package com.activeandroid;

/*

* Copyright (C) 2010 Michael Pardo

*

* 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.

*/

import java.io.BufferedReader;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

import com.activeandroid.util.Log;

import com.activeandroid.util.NaturalOrderComparator;

import com.activeandroid.util.SQLiteUtils;

public final class DatabaseHelper extends SQLiteOpenHelper {

//////////////////////////////////////////////////////////////////////////////////////

// PUBLIC CONSTANTS

//////////////////////////////////////////////////////////////////////////////////////

public final static String MIGRATION_PATH = "migrations";

//////////////////////////////////////////////////////////////////////////////////////

// CONSTRUCTORS

//////////////////////////////////////////////////////////////////////////////////////

public DatabaseHelper(Configuration configuration) {

super(configuration.getContext(), configuration.getDatabaseName(), null, configuration.getDatabaseVersion());

copyAttachedDatabase(configuration.getContext(), configuration.getDatabaseName());

}

//////////////////////////////////////////////////////////////////////////////////////

// OVERRIDEN METHODS

//////////////////////////////////////////////////////////////////////////////////////

@Override

public void onOpen(SQLiteDatabase db) {

executePragmas(db);

};

@Override

public void onCreate(SQLiteDatabase db) {

executePragmas(db);

executeCreate(db);

executeMigrations(db, -1, db.getVersion());

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

executePragmas(db);

executeCreate(db);

executeMigrations(db, oldVersion, newVersion);

}

//////////////////////////////////////////////////////////////////////////////////////

// PUBLIC METHODS

//////////////////////////////////////////////////////////////////////////////////////

public void copyAttachedDatabase(Context context, String databaseName) {

final File dbPath = context.getDatabasePath(databaseName);

// If the database already exists, return

if (dbPath.exists()) {

return;

}

// Make sure we have a path to the file

dbPath.getParentFile().mkdirs();

// Try to copy database file

try {

final InputStream inputStream = context.getAssets().open(databaseName);

final OutputStream output = new FileOutputStream(dbPath);

byte[] buffer = new byte[1024];

int length;

while ((length = inputStream.read(buffer)) > 0) {

output.write(buffer, 0, length);

}

output.flush();

output.close();

inputStream.close();

}

catch (IOException e) {

Log.e("Failed to open file", e);

}

}

//////////////////////////////////////////////////////////////////////////////////////

// PRIVATE METHODS

//////////////////////////////////////////////////////////////////////////////////////

private void executePragmas(SQLiteDatabase db) {

if (SQLiteUtils.FOREIGN_KEYS_SUPPORTED) {

db.execSQL("PRAGMA foreign_keys=ON;");

Log.i("Foreign Keys supported. Enabling foreign key features.");

}

}

private void executeCreate(SQLiteDatabase db) {

db.beginTransaction();

try {

for (TableInfo tableInfo : Cache.getTableInfos()) {

db.execSQL(SQLiteUtils.createTableDefinition(tableInfo));

}

db.setTransactionSuccessful();

}

finally {

db.endTransaction();

}

}

private boolean executeMigrations(SQLiteDatabase db, int oldVersion, int newVersion) {

boolean migrationExecuted = false;

try {

final List<String> files = Arrays.asList(Cache.getContext().getAssets().list(MIGRATION_PATH));

Collections.sort(files, new NaturalOrderComparator());

db.beginTransaction();

try {

for (String file : files) {

try {

final int version = Integer.valueOf(file.replace(".sql", ""));

if (version > oldVersion && version <= newVersion) {

executeSqlScript(db, file);

migrationExecuted = true;

Log.i(file + " executed succesfully.");

}

}

catch (NumberFormatException e) {

Log.w("Skipping invalidly named file: " + file, e);

}

}

db.setTransactionSuccessful();

}

finally {

db.endTransaction();

}

}

catch (IOException e) {

Log.e("Failed to execute migrations.", e);

}

return migrationExecuted;

}

private void executeSqlScript(SQLiteDatabase db, String file) {

try {

final InputStream input = Cache.getContext().getAssets().open(MIGRATION_PATH + "/" + file);

final BufferedReader reader = new BufferedReader(new InputStreamReader(input));

String line = null;

while ((line = reader.readLine()) != null) {

db.execSQL(line.replace(";", ""));

}

}

catch (IOException e) {

Log.e("Failed to execute " + file, e);

}

}

}