderHelper() {
 		// Utility class
@@ -32,7 +29,7 @@ private BatteryRangeSliderHelper() {
 	/**
 	 * Apply the shared bounds, integer step, minimum thumb separation, and a "{@code N%}" label
 	 * formatter to a slider. Does not set the thumb values — callers set those after clamping via
-	 * {@link #clampPair(int, int, int, int, int)}.
+	 * {@link #clampPair(LevelThresholds, int, int, int)}.
 	 *
 	 * @param slider        the range slider to configure
 	 * @param from          combined track start (critical floor)
@@ -50,22 +47,27 @@ public static void configure(final RangeSlider slider, final int from, final int
 	}
 
 	/**
-	 * Clamp a (critical, warning) pair into {@code [from, to]} while keeping them at least
-	 * {@code minSeparation} apart, so persisted or corrupted values can always be shown on the
-	 * slider without tripping its validation.
+	 * Clamp a {@link LevelThresholds} pair into {@code [from, to]} while keeping the two levels at least
+	 * {@code minSeparation} apart, so persisted or corrupted values can always be shown on the slider
+	 * without tripping its validation.
 	 *
-	 * @return a two-element array {@code {critical, warning}}
+	 * @param levels        the raw (critical, warning) pair to reconcile
+	 * @param from          combined track start (critical floor)
+	 * @param to            combined track end (warning ceiling)
+	 * @param minSeparation minimum gap between the two thumbs, in value units
+	 *
+	 * @return a clamped {@code (critical, warning)} pair the slider can always accept
 	 */
-	public static int[] clampPair(final int critical, final int warning,
-	                              final int from, final int to, final int minSeparation) {
-		int low = clamp(critical, from, to);
-		int high = clamp(warning, from, to);
+	public static LevelThresholds clampPair(final LevelThresholds levels,
+	                                        final int from, final int to, final int minSeparation) {
+		int low = clamp(levels.critical(), from, to);
+		int high = clamp(levels.warning(), from, to);
 		if (high - low < minSeparation) {
 			// Push the warning thumb up first; if that hits the ceiling, pull critical back down.
 			high = Math.min(to, low + minSeparation);
 			low = Math.max(from, high - minSeparation);
 		}
-		return new int[]{low, high};
+		return new LevelThresholds(low, high);
 	}
 
 	private static int clamp(final int value, final int lo, final int hi) {

app/src/main/java/com/almothafar/simplebatterynotifier/ui/preference/BatteryRangeSliderPreference.java

@@ -11,6 +11,8 @@
 import androidx.preference.PreferenceViewHolder;
 
 import com.almothafar.simplebatterynotifier.R;
+import com.almothafar.simplebatterynotifier.model.LevelThresholds;
+import com.almothafar.simplebatterynotifier.util.AppPrefs;
 import com.google.android.material.slider.RangeSlider;
 
 import java.util.List;
@@ -37,8 +39,8 @@ public class BatteryRangeSliderPreference extends Preference {
 	private int from = BatteryRangeSliderHelper.LEVEL_FROM;
 	private int to = BatteryRangeSliderHelper.LEVEL_TO;
 	private int minSeparation = BatteryRangeSliderHelper.MIN_SEPARATION;
-	private int criticalDefault = BatteryRangeSliderHelper.DEFAULT_CRITICAL;
-	private int warningDefault = BatteryRangeSliderHelper.DEFAULT_WARNING;
+	private int criticalDefault = AppPrefs.DEFAULT_CRITICAL_LEVEL;
+	private int warningDefault = AppPrefs.DEFAULT_WARNING_LEVEL;
 
 	public BatteryRangeSliderPreference(final Context context, final AttributeSet attrs,
 	                                    final int defStyleAttr, final int defStyleRes) {
@@ -102,15 +104,15 @@ public void onBindViewHolder(@NonNull final PreferenceViewHolder holder) {
 		slider.clearOnChangeListeners();
 		slider.clearOnSliderTouchListeners();
 
-		final int[] pair = readClampedValues();
-		slider.setValues((float) pair[0], (float) pair[1]);
-		updateCaptions(criticalCaption, warningCaption, pair[0], pair[1]);
+		final LevelThresholds pair = readClampedValues();
+		slider.setValues((float) pair.critical(), (float) pair.warning());
+		updateCaptions(criticalCaption, warningCaption, pair.critical(), pair.warning());
 
 		// Update the captions live while dragging; persist only when the drag ends to avoid a burst
 		// of writes and readers seeing half-applied intermediate values.
 		slider.addOnChangeListener((s, value, fromUser) -> {
-			final int[] current = currentValues(s);
-			updateCaptions(criticalCaption, warningCaption, current[0], current[1]);
+			final LevelThresholds current = currentValues(s);
+			updateCaptions(criticalCaption, warningCaption, current.critical(), current.warning());
 		});
 
 		slider.addOnSliderTouchListener(new RangeSlider.OnSliderTouchListener() {
@@ -121,8 +123,7 @@ public void onStartTrackingTouch(@NonNull final RangeSlider s) {
 
 			@Override
 			public void onStopTrackingTouch(@NonNull final RangeSlider s) {
-				final int[] current = currentValues(s);
-				persist(current[0], current[1]);
+				persist(currentValues(s));
 			}
 		});
 	}
@@ -131,19 +132,19 @@ public void onStopTrackingTouch(@NonNull final RangeSlider s) {
 	 * Read the persisted critical/warning values (falling back to the defaults) and clamp them into
 	 * the slider's bounds and separation so they can always be applied safely.
 	 */
-	private int[] readClampedValues() {
+	private LevelThresholds readClampedValues() {
 		final SharedPreferences prefs = getSharedPreferences();
 		final int critical = nonNull(prefs) ? prefs.getInt(criticalKey, criticalDefault) : criticalDefault;
 		final int warning = nonNull(prefs) ? prefs.getInt(warningKey, warningDefault) : warningDefault;
-		return BatteryRangeSliderHelper.clampPair(critical, warning, from, to, minSeparation);
+		return BatteryRangeSliderHelper.clampPair(new LevelThresholds(critical, warning), from, to, minSeparation);
 	}
 
-	private void persist(final int critical, final int warning) {
+	private void persist(final LevelThresholds levels) {
 		final SharedPreferences prefs = getSharedPreferences();
 		if (nonNull(prefs)) {
 			prefs.edit()
-					.putInt(criticalKey, critical)
-					.putInt(warningKey, warning)
+					.putInt(criticalKey, levels.critical())
+					.putInt(warningKey, levels.warning())
 					.apply();
 		}
 	}
@@ -158,9 +159,9 @@ private void updateCaptions(final TextView criticalCaption, final TextView warni
 		}
 	}
 
-	private static int[] currentValues(final RangeSlider slider) {
+	private static LevelThresholds currentValues(final RangeSlider slider) {
 		final List<Float> values = slider.getValues();
-		return new int[]{Math.round(values.get(0)), Math.round(values.get(1))};
+		return new LevelThresholds(Math.round(values.get(0)), Math.round(values.get(1)));
 	}
 
 	private static String orDefault(final String value, final String fallback) {