From ce272fe7f13c998001f30227f6e04c4bba8ad63e Mon Sep 17 00:00:00 2001
From: Branden Archer <Branden Archer b.m.archer4@gmail.com>
Date: Thu, 12 May 2016 22:53:52 -0400
Subject: [PATCH] Add ability to import/export cards to/from CSV

---
 app/build.gradle                              |   1 +
 app/src/main/AndroidManifest.xml              |   3 +-
 .../card_locker/CsvDatabaseExporter.java      |  50 +++++
 .../card_locker/CsvDatabaseImporter.java      | 135 ++++++++++++
 .../java/protect/card_locker/DataFormat.java  |   8 +
 .../protect/card_locker/DatabaseExporter.java |  17 ++
 .../protect/card_locker/DatabaseImporter.java |  19 ++
 .../protect/card_locker/FormatException.java  |  19 ++
 .../card_locker/MultiFormatExporter.java      |  57 +++++
 .../card_locker/MultiFormatImporter.java      |  62 ++++++
 .../protect/card_locker/ImportExportTest.java | 207 ++++++++++++++++++
 11 files changed, 577 insertions(+), 1 deletion(-)
 create mode 100644 app/src/main/java/protect/card_locker/CsvDatabaseExporter.java
 create mode 100644 app/src/main/java/protect/card_locker/CsvDatabaseImporter.java
 create mode 100644 app/src/main/java/protect/card_locker/DataFormat.java
 create mode 100644 app/src/main/java/protect/card_locker/DatabaseExporter.java
 create mode 100644 app/src/main/java/protect/card_locker/DatabaseImporter.java
 create mode 100644 app/src/main/java/protect/card_locker/FormatException.java
 create mode 100644 app/src/main/java/protect/card_locker/MultiFormatExporter.java
 create mode 100644 app/src/main/java/protect/card_locker/MultiFormatImporter.java
 create mode 100644 app/src/test/java/protect/card_locker/ImportExportTest.java

diff --git a/app/build.gradle b/app/build.gradle
index a05fd310d..53b8b1014 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -39,6 +39,7 @@ dependencies {
     compile 'com.android.support:design:23.1.1'
     compile 'com.journeyapps:zxing-android-embedded:3.2.0@aar'
     compile 'com.google.zxing:core:3.2.1'
+    compile 'org.apache.commons:commons-csv:1.2'
     testCompile 'junit:junit:4.12'
     testCompile "org.robolectric:robolectric:3.0"
 }
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index fdc322e6b..611e5bc82 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -5,7 +5,8 @@
     <uses-permission
         android:name="android.permission.CAMERA"/>
     <uses-permission
-        android:maxSdkVersion="18"
+        android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+    <uses-permission
         android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 
     <uses-feature
diff --git a/app/src/main/java/protect/card_locker/CsvDatabaseExporter.java b/app/src/main/java/protect/card_locker/CsvDatabaseExporter.java
new file mode 100644
index 000000000..17d8046b4
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/CsvDatabaseExporter.java
@@ -0,0 +1,50 @@
+package protect.card_locker;
+
+import android.database.Cursor;
+
+import org.apache.commons.csv.CSVFormat;
+import org.apache.commons.csv.CSVPrinter;
+
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+
+/**
+ * Class for exporting the database into CSV (Comma Separate Values)
+ * format.
+ */
+public class CsvDatabaseExporter implements DatabaseExporter
+{
+    public void exportData(DBHelper db, OutputStreamWriter output) throws IOException, InterruptedException
+    {
+        CSVPrinter printer = new CSVPrinter(output, CSVFormat.RFC4180);
+
+        // Print the header
+        printer.printRecord(DBHelper.LoyaltyCardDbIds.ID,
+                DBHelper.LoyaltyCardDbIds.STORE,
+                DBHelper.LoyaltyCardDbIds.NOTE,
+                DBHelper.LoyaltyCardDbIds.CARD_ID,
+                DBHelper.LoyaltyCardDbIds.BARCODE_TYPE);
+
+        Cursor cursor = db.getLoyaltyCardCursor();
+
+        while(cursor.moveToNext())
+        {
+            LoyaltyCard card = LoyaltyCard.toLoyaltyCard(cursor);
+
+            printer.printRecord(card.id,
+                    card.store,
+                    card.note,
+                    card.cardId,
+                    card.barcodeType);
+
+            if(Thread.currentThread().isInterrupted())
+            {
+                throw new InterruptedException();
+            }
+        }
+
+        cursor.close();
+
+        printer.close();
+    }
+}
diff --git a/app/src/main/java/protect/card_locker/CsvDatabaseImporter.java b/app/src/main/java/protect/card_locker/CsvDatabaseImporter.java
new file mode 100644
index 000000000..61a5e9f0a
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/CsvDatabaseImporter.java
@@ -0,0 +1,135 @@
+package protect.card_locker;
+
+import android.database.sqlite.SQLiteDatabase;
+
+import org.apache.commons.csv.CSVFormat;
+import org.apache.commons.csv.CSVParser;
+import org.apache.commons.csv.CSVRecord;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+/**
+ * Class for importing a database from CSV (Comma Separate Values)
+ * formatted data.
+ *
+ * The database's loyalty cards are expected to appear in the CSV data.
+ * A header is expected for the each table showing the names of the columns.
+ */
+public class CsvDatabaseImporter implements DatabaseImporter
+{
+    public void importData(DBHelper db, InputStreamReader input) throws IOException, FormatException, InterruptedException
+    {
+        final CSVParser parser = new CSVParser(input, CSVFormat.RFC4180.withHeader());
+
+        SQLiteDatabase database = db.getWritableDatabase();
+        database.beginTransaction();
+
+        try
+        {
+            for (CSVRecord record : parser)
+            {
+                importLoyaltyCard(database, db, record);
+
+                if(Thread.currentThread().isInterrupted())
+                {
+                    throw new InterruptedException();
+                }
+            }
+
+            parser.close();
+            database.setTransactionSuccessful();
+        }
+        catch(IllegalArgumentException e)
+        {
+            throw new FormatException("Issue parsing CSV data", e);
+        }
+        finally
+        {
+            database.endTransaction();
+            database.close();
+        }
+    }
+
+    /**
+     * Extract a string from the items array. The index into the array
+     * is determined by looking up the index in the fields map using the
+     * "key" as the key. If no such key exists, defaultValue is returned
+     * if it is not null. Otherwise, a FormatException is thrown.
+     */
+    private String extractString(String key, CSVRecord record, String defaultValue)
+            throws FormatException
+    {
+        String toReturn = defaultValue;
+
+        if(record.isMapped(key))
+        {
+            toReturn = record.get(key);
+        }
+        else
+        {
+            if(defaultValue == null)
+            {
+                throw new FormatException("Field not used but expected: " + key);
+            }
+        }
+
+        return toReturn;
+    }
+
+    /**
+     * Extract an integer from the items array. The index into the array
+     * is determined by looking up the index in the fields map using the
+     * "key" as the key. If no such key exists, or the data is not a valid
+     * int, a FormatException is thrown.
+     */
+    private int extractInt(String key, CSVRecord record)
+            throws FormatException
+    {
+        if(record.isMapped(key) == false)
+        {
+            throw new FormatException("Field not used but expected: " + key);
+        }
+
+        try
+        {
+            return Integer.parseInt(record.get(key));
+        }
+        catch(NumberFormatException e)
+        {
+            throw new FormatException("Failed to parse field: " + key, e);
+        }
+    }
+
+    /**
+     * Import a single loyalty card into the database using the given
+     * session.
+     */
+    private void importLoyaltyCard(SQLiteDatabase database, DBHelper helper, CSVRecord record)
+            throws IOException, FormatException
+    {
+        int id = extractInt(DBHelper.LoyaltyCardDbIds.ID, record);
+
+        String store = extractString(DBHelper.LoyaltyCardDbIds.STORE, record, "");
+        if(store.isEmpty())
+        {
+            throw new FormatException("No store listed, but is required");
+        }
+
+        String note = extractString(DBHelper.LoyaltyCardDbIds.NOTE, record, "");
+
+        String cardId = extractString(DBHelper.LoyaltyCardDbIds.CARD_ID, record, "");
+        if(cardId.isEmpty())
+        {
+            throw new FormatException("No card ID listed, but is required");
+        }
+
+        String barcodeType = extractString(DBHelper.LoyaltyCardDbIds.BARCODE_TYPE, record, "");
+        if(barcodeType.isEmpty())
+        {
+            throw new FormatException("No barcode type listed, but is required");
+        }
+
+        helper.insertLoyaltyCard(database, id, store, note, cardId, barcodeType);
+    }
+}
diff --git a/app/src/main/java/protect/card_locker/DataFormat.java b/app/src/main/java/protect/card_locker/DataFormat.java
new file mode 100644
index 000000000..722700f00
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/DataFormat.java
@@ -0,0 +1,8 @@
+package protect.card_locker;
+
+public enum DataFormat
+{
+    CSV,
+
+    ;
+}
diff --git a/app/src/main/java/protect/card_locker/DatabaseExporter.java b/app/src/main/java/protect/card_locker/DatabaseExporter.java
new file mode 100644
index 000000000..94e4949d6
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/DatabaseExporter.java
@@ -0,0 +1,17 @@
+package protect.card_locker;
+
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+
+/**
+ * Interface for a class which can export the contents of the database
+ * in a given format.
+ */
+public interface DatabaseExporter
+{
+    /**
+     * Export the database to the output stream in a given format.
+     * @throws IOException
+     */
+    void exportData(DBHelper db, OutputStreamWriter output) throws IOException, InterruptedException;
+}
diff --git a/app/src/main/java/protect/card_locker/DatabaseImporter.java b/app/src/main/java/protect/card_locker/DatabaseImporter.java
new file mode 100644
index 000000000..33d2797bf
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/DatabaseImporter.java
@@ -0,0 +1,19 @@
+package protect.card_locker;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+/**
+ * Interface for a class which can import the contents of a stream
+ * into the database.
+ */
+public interface DatabaseImporter
+{
+    /**
+     * Import data from the input stream in a given format into
+     * the database.
+     * @throws IOException
+     * @throws FormatException
+     */
+    void importData(DBHelper db, InputStreamReader input) throws IOException, FormatException, InterruptedException;
+}
diff --git a/app/src/main/java/protect/card_locker/FormatException.java b/app/src/main/java/protect/card_locker/FormatException.java
new file mode 100644
index 000000000..db23ebfd4
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/FormatException.java
@@ -0,0 +1,19 @@
+package protect.card_locker;
+
+/**
+ * Exception thrown when something unexpected is
+ * encountered with the format of data being
+ * imported or exported.
+ */
+public class FormatException extends Exception
+{
+    public FormatException(String message)
+    {
+        super(message);
+    }
+
+    public FormatException(String message, Exception rootCause)
+    {
+        super(message, rootCause);
+    }
+}
diff --git a/app/src/main/java/protect/card_locker/MultiFormatExporter.java b/app/src/main/java/protect/card_locker/MultiFormatExporter.java
new file mode 100644
index 000000000..68b01e761
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/MultiFormatExporter.java
@@ -0,0 +1,57 @@
+package protect.card_locker;
+
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+
+public class MultiFormatExporter
+{
+    private static final String TAG = "LoyaltyCardLocker";
+
+    /**
+     * Attempts to export data to the output stream in the
+     * given format, if possible.
+     *
+     * The output stream is closed on success.
+     *
+     * @return true if the database was successfully exported,
+     * false otherwise. If false, partial data may have been
+     * written to the output stream, and it should be discarded.
+     */
+    public static boolean exportData(DBHelper db, OutputStreamWriter output, DataFormat format)
+    {
+        DatabaseExporter exporter = null;
+
+        switch(format)
+        {
+            case CSV:
+                exporter = new CsvDatabaseExporter();
+                break;
+        }
+
+        if(exporter != null)
+        {
+            try
+            {
+                exporter.exportData(db, output);
+                return true;
+            }
+            catch(IOException e)
+            {
+                Log.e(TAG, "Failed to export data", e);
+            }
+            catch(InterruptedException e)
+            {
+                Log.e(TAG, "Failed to export data", e);
+            }
+
+            return false;
+        }
+        else
+        {
+            Log.e(TAG, "Unsupported data format exported: " + format.name());
+            return false;
+        }
+    }
+}
diff --git a/app/src/main/java/protect/card_locker/MultiFormatImporter.java b/app/src/main/java/protect/card_locker/MultiFormatImporter.java
new file mode 100644
index 000000000..3d5593868
--- /dev/null
+++ b/app/src/main/java/protect/card_locker/MultiFormatImporter.java
@@ -0,0 +1,62 @@
+package protect.card_locker;
+
+import android.util.Log;
+
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+public class MultiFormatImporter
+{
+    private static final String TAG = "LoyaltyCardLocker";
+
+    /**
+     * Attempts to import data from the input stream of the
+     * given format into the database.
+     *
+     * The input stream is not closed, and doing so is the
+     * responsibility of the caller.
+     *
+     * @return true if the database was successfully imported,
+     * false otherwise. If false, no data was written to
+     * the database.
+     */
+    public static boolean importData(DBHelper db, InputStreamReader input, DataFormat format)
+    {
+        DatabaseImporter importer = null;
+
+        switch(format)
+        {
+            case CSV:
+                importer = new CsvDatabaseImporter();
+                break;
+        }
+
+        if(importer != null)
+        {
+            try
+            {
+                importer.importData(db, input);
+                return true;
+            }
+            catch(IOException e)
+            {
+                Log.e(TAG, "Failed to input data", e);
+            }
+            catch(FormatException e)
+            {
+                Log.e(TAG, "Failed to input data", e);
+            }
+            catch(InterruptedException e)
+            {
+                Log.e(TAG, "Failed to input data", e);
+            }
+
+            return false;
+        }
+        else
+        {
+            Log.e(TAG, "Unsupported data format imported: " + format.name());
+            return false;
+        }
+    }
+}
diff --git a/app/src/test/java/protect/card_locker/ImportExportTest.java b/app/src/test/java/protect/card_locker/ImportExportTest.java
new file mode 100644
index 000000000..5e1b69900
--- /dev/null
+++ b/app/src/test/java/protect/card_locker/ImportExportTest.java
@@ -0,0 +1,207 @@
+package protect.card_locker;
+
+import android.app.Activity;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+
+import com.google.zxing.BarcodeFormat;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.Robolectric;
+import org.robolectric.RobolectricGradleTestRunner;
+import org.robolectric.annotation.Config;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.util.Calendar;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+@RunWith(RobolectricGradleTestRunner.class)
+@Config(constants = BuildConfig.class, sdk = 17)
+public class ImportExportTest
+{
+    private Activity activity;
+    private DBHelper db;
+    private long nowMs;
+    private long lastYearMs;
+    private final int MONTHS_PER_YEAR = 12;
+
+    private final String BARCODE_DATA = "428311627547";
+    private final String BARCODE_TYPE = BarcodeFormat.UPC_A.name();
+
+    @Before
+    public void setUp()
+    {
+        activity = Robolectric.setupActivity(MainActivity.class);
+        db = new DBHelper(activity);
+        nowMs = System.currentTimeMillis();
+
+        Calendar lastYear = Calendar.getInstance();
+        lastYear.set(Calendar.YEAR, lastYear.get(Calendar.YEAR)-1);
+        lastYearMs = lastYear.getTimeInMillis();
+    }
+
+    /**
+     * Add the given number of cards, each with
+     * an index in the store name.
+     * @param cardsToAdd
+     */
+    private void addLoyaltyCards(int cardsToAdd)
+    {
+        // Add in reverse order to test sorting
+        for(int index = cardsToAdd; index > 0; index--)
+        {
+            String storeName = String.format("store, \"%4d", index);
+            String note = String.format("note, \"%4d", index);
+            boolean result = db.insertLoyaltyCard(storeName, note, BARCODE_DATA, BARCODE_TYPE);
+            assertTrue(result);
+        }
+
+        assertEquals(cardsToAdd, db.getLoyaltyCardCount());
+    }
+
+    /**
+     * Check that all of the cards follow the pattern
+     * specified in addLoyaltyCards(), and are in sequential order
+     * where the smallest card's index is 1
+     */
+    private void checkLoyaltyCards()
+    {
+        Cursor cursor = db.getLoyaltyCardCursor();
+        int index = 1;
+
+        while(cursor.moveToNext())
+        {
+            LoyaltyCard card = LoyaltyCard.toLoyaltyCard(cursor);
+
+            String expectedStore = String.format("store, \"%4d", index);
+            String expectedNote = String.format("note, \"%4d", index);
+
+            assertEquals(expectedStore, card.store);
+            assertEquals(expectedNote, card.note);
+            assertEquals(BARCODE_DATA, card.cardId);
+            assertEquals(BARCODE_TYPE, card.barcodeType);
+
+            index++;
+        }
+        cursor.close();
+    }
+
+    /**
+     * Delete the contents of the database
+     */
+    private void clearDatabase()
+    {
+        SQLiteDatabase database = db.getWritableDatabase();
+        database.execSQL("delete from " + DBHelper.LoyaltyCardDbIds.TABLE);
+        database.close();
+
+        assertEquals(0, db.getLoyaltyCardCount());
+    }
+
+    @Test
+    public void multipleCardsExportImport() throws IOException
+    {
+        final int NUM_CARDS = 1000;
+
+        for(DataFormat format : DataFormat.values())
+        {
+            addLoyaltyCards(NUM_CARDS);
+
+            ByteArrayOutputStream outData = new ByteArrayOutputStream();
+            OutputStreamWriter outStream = new OutputStreamWriter(outData);
+
+            // Export data to CSV format
+            boolean result = MultiFormatExporter.exportData(db, outStream, format);
+            assertTrue(result);
+            outStream.close();
+
+            clearDatabase();
+
+            ByteArrayInputStream inData = new ByteArrayInputStream(outData.toByteArray());
+            InputStreamReader inStream = new InputStreamReader(inData);
+
+            // Import the CSV data
+            result = MultiFormatImporter.importData(db, inStream, DataFormat.CSV);
+            assertTrue(result);
+
+            assertEquals(NUM_CARDS, db.getLoyaltyCardCount());
+
+            checkLoyaltyCards();
+
+            // Clear the database for the next format under test
+            clearDatabase();
+        }
+    }
+
+    @Test
+    public void importExistingCardsNotReplace() throws IOException
+    {
+        final int NUM_CARDS = 1000;
+
+        for(DataFormat format : DataFormat.values())
+        {
+            addLoyaltyCards(NUM_CARDS);
+
+            ByteArrayOutputStream outData = new ByteArrayOutputStream();
+            OutputStreamWriter outStream = new OutputStreamWriter(outData);
+
+            // Export into CSV data
+            boolean result = MultiFormatExporter.exportData(db, outStream, format);
+            assertTrue(result);
+            outStream.close();
+
+            ByteArrayInputStream inData = new ByteArrayInputStream(outData.toByteArray());
+            InputStreamReader inStream = new InputStreamReader(inData);
+
+            // Import the CSV data on top of the existing database
+            result = MultiFormatImporter.importData(db, inStream, DataFormat.CSV);
+            assertTrue(result);
+
+            assertEquals(NUM_CARDS, db.getLoyaltyCardCount());
+
+            checkLoyaltyCards();
+
+            // Clear the database for the next format under test
+            clearDatabase();
+        }
+    }
+
+    @Test
+    public void corruptedImportNothingSaved() throws IOException
+    {
+        final int NUM_CARDS = 1000;
+
+        for(DataFormat format : DataFormat.values())
+        {
+            addLoyaltyCards(NUM_CARDS);
+
+            ByteArrayOutputStream outData = new ByteArrayOutputStream();
+            OutputStreamWriter outStream = new OutputStreamWriter(outData);
+
+            // Export data to CSV format
+            boolean result = MultiFormatExporter.exportData(db, outStream, format);
+            assertTrue(result);
+
+            clearDatabase();
+
+            String corruptEntry = "ThisStringIsLikelyNotPartOfAnyFormat";
+
+            ByteArrayInputStream inData = new ByteArrayInputStream((outData.toString() + corruptEntry).getBytes());
+            InputStreamReader inStream = new InputStreamReader(inData);
+
+            // Attempt to import the CSV data
+            result = MultiFormatImporter.importData(db, inStream, DataFormat.CSV);
+            assertEquals(false, result);
+
+            assertEquals(0, db.getLoyaltyCardCount());
+        }
+    }
+}