Kleinanzeigen/src/main/java/de/ph87/kleinanzeigen/telegram/TelegramService.java

package de.ph87.kleinanzeigen.telegram;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import de.ph87.kleinanzeigen.kleinanzeigen.offer.OfferDto;
import de.ph87.kleinanzeigen.kleinanzeigen.offer.OfferService;
import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Service;
import org.telegram.telegrambots.meta.api.methods.send.SendPhoto;
import org.telegram.telegrambots.meta.api.methods.updatingmessages.DeleteMessages;
import org.telegram.telegrambots.meta.api.methods.updatingmessages.EditMessageCaption;
import org.telegram.telegrambots.meta.api.objects.*;
import org.telegram.telegrambots.meta.api.objects.replykeyboard.InlineKeyboardMarkup;
import org.telegram.telegrambots.meta.api.objects.replykeyboard.buttons.InlineKeyboardButton;
import org.telegram.telegrambots.meta.exceptions.TelegramApiException;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;

@Slf4j
@Service
@RequiredArgsConstructor
public class TelegramService {

  private static final long CHAT_ID = 101138682L;

  private static final String ICON_CHECK = "✅";

  private static final String ICON_REMOVE = "❌";

  private byte[] NO_IMAGE = null;

  private final ObjectMapper objectMapper;

  private final OfferService offerService;

  private TelegramBot bot = null;

  @PostConstruct
  public void postConstruct() throws IOException {
    final BufferedImage img = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
    final ByteArrayOutputStream stream = new ByteArrayOutputStream();
    ImageIO.write(img, "PNG", stream);
    NO_IMAGE = stream.toByteArray();

    try {
      bot = new TelegramBot(readToken(), this::onUpdateReceived);
    } catch (TelegramApiException | IOException e) {
      log.error("Failed to start TelegramBot: {}", e.toString());
    }
  }

  @EventListener(OfferDto.class)
  public void onOfferChanged(final OfferDto offer) {
    if (offer.is_existing_()) {
      if (offer.getTelegramMessageId() == null) {
      send(offer);
      }else{
        updateMessage(offer.getTelegramMessageId(), offer.getTelegramMessageId().getChatId());
      }
    } else {
      remove(List.of(offer));
    }
  }

  @PreDestroy
  public void stop() {
    log.info("Stopping Telegram bot...");
    bot.stop();
    log.info("Telegram bot stopped");
  }

  private static String readToken() throws IOException {
    try (final FileInputStream stream = new FileInputStream("./telegram.token")) {
      return new String(stream.readAllBytes(), StandardCharsets.UTF_8).trim();
    }
  }

  private void onUpdateReceived(final Update update) {
    if (update.hasMessage() && update.getMessage().hasText()) {
      log.info("#{} \"{}\": {}", update.getMessage().getChat().getId(), update.getMessage().getChat().getUserName(), update.getMessage().getText());
    } else if (update.hasCallbackQuery()) {
      handleCallbackQuery(update.getCallbackQuery());
    }
  }

  private void handleCallbackQuery(final CallbackQuery query) {
    final MaybeInaccessibleMessage message = query.getMessage();
    if (message.getChatId() != CHAT_ID) {
      return;
    }
    try {
      final InlineDto dto = objectMapper.readValue(query.getData(), InlineDto.class);
      switch (dto.getCommand()) {
        case HIDE -> hide(message);
        case REMEMBER -> remember(message, true);
        case UNREMEMBER -> remember(message, false);
        default -> updateMessage(message, message.getChatId());
      }
    } catch (JsonProcessingException e) {
      log.error("Failed to read InlineDto.", e);
    }
  }

  private void hide(final MaybeInaccessibleMessage message) {
    offerService.hideByTelegramMessageId(message.getMessageId(), true);
    remove(message);
  }

  private void remember(final MaybeInaccessibleMessage message, final boolean remember) {
    offerService.rememberByTelegramMessageId(message.getMessageId(), remember).ifPresentOrElse(
      offer -> updateMessage(offer, message.getChatId(), message.getMessageId()),
      () -> remove(message)
    );
  }

  private void updateMessage(final MaybeInaccessibleMessage message, final Long chatId) {
    offerService.findByTelegramMessageId(message.getMessageId()).ifPresentOrElse(
      offer -> updateMessage(offer, chatId, message.getMessageId()),
      () -> remove(message)
    );
  }

  private void updateMessage(final OfferDto offer, final long chatId, final int messageId) {
    try {
      final EditMessageCaption edit = new EditMessageCaption(chatId + "", messageId, null, createText(offer), createKeyboard(offer), null, null);
      edit.setParseMode("Markdown");
      bot.execute(edit);
    } catch (TelegramApiException | JsonProcessingException e) {
      log.error("Failed to edit Message to #{}.", chatId, e);
    }
  }

  private void send(final OfferDto offer) {
    try {
      final InputFile inputFile = offer.getImageURL() == null ? new InputFile(new ByteArrayInputStream(NO_IMAGE), "[Kein Bild]") : new InputFile(offer.getImageURL());
      final SendPhoto send = new SendPhoto(CHAT_ID + "", inputFile);
      log.debug("{}", send);
      send.setCaption(createText(offer));
      send.setReplyMarkup(createKeyboard(offer));
      final Message message = bot.execute(send);

      offerService.setTelegramMessageId(offer, message.getMessageId());
    } catch (TelegramApiException | JsonProcessingException e) {
      log.error("Failed to send Message to #{}.", CHAT_ID, e);
    }
  }

  private String createText(final OfferDto offer) {
    return "[%s](%s)\n%s\n%s".formatted(
      offer.getTitle().replaceAll("\\[", "(").replaceAll("]", ")"),
      offer.getArticleURL(),
      offer.combineLocation(),
      offer.getDescription()
    );
  }

  private InlineKeyboardMarkup createKeyboard(final OfferDto offer) throws JsonProcessingException {
    final InlineKeyboardMarkup markup = new InlineKeyboardMarkup();
    final ArrayList<List<InlineKeyboardButton>> keyboard = new ArrayList<>();
    final ArrayList<InlineKeyboardButton> row = new ArrayList<>();
    if (offer.isRemember()) {
      addButton(row, ICON_CHECK + ICON_CHECK + ICON_CHECK + " Gemerkt " + ICON_CHECK + ICON_CHECK + ICON_CHECK, InlineCommand.UNREMEMBER);
    } else {
      addButton(row, ICON_REMOVE + " Entfernen", InlineCommand.HIDE);
      addButton(row, ICON_CHECK + " Merken", InlineCommand.REMEMBER);
    }
    keyboard.add(row);
    markup.setKeyboard(keyboard);
    return markup;
  }

  private void addButton(final ArrayList<InlineKeyboardButton> row, final String caption, final InlineCommand command) throws JsonProcessingException {
    final String data = objectMapper.writeValueAsString(new InlineDto(command));
    row.add(new InlineKeyboardButton(caption, null, data, null, null, null, null, null, null));
  }

  private void remove(final List<OfferDto> offers) {
    _remove(offers.stream().map(OfferDto::getTelegramMessageId).filter(Objects::nonNull).toList());
  }

  private void remove(final MaybeInaccessibleMessage... messages) {
    _remove(Arrays.stream(messages).map(MaybeInaccessibleMessage::getMessageId).toList());
  }

  private void _remove(final List<Integer> messageIds) {
    if (messageIds.isEmpty()) {
      return;
    }
    try {
      bot.execute(new DeleteMessages(CHAT_ID + "", messageIds));
    } catch (TelegramApiException e) {
      log.error("Failed to remove Message to #{}.", CHAT_ID, e);
    }
  }

}