/*
 * Copyright (C) 2008-2017, Juick
 *
 * 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.server;

import com.juick.User;
import com.juick.model.AnonymousUser;
import com.juick.model.CommandResult;
import com.juick.server.util.HttpUtils;
import com.juick.service.MessagesService;
import com.juick.service.TelegramService;
import com.juick.service.UserService;
import com.juick.service.component.LikeEvent;
import com.juick.service.component.MessageEvent;
import com.juick.service.component.MessageReadEvent;
import com.juick.service.component.NotificationListener;
import com.juick.service.component.PingEvent;
import com.juick.service.component.SubscribeEvent;
import com.juick.service.component.TopEvent;
import com.juick.util.MessageUtils;
import com.pengrad.telegrambot.Callback;
import com.pengrad.telegrambot.TelegramBot;
import com.pengrad.telegrambot.UpdatesListener;
import com.pengrad.telegrambot.model.Message;
import com.pengrad.telegrambot.model.MessageEntity;
import com.pengrad.telegrambot.model.PhotoSize;
import com.pengrad.telegrambot.model.Update;
import com.pengrad.telegrambot.model.request.ParseMode;
import com.pengrad.telegrambot.request.GetFile;
import com.pengrad.telegrambot.request.SendMessage;
import com.pengrad.telegrambot.request.SendPhoto;
import com.pengrad.telegrambot.request.SetWebhook;
import com.pengrad.telegrambot.response.GetFileResponse;
import com.pengrad.telegrambot.response.SendResponse;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.tuple.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;

import javax.annotation.Nonnull;
import javax.annotation.PostConstruct;
import javax.inject.Inject;
import java.io.IOException;
import java.net.URI;
import java.net.URL;
import java.util.*;

import static com.juick.formatters.PlainTextFormatter.formatPost;
import static com.juick.formatters.PlainTextFormatter.formatUrl;

/**
 * Created by vt on 12/05/16.
 */
public class TelegramBotManager implements NotificationListener {
    private static final Logger logger = LoggerFactory.getLogger("Telegram");

    private TelegramBot bot;

    @Value("${telegram_api_url:}")
    private String apiUrl;
    @Value("${telegram_file_api_url:}")
    private String fileApiUrl;
    @Value("${telegram_webhook_url:}")
    private String webhookUrl;
    @Value("${telegram_token:12345678}")
    private String telegramToken;
    @Value("${telegram_debug:false}")
    private boolean telegramDebug;
    @Inject
    private TelegramService telegramService;
    @Inject
    private MessagesService messagesService;
    @Inject
    private UserService userService;
    @Inject
    private CommandsManager commandsManager;
    @Inject
    private ApplicationEventPublisher applicationEventPublisher;
    @Value("${upload_tmp_dir:#{systemEnvironment['TEMP'] ?: '/tmp'}}")
    private String tmpDir;

    private static final String MSG_LINK = "🔗";

    @PostConstruct
    public void init() {
        TelegramBot.Builder tgBuilder = new TelegramBot.Builder(telegramToken);
        if (StringUtils.isNotEmpty(apiUrl)) {
            tgBuilder.apiUrl(apiUrl).fileApiUrl(fileApiUrl);
        }
        bot =  tgBuilder.build();
        if (!telegramDebug) {
            try {
                SetWebhook webhook = new SetWebhook().url(webhookUrl);
                if (!bot.execute(webhook).isOk()) {
                    logger.error("error setting webhook");
                }
            } catch (Exception e) {
                logger.warn("couldn't initialize telegram bot", e);
            }
        } else {
            bot.setUpdatesListener(updates -> {
                logger.info("got updates: {}",  updates);
                updates.forEach(this::processUpdate);
                return UpdatesListener.CONFIRMED_UPDATES_ALL;
            });
        }
    }

    public void processUpdate(Update update) {
        logger.debug("Update: {}", update);
        Message message = update.message();
        if (update.message() == null) {
            message = update.editedMessage();
            if (message == null) {
                logger.error("error parsing telegram update: {}", update);
                return;
            }
            User user_from = userService.getUserByUID(telegramService.getUser(message.chat().id())).orElse(AnonymousUser.INSTANCE);
            logger.info("Found juick user {}", user_from.getUid());
            Optional<Pair<Integer, Integer>> originalMessageData = messagesService.findMessageByProperty("durovId",
                    String.valueOf(message.messageId()));
            if (originalMessageData.isPresent()) {
                int mid = originalMessageData.get().getLeft();
                int rid = originalMessageData.get().getRight();
                // TODO: this is copypaste from api, need switch to api
                com.juick.Message originalMessage = rid == 0 ? messagesService.getMessage(mid).orElseThrow(IllegalStateException::new)
                        : messagesService.getReply(mid, rid);
                User author = originalMessage.getUser();
                String newMessageText = StringUtils.defaultString(message.text());
                if (user_from.equals(author) && canUpdateMessage(originalMessage, newMessageText)) {
                    if (messagesService.updateMessage(mid, rid, newMessageText)) {
                        telegramNotify(message.chat().id(), "Message updated", new com.juick.Message());
                        return;
                    }
                }
                telegramNotify(message.chat().id(), "Error updating message", new com.juick.Message());
            }
        } else {
            User user_from = userService.getUserByUID(telegramService.getUser(message.chat().id())).orElse(AnonymousUser.INSTANCE);
            logger.info("Found juick user {}", user_from.getUid());

            String username = message.from().username();
            if (username == null) {
                username = message.from().firstName();
            }
            if (!user_from.isAnonymous()) {
                URI attachment = URI.create(StringUtils.EMPTY);
                if (message.photo() != null) {
                    String fileId = Arrays.stream(message.photo()).max(Comparator.comparingInt(PhotoSize::fileSize))
                            .orElse(new PhotoSize()).fileId();
                    if (StringUtils.isNotEmpty(fileId)) {
                        GetFile request = new GetFile(fileId);
                        GetFileResponse response = bot.execute(request);
                        logger.info("got file {}", response.file());
                        try {
                            URL fileURL = new URL(bot.getFullFilePath(response.file()));
                            attachment = HttpUtils.downloadImage(fileURL, tmpDir);
                        } catch (Exception e) {
                            logger.warn("attachment exception", e);
                        }
                        logger.info("received {}", attachment);
                    }
                }
                String text = message.text();
                if (StringUtils.isBlank(text)) {
                    text = message.caption();
                }
                if (StringUtils.isBlank(text)) {
                    text = StringUtils.EMPTY;
                }
                if (StringUtils.isNotEmpty(text) || StringUtils.isNotEmpty(attachment.toString())) {
                    if (text.equalsIgnoreCase("LOGIN")
                            || text.equalsIgnoreCase("PING")
                            || text.equalsIgnoreCase("HELP")
                            || text.equalsIgnoreCase("/login")
                            || text.equalsIgnoreCase("/logout")
                            || text.equalsIgnoreCase("/start")
                            || text.equalsIgnoreCase("/help")) {
                        String msgUrl = "http://juick.com/login?hash=" + userService.getHashByUID(user_from.getUid());
                        String msg = String.format("Hi, %s!\nYou can post messages and images to Juick there.\n" +
                                "Tap to [log into website](%s) to get more info", user_from.getName(), msgUrl);
                        telegramNotify(message.from().id().longValue(), msg, new com.juick.Message());
                    } else {
                        Message replyMessage = message.replyToMessage();
                        if (replyMessage != null) {
                            MessageEntity[] entities = replyMessage.entities();
                            if (entities == null) {
                                entities = replyMessage.captionEntities();
                            }
                            if (entities != null) {
                                Optional<MessageEntity> juickLink = Arrays.stream(entities)
                                        .filter(this::isJuickLink)
                                        .findFirst();
                                if (juickLink.isPresent()) {
                                    if (StringUtils.isNotEmpty(juickLink.get().url())) {
                                        UriComponents uriComponents = UriComponentsBuilder.fromUriString(
                                                juickLink.get().url()).build();
                                        String path = uriComponents.getPath();
                                        if (StringUtils.isNotEmpty(path) && path.length() > 1) {
                                            int mid = 0;
                                            try {
                                                mid = Integer.valueOf(path.substring(3));
                                            } catch (NumberFormatException e) {
                                                logger.warn("wrong mid received");
                                                return;
                                            }
                                            String prefix = String.format("#%d ", mid);
                                            if (StringUtils.isNotEmpty(uriComponents.getFragment())) {
                                                int rid = Integer.valueOf(uriComponents.getFragment());
                                                prefix = String.format("#%d/%d ", mid, rid);
                                            }
                                            executeCommand(message.messageId(), message.from().id().longValue(),
                                                    user_from, prefix + text, attachment);
                                        } else {
                                            logger.warn("invalid path: {}", path);
                                        }
                                    } else {
                                        logger.warn("invalid entity: {}", juickLink);
                                    }
                                } else {
                                    telegramNotify(message.from().id().longValue(),
                                            "Can not reply to this message", replyMessage.messageId(), new com.juick.Message());
                                }
                            } else {
                                telegramNotify(message.from().id().longValue(),
                                        "Can not reply to this message", replyMessage.messageId(), new com.juick.Message());
                            }
                        } else {
                            executeCommand(message.messageId(), message.from().id().longValue(),
                                    user_from, text, attachment);
                        }
                    }
                }
                messagesService.getUnread(user_from).forEach(mid -> messagesService.setRead(user_from, mid));
            } else {
                List<Long> chats = telegramService.getAnonymous();
                if (!chats.contains(message.chat().id())) {
                    logger.info("added chat with {}", username);
                    telegramService.createTelegramUser(message.from().id(), username);
                }
                telegramSignupNotify(message.from().id().longValue(), userService.getSignUpHashByTelegramID(message.from().id().longValue(), username));
            }
        }
    }

    /*
        validate user input
     */
    private boolean canUpdateMessage(com.juick.Message message, String newData) {
        if (StringUtils.isEmpty(newData)) {
            // allow empty text only when image is present
            return StringUtils.isNotEmpty(message.getAttachmentType());
        }
        return true;
    }

    private void executeCommand(Integer messageId, Long userId, User user_from, String text, URI attachment) {
        try {
            CommandResult result = commandsManager.processCommand(user_from, text, attachment);
            if (result.getNewMessage().isPresent()) {
                com.juick.Message newMessage = result.getNewMessage().get();
                messagesService.setMessageProperty(newMessage.getMid(), newMessage.getRid(), "durovId",
                        String.valueOf(messageId));
            }
            String messageTxt = StringUtils.isNotEmpty(result.getMarkdown()) ? result.getMarkdown()
                    : "Unknown error or unsupported command";
            telegramNotify(userId, messageTxt, new com.juick.Message());
        } catch (Exception e) {
            logger.warn("telegram exception", e);
        }
    }

    private boolean isJuickLink(MessageEntity e) {
        return e.offset() == 0 && e.type().equals(MessageEntity.Type.text_link) && e.length() == 2;
    }

    public void telegramNotify(Long chatId, String msg, @Nonnull com.juick.Message source) {
        telegramNotify(chatId, msg, 0, source);
    }

    public void telegramNotify(Long chatId, String msg, Integer replyTo, @Nonnull com.juick.Message source) {
        String attachment = MessageUtils.attachmentUrl(source);
        boolean isSendTxt = true;
        if (!StringUtils.isEmpty(attachment)) {
            SendPhoto telegramPhoto = new SendPhoto(chatId, attachment);
            if (replyTo > 0) {
                telegramPhoto.replyToMessageId(replyTo);
            }
            telegramPhoto.parseMode(ParseMode.Markdown);
            if(msg.length() < 1024) {
                telegramPhoto.caption(msg);
                isSendTxt = false;
            }
            bot.execute(telegramPhoto, new Callback<>() {
                @Override
                public void onResponse(SendPhoto request, SendResponse response) {
                    processTelegramResponse(chatId, response, source);
                }

                @Override
                public void onFailure(SendPhoto request, IOException e) {
                    logger.warn("telegram failure", e);
                }
            });
        }
        if (isSendTxt){
            SendMessage telegramMessage = new SendMessage(chatId, msg);
            if (replyTo > 0) {
                telegramMessage.replyToMessageId(replyTo);
            }
            telegramMessage.parseMode(ParseMode.Markdown).disableWebPagePreview(true);
            bot.execute(telegramMessage, new Callback<>() {
                @Override
                public void onResponse(SendMessage request, SendResponse response) {
                    processTelegramResponse(chatId, response, source);
                }

                @Override
                public void onFailure(SendMessage request, IOException e) {
                    logger.warn("telegram failure", e);
                }
            });
        }
    }

    private void processTelegramResponse(Long chatId, SendResponse response, com.juick.Message source) {
        int userId = telegramService.getUser(chatId);
        if (!response.isOk()) {
            if (response.errorCode() == 403) {
                // remove from anonymous users
                telegramService.getAnonymous().stream().filter(c -> c.equals(chatId)).findFirst().ifPresent(
                        d -> {
                            telegramService.deleteAnonymous(d);
                            logger.info("deleted {} chat", d);
                        }
                );
                if (userId > 0) {
                    User userToDelete = userService.getUserByUID(userId)
                            .orElseThrow(IllegalStateException::new);
                    boolean status = telegramService.deleteTelegramUser(userToDelete.getUid());
                    logger.info("deleting telegram id of @{} : {}", userToDelete.getName(), status);
                }
            } else {
                logger.warn("error response, isOk: {}, errorCode: {}, description: {}",
                        response.isOk(), response.errorCode(), response.description());
            }
        } else {
            if (MessageUtils.isReply(source)) {
                messagesService.setLastReadComment(userService.getUserByUID(userId)
                        .orElseThrow(IllegalStateException::new), source.getMid(), source.getRid());
                User user = userService.getUserByUID(userId).orElseThrow(IllegalStateException::new);
                userService.updateLastSeen(user);
                applicationEventPublisher.publishEvent(
                        new MessageReadEvent(this, user, source));
            }
        }
    }

    public void telegramSignupNotify(Long telegramId, String hash) {
        bot.execute(new SendMessage(telegramId,
                String.format("You are subscribed to all Juick messages. " +
                        "[Create or link](http://juick.com/signup?type=durov&hash=%s) " +
                        "an existing Juick account to get your subscriptions and ability to post messages", hash))
                .parseMode(ParseMode.Markdown), new Callback<>() {
            @Override
            public void onResponse(SendMessage request, SendResponse response) {
                logger.info("got response: {}", response.message());
            }

            @Override
            public void onFailure(SendMessage request, IOException e) {
                logger.warn("telegram failure", e);
            }
        });
    }

    @Override
    public void processMessageEvent(MessageEvent messageEvent) {
        com.juick.Message jmsg = messageEvent.getMessage();
        List<User> subscribedUsers = messageEvent.getUsers();
        if (jmsg.isService()) {
            return;
        }
        String msgUrl = formatUrl(jmsg);
        if (MessageUtils.isPM(jmsg)) {
            telegramService.getTelegramIdentifiers(Collections.singletonList(jmsg.getTo()))
                    .forEach(c -> telegramNotify(c, formatPost(jmsg, true), jmsg));
        } else if (MessageUtils.isReply(jmsg)) {
            String fmsg = String.format("[%s](%s) %s", MSG_LINK, msgUrl, formatPost(jmsg, true));
            telegramService.getTelegramIdentifiers(
                    subscribedUsers
            ).forEach(c -> telegramNotify(c, fmsg, jmsg));
        } else {
            String msg = String.format("[%s](%s) %s", MSG_LINK, msgUrl, formatPost(jmsg, true));

            List<Long> users = telegramService.getTelegramIdentifiers(subscribedUsers);
            List<Long> chats = telegramService.getAnonymous();
            // registered subscribed users

            users.forEach(c -> telegramNotify(c, msg, jmsg));
            // anonymous
            chats.stream().filter(u -> telegramService.getUser(u) == 0).forEach(c -> telegramNotify(c, msg, jmsg));
        }
    }

    @Override
    public void processLikeEvent(LikeEvent likeEvent) {
        User liker = likeEvent.getUser();
        com.juick.Message message = likeEvent.getMessage();
        List<User> subscribers = likeEvent.getSubscribers();
        logger.info("Like received in tg listener");
        if (!userService.isInBLAny(message.getUser().getUid(), liker.getUid())) {
            telegramService.getTelegramIdentifiers(Collections.singletonList(message.getUser()))
                    .forEach(c -> telegramNotify(c, String.format("%s recommends your [post](%s)",
                            MessageUtils.getMarkdownUser(liker), formatUrl(message)), new com.juick.Message()));
        }
        telegramService.getTelegramIdentifiers(subscribers)
                .forEach(c -> telegramNotify(c, String.format("%s recommends you someone's [post](%s)",
                        MessageUtils.getMarkdownUser(liker), formatUrl(message)), new com.juick.Message()));
    }

    @Override
    public void processPingEvent(PingEvent pingEvent) {

    }

    @Override
    public void processMessageReadEvent(MessageReadEvent messageReadEvent) {

    }

    @Override
    public void processTopEvent(TopEvent topEvent) {
        com.juick.Message message = topEvent.getMessage();
        telegramService.getTelegramIdentifiers(Collections.singletonList(message.getUser()))
                .forEach(c -> telegramNotify(c, String.format("Your [post](%s) became popular!",
                        formatUrl(message)), new com.juick.Message()));
    }

    @Override
    public void processSubscribeEvent(SubscribeEvent subscribeEvent) {
        User subscriber = subscribeEvent.getUser();
        User target = subscribeEvent.getToUser();
        telegramService.getTelegramIdentifiers(Collections.singletonList(target))
                .forEach(c -> telegramNotify(c, String.format("%s subscribed to your blog",
                        MessageUtils.getMarkdownUser(subscriber)), new com.juick.Message()));
    }
}