/*
 * Copyright (C) 2008 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.email.activity;

import com.android.email.Account;
import com.android.email.AccountBackupRestore;
import com.android.email.ExchangeUtils;
import com.android.email.Preferences;
import com.android.email.activity.setup.AccountSetupBasics;
import com.android.email.provider.EmailContent;
import com.android.email.provider.EmailContent.Mailbox;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;

/**
 * The Welcome activity initializes the application and decides what Activity
 * the user should start with.
 * If no accounts are configured the user is taken to the AccountSetupBasics Activity where they
 * can configure an account.
 * If a single account is configured the user is taken directly to the MessageList for
 * the INBOX of that account.
 * If more than one account is configured the user is taken to the AccountFolderList Activity so
 * they can select an account.
 */
public class Welcome extends Activity {

    /** DO NOT CHECK IN AS 'TRUE' - DEVELOPMENT ONLY */
    private static final boolean DEBUG_FORCE_UPGRADES = false;

    public static void actionStart(Activity fromActivity) {
        Intent i = new Intent(fromActivity, Welcome.class);
        fromActivity.startActivity(i);
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        // Quickly check for bulk upgrades (from older app versions) and switch to the
        // upgrade activity if necessary
        if (bulkUpgradesRequired(this, Preferences.getPreferences(this))) {
            UpgradeAccounts.actionStart(this);
            finish();
            return;
        }

        // Restore accounts, if it has not happened already
        // NOTE:  This is blocking, which it should not be (in the UI thread)
        // We're going to live with this for the short term and replace with something
        // smarter.  Long-term fix:  Move this, and most of the code below, to an AsyncTask
        // and do the DB work in a thread.  Then post handler to finish() as appropriate.
        AccountBackupRestore.restoreAccountsIfNeeded(this);

        // Because the app could be reloaded (for debugging, etc.), we need to make sure that
        // SyncManager gets a chance to start.  There is no harm to starting it if it has already
        // been started
        // TODO More completely separate SyncManager from Email app
        ExchangeUtils.startExchangeService(this);

        // Find out how many accounts we have, and if there's just one, go directly to it
        Cursor c = null;
        try {
            c = getContentResolver().query(
                    EmailContent.Account.CONTENT_URI,
                    EmailContent.Account.ID_PROJECTION,
                    null, null, null);
            switch (c.getCount()) {
                case 0:
                    AccountSetupBasics.actionNewAccount(this);
                    break;
                case 1:
                    c.moveToFirst();
                    long accountId = c.getLong(EmailContent.Account.CONTENT_ID_COLUMN);
                    MessageList.actionHandleAccount(this, accountId, Mailbox.TYPE_INBOX);
                    break;
                default:
                    AccountFolderList.actionShowAccounts(this);
                    break;
            }
        } finally {
            if (c != null) {
                c.close();
            }
        }

        // In all cases, do not return to this activity
        finish();
    }

    /**
     * Test for bulk upgrades and return true if necessary
     * 
     * TODO should be in an AsyncTask since it has DB ops
     *
     * @return true if upgrades required (old accounts exit).  false otherwise.
     */
    /* package */ boolean bulkUpgradesRequired(Context context, Preferences preferences) {
        if (DEBUG_FORCE_UPGRADES) {
            // build at least one fake account
            Account fake = new Account(this);
            fake.setDescription("Fake Account");
            fake.setEmail("user@gmail.com");
            fake.setName("First Last");
            fake.setSenderUri("smtp://user:password@smtp.gmail.com");
            fake.setStoreUri("imap://user:password@imap.gmail.com");
            fake.save(preferences);
            return true;
        }

        // 1. Get list of legacy accounts and look for any non-backup entries
        Account[] legacyAccounts = preferences.getAccounts();
        if (legacyAccounts.length == 0) {
            return false;
        }

        // 2. Look at the first legacy account and decide what to do
        // We only need to look at the first:  If it's not a backup account, then it's a true
        // legacy account, and there are one or more accounts needing upgrade.  If it is a backup
        // account, then we know for sure that there are no legacy accounts (backup deletes all
        // old accounts, and indicates that "modern" code has already run on this device.)
        if (0 != (legacyAccounts[0].getBackupFlags() & Account.BACKUP_FLAGS_IS_BACKUP)) {
            return false;
        } else {
            return true; 
        }
    }
}