Add transition point to low lux modifier

- Add transition point to brightness low lux modifier
- Pass in nits -> brightness splines from ddc.
- Only activate even dimmer if autobrightness is on.

Bug: 179428400
Test: atest DisplayServiceTests
Change-Id: I37c2ddca6c111c11b90525222d22a77ccfd3665f

12 files changed, 337 insertions, 63 deletions

diff --git a/services/core/java/com/android/server/display/DisplayDeviceConfig.java b/services/core/java/com/android/server/display/DisplayDeviceConfig.java
index 851d1978dd98..1ff285e16aa2 100644
--- a/services/core/java/com/android/server/display/DisplayDeviceConfig.java
+++ b/services/core/java/com/android/server/display/DisplayDeviceConfig.java
@@ -1097,13 +1097,34 @@ public class DisplayDeviceConfig {
         return mBrightnessToBacklightSpline.interpolate(brightness);
     }
 
-    private float getBrightnessFromBacklight(float brightness) {
+    /**
+     * Calculates the screen brightness value - as used among the system from the HAL backlight
+     * level
+     * @param backlight value from 0-1 HAL scale
+     * @return brightness value from 0-1 framework scale
+     */
+    public float getBrightnessFromBacklight(float backlight) {
         if (mLowBrightnessData != null) {
-            return mLowBrightnessData.mBacklightToBrightness.interpolate(brightness);
+            return mLowBrightnessData.mBacklightToBrightness.interpolate(backlight);
         }
-        return mBacklightToBrightnessSpline.interpolate(brightness);
+        return mBacklightToBrightnessSpline.interpolate(backlight);
     }
 
+    /**
+     *
+     * @return low brightness mode transition point
+     */
+    public float getLowBrightnessTransitionPoint() {
+        if (mLowBrightnessData == null) {
+            return PowerManager.BRIGHTNESS_MIN;
+        }
+        return mLowBrightnessData.mTransitionPoint;
+    }
+
+    /**
+     *
+     * @return HAL backlight mapping to framework brightness
+     */
     private Spline getBacklightToBrightnessSpline() {
         if (mLowBrightnessData != null) {
             return mLowBrightnessData.mBacklightToBrightness;
@@ -1133,7 +1154,12 @@ public class DisplayDeviceConfig {
         return mBacklightToNitsSpline.interpolate(backlight);
     }
 
-    private float getBacklightFromNits(float nits) {
+    /**
+     *
+     * @param nits - display brightness
+     * @return corresponding HAL backlight value
+     */
+    public float getBacklightFromNits(float nits) {
         if (mLowBrightnessData != null) {
             return mLowBrightnessData.mNitsToBacklight.interpolate(nits);
         }
@@ -1148,6 +1174,18 @@ public class DisplayDeviceConfig {
     }
 
     /**
+     *
+     * @param lux - ambient brightness
+     * @return minimum allowed nits, given the lux.
+     */
+    public float getMinNitsFromLux(float lux) {
+        if (mLowBrightnessData == null) {
+            return INVALID_NITS;
+        }
+        return mLowBrightnessData.mMinLuxToNits.interpolate(lux);
+    }
+
+    /**
      * @return true if there is sdrHdrRatioMap, false otherwise.
      */
     public boolean hasSdrToHdrRatioSpline() {
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index 90ad8c02c29c..cb07cf47413a 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -1426,12 +1426,14 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                 && (mAutomaticBrightnessStrategy.getAutoBrightnessAdjustmentChanged()
                 || userSetBrightnessChanged);
 
-        mBrightnessRangeController.setAutoBrightnessEnabled(
-                mAutomaticBrightnessStrategy.isAutoBrightnessEnabled()
+        final int autoBrightnessState = mAutomaticBrightnessStrategy.isAutoBrightnessEnabled()
                 ? AutomaticBrightnessController.AUTO_BRIGHTNESS_ENABLED
                 : mAutomaticBrightnessStrategy.isAutoBrightnessDisabledDueToDisplayOff()
                         ? AutomaticBrightnessController.AUTO_BRIGHTNESS_OFF_DUE_TO_DISPLAY_STATE
-                        : AutomaticBrightnessController.AUTO_BRIGHTNESS_DISABLED);
+                        : AutomaticBrightnessController.AUTO_BRIGHTNESS_DISABLED;
+
+        mBrightnessRangeController.setAutoBrightnessEnabled(autoBrightnessState);
+        mBrightnessClamperController.setAutoBrightnessState(autoBrightnessState);
 
         boolean updateScreenBrightnessSetting =
                 displayBrightnessState.shouldUpdateScreenBrightnessSetting();
diff --git a/services/core/java/com/android/server/display/brightness/clamper/BrightnessClamperController.java b/services/core/java/com/android/server/display/brightness/clamper/BrightnessClamperController.java
index d8a45009f236..9c7504db0cf0 100644
--- a/services/core/java/com/android/server/display/brightness/clamper/BrightnessClamperController.java
+++ b/services/core/java/com/android/server/display/brightness/clamper/BrightnessClamperController.java
@@ -66,6 +66,7 @@ public class BrightnessClamperController {
     private float mCustomAnimationRate = DisplayBrightnessState.CUSTOM_ANIMATION_RATE_NOT_SET;
     @Nullable
     private Type mClamperType = null;
+    private int mAutoBrightnessState = -1;
 
     private boolean mClamperApplied = false;
 
@@ -94,7 +95,8 @@ public class BrightnessClamperController {
 
         mClampers = injector.getClampers(handler, clamperChangeListenerInternal, data, flags,
                 context);
-        mModifiers = injector.getModifiers(flags, context, handler, clamperChangeListener);
+        mModifiers = injector.getModifiers(flags, context, handler, clamperChangeListener,
+                data.mDisplayDeviceConfig);
         mOnPropertiesChangedListener =
                 properties -> mClampers.forEach(BrightnessClamper::onDeviceConfigChanged);
         start();
@@ -197,6 +199,19 @@ public class BrightnessClamperController {
         mModifiers.forEach(modifier -> modifier.onAmbientLuxChange(ambientLux));
     }
 
+    /**
+     * Sets the autobrightness state for clampers that need to be aware of the state.
+     * @param state autobrightness state
+     */
+    public void setAutoBrightnessState(int state) {
+        if (state == mAutoBrightnessState) {
+            return;
+        }
+        mModifiers.forEach(modifier -> modifier.setAutoBrightnessState(state));
+        mAutoBrightnessState = state;
+        recalculateBrightnessCap();
+    }
+
     // Called in DisplayControllerHandler
     private void recalculateBrightnessCap() {
         float brightnessCap = PowerManager.BRIGHTNESS_MAX;
@@ -265,12 +280,14 @@ public class BrightnessClamperController {
         }
 
         List<BrightnessStateModifier> getModifiers(DisplayManagerFlags flags, Context context,
-                Handler handler, ClamperChangeListener listener) {
+                Handler handler, ClamperChangeListener listener,
+                DisplayDeviceConfig displayDeviceConfig) {
             List<BrightnessStateModifier> modifiers = new ArrayList<>();
             modifiers.add(new DisplayDimModifier(context));
             modifiers.add(new BrightnessLowPowerModeModifier());
             if (flags.isEvenDimmerEnabled()) {
-                modifiers.add(new BrightnessLowLuxModifier(handler, listener, context));
+                modifiers.add(new BrightnessLowLuxModifier(handler, listener, context,
+                        displayDeviceConfig));
             }
             return modifiers;
         }
diff --git a/services/core/java/com/android/server/display/brightness/clamper/BrightnessLowLuxModifier.java b/services/core/java/com/android/server/display/brightness/clamper/BrightnessLowLuxModifier.java
index a91bb59b0bc0..7f88c3029820 100644
--- a/services/core/java/com/android/server/display/brightness/clamper/BrightnessLowLuxModifier.java
+++ b/services/core/java/com/android/server/display/brightness/clamper/BrightnessLowLuxModifier.java
@@ -16,13 +16,14 @@
 
 package com.android.server.display.brightness.clamper;
 
+import static com.android.server.display.AutomaticBrightnessController.AUTO_BRIGHTNESS_ENABLED;
+
 import android.content.ContentResolver;
 import android.content.Context;
 import android.database.ContentObserver;
 import android.hardware.display.DisplayManagerInternal;
 import android.net.Uri;
 import android.os.Handler;
-import android.os.PowerManager;
 import android.os.UserHandle;
 import android.provider.Settings;
 import android.util.Slog;
@@ -30,6 +31,7 @@ import android.util.Slog;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.display.BrightnessSynchronizer;
 import com.android.server.display.DisplayBrightnessState;
+import com.android.server.display.DisplayDeviceConfig;
 import com.android.server.display.brightness.BrightnessReason;
 import com.android.server.display.utils.DebugUtils;
 
@@ -45,19 +47,23 @@ public class BrightnessLowLuxModifier extends BrightnessModifier {
     // 'adb shell setprop persist.log.tag.BrightnessLowLuxModifier DEBUG && adb reboot'
     private static final String TAG = "BrightnessLowLuxModifier";
     private static final boolean DEBUG = DebugUtils.isDebuggable(TAG);
-    private static final float MIN_NITS = 2.0f;
+    private static final float MIN_NITS_DEFAULT = 0.2f;
     private final SettingsObserver mSettingsObserver;
     private final ContentResolver mContentResolver;
     private final Handler mHandler;
     private final BrightnessClamperController.ClamperChangeListener mChangeListener;
     private int mReason;
     private float mBrightnessLowerBound;
+    private float mMinNitsAllowed;
     private boolean mIsActive;
+    private boolean mAutoBrightnessEnabled;
     private float mAmbientLux;
+    private final DisplayDeviceConfig mDisplayDeviceConfig;
 
     @VisibleForTesting
     BrightnessLowLuxModifier(Handler handler,
-            BrightnessClamperController.ClamperChangeListener listener, Context context) {
+            BrightnessClamperController.ClamperChangeListener listener, Context context,
+            DisplayDeviceConfig displayDeviceConfig) {
         super();
 
         mChangeListener = listener;
@@ -67,6 +73,8 @@ public class BrightnessLowLuxModifier extends BrightnessModifier {
         mHandler.post(() -> {
             start();
         });
+
+        mDisplayDeviceConfig = displayDeviceConfig;
     }
 
     /**
@@ -78,41 +86,45 @@ public class BrightnessLowLuxModifier extends BrightnessModifier {
         int userId = UserHandle.USER_CURRENT;
         float settingNitsLowerBound = Settings.Secure.getFloatForUser(
                 mContentResolver, Settings.Secure.EVEN_DIMMER_MIN_NITS,
-                /* def= */ MIN_NITS, userId);
+                /* def= */ MIN_NITS_DEFAULT, userId);
 
         boolean isActive = Settings.Secure.getFloatForUser(mContentResolver,
                 Settings.Secure.EVEN_DIMMER_ACTIVATED,
-                /* def= */ 0, userId) == 1.0f;
-
-        // TODO: luxBasedNitsLowerBound = mMinLuxToNitsSpline(currentLux);
-        float luxBasedNitsLowerBound = 2.0f;
-
-        final float nitsLowerBound = isActive ? Math.max(settingNitsLowerBound,
-                 luxBasedNitsLowerBound) : MIN_NITS;
-
-        final int reason = settingNitsLowerBound > luxBasedNitsLowerBound
-                ? BrightnessReason.MODIFIER_MIN_USER_SET_LOWER_BOUND
-                : BrightnessReason.MODIFIER_MIN_LUX;
-
-        // TODO: brightnessLowerBound = nitsToBrightnessSpline(nitsLowerBound);
-        final float brightnessLowerBound = PowerManager.BRIGHTNESS_MIN;
+                /* def= */ 0, userId) == 1.0f && mAutoBrightnessEnabled;
+
+        float luxBasedNitsLowerBound = mDisplayDeviceConfig.getMinNitsFromLux(mAmbientLux);
+
+        final int reason;
+        float minNitsAllowed = -1f; // undefined, if setting is off.
+        final float minBrightnessAllowed;
+
+        if (isActive) {
+            minNitsAllowed = Math.max(settingNitsLowerBound,
+                    luxBasedNitsLowerBound);
+            minBrightnessAllowed = getBrightnessFromNits(minNitsAllowed);
+            reason = settingNitsLowerBound > luxBasedNitsLowerBound
+                    ? BrightnessReason.MODIFIER_MIN_USER_SET_LOWER_BOUND
+                    : BrightnessReason.MODIFIER_MIN_LUX;
+        } else {
+            minBrightnessAllowed = mDisplayDeviceConfig.getLowBrightnessTransitionPoint();
+            reason = 0;
+        }
 
-        if (mBrightnessLowerBound != brightnessLowerBound
+        if (mBrightnessLowerBound != minBrightnessAllowed
                 || mReason != reason
                 || mIsActive != isActive) {
             mIsActive = isActive;
             mReason = reason;
             if (DEBUG) {
                 Slog.i(TAG, "isActive: " + isActive
-                        + ", brightnessLowerBound: " + brightnessLowerBound
+                        + ", minBrightnessAllowed: " + minBrightnessAllowed
                         + ", mAmbientLux: " + mAmbientLux
-                        + ", mReason: " + (
-                        mReason == BrightnessReason.MODIFIER_MIN_USER_SET_LOWER_BOUND ? "minSetting"
-                                : "lux")
-                        + ", nitsLowerBound: " + nitsLowerBound
+                        + ", mReason: " + (mReason)
+                        + ", minNitsAllowed: " + minNitsAllowed
                 );
             }
-            mBrightnessLowerBound = brightnessLowerBound;
+            mMinNitsAllowed = minNitsAllowed;
+            mBrightnessLowerBound = minBrightnessAllowed;
             mChangeListener.onChanged();
         }
     }
@@ -177,11 +189,23 @@ public class BrightnessLowLuxModifier extends BrightnessModifier {
     }
 
     @Override
+    public void setAutoBrightnessState(int state) {
+        mAutoBrightnessEnabled = state == AUTO_BRIGHTNESS_ENABLED;
+    }
+
+    @Override
     public void dump(PrintWriter pw) {
         pw.println("BrightnessLowLuxModifier:");
         pw.println("  mIsActive=" + mIsActive);
         pw.println("  mBrightnessLowerBound=" + mBrightnessLowerBound);
         pw.println("  mReason=" + mReason);
+        pw.println("  mAmbientLux=" + mAmbientLux);
+        pw.println("  mMinNitsAllowed=" + mMinNitsAllowed);
+    }
+
+    private float getBrightnessFromNits(float nits) {
+        return mDisplayDeviceConfig.getBrightnessFromBacklight(
+                mDisplayDeviceConfig.getBacklightFromNits(nits));
     }
 
     private final class SettingsObserver extends ContentObserver {
diff --git a/services/core/java/com/android/server/display/brightness/clamper/BrightnessModifier.java b/services/core/java/com/android/server/display/brightness/clamper/BrightnessModifier.java
index 2a3dd8752615..db5a524da71d 100644
--- a/services/core/java/com/android/server/display/brightness/clamper/BrightnessModifier.java
+++ b/services/core/java/com/android/server/display/brightness/clamper/BrightnessModifier.java
@@ -73,4 +73,9 @@ abstract class BrightnessModifier implements BrightnessStateModifier {
     public void onAmbientLuxChange(float ambientLux) {
         // do nothing
     }
+
+    @Override
+    public void setAutoBrightnessState(int state) {
+        // do nothing
+    }
 }
diff --git a/services/core/java/com/android/server/display/brightness/clamper/BrightnessStateModifier.java b/services/core/java/com/android/server/display/brightness/clamper/BrightnessStateModifier.java
index 22342581fa8b..1606159cb247 100644
--- a/services/core/java/com/android/server/display/brightness/clamper/BrightnessStateModifier.java
+++ b/services/core/java/com/android/server/display/brightness/clamper/BrightnessStateModifier.java
@@ -48,4 +48,10 @@ public interface BrightnessStateModifier {
      * @param ambientLux current debounced lux.
      */
     void onAmbientLuxChange(float ambientLux);
+
+    /**
+     * Sets the autobrightness state for clampers that need to be aware of the state.
+     * @param state autobrightness state
+     */
+    void setAutoBrightnessState(int state);
 }
diff --git a/services/core/java/com/android/server/display/config/LowBrightnessData.java b/services/core/java/com/android/server/display/config/LowBrightnessData.java
index aa82533bf6a7..1a4e807fece6 100644
--- a/services/core/java/com/android/server/display/config/LowBrightnessData.java
+++ b/services/core/java/com/android/server/display/config/LowBrightnessData.java
@@ -66,11 +66,13 @@ public class LowBrightnessData {
      * Spline, mapping between backlight and brightness
      */
     public final Spline mBacklightToBrightness;
+    public final Spline mMinLuxToNits;
 
     @VisibleForTesting
     public LowBrightnessData(float transitionPoint, float[] nits,
             float[] backlight, float[] brightness, Spline backlightToNits,
-            Spline nitsToBacklight, Spline brightnessToBacklight, Spline backlightToBrightness) {
+            Spline nitsToBacklight, Spline brightnessToBacklight, Spline backlightToBrightness,
+            Spline minLuxToNits) {
         mTransitionPoint = transitionPoint;
         mNits = nits;
         mBacklight = backlight;
@@ -79,6 +81,7 @@ public class LowBrightnessData {
         mNitsToBacklight = nitsToBacklight;
         mBrightnessToBacklight = brightnessToBacklight;
         mBacklightToBrightness = backlightToBrightness;
+        mMinLuxToNits = minLuxToNits;
     }
 
     @Override
@@ -92,6 +95,7 @@ public class LowBrightnessData {
                 + ", mNitsToBacklight: " + mNitsToBacklight
                 + ", mBrightnessToBacklight: " + mBrightnessToBacklight
                 + ", mBacklightToBrightness: " + mBacklightToBrightness
+                + ", mMinLuxToNits: " + mMinLuxToNits
                 + "} ";
     }
 
@@ -132,11 +136,40 @@ public class LowBrightnessData {
             brightness[i] = brightnessList.get(i);
         }
 
+        final NitsMap map = lbm.getLuxToMinimumNitsMap();
+        if (map == null) {
+            Slog.e(TAG, "Invalid min lux to nits mapping");
+            return null;
+        }
+        final List<Point> points = map.getPoint();
+        final int size = points.size();
+
+        float[] minLux = new float[size];
+        float[] minNits = new float[size];
+
+        int i = 0;
+        for (Point point : points) {
+            minLux[i] = point.getValue().floatValue();
+            minNits[i] = point.getNits().floatValue();
+            if (i > 0) {
+                if (minLux[i] < minLux[i - 1]) {
+                    Slog.e(TAG, "minLuxToNitsSpline must be non-decreasing, ignoring rest "
+                            + " of configuration. Value: " + minLux[i] + " < " + minLux[i - 1]);
+                }
+                if (minNits[i] < minNits[i - 1]) {
+                    Slog.e(TAG, "minLuxToNitsSpline must be non-decreasing, ignoring rest "
+                            + " of configuration. Nits: " + minNits[i] + " < " + minNits[i - 1]);
+                }
+            }
+            ++i;
+        }
+
         return new LowBrightnessData(transitionPoints, nits, backlight, brightness,
                 Spline.createSpline(backlight, nits),
                 Spline.createSpline(nits, backlight),
                 Spline.createSpline(brightness, backlight),
-                Spline.createSpline(backlight, brightness)
-                );
+                Spline.createSpline(backlight, brightness),
+                Spline.createSpline(minLux, minNits)
+        );
     }
 }
diff --git a/services/core/xsd/display-device-config/display-device-config.xsd b/services/core/xsd/display-device-config/display-device-config.xsd
index 1f5451813dae..912ff4ae2022 100644
--- a/services/core/xsd/display-device-config/display-device-config.xsd
+++ b/services/core/xsd/display-device-config/display-device-config.xsd
@@ -232,6 +232,9 @@
             </xs:element>
             <xs:element name="brightness" type="xs:float" maxOccurs="unbounded">
             </xs:element>
+            <!-- Mapping of current lux to minimum allowed nits values. -->
+            <xs:element name="luxToMinimumNitsMap" type="nitsMap" maxOccurs="1">
+            </xs:element>
         </xs:sequence>
         <xs:attribute name="enabled" type="xs:boolean" use="optional"/>
     </xs:complexType>
diff --git a/services/core/xsd/display-device-config/schema/current.txt b/services/core/xsd/display-device-config/schema/current.txt
index c39c3d7ee7c6..3c708900c64e 100644
--- a/services/core/xsd/display-device-config/schema/current.txt
+++ b/services/core/xsd/display-device-config/schema/current.txt
@@ -255,9 +255,11 @@ package com.android.server.display.config {
     method public java.util.List<java.lang.Float> getBacklight();
     method public java.util.List<java.lang.Float> getBrightness();
     method public boolean getEnabled();
+    method public com.android.server.display.config.NitsMap getLuxToMinimumNitsMap();
     method public java.util.List<java.lang.Float> getNits();
     method public java.math.BigDecimal getTransitionPoint();
     method public void setEnabled(boolean);
+    method public void setLuxToMinimumNitsMap(com.android.server.display.config.NitsMap);
     method public void setTransitionPoint(java.math.BigDecimal);
   }
 
diff --git a/services/tests/displayservicetests/src/com/android/server/display/DisplayDeviceConfigTest.java b/services/tests/displayservicetests/src/com/android/server/display/DisplayDeviceConfigTest.java
index 73a2f655da8d..5a022c0f5d27 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/DisplayDeviceConfigTest.java
+++ b/services/tests/displayservicetests/src/com/android/server/display/DisplayDeviceConfigTest.java
@@ -1651,6 +1651,17 @@ public final class DisplayDeviceConfigTest {
                 + "  <brightness>0.1</brightness>\n"
                 + "  <brightness>0.5</brightness>\n"
                 + "  <brightness>1.0</brightness>\n"
+                + " <luxToMinimumNitsMap>\n"
+                + "     <point>\n"
+                + "         <value>10</value> <nits>0.3</nits>\n"
+                + "     </point>\n"
+                + "     <point>\n"
+                + "         <value>50</value> <nits>0.7</nits>\n"
+                + "     </point>\n"
+                + "     <point>\n"
+                + "         <value>100</value> <nits>1.0</nits>\n"
+                + "     </point>\n"
+                + " </luxToMinimumNitsMap>\n"
                 + "</lowBrightness>";
     }
 
diff --git a/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessClamperControllerTest.java b/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessClamperControllerTest.java
index 5294943fa387..5487bc53ffce 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessClamperControllerTest.java
+++ b/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessClamperControllerTest.java
@@ -35,6 +35,7 @@ import androidx.test.filters.SmallTest;
 import androidx.test.platform.app.InstrumentationRegistry;
 
 import com.android.server.display.DisplayBrightnessState;
+import com.android.server.display.DisplayDeviceConfig;
 import com.android.server.display.brightness.BrightnessReason;
 import com.android.server.display.feature.DeviceConfigParameterProvider;
 import com.android.server.display.feature.DisplayManagerFlags;
@@ -280,7 +281,8 @@ public class BrightnessClamperControllerTest {
 
         @Override
         List<BrightnessStateModifier> getModifiers(DisplayManagerFlags flags, Context context,
-                Handler handler, BrightnessClamperController.ClamperChangeListener listener) {
+                Handler handler, BrightnessClamperController.ClamperChangeListener listener,
+                DisplayDeviceConfig displayDeviceConfig) {
             return mModifiers;
         }
     }
diff --git a/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessLowLuxModifierTest.kt b/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessLowLuxModifierTest.kt
index e4a7d982514f..749c400f819e 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessLowLuxModifierTest.kt
+++ b/services/tests/displayservicetests/src/com/android/server/display/brightness/clamper/BrightnessLowLuxModifierTest.kt
@@ -15,13 +15,18 @@
  */
 package com.android.server.display.brightness.clamper
 
-import android.os.PowerManager
 import android.os.UserHandle
+import android.platform.test.annotations.RequiresFlagsEnabled
 import android.provider.Settings
 import android.testing.TestableContext
 import androidx.test.platform.app.InstrumentationRegistry
+import com.android.server.display.AutomaticBrightnessController.AUTO_BRIGHTNESS_DISABLED
+import com.android.server.display.AutomaticBrightnessController.AUTO_BRIGHTNESS_ENABLED
+import com.android.server.display.DisplayDeviceConfig
 import com.android.server.display.brightness.BrightnessReason
+import com.android.server.display.feature.flags.Flags
 import com.android.server.testutils.TestHandler
+import com.android.server.testutils.whenever
 import com.google.common.truth.Truth.assertThat
 import org.junit.Before
 import org.junit.Test
@@ -32,71 +37,197 @@ private const val userId = UserHandle.USER_CURRENT
 class BrightnessLowLuxModifierTest {
 
     private var mockClamperChangeListener =
-            mock<BrightnessClamperController.ClamperChangeListener>()
+        mock<BrightnessClamperController.ClamperChangeListener>()
 
     val context = TestableContext(
-            InstrumentationRegistry.getInstrumentation().getContext())
+        InstrumentationRegistry.getInstrumentation().getContext())
 
     private val testHandler = TestHandler(null)
     private lateinit var modifier: BrightnessLowLuxModifier
 
+    private var mockDisplayDeviceConfig = mock<DisplayDeviceConfig>()
+
+    private val LOW_LUX_BRIGHTNESS = 0.1f
+    private val TRANSITION_POINT = 0.25f
+    private val NORMAL_RANGE_BRIGHTNESS = 0.3f
+
     @Before
     fun setUp() {
-        modifier = BrightnessLowLuxModifier(testHandler, mockClamperChangeListener, context)
+        modifier =
+            BrightnessLowLuxModifier(testHandler,
+                mockClamperChangeListener,
+                context,
+                mockDisplayDeviceConfig)
+
+        // values below transition point (even dimmer range)
+        // nits: 0.1 -> backlight 0.02 -> brightness -> 0.1
+        whenever(mockDisplayDeviceConfig.getBacklightFromNits(/* nits= */ 1.0f))
+                .thenReturn(0.02f)
+        whenever(mockDisplayDeviceConfig.getBrightnessFromBacklight(/* backlight = */ 0.02f))
+                .thenReturn(LOW_LUX_BRIGHTNESS)
+
+        // values above transition point (noraml range)
+        // nits: 10 -> backlight 0.2 -> brightness -> 0.3
+        whenever(mockDisplayDeviceConfig.getBacklightFromNits(/* nits= */ 2f))
+                .thenReturn(0.15f)
+        whenever(mockDisplayDeviceConfig.getBrightnessFromBacklight(/* backlight = */ 0.15f))
+                .thenReturn(0.24f)
+
+        // values above transition point (normal range)
+        // nits: 10 -> backlight 0.2 -> brightness -> 0.3
+        whenever(mockDisplayDeviceConfig.getBacklightFromNits(/* nits= */ 10f))
+                .thenReturn(0.2f)
+        whenever(mockDisplayDeviceConfig.getBrightnessFromBacklight(/* backlight = */ 0.2f))
+                .thenReturn(NORMAL_RANGE_BRIGHTNESS)
+
+        // min nits when lux of 400
+        whenever(mockDisplayDeviceConfig.getMinNitsFromLux(/* lux= */ 400f))
+                .thenReturn(1.0f)
+
+
+        whenever(mockDisplayDeviceConfig.lowBrightnessTransitionPoint).thenReturn(TRANSITION_POINT)
+
         testHandler.flush()
     }
 
     @Test
-    fun testThrottlingBounds() {
+    fun testSettingOffDisablesModifier() {
+        // test transition point ensures brightness doesn't drop when setting is off.
         Settings.Secure.putIntForUser(context.contentResolver,
-                Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId) // true
-        Settings.Secure.putFloatForUser(context.contentResolver,
-                Settings.Secure.EVEN_DIMMER_MIN_NITS, 0.7f, userId)
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 0, userId)
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_ENABLED)
         modifier.recalculateLowerBound()
         testHandler.flush()
-        assertThat(modifier.isActive).isTrue()
+        assertThat(modifier.brightnessLowerBound).isEqualTo(TRANSITION_POINT)
+        assertThat(modifier.brightnessReason).isEqualTo(0) // no reason - ie off
+        modifier.onAmbientLuxChange(3000.0f)
+        testHandler.flush()
+        assertThat(modifier.isActive).isFalse()
+        assertThat(modifier.brightnessLowerBound).isEqualTo(TRANSITION_POINT)
+        assertThat(modifier.brightnessReason).isEqualTo(0) // no reason - ie off
+    }
 
-        // TODO: code currently returns MIN/MAX; update with lux values
-        assertThat(modifier.brightnessLowerBound).isEqualTo(PowerManager.BRIGHTNESS_MIN)
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_EVEN_DIMMER)
+    fun testLuxRestrictsBrightnessRange() {
+        // test that high lux prevents low brightness range.
+        Settings.Secure.putIntForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId)
+        Settings.Secure.putFloatForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_MIN_NITS, 0.1f, userId)
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_ENABLED)
+        modifier.onAmbientLuxChange(400.0f)
+        testHandler.flush()
+
+        assertThat(modifier.isActive).isTrue()
+        // Test restriction from lux setting
+        assertThat(modifier.brightnessReason).isEqualTo(BrightnessReason.MODIFIER_MIN_LUX)
+        assertThat(modifier.brightnessLowerBound).isEqualTo(LOW_LUX_BRIGHTNESS)
     }
 
     @Test
-    fun testGetReason_UserSet() {
+    @RequiresFlagsEnabled(Flags.FLAG_EVEN_DIMMER)
+    fun testUserRestrictsBrightnessRange() {
+        // test that user minimum nits setting prevents low brightness range.
         Settings.Secure.putIntForUser(context.contentResolver,
-                Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId)
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId)
         Settings.Secure.putFloatForUser(context.contentResolver,
-                Settings.Secure.EVEN_DIMMER_MIN_NITS, 30.0f, userId)
+            Settings.Secure.EVEN_DIMMER_MIN_NITS, 10.0f, userId)
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_ENABLED)
         modifier.recalculateLowerBound()
         testHandler.flush()
-        assertThat(modifier.isActive).isTrue()
 
         // Test restriction from user setting
+        assertThat(modifier.isActive).isTrue()
         assertThat(modifier.brightnessReason)
                 .isEqualTo(BrightnessReason.MODIFIER_MIN_USER_SET_LOWER_BOUND)
+        assertThat(modifier.brightnessLowerBound).isEqualTo(NORMAL_RANGE_BRIGHTNESS)
     }
 
     @Test
-    fun testGetReason_Lux() {
+    @RequiresFlagsEnabled(Flags.FLAG_EVEN_DIMMER)
+    fun testOnToOff() {
+        // test that high lux prevents low brightness range.
         Settings.Secure.putIntForUser(context.contentResolver,
-                Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId)
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId) // on
         Settings.Secure.putFloatForUser(context.contentResolver,
-                Settings.Secure.EVEN_DIMMER_MIN_NITS, 0.0f, userId)
-        modifier.onAmbientLuxChange(3000.0f)
+            Settings.Secure.EVEN_DIMMER_MIN_NITS, 1.0f, userId)
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_ENABLED)
+        modifier.onAmbientLuxChange(400.0f)
         testHandler.flush()
+
         assertThat(modifier.isActive).isTrue()
+        // Test restriction from lux setting
+        assertThat(modifier.brightnessReason).isEqualTo(BrightnessReason.MODIFIER_MIN_LUX)
+        assertThat(modifier.brightnessLowerBound).isEqualTo(LOW_LUX_BRIGHTNESS)
+
+        Settings.Secure.putIntForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 0, userId) // off
+
+        modifier.recalculateLowerBound()
+        testHandler.flush()
+
+        assertThat(modifier.isActive).isFalse()
+        assertThat(modifier.brightnessLowerBound).isEqualTo(TRANSITION_POINT)
+        assertThat(modifier.brightnessReason).isEqualTo(0) // no reason - ie off
+    }
+
+    @Test
+    @RequiresFlagsEnabled(Flags.FLAG_EVEN_DIMMER)
+    fun testOffToOn() {
+        // test that high lux prevents low brightness range.
+        Settings.Secure.putIntForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 0, userId) // off
+        Settings.Secure.putFloatForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_MIN_NITS, 1.0f, userId)
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_ENABLED)
+        modifier.onAmbientLuxChange(400.0f)
+        testHandler.flush()
+
+        assertThat(modifier.isActive).isFalse()
+        assertThat(modifier.brightnessLowerBound).isEqualTo(TRANSITION_POINT)
+        assertThat(modifier.brightnessReason).isEqualTo(0) // no reason - ie off
+
+
+
+        Settings.Secure.putIntForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId) // on
+        modifier.recalculateLowerBound()
+        testHandler.flush()
 
+        assertThat(modifier.isActive).isTrue()
         // Test restriction from lux setting
         assertThat(modifier.brightnessReason).isEqualTo(BrightnessReason.MODIFIER_MIN_LUX)
+        assertThat(modifier.brightnessLowerBound).isEqualTo(LOW_LUX_BRIGHTNESS)
     }
 
     @Test
-    fun testSettingOffDisablesModifier() {
+    @RequiresFlagsEnabled(Flags.FLAG_EVEN_DIMMER)
+    fun testDisabledWhenAutobrightnessIsOff() {
+        // test that high lux prevents low brightness range.
         Settings.Secure.putIntForUser(context.contentResolver,
-            Settings.Secure.EVEN_DIMMER_ACTIVATED, 0, userId)
-        assertThat(modifier.brightnessLowerBound).isEqualTo(PowerManager.BRIGHTNESS_MIN)
-        modifier.onAmbientLuxChange(3000.0f)
+            Settings.Secure.EVEN_DIMMER_ACTIVATED, 1, userId) // on
+        Settings.Secure.putFloatForUser(context.contentResolver,
+            Settings.Secure.EVEN_DIMMER_MIN_NITS, 1.0f, userId)
+
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_ENABLED)
+        modifier.onAmbientLuxChange(400.0f)
         testHandler.flush()
+
+        assertThat(modifier.isActive).isTrue()
+        // Test restriction from lux setting
+        assertThat(modifier.brightnessReason).isEqualTo(BrightnessReason.MODIFIER_MIN_LUX)
+        assertThat(modifier.brightnessLowerBound).isEqualTo(LOW_LUX_BRIGHTNESS)
+
+
+        modifier.setAutoBrightnessState(AUTO_BRIGHTNESS_DISABLED)
+        modifier.onAmbientLuxChange(400.0f)
+        testHandler.flush()
+
         assertThat(modifier.isActive).isFalse()
-        assertThat(modifier.brightnessLowerBound).isEqualTo(PowerManager.BRIGHTNESS_MIN)
+        // Test restriction from lux setting
+        assertThat(modifier.brightnessReason).isEqualTo(0)
+        assertThat(modifier.brightnessLowerBound).isEqualTo(TRANSITION_POINT)
     }
 }
+