/*
 * Copyright (C) 2008 The Android Open Source P-roject
 *
 * 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.mail;

import android.content.Context;
import android.os.Bundle;

import com.android.email.R;
import com.android.email.mail.store.ImapStore;
import com.android.email.mail.store.Pop3Store;
import com.android.email.mail.store.ServiceStore;
import com.android.email.mail.transport.MailTransport;
import com.android.emailcommon.Logging;
import com.android.emailcommon.mail.Folder;
import com.android.emailcommon.mail.MessagingException;
import com.android.emailcommon.provider.Account;
import com.android.emailcommon.provider.EmailContent;
import com.android.emailcommon.provider.HostAuth;
import com.android.emailcommon.provider.Mailbox;
import com.android.mail.utils.LogUtils;
import com.google.common.annotations.VisibleForTesting;

import java.lang.reflect.Method;
import java.util.HashMap;

/**
 * Store is the legacy equivalent of the Account class
 */
public abstract class Store {
    /**
     * A global suggestion to Store implementors on how much of the body
     * should be returned on FetchProfile.Item.BODY_SANE requests. We'll use 125k now.
     */
    public static final int FETCH_BODY_SANE_SUGGESTED_SIZE = (125 * 1024);

    @VisibleForTesting
    static final HashMap<HostAuth, Store> sStores = new HashMap<HostAuth, Store>();
    protected Context mContext;
    protected Account mAccount;
    protected MailTransport mTransport;
    protected String mUsername;
    protected String mPassword;

    static final HashMap<String, Class<? extends Store>> sStoreClasses =
        new HashMap<String, Class<? extends Store>>();

    /**
     * Static named constructor.  It should be overrode by extending class.
     * Because this method will be called through reflection, it can not be protected.
     */
    static Store newInstance(Account account) throws MessagingException {
        throw new MessagingException("Store#newInstance: Unknown scheme in "
                + account.mDisplayName);
    }

    /**
     * Get an instance of a mail store for the given account. The account must be valid (i.e. has
     * at least an incoming server name).
     *
     * NOTE: The internal algorithm used to find a cached store depends upon the account's
     * HostAuth row. If this ever changes (e.g. such as the user updating the
     * host name or port), we will leak entries. This should not be typical, so, it is not
     * a critical problem. However, it is something we should consider fixing.
     *
     * @param account The account of the store.
     * @param context For all the usual context-y stuff
     * @return an initialized store of the appropriate class
     * @throws MessagingException If the store cannot be obtained or if the account is invalid.
     */
    public synchronized static Store getInstance(Account account, Context context)
            throws MessagingException {
        if (sStores.isEmpty()) {
            sStoreClasses.put(context.getString(R.string.protocol_pop3), Pop3Store.class);
            sStoreClasses.put(context.getString(R.string.protocol_legacy_imap), ImapStore.class);
        }
        HostAuth hostAuth = account.getOrCreateHostAuthRecv(context);
        // An existing account might have been deleted
        if (hostAuth == null) return null;
        if (!account.isTemporary()) {
            Store store = sStores.get(hostAuth);
            if (store == null) {
                store = createInstanceInternal(account, context, true);
            } else {
                // Make sure the account object is up to date (according to the caller, at least)
                store.mAccount = account;
            }
            return store;
        } else {
            return createInstanceInternal(account, context, false);
        }
    }

    private synchronized static Store createInstanceInternal(final Account account,
            final Context context, final boolean cacheInstance)
            throws MessagingException {
        Context appContext = context.getApplicationContext();
        final HostAuth hostAuth = account.getOrCreateHostAuthRecv(context);
        Class<? extends Store> klass = sStoreClasses.get(hostAuth.mProtocol);
        if (klass == null) {
            klass = ServiceStore.class;
        }
        final Store store;
        try {
            // invoke "newInstance" class method
            Method m = klass.getMethod("newInstance", Account.class, Context.class);
            store = (Store)m.invoke(null, account, appContext);
        } catch (Exception e) {
            LogUtils.d(Logging.LOG_TAG, String.format(
                    "exception %s invoking method %s#newInstance(Account, Context) for %s",
                    e.toString(), klass.getName(), account.mDisplayName));
            throw new MessagingException("Can't instantiate Store for " + account.mDisplayName);
        }
        // Don't cache this unless it's we've got a saved HostAuth
        if (hostAuth.mId != EmailContent.NOT_SAVED && cacheInstance) {
            sStores.put(hostAuth, store);
        }
        return store;
    }

    /**
     * Delete the mail store associated with the given account. The account must be valid (i.e. has
     * at least an incoming server name).
     *
     * The store should have been notified already by calling delete(), and the caller should
     * also take responsibility for deleting the matching LocalStore, etc.
     *
     * @throws MessagingException If the store cannot be removed or if the account is invalid.
     */
    public synchronized static Store removeInstance(Account account, Context context)
            throws MessagingException {
        return sStores.remove(HostAuth.restoreHostAuthWithId(context, account.mHostAuthKeyRecv));
    }

    /**
     * Some protocols require that a sent message be copied (uploaded) into the Sent folder
     * while others can take care of it automatically (ideally, on the server).  This function
     * allows a given store to indicate which mode(s) it supports.
     * @return true if the store requires an upload into "sent", false if this happens automatically
     * for any sent message.
     */
    public boolean requireCopyMessageToSentFolder() {
        return true;
    }

    /**
     * Some protocols allow for syncing of folder types other than inbox. The store for any such
     * protocol should override this to return what types can be synced.
     * @param type The type of mailbox
     * @return true if the given type of mailbox can be synced.
     */
    public boolean canSyncFolderType(final int type) {
        return (type == Mailbox.TYPE_INBOX);
    }

    public Folder getFolder(String name) throws MessagingException {
        return null;
    }

    /**
     * Updates the local list of mailboxes according to what is located on the remote server.
     * <em>Note: This does not perform folder synchronization and it will not remove mailboxes
     * that are stored locally but not remotely.</em>
     * @return The set of remote folders
     * @throws MessagingException If there was a problem connecting to the remote server
     */
    public Folder[] updateFolders() throws MessagingException {
        return null;
    }

    public abstract Bundle checkSettings() throws MessagingException;

    /**
     * Handle discovery of account settings using only the user's email address and password
     * @param context the context of the caller
     * @param emailAddress the email address of the exchange user
     * @param password the password of the exchange user
     * @return a Bundle containing an error code and a HostAuth (if successful)
     * @throws MessagingException
     */
    public Bundle autoDiscover(Context context, String emailAddress, String password)
            throws MessagingException {
        return null;
    }

    /**
     * Updates the fields within the given mailbox. Only the fields that are important to
     * non-EAS accounts are modified.
     */
    protected static void updateMailbox(Mailbox mailbox, long accountId, String mailboxPath,
            char delimiter, boolean selectable, int type) {
        mailbox.mAccountKey = accountId;
        mailbox.mDelimiter = delimiter;
        String displayPath = mailboxPath;
        int pathIndex = mailboxPath.lastIndexOf(delimiter);
        if (pathIndex > 0) {
            displayPath = mailboxPath.substring(pathIndex + 1);
        }
        mailbox.mDisplayName = displayPath;
        if (selectable) {
            mailbox.mFlags = Mailbox.FLAG_HOLDS_MAIL | Mailbox.FLAG_ACCEPTS_MOVED_MAIL;
        }
        mailbox.mFlagVisible = true;
        //mailbox.mParentKey;
        //mailbox.mParentServerId;
        mailbox.mServerId = mailboxPath;
        //mailbox.mServerId;
        //mailbox.mSyncFrequency;
        //mailbox.mSyncKey;
        //mailbox.mSyncLookback;
        //mailbox.mSyncTime;
        mailbox.mType = type;
        //box.mUnreadCount;
    }

    public void closeConnections() {
        // Base implementation does nothing.
    }

    public Account getAccount() {
        return mAccount;
    }
}