/*
 * Copyright (C) 2014 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 android.bluetooth.le;

import android.bluetooth.BluetoothAdapter;
import android.util.SparseArray;

import java.util.Arrays;
import java.util.Iterator;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.UUID;

/**
 * Helper class for Bluetooth LE utils.
 *
 * @hide
 */
public class BluetoothLeUtils {
    /** Returns a string composed from a byte array. */
    static String toString(byte[] data) {
        if (data == null) {
            return "null";
        }
        if (data.length == 0) {
            return "{}";
        }
        StringBuilder buffer = new StringBuilder();
        buffer.append('{');
        for (int i = 0; i < data.length; i++) {
            buffer.append(data[i]);
            if ((i + 1) < data.length) {
                buffer.append(", ");
            }
        }
        buffer.append('}');
        return buffer.toString();
    }

    /** Returns a string composed from a {@link SparseArray}. */
    static String toString(SparseArray<byte[]> array) {
        if (array == null) {
            return "null";
        }
        if (array.size() == 0) {
            return "{}";
        }
        StringBuilder buffer = new StringBuilder();
        buffer.append('{');
        for (int i = 0; i < array.size(); ++i) {
            buffer.append(array.keyAt(i)).append("=").append(Arrays.toString(array.valueAt(i)));
        }
        buffer.append('}');
        return buffer.toString();
    }

    /** Returns a string composed from a {@link Map}. */
    static <T> String toString(Map<T, byte[]> map) {
        if (map == null) {
            return "null";
        }
        if (map.isEmpty()) {
            return "{}";
        }
        StringBuilder buffer = new StringBuilder();
        buffer.append('{');
        Iterator<Map.Entry<T, byte[]>> it = map.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry<T, byte[]> entry = it.next();
            Object key = entry.getKey();
            buffer.append(key).append("=").append(Arrays.toString(map.get(key)));
            if (it.hasNext()) {
                buffer.append(", ");
            }
        }
        buffer.append('}');
        return buffer.toString();
    }

    /** Check whether two {@link SparseArray} equal. */
    static boolean equals(SparseArray<byte[]> array, SparseArray<byte[]> otherArray) {
        if (array == otherArray) {
            return true;
        }
        if (array == null || otherArray == null) {
            return false;
        }
        if (array.size() != otherArray.size()) {
            return false;
        }

        // Keys are guaranteed in ascending order when indices are in ascending order.
        for (int i = 0; i < array.size(); ++i) {
            if (array.keyAt(i) != otherArray.keyAt(i)
                    || !Arrays.equals(array.valueAt(i), otherArray.valueAt(i))) {
                return false;
            }
        }
        return true;
    }

    /** Check whether two {@link Map} equal. */
    static <T> boolean equals(Map<T, byte[]> map, Map<T, byte[]> otherMap) {
        if (map == otherMap) {
            return true;
        }
        if (map == null || otherMap == null) {
            return false;
        }
        if (map.size() != otherMap.size()) {
            return false;
        }
        Set<T> keys = map.keySet();
        if (!keys.equals(otherMap.keySet())) {
            return false;
        }
        for (T key : keys) {
            if (!Objects.deepEquals(map.get(key), otherMap.get(key))) {
                return false;
            }
        }
        return true;
    }

    /**
     * Ensure Bluetooth is turned on.
     *
     * @throws IllegalStateException If {@code adapter} is null or Bluetooth state is not {@link
     *     BluetoothAdapter#STATE_ON}.
     */
    static void checkAdapterStateOn(BluetoothAdapter adapter) {
        if (adapter == null || !adapter.isLeEnabled()) {
            throw new IllegalStateException("BT Adapter is not turned ON");
        }
    }

    /**
     * Compares two UUIDs with a UUID mask.
     *
     * @param data first {@link #UUID} to compare.
     * @param uuid second {@link #UUID} to compare.
     * @param mask mask {@link #UUID}.
     * @return true if both UUIDs are equals when masked, false otherwise.
     */
    static boolean maskedEquals(UUID data, UUID uuid, UUID mask) {
        if (mask == null) {
            return Objects.equals(data, uuid);
        }
        return (data.getLeastSignificantBits() & mask.getLeastSignificantBits())
                        == (uuid.getLeastSignificantBits() & mask.getLeastSignificantBits())
                && (data.getMostSignificantBits() & mask.getMostSignificantBits())
                        == (uuid.getMostSignificantBits() & mask.getMostSignificantBits());
    }
}