Requre a minimum remaining battery capacity to install updates

The recovery doesn't install the update if the remaining battery
capacity isn't at least 20% (or 15% if charging). Require at least
40%, just to be safe.

Change-Id: I5cd7c40f029141cde2b0922b25fece2b55989710

3 files changed, 24 insertions, 0 deletions

diff --git a/res/values/integers.xml b/res/values/integers.xml
new file mode 100644
index 0000000..5b68147
--- /dev/null
+++ b/res/values/integers.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="battery_ok_percentage">40</integer>
+</resources>
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 8e7a8fb..d4709c5 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -56,6 +56,8 @@
     <string name="finalizing_package">Finalizing package installation</string>
     <string name="preparing_ota_first_boot">Preparing for first boot</string>
     <string name="dialog_prepare_zip_message">Preliminary update preparation</string>
+    <string name="dialog_battery_low_title">Low battery</string>
+    <string name="dialog_battery_low_message">The battery level is too low, please charge your device to continue.</string>
 
     <string name="reboot">Reboot</string>
 
diff --git a/src/org/lineageos/updater/controller/UpdateInstaller.java b/src/org/lineageos/updater/controller/UpdateInstaller.java
index a9e1595..bb81a0a 100644
--- a/src/org/lineageos/updater/controller/UpdateInstaller.java
+++ b/src/org/lineageos/updater/controller/UpdateInstaller.java
@@ -17,11 +17,14 @@ package org.lineageos.updater.controller;
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.os.BatteryManager;
 import android.os.SystemClock;
 import android.os.SystemProperties;
+import android.support.v7.app.AlertDialog;
 import android.support.v7.preference.PreferenceManager;
 import android.util.Log;
 
+import org.lineageos.updater.R;
 import org.lineageos.updater.misc.Constants;
 import org.lineageos.updater.misc.FileUtils;
 import org.lineageos.updater.misc.Utils;
@@ -65,12 +68,27 @@ class UpdateInstaller {
         return sInstallingUpdate != null && sInstallingUpdate.equals(downloadId);
     }
 
+    private static boolean isBatteryLevelOk(Context context) {
+        BatteryManager bm = context.getSystemService(BatteryManager.class);
+        int percent = bm.getIntProperty(BatteryManager.BATTERY_PROPERTY_CAPACITY);
+        return percent >= context.getResources().getInteger(R.integer.battery_ok_percentage);
+    }
+
     void install(String downloadId) {
         if (isInstalling()) {
             Log.e(TAG, "Already installing an update");
             return;
         }
 
+        if (!isBatteryLevelOk(mContext)) {
+            new AlertDialog.Builder(mContext)
+                    .setTitle(R.string.dialog_battery_low_title)
+                    .setMessage(R.string.dialog_battery_low_message)
+                    .setPositiveButton(android.R.string.ok, null)
+                    .show();
+            return;
+        }
+
         UpdateInfo update = mUpdaterController.getUpdate(downloadId);
         SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(mContext);
         long buildTimestamp = SystemProperties.getLong(Constants.PROP_BUILD_DATE, 0);