package com.juick.server.api.activity;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.juick.User;
import com.juick.server.ActivityPubManager;
import com.juick.server.KeystoreManager;
import com.juick.server.SignatureManager;
import com.juick.server.api.activity.model.*;
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.activities.Follow;
import com.juick.server.api.activity.model.activities.Undo;
import com.juick.server.util.HttpBadRequestException;
import com.juick.server.util.HttpNotFoundException;
import com.juick.server.util.UserUtils;
import com.juick.service.MessagesService;
import com.juick.service.UserService;
import com.juick.service.activities.DeleteUserEvent;
import com.juick.service.activities.FollowEvent;
import com.juick.service.activities.UndoFollowEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;

import javax.inject.Inject;
import java.net.URI;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@RestController
public class Profile {
    private static final Logger logger = LoggerFactory.getLogger(Profile.class);
    @Inject
    private UserService userService;
    @Inject
    private MessagesService messagesService;
    @Inject
    private KeystoreManager keystoreManager;
    @Inject
    private SignatureManager signatureManager;
    @Inject
    private ActivityPubManager activityPubManager;
    @Inject
    private ApplicationEventPublisher applicationEventPublisher;
    @Value("${web_domain:localhost}")
    private String domain;
    @Value("${ap_base_uri:http://localhost:8080/}")
    private String baseUri;
    @Value("${img_url:http://localhost:8080/i/}")
    private String baseImagesUri;
    @Inject
    private ObjectMapper jsonMapper;

    @GetMapping(value = "/u/{userName}", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public Person getUser(@PathVariable String userName) {
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            Person person = new Person();
            person.setId(activityPubManager.personUri(user));
            person.setUrl(activityPubManager.personWebUri(user));
            person.setName(userName);
            person.setPreferredUsername(userName);
            Key publicKey = new Key();
            publicKey.setId(person.getId() + "#main-key");
            publicKey.setOwner(person.getId());
            publicKey.setPublicKeyPem(keystoreManager.getPublicKeyPem());
            person.setPublicKey(publicKey);
            person.setInbox(activityPubManager.inboxUri());
            person.setOutbox(activityPubManager.outboxUri(user));
            person.setFollowers(activityPubManager.followersUri(user));
            person.setFollowing(activityPubManager.followingUri(user));
            UriComponentsBuilder image = UriComponentsBuilder.fromUriString(baseImagesUri);
            image.path(String.format("/a/%d.png", user.getUid()));
            Image avatar = new Image();
            avatar.setUrl(image.toUriString());
            avatar.setMediaType("image/png");
            person.setIcon(avatar);
            return (Person) Context.build(person);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/u/{userName}/blog/toc", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public OrderedCollection getOutbox(@PathVariable String userName) {
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromUriString(baseUri);
            OrderedCollection blog = new OrderedCollection();
            blog.setId(ServletUriComponentsBuilder.fromCurrentRequestUri().toUriString());
            blog.setTotalItems(userService.getStatsMessages(user.getUid()));
            blog.setFirst(uriComponentsBuilder.path(String.format("/u/%s/blog", userName)).toUriString());
            return (OrderedCollection) Context.build(blog);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/u/{userName}/blog", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public OrderedCollectionPage getOutboxPage(@PathVariable String userName,
                                               @RequestParam(required = false, defaultValue = "0") int before) {
        User visitor = UserUtils.getCurrentUser();
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            UriComponentsBuilder uri = UriComponentsBuilder.fromUriString(baseUri);
            String personUri = uri.path(String.format("/u/%s", userName)).toUriString();
            List<Integer> mids = messagesService.getUserBlog(user.getUid(), 0, before);
            List<Note> notes = messagesService.getMessages(visitor, mids).stream().map(activityPubManager::makeNote).collect(Collectors.toList());
            OrderedCollectionPage page = new OrderedCollectionPage();
            page.setPartOf(uri.replacePath(String.format("/u/%s/blog/toc", userName)).toUriString());
            page.setFirst(uri.replacePath(String.format("/u/%s/blog", userName)).toUriString());
            page.setId(ServletUriComponentsBuilder.fromCurrentRequestUri().toUriString());
            page.setOrderedItems(notes.stream().map(a -> {
                Create create = new Create();
                create.setId(a.getId() + "#Create");
                create.setTo(a.getTo());
                create.setActor(personUri);
                create.setObject(a);
                create.setPublished(a.getPublished());
                return create;
            }).collect(Collectors.toList()));
            int beforeNext = mids.stream().reduce((fst, second) -> second).orElse(0);
            if (beforeNext > 0) {
                page.setNext(uri.queryParam("before", beforeNext).toUriString());
            }
            page.setLast(uri.replaceQueryParam("before", "1").toUriString());
            return (OrderedCollectionPage) Context.build(page);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/u/{userName}/followers/toc", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public OrderedCollection getFollowers(@PathVariable String userName) {
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromUriString(baseUri);
            OrderedCollection followers = new OrderedCollection();
            followers.setId(ServletUriComponentsBuilder.fromCurrentRequestUri().toUriString());
            followers.setTotalItems(userService.getStatsMyReaders(user.getUid()));
            followers.setFirst(uriComponentsBuilder.path(String.format("/u/%s/followers", userName)).toUriString());
            return (OrderedCollection) Context.build(followers);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/u/{userName}/followers", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public OrderedCollectionPage getFollowersPage(@PathVariable String userName,
                                                  @RequestParam(required = false, defaultValue = "0") int page) {
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromUriString(baseUri);
            uriComponentsBuilder.path(String.format("/u/%s/followers", userName));
            List<User> followers = userService.getUserReaders(user.getUid());
            Stream<User> followersPage = followers.stream().skip(20 * page).limit(20);

            OrderedCollectionPage result = new OrderedCollectionPage();
            result.setId(ServletUriComponentsBuilder.fromCurrentRequestUri().toUriString());
            result.setOrderedItems(followersPage.map(a -> {
                Person follower = new Person();
                follower.setName(a.getName());
                follower.setPreferredUsername(a.getName());
                follower.setUrl(activityPubManager.personWebUri(a));
                return follower;
            }).collect(Collectors.toList()));
            boolean hasNext = followers.size() <= 20 * page;
            if (hasNext) {
                result.setNext(uriComponentsBuilder.queryParam("page", page + 1).toUriString());
            }
            return (OrderedCollectionPage) Context.build(result);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/u/{userName}/following/toc", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public OrderedCollection getFollowing(@PathVariable String userName) {
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromUriString(baseUri);
            OrderedCollection following = new OrderedCollection();
            following.setId(ServletUriComponentsBuilder.fromCurrentRequestUri().toUriString());
            following.setTotalItems(userService.getUserFriends(user.getUid()).size());
            following.setFirst(uriComponentsBuilder.path(String.format("/u/%s/followers", userName)).toUriString());
            return (OrderedCollection) Context.build(following);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/u/{userName}/following", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public OrderedCollectionPage getFollowingPage(@PathVariable String userName,
                                                  @RequestParam(required = false, defaultValue = "0") int page) {
        User user = userService.getUserByName(userName);
        if (!user.isAnonymous()) {
            UriComponentsBuilder uriComponentsBuilder = UriComponentsBuilder.fromUriString(baseUri);
            uriComponentsBuilder.path(String.format("/u/%s/following", userName));
            List<User> following = userService.getUserFriends(user.getUid());
            Stream<User> followingPage = following.stream().skip(20 * page).limit(20);

            OrderedCollectionPage result = new OrderedCollectionPage();
            result.setId(ServletUriComponentsBuilder.fromCurrentRequestUri().toUriString());
            result.setOrderedItems(followingPage.map(a -> {
                Person follower = new Person();
                follower.setName(a.getName());
                follower.setPreferredUsername(a.getName());
                follower.setUrl(activityPubManager.personWebUri(a));
                return follower;
            }).collect(Collectors.toList()));
            boolean hasNext = following.size() <= 20 * page;
            if (hasNext) {
                result.setNext(uriComponentsBuilder.queryParam("page", page + 1).toUriString());
            }
            return (OrderedCollectionPage) Context.build(result);
        }
        throw new HttpNotFoundException();
    }

    @GetMapping(value = "/n/{mid}-{rid}", produces = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public Context showNote(@PathVariable int mid, @PathVariable int rid) {
        if (rid > 0) {
            // reply
            return Context.build(activityPubManager.makeNote(
                    messagesService.getReply(mid, rid)));
        }
        return Context.build(activityPubManager.makeNote(
                messagesService.getMessage(mid)));
    }

    @PostMapping(value = "/api/inbox", consumes = {Context.LD_JSON_MEDIA_TYPE, Context.ACTIVITY_JSON_MEDIA_TYPE})
    public ResponseEntity<Void> processInbox(@RequestBody Activity activity,
                                             @RequestHeader(name = "Host") String host,
                                             @RequestHeader(name = "Date") String date,
                                             @RequestHeader(name = "Digest", required = false) String digest,
                                             @RequestHeader(name = "Content-Type") String contentType,
                                             @RequestHeader(name = "User-Agent", required = false) String userAgent,
                                             @RequestHeader(name = "Accept-Encoding", required = false) String acceptEncoding,
                                             @RequestHeader(name = "Signature", required = false) String signature) throws JsonProcessingException {
        UriComponents componentsBuilder = ServletUriComponentsBuilder.fromCurrentRequestUri().build();
        Map<String, String> headers = new HashMap<>();
        headers.put("host", host.split(":", 2)[0]);
        headers.put("date", date);
        headers.put("digest", digest);
        headers.put("content-type", contentType);
        headers.put("user-agent", userAgent);
        headers.put("accept-encoding", acceptEncoding);
        boolean valid = signatureManager.verifySignature(signature, URI.create(activity.getActor()), "POST",
                componentsBuilder.getPath(), headers);
        if (valid) {
            if (activity instanceof Follow) {
                Follow followRequest = (Follow) activity;
                applicationEventPublisher.publishEvent(
                        new FollowEvent(this, followRequest));
                return new ResponseEntity<>(HttpStatus.ACCEPTED);
            }
            if (activity instanceof Undo) {
                String follower = (String) ((Map) activity.getObject()).get("object");
                applicationEventPublisher.publishEvent(new UndoFollowEvent(this, activity.getActor(), follower));
                return new ResponseEntity<>(HttpStatus.OK);
            }
            if (activity instanceof Delete) {
                if (activity.getObject() instanceof String) {
                    // Delete user
                    applicationEventPublisher.publishEvent(new DeleteUserEvent(this, (String)activity.getObject()));
                }
            }
            logger.warn("Unknown activity: {}", jsonMapper.writeValueAsString(activity));
            return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
        }
        return new ResponseEntity<>(HttpStatus.UNAUTHORIZED);
    }
    @PostMapping(value = "/u/", produces = MediaType.APPLICATION_JSON_UTF8_VALUE)
    public User fetchUser(@RequestParam URI uri) {
        Person person = (Person) signatureManager.getContext(uri).orElseThrow(HttpBadRequestException::new);
        User user = new User();
        user.setUri(URI.create(person.getUrl()));
        user.setName(person.getPreferredUsername());
        if (person.getIcon() != null) {
            user.setAvatar(person.getIcon().getUrl());
        }
        return user;
    }
}