/*
 * Juick
 * Copyright (C) 2013, Ugnich Anton
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.juick.components;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.juick.ExternalToken;
import com.juick.User;
import com.juick.service.component.DisconnectedEvent;
import com.juick.service.component.MessageEvent;
import com.juick.service.component.MessageReadEvent;
import com.juick.util.MessageUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.PingMessage;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.ConcurrentWebSocketSessionDecorator;
import org.springframework.web.socket.handler.TextWebSocketHandler;

import javax.annotation.Nonnull;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.inject.Inject;
import java.io.IOException;
import java.util.*;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.stream.Collectors;

/**
 * @author Ugnich Anton
 */
@Component
public class NotificationsManager extends TextWebSocketHandler {
    private static Logger logger = LoggerFactory.getLogger(NotificationsManager.class);

    @Inject
    private RestTemplate rest;

    @Inject
    private ObjectMapper jsonMapper;

    private final Set<String> invalidGCMTokens = Collections.synchronizedSet(new HashSet<>());
    private final Set<String> invalidMPNSTokens = Collections.synchronizedSet(new HashSet<>());
    private final Set<String> invalidAPNSTokens = Collections.synchronizedSet(new HashSet<>());

    @PostConstruct
    public void init() {
        closeFlag.set(false);
    }
    public void messageReceived(@Nonnull com.juick.Message jmsg) {
        if (jmsg.isService()) {
            serviceMessageReceived(jmsg);
            return;
        }
        User pmTo = jmsg.getTo();
        final List<User> users = new ArrayList<>();
        if (MessageUtils.isPM(jmsg)) {
            users.addAll(rest.exchange(String.format("http://api.juick.com/notifications?uid=%d",
                    pmTo.getUid()),
                    HttpMethod.GET, null, new ParameterizedTypeReference<List<User>>() {
                    }).getBody());
        } else if (MessageUtils.isReply(jmsg)) {
            users.addAll(rest.exchange(String.format("http://api.juick.com/notifications?uid=%d&mid=%d&rid=%d",
                    jmsg.getUser().getUid(), jmsg.getMid(), jmsg.getRid()),
                    HttpMethod.GET, null, new ParameterizedTypeReference<List<User>>() {
                    }).getBody());
        } else {
            users.addAll(rest.exchange(String.format("http://api.juick.com/notifications?uid=%s&mid=%s",
                    jmsg.getUser().getUid(), jmsg.getMid()),
                    HttpMethod.GET, null, new ParameterizedTypeReference<List<User>>() {
                    }).getBody());
        }
        applicationEventPublisher.publishEvent(new MessageEvent(this, jmsg, users));
    }
    private void serviceMessageReceived(@Nonnull com.juick.Message jmsg) {
        logger.info("Message read event from {} for {}", jmsg.getUser().getName(), jmsg.getMid());
        List<User> users = rest.exchange(String.format("http://api.juick.com/notifications?uid=%d",
                jmsg.getUser().getUid()),
                HttpMethod.GET, null, new ParameterizedTypeReference<List<User>>() {
                }).getBody();
        users.forEach(user -> {
            applicationEventPublisher.publishEvent(new MessageReadEvent(this, user, jmsg));
        });
    }

    public void addInvalidGCMToken(String token) {
        synchronized (invalidGCMTokens) {
            invalidGCMTokens.add(token);
        }
    }
    public Set<String> getInvalidGCMTokens() {
        return invalidGCMTokens;
    }
    public void cleanupGCMTokens() {
        logger.info("removed {} GCM tokens", invalidGCMTokens.size());
        synchronized (invalidGCMTokens) {
            invalidGCMTokens.clear();
        }
    }
    public void addInvalidMPNSToken(String token) {
        synchronized (invalidMPNSTokens) {
            invalidMPNSTokens.add(token);
        }
    }
    public Set<String> getInvalidMPNSTokens() {
        return invalidMPNSTokens;
    }
    public void cleanupMPNSTokens() {
        logger.info("removed {} MPNS tokens", invalidMPNSTokens.size());
        synchronized (invalidMPNSTokens) {
            invalidMPNSTokens.clear();
        }
    }

    public Set<String> getInvalidAPNSTokens() {
        return invalidAPNSTokens;
    }
    @Inject
    private ApplicationEventPublisher applicationEventPublisher;

    private ConcurrentWebSocketSessionDecorator session;
    private final AtomicBoolean closeFlag = new AtomicBoolean(false);

    @Override
    public void afterConnectionEstablished(WebSocketSession session) {
        if (!closeFlag.get()) {
            logger.info("WebSocket connected");
            this.session = new ConcurrentWebSocketSessionDecorator(session, 60000, 65535);
        }
    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
        if (!closeFlag.get()) {
            logger.info("WebSocket disconnected with code {}: {}", status.getCode(), status.getReason());
            applicationEventPublisher.publishEvent(new DisconnectedEvent(this));
        }
    }

    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage text) throws Exception {
        if (!closeFlag.get() && this.session.getDelegate().equals(session)) {
            com.juick.Message jmsg = jsonMapper.readValue(text.asBytes(), com.juick.Message.class);

            if (logger.isInfoEnabled()) // prevent writeValueAsString execution if logger disabled
                logger.info("got jmsg: {}", jsonMapper.writeValueAsString(jmsg));
            messageReceived(jmsg);
        }
    }

    @Scheduled(fixedRate = 30000, initialDelay = 30000)
    public void ping() throws IOException {
        if (!closeFlag.get()) {
            if (session != null && session.isOpen()) {
                logger.debug("Sending WebSocket ping");
                session.sendMessage(new PingMessage());
            } else {
                applicationEventPublisher.publishEvent(new DisconnectedEvent(this));
            }
        }
    }
    @PreDestroy
    public void close() {
        closeFlag.set(true);
    }
    @Scheduled(fixedRate = 600000)
    public void cleanupTokens() {
        if (!closeFlag.get()) {
            logger.debug("initializing GCM tokens cleanup: {} tokens", getInvalidGCMTokens().size());
            deleteTokens("gcm", new ArrayList<>(getInvalidGCMTokens()));
            cleanupGCMTokens();
            logger.debug("initializing MPNS tokens cleanup: {} tokens", getInvalidMPNSTokens().size());
            deleteTokens("mpns", new ArrayList<>(getInvalidMPNSTokens()));
            cleanupMPNSTokens();
            logger.debug("initializing APNS tokens cleanup: {} tokens", getInvalidAPNSTokens().size());
            deleteTokens("apns", new ArrayList<>(getInvalidAPNSTokens()));
            cleanupMPNSTokens();
        }
    }
    private void deleteTokens(String type, List<String> devices) {
        if (devices.size() > 0) {
            List<ExternalToken> list = devices.stream()
                    .map(d -> new ExternalToken(null, type, d, null)).collect(Collectors.toList());
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
            rest.exchange("http://api.juick.com/notifications",
                    HttpMethod.DELETE, new HttpEntity<>(list, headers), new ParameterizedTypeReference<Void>() {
                    });
        }
    }
}