/*
 * 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.Email;
import com.android.email.ExchangeUtils;
import com.android.email.activity.setup.AccountSetupBasics;
import com.android.email.provider.AccountBackupRestore;
import com.android.email.service.MailService;
import com.android.emailcommon.provider.EmailContent;
import com.android.emailcommon.provider.EmailContent.Account;
import com.android.emailcommon.utility.EmailAsyncTask;
import com.google.common.annotations.VisibleForTesting;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.text.TextUtils;

/**
 * The Welcome activity initializes the application and decides what Activity
 * the user should start with.
 *
 * This class knows which activity should be launched under the current configuration (screen size)
 * and the number of accounts configured.  So if you want to open an account or a mailbox,
 * you should always do so via its static methods, such as {@link #actionOpenAccountInbox}.
 */
public class Welcome extends Activity {
    /*
     * Commands for testing...
     *  Open 1 pane
        adb shell am start -a android.intent.action.MAIN \
            -d '"content://ui.email.android.com/view/mailbox"' \
            -e DEBUG_PANE_MODE 1

     *  Open 2 pane
        adb shell am start -a android.intent.action.MAIN \
            -d '"content://ui.email.android.com/view/mailbox"' \
            -e DEBUG_PANE_MODE 2

     *  Open an account (ID=1) in 2 pane
        adb shell am start -a android.intent.action.MAIN \
            -d '"content://ui.email.android.com/view/mailbox?ACCOUNT_ID=1"' \
            -e DEBUG_PANE_MODE 2

     *  Open a message (account id=1, mailbox id=2, message id=3)
        adb shell am start -a android.intent.action.MAIN \
            -d '"content://ui.email.android.com/view/mailbox?ACCOUNT_ID=1&MAILBOX_ID=2&MESSAGE_ID=3"' \
            -e DEBUG_PANE_MODE 2 \

     */

    /**
     * Extra for debugging.  Set 1 to force one-pane.  Set 2 to force two-pane.
     */
    private static final String EXTRA_DEBUG_PANE_MODE = "DEBUG_PANE_MODE";

    private static final String VIEW_MAILBOX_INTENT_URL_PATH = "/view/mailbox";

    private final EmailAsyncTask.Tracker mTaskTracker = new EmailAsyncTask.Tracker();

    /**
     * Launch this activity.  Note:  It's assumed that this activity is only called as a means to
     * 'reset' the UI state; Because of this, it is always launched with FLAG_ACTIVITY_CLEAR_TOP,
     * which will drop any other activities on the stack (e.g. AccountFolderList or MessageList).
     */
    public static void actionStart(Activity fromActivity) {
        Intent i = IntentUtilities.createRestartAppIntent(fromActivity, Welcome.class);
        fromActivity.startActivity(i);
    }

    /**
     * Create an Intent to open email activity. If <code>accountId</code> is not -1, the
     * specified account will be automatically be opened when the activity starts.
     */
    public static Intent createOpenAccountInboxIntent(Context context, long accountId) {
        final Uri.Builder b = IntentUtilities.createActivityIntentUrlBuilder(
                VIEW_MAILBOX_INTENT_URL_PATH);
        IntentUtilities.setAccountId(b, accountId);
        return IntentUtilities.createRestartAppIntent(b.build());
    }

    /**
     * Create an Intent to open a message.
     */
    public static Intent createOpenMessageIntent(Context context, long accountId,
            long mailboxId, long messageId) {
        final Uri.Builder b = IntentUtilities.createActivityIntentUrlBuilder(
                VIEW_MAILBOX_INTENT_URL_PATH);
        IntentUtilities.setAccountId(b, accountId);
        IntentUtilities.setMailboxId(b, mailboxId);
        IntentUtilities.setMessageId(b, messageId);
        return IntentUtilities.createRestartAppIntent(b.build());
    }

    /**
     * Open account's inbox.
     */
    public static void actionOpenAccountInbox(Activity fromActivity, long accountId) {
        fromActivity.startActivity(createOpenAccountInboxIntent(fromActivity, accountId));
    }

    /**
     * Create an {@link Intent} for account shortcuts.  The returned intent stores the account's
     * UUID rather than the account ID, which will be changed after account restore.
     */
    public static Intent createAccountShortcutIntent(Context context, Account account) {
        final Uri.Builder b = IntentUtilities.createActivityIntentUrlBuilder(
                VIEW_MAILBOX_INTENT_URL_PATH);
        IntentUtilities.setAccountUuid(b, account.mCompatibilityUuid);
        return IntentUtilities.createRestartAppIntent(b.build());
    }

    /**
     * Parse the {@link #EXTRA_DEBUG_PANE_MODE} extra and return 1 or 2, if it's set to "1" or "2".
     * Return 0 otherwise.
     */
    private static int getDebugPaneMode(Intent i) {
        Bundle extras = i.getExtras();
        if (extras != null) {
            String s = extras.getString(EXTRA_DEBUG_PANE_MODE);
            if ("1".equals(s)) {
                return 1;
            } else if ("2".equals(s)) {
                return 2;
            }
        }
        return 0;
    }

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

        // Reset the "accounts changed" notification, now that we're here
        Email.setNotifyUiAccountsChanged(false);

        // 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.restoreIfNeeded(this);

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

        new MainActivityLauncher(this, getIntent()).executeParallel();
    }

    @Override
    public void onDestroy() {
        mTaskTracker.cancellAllInterrupt();
        super.onDestroy();
    }

    /**
     * Open an account with the Activity appropriate to the current configuration.
     * If there's no accounts set up, open the "add account" screen.
     *
     * if {@code account} is -1, open the default account.
     */
    @VisibleForTesting
    static class MainActivityLauncher extends EmailAsyncTask<Void, Void, Void> {
        private final Welcome mFromActivity;
        private final int mDebugPaneMode;
        private final long mAccountId;
        private final long mMailboxId;
        private final long mMessageId;
        private final String mAccountUuid;

        public MainActivityLauncher(Welcome fromActivity, Intent intent) {
            super(fromActivity.mTaskTracker);
            mFromActivity = fromActivity;

            mAccountId = IntentUtilities.getAccountIdFromIntent(intent);
            mMailboxId = IntentUtilities.getMailboxIdFromIntent(intent);
            mMessageId = IntentUtilities.getMessageIdFromIntent(intent);
            mAccountUuid = IntentUtilities.getAccountUuidFromIntent(intent);
            mDebugPaneMode = getDebugPaneMode(intent);
        }

        private boolean isMailboxSelected() {
            return mMailboxId != -1;
        }

        private boolean isMessageSelected() {
            return mMessageId != -1;
        }

        @VisibleForTesting
        static long resolveAccountId(Context context, long accountId, String uuid) {
            // TODO show "account may have been removed" toast when an account is specified but
            // can't find it.
            if (!TextUtils.isEmpty(uuid)) {
                accountId = Account.getAccountIdFromUuid(context, uuid);
            }
            if (accountId == -1 || !Account.isValidId(context, accountId)) {
                accountId = EmailContent.Account.getDefaultAccountId(context);
            }
            return accountId;
        }

        @Override
        protected Void doInBackground(Void... params) {
            // Reconcile POP/IMAP accounts.  EAS accounts are taken care of by ExchangeService.
            MailService.reconcilePopImapAccountsSync(mFromActivity);

            final int numAccount =
                    EmailContent.count(mFromActivity, EmailContent.Account.CONTENT_URI);
            if (numAccount == 0) {
                AccountSetupBasics.actionNewAccount(mFromActivity);
            } else {
                final long accountId = resolveAccountId(mFromActivity, mAccountId, mAccountUuid);

                final Intent i;
                if (isMessageSelected()) {
                    i = EmailActivity.createOpenMessageIntent(mFromActivity, accountId,
                            mMailboxId, mMessageId);
                } else if (isMailboxSelected()) {
                    i = EmailActivity.createOpenMailboxIntent(mFromActivity, accountId,
                                mMailboxId);
                } else {
                    i = EmailActivity.createOpenAccountIntent(mFromActivity, accountId);
                }
                if (mDebugPaneMode != 0) {
                    EmailActivity.forcePaneMode(i, mDebugPaneMode == 2);
                }
                mFromActivity.startActivity(i);
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            mFromActivity.finish();
        }
    }
}