/*
 * Copyright 2021 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package androidx.core.location;

import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;

import android.location.Location;
import android.os.Build.VERSION;
import android.os.Bundle;
import android.os.SystemClock;

import androidx.annotation.DoNotInline;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * Helper for accessing features in {@link android.location.Location}.
 */
public final class LocationCompat {

    /**
     * Constant used as a key to store mock location status in {@link Location#getExtras()} for
     * Android SDK levels below JBMR2 (18).
     */
    @SuppressWarnings("ActionValue") // legacy value
    public static final String EXTRA_IS_MOCK = "mockLocation";

    /**
     * Constant used as a key to store vertical accuracy in {@link Location#getExtras()} for
     * Android SDK levels below Oreo (26).
     */
    @SuppressWarnings("ActionValue") // legacy value
    public static final String EXTRA_VERTICAL_ACCURACY = "verticalAccuracy";

    /**
     * Constant used as a key to store speed accuracy in {@link Location#getExtras()} for
     * Android SDK levels below Oreo (26).
     */
    @SuppressWarnings("ActionValue") // legacy value
    public static final String EXTRA_SPEED_ACCURACY = "speedAccuracy";

    /**
     * Constant used as a key to store bearing accuracy in {@link Location#getExtras()} for
     * Android SDK levels below Oreo (26).
     */
    @SuppressWarnings("ActionValue") // legacy value
    public static final String EXTRA_BEARING_ACCURACY = "bearingAccuracy";

    @Nullable
    private static Method sSetIsFromMockProviderMethod;

    private LocationCompat() {}

    /**
     * Return the time of this fix, in nanoseconds of elapsed real-time since system boot.
     *
     * <p>This value can be reliably compared to SystemClock.elapsedRealtimeNanos(), to calculate
     * the age of a fix and to compare location fixes. This is reliable because elapsed real-time
     * is guaranteed monotonic for each system boot and continues to increment even when the
     * system is in deep sleep (unlike getTime().
     *
     * <p>All locations generated by the LocationManager are guaranteed to have a valid elapsed
     * real-time.
     *
     * <p>NOTE: On API levels below 17, this method will attempt to provide an elapsed realtime
     * based on the difference between system time and the location time. This should be taken as a
     * best "guess" at what the elapsed realtime might have been, but if the clock used for
     * location derivation is different from the system clock, the results may be inaccurate.
     */
    public static long getElapsedRealtimeNanos(@NonNull Location location) {
        if (VERSION.SDK_INT >= 17) {
            return Api17Impl.getElapsedRealtimeNanos(location);
        } else {
            return MILLISECONDS.toNanos(getElapsedRealtimeMillis(location));
        }
    }

    /**
     * Return the time of this fix, in milliseconds of elapsed real-time since system boot.
     *
     * @see #getElapsedRealtimeNanos(Location)
     */
    public static long getElapsedRealtimeMillis(@NonNull Location location) {
        if (VERSION.SDK_INT >= 17) {
            return NANOSECONDS.toMillis(Api17Impl.getElapsedRealtimeNanos(location));
        } else {
            long timeDeltaMs = System.currentTimeMillis() - location.getTime();
            long elapsedRealtimeMs = SystemClock.elapsedRealtime();
            if (timeDeltaMs < 0) {
                // don't return an elapsed realtime from the future
                return elapsedRealtimeMs;
            } else if (timeDeltaMs > elapsedRealtimeMs) {
                // don't return an elapsed realtime from before boot
                return 0;
            } else {
                return elapsedRealtimeMs - timeDeltaMs;
            }
        }
    }

    /**
     * Returns true if this location has a vertical accuracy.
     *
     * @see Location#hasVerticalAccuracy()
     */
    public static boolean hasVerticalAccuracy(@NonNull Location location) {
        if (VERSION.SDK_INT >= 26) {
            return Api26Impl.hasVerticalAccuracy(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return false;
            }

            return extras.containsKey(EXTRA_VERTICAL_ACCURACY);
        }
    }

    /**
     * Get the estimated vertical accuracy of this location in meters.
     *
     * <p>NOTE: On API levels below 26, the concept of vertical accuracy does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to read a
     * float extra with the key {@link #EXTRA_VERTICAL_ACCURACY} and return the result.
     *
     * @see Location#getVerticalAccuracyMeters()
     */
    public static float getVerticalAccuracyMeters(@NonNull Location location) {
        if (VERSION.SDK_INT >= 26) {
            return Api26Impl.getVerticalAccuracyMeters(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return 0.0f;
            }

            return extras.getFloat(EXTRA_VERTICAL_ACCURACY, 0.0f);
        }
    }

    /**
     * Set the estimated vertical accuracy of this location in meters.
     *
     * <p>NOTE: On API levels below 26, the concept of vertical accuracy does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to set a
     * float extra with the key {@link #EXTRA_VERTICAL_ACCURACY} to include vertical accuracy. Be
     * aware that this will overwrite any prior extra value under the same key.
     *
     * @see Location#setVerticalAccuracyMeters(float)
     */
    public static void setVerticalAccuracyMeters(@NonNull Location location,
            float verticalAccuracyM) {
        if (VERSION.SDK_INT >= 26) {
            Api26Impl.setVerticalAccuracyMeters(location, verticalAccuracyM);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                location.setExtras(new Bundle());
                extras = location.getExtras();
            }

            extras.putFloat(EXTRA_VERTICAL_ACCURACY, verticalAccuracyM);
        }
    }

    /**
     * Returns true if this location has a speed accuracy.
     *
     * @see Location#hasSpeedAccuracy()
     */
    public static boolean hasSpeedAccuracy(@NonNull Location location) {
        if (VERSION.SDK_INT >= 26) {
            return Api26Impl.hasSpeedAccuracy(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return false;
            }

            return extras.containsKey(EXTRA_SPEED_ACCURACY);
        }
    }

    /**
     * Get the estimated speed accuracy of this location in meters per second.
     *
     * <p>NOTE: On API levels below 26, the concept of speed accuracy does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to read a
     * float extra with the key {@link #EXTRA_SPEED_ACCURACY} and return the result.
     *
     * @see Location#getSpeedAccuracyMetersPerSecond()
     */
    public static float getSpeedAccuracyMetersPerSecond(@NonNull Location location) {
        if (VERSION.SDK_INT >= 26) {
            return Api26Impl.getSpeedAccuracyMetersPerSecond(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return 0.0f;
            }

            return extras.getFloat(EXTRA_SPEED_ACCURACY, 0.0f);
        }
    }

    /**
     * Set the estimated speed accuracy of this location in meters per second.
     *
     * <p>NOTE: On API levels below 26, the concept of speed accuracy does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to set a
     * float extra with the key {@link #EXTRA_SPEED_ACCURACY} to include speed accuracy. Be
     * aware that this will overwrite any prior extra value under the same key.
     *
     * @see Location#setSpeedAccuracyMetersPerSecond(float)
     */
    public static void setSpeedAccuracyMetersPerSecond(@NonNull Location location,
            float speedAccuracyMps) {
        if (VERSION.SDK_INT >= 26) {
            Api26Impl.setSpeedAccuracyMetersPerSecond(location, speedAccuracyMps);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                location.setExtras(new Bundle());
                extras = location.getExtras();
            }

            extras.putFloat(EXTRA_SPEED_ACCURACY, speedAccuracyMps);
        }
    }

    /**
     * Returns true if this location has a bearing accuracy.
     *
     * @see Location#hasBearingAccuracy()
     */
    public static boolean hasBearingAccuracy(@NonNull Location location) {
        if (VERSION.SDK_INT >= 26) {
            return Api26Impl.hasBearingAccuracy(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return false;
            }

            return extras.containsKey(EXTRA_BEARING_ACCURACY);
        }
    }

    /**
     * Get the estimated bearing accuracy of this location in degrees.
     *
     * <p>NOTE: On API levels below 26, the concept of bearing accuracy does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to read a
     * float extra with the key {@link #EXTRA_BEARING_ACCURACY} and return the result.
     *
     * @see Location#getBearingAccuracyDegrees()
     */
    public static float getBearingAccuracyDegrees(@NonNull Location location) {
        if (VERSION.SDK_INT >= 26) {
            return Api26Impl.getBearingAccuracyDegrees(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return 0.0f;
            }

            return extras.getFloat(EXTRA_BEARING_ACCURACY, 0.0f);
        }
    }

    /**
     * Set the estimated bearing accuracy of this location in degrees.
     *
     * <p>NOTE: On API levels below 26, the concept of bearing accuracy does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to set a
     * float extra with the key {@link #EXTRA_BEARING_ACCURACY} to include bearing accuracy. Be
     * aware that this will overwrite any prior extra value under the same key.
     *
     * @see Location#setBearingAccuracyDegrees(float)
     */
    public static void setBearingAccuracyDegrees(@NonNull Location location,
            float bearingAccuracyD) {
        if (VERSION.SDK_INT >= 26) {
            Api26Impl.setBearingAccuracyDegrees(location, bearingAccuracyD);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                location.setExtras(new Bundle());
                extras = location.getExtras();
            }

            extras.putFloat(EXTRA_BEARING_ACCURACY, bearingAccuracyD);
        }
    }

    /**
     * Returns true if this location is marked as a mock location. If this location comes from the
     * Android framework, this indicates that the location was provided by a test location provider,
     * and thus may not be related to the actual location of the device.
     *
     * <p>NOTE: On API levels below 18, the concept of a mock location does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to read a
     * boolean extra with the key {@link #EXTRA_IS_MOCK} and use the result to determine whether
     * this should be considered a mock location.
     *
     * @see android.location.LocationManager#addTestProvider
     */
    public static boolean isMock(@NonNull Location location) {
        if (VERSION.SDK_INT >= 18) {
            return Api18Impl.isMock(location);
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                return false;
            }

            return extras.getBoolean(EXTRA_IS_MOCK, false);
        }
    }

    /**
     * Sets whether this location is marked as a mock location.
     *
     * <p>NOTE: On API levels below 18, the concept of a mock location does not exist. In order to
     * allow for backwards compatibility and testing however, this method will attempt to set a
     * boolean extra with the key {@link #EXTRA_IS_MOCK} to mark the location as mock. Be aware that
     * this will overwrite any prior extra value under the same key.
     */
    public static void setMock(@NonNull Location location, boolean mock) {
        if (VERSION.SDK_INT >= 18) {
            try {
                getSetIsFromMockProviderMethod().invoke(location, mock);
            } catch (NoSuchMethodException e) {
                Error error = new NoSuchMethodError();
                error.initCause(e);
                throw error;
            } catch (IllegalAccessException e) {
                Error error = new IllegalAccessError();
                error.initCause(e);
                throw error;
            } catch (InvocationTargetException e) {
                throw new RuntimeException(e);
            }
        } else {
            Bundle extras = location.getExtras();
            if (extras == null) {
                if (mock) {
                    extras = new Bundle();
                    extras.putBoolean(EXTRA_IS_MOCK, true);
                    location.setExtras(extras);
                }
            } else {
                if (mock) {
                    extras.putBoolean(EXTRA_IS_MOCK, true);
                } else {
                    extras.remove(EXTRA_IS_MOCK);
                    if (extras.isEmpty()) {
                        location.setExtras(null);
                    }
                }
            }
        }
    }

    @RequiresApi(26)
    private static class Api26Impl {

        private Api26Impl() {}

        @DoNotInline
        static boolean hasVerticalAccuracy(Location location) {
            return location.hasVerticalAccuracy();
        }

        @DoNotInline
        static float getVerticalAccuracyMeters(Location location) {
            return location.getVerticalAccuracyMeters();
        }

        @DoNotInline
        static void setVerticalAccuracyMeters(Location location, float verticalAccuracyM) {
            location.setVerticalAccuracyMeters(verticalAccuracyM);
        }

        @DoNotInline
        static boolean hasSpeedAccuracy(Location location) {
            return location.hasSpeedAccuracy();
        }

        @DoNotInline
        static float getSpeedAccuracyMetersPerSecond(Location location) {
            return location.getSpeedAccuracyMetersPerSecond();
        }

        @DoNotInline
        static void setSpeedAccuracyMetersPerSecond(Location location, float speedAccuracyMps) {
            location.setSpeedAccuracyMetersPerSecond(speedAccuracyMps);
        }

        @DoNotInline
        static boolean hasBearingAccuracy(Location location) {
            return location.hasBearingAccuracy();
        }

        @DoNotInline
        static float getBearingAccuracyDegrees(Location location) {
            return location.getBearingAccuracyDegrees();
        }

        @DoNotInline
        static void setBearingAccuracyDegrees(Location location, float bearingAccuracyD) {
            location.setBearingAccuracyDegrees(bearingAccuracyD);
        }
    }

    @RequiresApi(18)
    private static class Api18Impl {

        private Api18Impl() {}

        @DoNotInline
        static boolean isMock(Location location) {
            return location.isFromMockProvider();
        }
    }

    @RequiresApi(17)
    private static class Api17Impl {

        private Api17Impl() {}

        @DoNotInline
        static long getElapsedRealtimeNanos(Location location) {
            return location.getElapsedRealtimeNanos();
        }
    }

    private static Method getSetIsFromMockProviderMethod() throws NoSuchMethodException {
        if (sSetIsFromMockProviderMethod == null) {
            sSetIsFromMockProviderMethod = Location.class.getDeclaredMethod("setIsFromMockProvider",
                    boolean.class);
            sSetIsFromMockProviderMethod.setAccessible(true);
        }

        return sSetIsFromMockProviderMethod;
    }
}