/*
 * Copyright © 2013 – 2016 Ricki Hirner (bitfire web engineering).
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 */

package at.bitfire.davdroid;

import android.accounts.Account;
import android.accounts.AccountManager;
import android.annotation.SuppressLint;
import android.app.Service;
import android.content.Intent;
import android.database.DatabaseUtils;
import android.database.sqlite.SQLiteDatabase;
import android.os.Binder;
import android.os.IBinder;
import android.support.annotation.NonNull;
import android.text.TextUtils;

import java.lang.ref.WeakReference;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

import at.bitfire.davdroid.model.ServiceDB.OpenHelper;
import at.bitfire.davdroid.model.ServiceDB.Services;

public class DavService extends Service {

    public static final String
            ACTION_ACCOUNTS_UPDATED = "accountsUpdated",
            EXTRA_DAV_SERVICE_ID = "davServiceID";

    private final IBinder binder = new InfoBinder();

    private final Set<Long> runningRefresh = new HashSet<>();
    private final List<WeakReference<RefreshingStatusListener>> refreshingStatusListeners = new LinkedList<>();


    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if (intent != null) {
            String action = intent.getAction();
            long id = intent.getLongExtra(EXTRA_DAV_SERVICE_ID, -1);

            switch (action) {
                case ACTION_ACCOUNTS_UPDATED:
                    cleanupAccounts();
                    break;
            }
        }

        return START_NOT_STICKY;
    }


    /* BOUND SERVICE PART
       for communicating with the activities
    */

    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }

    public interface RefreshingStatusListener {
        void onDavRefreshStatusChanged(long id, boolean refreshing);
    }

    public class InfoBinder extends Binder {
        public boolean isRefreshing(long id) {
            return runningRefresh.contains(id);
        }

        public void addRefreshingStatusListener(@NonNull RefreshingStatusListener listener, boolean callImmediate) {
            refreshingStatusListeners.add(new WeakReference<>(listener));
            if (callImmediate)
                for (long id : runningRefresh)
                    listener.onDavRefreshStatusChanged(id, true);
        }

        public void removeRefreshingStatusListener(@NonNull RefreshingStatusListener listener) {
            for (Iterator<WeakReference<RefreshingStatusListener>> iterator = refreshingStatusListeners.iterator(); iterator.hasNext(); ) {
                RefreshingStatusListener item = iterator.next().get();
                if (listener.equals(item))
                    iterator.remove();
            }
        }
    }


    /* ACTION RUNNABLES
       which actually do the work
     */

    @SuppressLint("MissingPermission")
    void cleanupAccounts() {
        App.log.info("Cleaning up orphaned accounts");

        final OpenHelper dbHelper = new OpenHelper(this);
        try {
            SQLiteDatabase db = dbHelper.getWritableDatabase();

            List<String> sqlAccountNames = new LinkedList<>();
            AccountManager am = AccountManager.get(this);
            for (Account account : am.getAccountsByType(Constants.ACCOUNT_TYPE))
                sqlAccountNames.add(DatabaseUtils.sqlEscapeString(account.name));

            if (sqlAccountNames.isEmpty())
                db.delete(Services._TABLE, null, null);
            else
                db.delete(Services._TABLE, Services.ACCOUNT_NAME + " NOT IN (" + TextUtils.join(",", sqlAccountNames) + ")", null);
        } finally {
            dbHelper.close();
        }
    }
}