// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.chrome.browser.identity;

import android.content.Context;
import android.provider.Settings;

import com.google.common.annotations.VisibleForTesting;

import org.chromium.chrome.browser.util.HashUtil;

import javax.annotation.Nullable;

/**
 * Unique identificator implementation that uses the Settings.Secure.ANDROID_ID field and MD5
 * hashing.
 */
public class SettingsSecureBasedIdentificationGenerator implements UniqueIdentificationGenerator {
    public static final String GENERATOR_ID = "SETTINGS_SECURE_ANDROID_ID";
    private final Context mContext;

    public SettingsSecureBasedIdentificationGenerator(Context context) {
        // Since we do not know the lifetime of the given context, we get the application context
        // to ensure it is always possible to use it.
        mContext = context.getApplicationContext();
    }

    @Override
    public String getUniqueId(@Nullable String salt) {
        String androidId = getAndroidId();
        if (androidId == null) {
            return "";
        }

        String md5Hash = HashUtil.getMd5Hash(
                new HashUtil.Params(androidId).withSalt(salt));
        return md5Hash == null ? "" : md5Hash;
    }

    @VisibleForTesting
    String getAndroidId() {
        return Settings.Secure.getString(mContext.getContentResolver(), Settings.Secure.ANDROID_ID);
    }
}