package com.juick.server.api;

import com.juick.Message;
import com.juick.User;
import com.juick.server.CommandsManager;
import com.juick.server.EmailManager;
import com.juick.server.ServerManager;
import com.juick.server.util.HttpForbiddenException;
import com.juick.server.util.UserUtils;
import com.juick.service.EmailService;
import com.juick.service.UserService;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.RandomStringUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.mail.util.MimeMessageParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.context.request.async.AsyncRequestTimeoutException;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
import springfox.documentation.annotations.ApiIgnore;

import javax.inject.Inject;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.nio.file.Paths;
import java.util.*;

@Controller
public class Service {
    private static Logger logger = LoggerFactory.getLogger(Service.class);
    @Inject
    private UserService userService;
    @Inject
    private EmailService emailService;
    @Inject
    private CommandsManager commandsManager;
    @Inject
    private EmailManager emailManager;
    @Value("${api_user:juick}")
    private String serviceUser;
    @Value("${upload_tmp_dir:#{systemEnvironment['TEMP'] ?: '/tmp'}}")
    private String tmpDir;
    @Value("${banned_emails:}")
    private String[] ignoredEmails;
    @Inject
    private ServerManager serverManager;

    private Session session = Session.getDefaultInstance(new Properties());

    @ApiIgnore
    @PostMapping("/api/mail")
    @ResponseStatus(value = HttpStatus.OK)
    public void processMail(InputStream data) throws Exception {
        if (UserUtils.getCurrentUser().getName().equals(serviceUser)) {
            MimeMessage msg = new MimeMessage(session, data);
            String[] returnPaths = msg.getHeader("Return-Path");
            if (returnPaths != null) {
                logger.info("got msg with return path {}", returnPaths[0]);
                if (returnPaths[0].equals("<>")) {
                    return;
                }
            }
            String from = msg.getFrom() == null || msg.getFrom().length > 1 ? ((InternetAddress) msg.getSender()).getAddress()
                    : ((InternetAddress) msg.getFrom()[0]).getAddress();

            User visitor = userService.getUserByEmail(from);
            if (!visitor.isAnonymous()) {
                MimeMessageParser parser = new MimeMessageParser(msg);
                parser.parse();
                final String[] body = {parser.getPlainContent()};
                if (body[0] == null) {
                    parser.getAttachmentList().stream()
                            .filter(a -> a.getContentType().equals("text/plain")).findFirst()
                            .ifPresent(a -> {
                                try {
                                    body[0] = IOUtils.toString(a.getInputStream(), StandardCharsets.UTF_8);
                                    logger.info("got text: {}", body[0]);
                                } catch (IOException e) {
                                    logger.info("attachment error: {}", e);
                                }
                            });
                }
                final String[] attachmentFName = new String[1];
                parser.getAttachmentList().stream().filter(a ->
                        a.getContentType().equals("image/jpeg") || a.getContentType().equals("image/png"))
                        .findFirst().ifPresent(a -> {
                    logger.info("got attachment: {}", a.getContentType());
                    String attachmentType;
                    if (a.getContentType().equals("image/jpeg")) {
                        attachmentType = "jpg";
                    } else {
                        attachmentType = "png";
                    }
                    attachmentFName[0] = DigestUtils.md5Hex(UUID.randomUUID().toString()) + "." + attachmentType;
                    try {
                        logger.info("got inputstream: {}", a.getInputStream());
                        FileOutputStream fos = new FileOutputStream(Paths.get(tmpDir, attachmentFName[0]).toString());
                        IOUtils.copy(a.getInputStream(), fos);
                        fos.close();
                    } catch (IOException e) {
                        logger.info("attachment error", e);
                    }
                });
                String[] inReplyToHeaders = msg.getHeader("In-Reply-To");
                if (inReplyToHeaders != null && inReplyToHeaders.length > 0) {
                    Scanner inReplyToScanner = new Scanner(inReplyToHeaders[0].trim()).useDelimiter(EmailManager.MSGID_PATTERN);
                    int mid = Integer.parseInt(inReplyToScanner.next());
                    int rid = Integer.parseInt(inReplyToScanner.next());
                    logger.info("Message is reply to #{}/{}", mid, rid);
                    body[0] = rid > 0 ? String.format("#%d/%d %s", mid, rid, body[0])
                            : String.format("#%d %s", mid, body[0]);
                }
                URI attachmentUri = StringUtils.isNotEmpty(attachmentFName[0]) ? URI.create(String.format("juick://%s", attachmentFName[0]))
                        : URI.create(StringUtils.EMPTY);
                commandsManager.processCommand(visitor, body[0], attachmentUri);
            } else {
                if (!Arrays.asList(ignoredEmails).contains(from)) {
                    String verificationCode = RandomStringUtils.randomAlphanumeric(8).toUpperCase();
                    emailService.addVerificationCode(null, from, verificationCode);
                    String signupUrl = String.format("Follow this link to create Juick account: https://juick.com/signup?type=email&hash=%s", verificationCode);
                    emailManager.sendEmail(from, "Juick registration", signupUrl, StringUtils.EMPTY, Collections.emptyMap());
                }
            }
        } else {
            throw new HttpForbiddenException();
        }
    }
    private void endSession(SseEmitter emitter) {
        serverManager.getSessions().stream()
                .filter(s -> s.getEmitter().equals(emitter))
                .forEach(session -> serverManager.getSessions().remove(session));
    }
    @GetMapping("/api/events")
    public SseEmitter handle() throws IOException {
        User visitor = UserUtils.getCurrentUser();
        logger.info("{} connected", visitor.getName());
        if (!visitor.isAnonymous()) {
            userService.updateLastSeen(visitor);
        }
        SseEmitter emitter = new SseEmitter(600000L);
        serverManager.getSessions().add(new ServerManager.EventSession(visitor, emitter));

        emitter.onCompletion(() -> endSession(emitter));
        emitter.onTimeout(() -> endSession(emitter));

        return emitter;
    }
    @ExceptionHandler(AsyncRequestTimeoutException.class)
    public void eventErrorHandler(Exception ex) {
        logger.debug("SSE timeout", ex);
    }
}