package com.juick.server;

import com.juick.Message;
import com.juick.User;
import com.juick.formatters.PlainTextFormatter;
import com.juick.server.api.activity.model.Context;
import com.juick.server.api.activity.model.activities.Accept;
import com.juick.server.api.activity.model.activities.Announce;
import com.juick.server.api.activity.model.activities.Create;
import com.juick.server.api.activity.model.activities.Delete;
import com.juick.server.api.activity.model.objects.Hashtag;
import com.juick.server.api.activity.model.objects.Image;
import com.juick.server.api.activity.model.objects.Mention;
import com.juick.server.api.activity.model.objects.Note;
import com.juick.server.api.activity.model.objects.Person;
import com.juick.server.util.HttpUtils;
import com.juick.service.SocialService;
import com.juick.service.UserService;
import com.juick.service.activities.*;
import com.juick.service.component.*;
import com.juick.util.MessageUtils;
import com.mitchellbosecke.pebble.PebbleEngine;
import com.mitchellbosecke.pebble.template.PebbleTemplate;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.util.UriComponentsBuilder;

import javax.annotation.Nonnull;
import javax.annotation.PostConstruct;
import javax.inject.Inject;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;

@Component
public class ActivityPubManager implements ActivityListener, NotificationListener {
    private static final Logger logger = LoggerFactory.getLogger(ActivityPubManager.class);
    @Inject
    private SignatureManager signatureManager;
    @Inject
    private SocialService socialService;
    @Inject
    private UserService userService;
    @Inject
    private PebbleEngine pebbleEngine;
    @Value("${ap_base_uri:http://localhost:8080/}")
    private String baseUri;
    @Value("${service_user:juick}")
    private String serviceUsername;

    private User serviceUser;

    @PostConstruct
    public void init() {
        serviceUser = userService.getUserByName(serviceUsername);
    }

    @Override
    public void processFollowEvent(@Nonnull FollowEvent followEvent) {
        String acct = (String)followEvent.getRequest().getObject();
        logger.info("received follower request to {}", acct);
        User followedUser = socialService.getUserByAccountUri(acct);
        if (!followedUser.isAnonymous()) {
            // automatically accept follower requests
            Person me = (Person) signatureManager.getContext(URI.create(acct)).get();
            Person follower = (Person) signatureManager.getContext(URI.create(followEvent.getRequest().getActor())).get();
            Accept accept = new Accept();
            accept.setActor(me.getId());
            accept.setObject(followEvent.getRequest());
            try {
                signatureManager.post(me, follower, accept);
                socialService.addFollower(followedUser, follower.getId());
                logger.info("Follower added for {}", followedUser.getName());
            } catch (IOException e) {
                logger.info("activitypub exception", e);
            }
        }
    }

    @Override
    public void undoFollowEvent(UndoFollowEvent event) {
        String actor = event.getActor();
        String me = event.getObject();
        logger.info("{} stopping to follow {}", actor, me);
        User followedUser = socialService.getUserByAccountUri(me);
        if (!followedUser.isAnonymous()) {
            socialService.removeFollower(followedUser, actor);
        }
    }

    @Override
    public void deleteUserEvent(DeleteUserEvent event) {
        String acct = event.getUserUri();
        logger.info("Deleting {} from followers", acct);
        socialService.removeAccount(acct);
    }

    @Override
    public void deleteMessageEvent(DeleteMessageEvent event) {
        Message msg = event.getMessage();
        User user = msg.getUser();
        String userUri = personUri(user);
        Note note = makeNote(msg);
        Person me = (Person) signatureManager.getContext(URI.create(userUri)).get();
        socialService.getFollowers(user).forEach(acct -> {
            Person follower = (Person) signatureManager.getContext(URI.create(acct)).get();
            Delete delete = new Delete();
            delete.setId(note.getId());
            delete.setActor(me.getId());
            delete.setPublished(note.getPublished());
            delete.setObject(note);
            try {
                logger.info("Deletion to follower {}", follower.getId());
                signatureManager.post(me, follower, delete);
            } catch (IOException e) {
                logger.warn("activitypub exception", e);
            }
        });
    }

    @Override
    public void processMessageEvent(MessageEvent messageEvent) {
        Message msg = messageEvent.getMessage();
        if (MessageUtils.isPM(msg)) {
            return;
        }
        User user = msg.getUser();
        String userUri = personUri(user);
        Note note = makeNote(msg);
        Person me = (Person) signatureManager.getContext(URI.create(userUri)).get();
        Set<String> subscribers = new HashSet<>(socialService.getFollowers(user));
        if (MessageUtils.isReply(msg) && msg.getTo().getUri().toASCIIString().length() > 0) {
            String replier = msg.getTo().getUri().toASCIIString();
            subscribers.add(replier);
            List<String> cc = new ArrayList<>(note.getCc());
            cc.add(replier);
            note.setCc(cc);
        }
        subscribers.forEach(acct -> {
            Optional<Context> context = signatureManager.getContext(URI.create(acct));
            if (context.isPresent()) {
                Person follower = (Person)context.get();
                Create create = new Create();
                create.setId(note.getId());
                create.setActor(me.getId());
                create.setPublished(note.getPublished());
                create.setObject(note);
                try {
                    logger.info("Posting to subscriber {}", follower.getId());
                    signatureManager.post(me, follower, create);
                } catch (IOException e) {
                    logger.warn("activitypub exception", e);
                }
            }
        });
    }

    public String inboxUri() {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath("/api/inbox").toUriString();
    }

    public String outboxUri(User user) {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath(String.format("/u/%s/blog/toc", user.getName())).toUriString();
    }

    public String personUri(User user) {
        if (user.getUri().toString().length() > 0) {
            return user.getUri().toASCIIString();
        }
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath(String.format("/u/%s", user.getName())).toUriString();
    }
    public String personWebUri(User user) {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath(String.format("/%s/", user.getName())).toUriString();
    }

    public String followersUri(User user) {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath(String.format("/u/%s/followers/toc", user.getName())).toUriString();
    }

    public String followingUri(User user) {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath(String.format("/u/%s/following/toc", user.getName())).toUriString();
    }
    public String messageUri(Message msg) {
        return messageUri(msg.getMid(), msg.getRid());
    }
    public String messageUri(int mid, int rid) {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        uri.replacePath(String.format("/n/%d-%d", mid, rid));
        return uri.toUriString();
    }
    public String tagUri(com.juick.Tag tag) {
        UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
        return uri.replacePath(String.format("/t/%s", tag.getName())).toUriString();
    }

    public Note makeNote(Message msg) {
        Note note = new Note();
        note.setId(messageUri(msg));
        note.setUrl(PlainTextFormatter.formatUrl(msg));
        note.setAttributedTo(personUri(msg.getUser()));
        if (MessageUtils.isReply(msg)) {
            if (msg.getReplyToUri().toASCIIString().length() > 0) {
                note.setInReplyTo(msg.getReplyToUri().toASCIIString());
            } else {
                note.setInReplyTo(messageUri(msg.getMid(), msg.getReplyto()));
            }
        }
        if (MessageUtils.isPM(msg)) {
            note.setTo(Collections.singletonList(personUri(msg.getTo())));
        } else {
            note.setTo(Collections.singletonList("https://www.w3.org/ns/activitystreams#Public"));
            note.setCc(Collections.singletonList(followersUri(msg.getUser())));
        }
        note.setPublished(msg.getTimestamp());
        if (StringUtils.isNotBlank(msg.getAttachmentType())) {
            Image attachment = new Image();
            attachment.setId(msg.getAttachment().getMedium().getUrl());
            attachment.setUrl(msg.getAttachment().getMedium().getUrl());
            attachment.setMediaType(HttpUtils.mediaType(msg.getAttachmentType()));
            note.setAttachment(Collections.singletonList(attachment));
        }
        note.setTags(msg.getTags().stream().map(t -> {
            Hashtag hashtag = new Hashtag();
            hashtag.setId(tagUri(t));
            hashtag.setName(t.getName());
            return hashtag;
        }).collect(Collectors.toList()));
        if (msg.getReplyToUri() != null && msg.getReplyToUri().toASCIIString().length() > 0) {
            Optional<Context> noteContext = signatureManager.getContext(msg.getReplyToUri());
            if (noteContext.isPresent()) {
                Note activity = (Note) noteContext.get();
                Optional<Context> personContext = signatureManager.getContext(URI.create(activity.getAttributedTo()));
                if (personContext.isPresent()) {
                    Person person = (Person) personContext.get();
                    note.getTags().add(new Mention(person.getUrl(), person.getPreferredUsername()));
                    msg.getTo().setName(person.getPreferredUsername());
                    note.setInReplyTo(activity.getInReplyTo());
                }
            }
        } else if (MessageUtils.isReply(msg)) {
            note.getTags().add(new Mention(personWebUri(msg.getTo()), msg.getTo().getName()));
        }
        MessageUtils.getGlobalMentions(msg).forEach(m -> {
            // @user@server.tld -> user@server.tld
            Optional<Context> personContext = signatureManager.discoverPerson(m.substring(1));
            if (personContext.isPresent()) {
                Person person = (Person) personContext.get();
                note.getTags().add(new Mention(person.getUrl(), person.getPreferredUsername()));
                List<String> cc = new ArrayList<>(note.getCc());
                cc.add(person.getUrl());
                note.setCc(cc);
            }
        });
        if (msg.isHtml()) {
            note.setContent(msg.getText());
        } else {
            PebbleTemplate noteTemplate = pebbleEngine.getTemplate("layouts/note");
            Map<String, Object> context = new HashMap<>();
            context.put("msg", msg);
            context.put("baseUri", baseUri);
            try {
                Writer writer = new StringWriter();
                noteTemplate.evaluate(writer, context);
                note.setContent(writer.toString());
            } catch (IOException e) {
                logger.warn("template not rendered, falling back");
                note.setContent(MessageUtils.formatMessage(StringUtils.defaultString(msg.getText())));
            }
        }
        return note;
    }

    @Override
    public void processSubscribeEvent(SubscribeEvent subscribeEvent) {

    }

    @Override
    public void processLikeEvent(LikeEvent likeEvent) {

    }

    @Override
    public void processPingEvent(PingEvent pingEvent) {

    }

    @Override
    public void processMessageReadEvent(MessageReadEvent messageReadEvent) {

    }

    @Override
    public void processTopEvent(TopEvent topEvent) {
        Message message = topEvent.getMessage();
        Note note = makeNote(message);
        Announce announce = new Announce();
        announce.setId(note.getId() + "#top");
        announce.setActor(personUri(serviceUser));
        announce.setObject(note);
        Person me = (Person) signatureManager.getContext(URI.create(announce.getActor())).get();
        socialService.getFollowers(serviceUser).forEach(acct -> {
            Person follower = (Person) signatureManager.getContext(URI.create(acct)).get();
            try {
                logger.info("Announcing top: {}", message.getMid());
                signatureManager.post(me, follower, announce);
            } catch (IOException e) {
                logger.warn("activitypub exception", e);
            }
        });
    }
}