/*
 * Copyright (C) 2015 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 com.android.settingslib;

import android.content.Context;
import android.content.Intent;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Build;
import android.text.TextUtils;
import android.text.format.DateFormat;
import android.util.Log;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class DeviceInfoUtils {
    private static final String TAG = "DeviceInfoUtils";

    private static final String FILENAME_PROC_VERSION = "/proc/version";
    private static final String FILENAME_MSV = "/sys/board_properties/soc/msv";

    /**
     * Reads a line from the specified file.
     * @param filename the file to read from
     * @return the first line, if any.
     * @throws IOException if the file couldn't be read
     */
    private static String readLine(String filename) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(filename), 256);
        try {
            return reader.readLine();
        } finally {
            reader.close();
        }
    }

    public static String getFormattedKernelVersion() {
        try {
            return formatKernelVersion(readLine(FILENAME_PROC_VERSION));
        } catch (IOException e) {
            Log.e(TAG, "IO Exception when getting kernel version for Device Info screen",
                    e);

            return "Unavailable";
        }
    }

    public static String formatKernelVersion(String rawKernelVersion) {
        // Example (see tests for more):
        // Linux version 3.0.31-g6fb96c9 (android-build@xxx.xxx.xxx.xxx.com) \
        //     (gcc version 4.6.x-xxx 20120106 (prerelease) (GCC) ) #1 SMP PREEMPT \
        //     Thu Jun 28 11:02:39 PDT 2012

        final String PROC_VERSION_REGEX =
                "Linux version (\\S+) " + /* group 1: "3.0.31-g6fb96c9" */
                "\\((\\S+?)\\) " +        /* group 2: "x@y.com" (kernel builder) */
                "(?:\\(gcc.+? \\)) " +    /* ignore: GCC version information */
                "(#\\d+) " +              /* group 3: "#1" */
                "(?:.*?)?" +              /* ignore: optional SMP, PREEMPT, and any CONFIG_FLAGS */
                "((Sun|Mon|Tue|Wed|Thu|Fri|Sat).+)"; /* group 4: "Thu Jun 28 11:02:39 PDT 2012" */

        Matcher m = Pattern.compile(PROC_VERSION_REGEX).matcher(rawKernelVersion);
        if (!m.matches()) {
            Log.e(TAG, "Regex did not match on /proc/version: " + rawKernelVersion);
            return "Unavailable";
        } else if (m.groupCount() < 4) {
            Log.e(TAG, "Regex match on /proc/version only returned " + m.groupCount()
                    + " groups");
            return "Unavailable";
        }
        return m.group(1) + "\n" +                 // 3.0.31-g6fb96c9
                m.group(2) + " " + m.group(3) + "\n" + // x@y.com #1
                m.group(4);                            // Thu Jun 28 11:02:39 PDT 2012
    }

    /**
     * Returns " (ENGINEERING)" if the msv file has a zero value, else returns "".
     * @return a string to append to the model number description.
     */
    public static String getMsvSuffix() {
        // Production devices should have a non-zero value. If we can't read it, assume it's a
        // production device so that we don't accidentally show that it's an ENGINEERING device.
        try {
            String msv = readLine(FILENAME_MSV);
            // Parse as a hex number. If it evaluates to a zero, then it's an engineering build.
            if (Long.parseLong(msv, 16) == 0) {
                return " (ENGINEERING)";
            }
        } catch (IOException|NumberFormatException e) {
            // Fail quietly, as the file may not exist on some devices, or may be unreadable
        }
        return "";
    }

    public static String getFeedbackReporterPackage(Context context) {
        final String feedbackReporter =
                context.getResources().getString(R.string.oem_preferred_feedback_reporter);
        if (TextUtils.isEmpty(feedbackReporter)) {
            // Reporter not configured. Return.
            return feedbackReporter;
        }
        // Additional checks to ensure the reporter is on system image, and reporter is
        // configured to listen to the intent. Otherwise, dont show the "send feedback" option.
        final Intent intent = new Intent(Intent.ACTION_BUG_REPORT);

        PackageManager pm = context.getPackageManager();
        List<ResolveInfo> resolvedPackages =
                pm.queryIntentActivities(intent, PackageManager.GET_RESOLVED_FILTER);
        for (ResolveInfo info : resolvedPackages) {
            if (info.activityInfo != null) {
                if (!TextUtils.isEmpty(info.activityInfo.packageName)) {
                    try {
                        ApplicationInfo ai =
                                pm.getApplicationInfo(info.activityInfo.packageName, 0);
                        if ((ai.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
                            // Package is on the system image
                            if (TextUtils.equals(
                                    info.activityInfo.packageName, feedbackReporter)) {
                                return feedbackReporter;
                            }
                        }
                    } catch (PackageManager.NameNotFoundException e) {
                        // No need to do anything here.
                    }
                }
            }
        }
        return null;
    }

    public static String getSecurityPatch() {
        String patch = Build.VERSION.SECURITY_PATCH;
        if (!"".equals(patch)) {
            try {
                SimpleDateFormat template = new SimpleDateFormat("yyyy-MM-dd");
                Date patchDate = template.parse(patch);
                String format = DateFormat.getBestDateTimePattern(Locale.getDefault(), "dMMMMyyyy");
                patch = DateFormat.format(format, patchDate).toString();
            } catch (ParseException e) {
                // broken parse; fall through and use the raw string
            }
            return patch;
        } else {
            return null;
        }
    }

}