<?php

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the GNU Affero General Public License v3.0.
// See the LICENCE file in the repository root for full licence text.

namespace App\Http\Controllers\Forum;

use App\Exceptions\ModelNotSavedException;
use App\Jobs\Notifications\ForumTopicReply;
use App\Libraries\NewForumTopic;
use App\Models\Forum\FeatureVote;
use App\Models\Forum\Forum;
use App\Models\Forum\PollOption;
use App\Models\Forum\Post;
use App\Models\Forum\Topic;
use App\Models\Forum\TopicCover;
use App\Models\Forum\TopicPoll;
use App\Models\Forum\TopicWatch;
use App\Models\UserProfileCustomization;
use App\Transformers\Forum\TopicCoverTransformer;
use Auth;
use DB;
use Request;

/**
 * @group Forum
 */
class TopicsController extends Controller
{
    private static function nextUrl($topic, $sort, $cursor, $withDeleted)
    {
        return route('forum.topics.show', [
            'cursor_string' => cursor_encode($cursor),
            'skip_layout' => 1,
            'sort' => $sort,
            'topic' => $topic,
            'with_deleted' => $withDeleted,
        ]);
    }

    public function __construct()
    {
        parent::__construct();

        $this->middleware('auth', ['only' => [
            'create',
            'lock',
            'preview',
            'reply',
            'store',
        ]]);

        $this->middleware('require-scopes:public', ['only' => ['show']]);
        $this->middleware('require-scopes:forum.write', ['only' => ['reply', 'store', 'update']]);
    }

    public function create()
    {
        $forum = Forum::findOrFail(request('forum_id'));

        priv_check('ForumTopicStore', $forum)->ensureCan();

        return ext_view(
            'forum.topics.create',
            (new NewForumTopic($forum, Auth::user()))->toArray()
        );
    }

    public function destroy($id)
    {
        $topic = Topic::withTrashed()->findOrFail($id);

        priv_check('ForumTopicDelete', $topic)->ensureCan();

        DB::transaction(function () use ($topic) {
            if ((auth()->user()->user_id ?? null) !== $topic->topic_poster) {
                $this->logModerate(
                    'LOG_DELETE_TOPIC',
                    [$topic->topic_title],
                    $topic
                );
            }

            if (!$topic->delete()) {
                throw new ModelNotSavedException($topic->validationErrors()->toSentence());
            }
        });

        if (priv_check('ForumModerate', $topic->forum)->can()) {
            return ext_view('forum.topics.delete', ['post' => $topic->firstPost], 'js');
        } else {
            return ujs_redirect(route('forum.forums.show', $topic->forum));
        }
    }

    public function restore($id)
    {
        $topic = Topic::withTrashed()->findOrFail($id);

        priv_check('ForumModerate', $topic->forum)->ensureCan();

        DB::transaction(function () use ($topic) {
            $this->logModerate(
                'LOG_RESTORE_TOPIC',
                [$topic->topic_title],
                $topic
            );

            if (!$topic->restore()) {
                throw new ModelNotSavedException($topic->validationErrors()->toSentence());
            }
        });

        return ext_view('forum.topics.restore', ['post' => $topic->firstPost], 'js');
    }

    public function editPollGet($topicId)
    {
        $topic = Topic::findOrFail($topicId);

        priv_check('ForumTopicPollEdit', $topic)->ensureCan();

        return ext_view('forum.topics._edit_poll', compact('topic'));
    }

    public function editPollPost($topicId)
    {
        $topic = Topic::findOrFail($topicId);

        priv_check('ForumTopicPollEdit', $topic)->ensureCan();

        $poll = (new TopicPoll())->fill($this->getPollParams());
        $poll->setTopic($topic);

        $topic->getConnection()->transaction(function () use ($poll, $topic) {
            if (!$poll->save()) {
                return;
            }

            if (Auth::user()->getKey() !== $topic->topic_poster) {
                $this->logModerate(
                    'LOG_EDIT_POLL',
                    [$topic->poll_title],
                    $topic
                );
            }
        });

        if ($poll->validationErrors()->isAny()) {
            return error_popup($poll->validationErrors()->toSentence());
        }

        $pollSummary = PollOption::summary($topic, Auth::user());
        $canEditPoll = $poll->canEdit();

        return ext_view('forum.topics._poll', compact('canEditPoll', 'pollSummary', 'topic'));
    }

    public function issueTag($id)
    {
        $topic = Topic::findOrFail($id);

        priv_check('ForumModerate', $topic->forum)->ensureCan();

        $issueTag = presence(Request::input('issue_tag'));
        $state = get_bool(Request::input('state'));
        $type = 'issue_tag_'.$issueTag;

        if ($issueTag === null || !$topic->isIssue() || !in_array($issueTag, $topic::ISSUE_TAGS, true)) {
            abort(422);
        }

        $this->logModerate('LOG_ISSUE_TAG', compact('issueTag', 'state'), $topic);

        $method = $state ? 'setIssueTag' : 'unsetIssueTag';

        $topic->$method($issueTag);

        return ext_view('forum.topics.replace_button', compact('topic', 'type', 'state'), 'js');
    }

    public function lock($id)
    {
        $topic = Topic::withTrashed()->findOrFail($id);

        priv_check('ForumModerate', $topic->forum)->ensureCan();

        $type = 'lock';
        $state = get_bool(Request::input('lock'));
        $this->logModerate($state ? 'LOG_LOCK' : 'LOG_UNLOCK', [$topic->topic_title], $topic);
        $topic->lock($state);

        return ext_view('forum.topics.replace_button', compact('topic', 'type', 'state'), 'js');
    }

    public function move($id)
    {
        $topic = Topic::withTrashed()->findOrFail($id);
        $originForum = $topic->forum;
        $destinationForum = Forum::findOrFail(Request::input('destination_forum_id'));

        priv_check('ForumModerate', $originForum)->ensureCan();
        priv_check('ForumModerate', $destinationForum)->ensureCan();

        $this->logModerate('LOG_MOVE', [$originForum->forum_name], $topic);
        if ($topic->moveTo($destinationForum)) {
            return ext_view('layout.ujs-reload', [], 'js');
        } else {
            abort(422);
        }
    }

    public function pin($id)
    {
        $topic = Topic::withTrashed()->findOrFail($id);

        priv_check('ForumModerate', $topic->forum)->ensureCan();

        $type = 'moderate_pin';
        $state = get_int(Request::input('pin'));
        DB::transaction(function () use ($topic, $state) {
            $topic->pin($state);

            $this->logModerate(
                'LOG_TOPIC_TYPE',
                ['title' => $topic->topic_title, 'type' => $topic->topic_type],
                $topic
            );
        });

        return ext_view('forum.topics.replace_button', compact('topic', 'type', 'state'), 'js');
    }

    /**
     * Reply Topic
     *
     * Create a post replying to the specified topic.
     *
     * ---
     *
     * ### Response Format
     *
     * [ForumPost](#forum-post) with `body` included.
     *
     * @urlParam topic integer required Id of the topic to be replied to. Example: 1
     *
     * @bodyParam body string required Content of the reply post. Example: hello
     */
    public function reply($id)
    {
        $topic = Topic::findOrFail($id);

        priv_check('ForumTopicReply', $topic)->ensureCan();

        $user = \Auth::user();
        $post = Post::createNew($topic, $user, get_string(request('body')));

        $post->markRead($user);
        (new ForumTopicReply($post, $user))->dispatch();

        $watch = $user->user_notify
            ? TopicWatch::setState($topic, $user, 'watching_mail')
            : TopicWatch::lookup($topic, $user);

        if (is_api_request()) {
            return json_item($post, 'Forum\Post', ['body']);
        } else {
            return [
                'posts' => view('forum.topics._posts', [
                    'firstPostPosition' => $topic->postPosition($post->post_id),
                    'posts' => collect([$post]),
                    'topic' => $topic,
                ])->render(),
                'watch' => view('forum.topics._watch', [
                    'state' => $watch,
                    'topic' => $topic,
                ])->render(),
            ];
        }
    }

    /**
     * Get Topic and Posts
     *
     * Get topic and its posts.
     *
     * ---
     *
     * ### Response Format
     *
     * Field         | Type                          | Notes
     * ------------- | ----------------------------- | -----
     * cursor_string | [CursorString](#cursorstring) | |
     * posts         | [ForumPost](#forum-post)[]    | Includes `body`.
     * search        |                               | Parameters used for current request excluding cursor.
     * topic         | [ForumTopic](#forum-topic)    | |
     *
     * @urlParam topic integer required Id of the topic. Example: 1
     *
     * @usesCursor
     * @queryParam sort Post sorting option. Valid values are `id_asc` (default) and `id_desc`. No-example
     * @queryParam limit Maximum number of posts to be returned (20 default, 50 at most). No-example
     * @queryParam start First post id to be returned with `sort` set to `id_asc`. This parameter is ignored if `cursor_string` is specified. No-example
     * @queryParam end First post id to be returned with `sort` set to `id_desc`. This parameter is ignored if `cursor_string` is specified. No-example
     *
     * @response {
     *   "topic": { "id": 1, "...": "..." },
     *   "posts": [
     *     { "id": 1, "...": "..." },
     *     { "id": 2, "...": "..." }
     *   ],
     *   "cursor_string": "eyJoZWxsbyI6IndvcmxkIn0",
     *   "sort": "id_asc"
     * }
     */
    public function show($id)
    {
        $topic = Topic::with(['forum'])->withTrashed()->findOrFail($id);

        $userCanModerate = priv_check('ForumModerate', $topic->forum)->can();

        if ($topic->trashed() && !$userCanModerate) {
            abort(404);
        }

        // TODO: firstPost is sometimes null when created by legacy process.
        // Create an endpoint so the post is properly created in a transaction.
        if ($topic->forum === null || $topic->firstPost === null) {
            abort(404);
        }

        priv_check('ForumView', $topic->forum)->ensureCan();

        $currentUser = auth()->user();
        $params = $this->getIndexParams($topic, $currentUser, $userCanModerate);

        $skipLayout = $params['skip_layout'];
        $showDeleted = $params['with_deleted'];

        $cursorHelper = Post::makeDbCursorHelper($params['sort']);

        $postsQueryBase = $topic->posts()->showDeleted($showDeleted)->limit($params['limit']);
        $posts = (clone $postsQueryBase)->cursorSort($cursorHelper, $params['cursor'])->get();

        $isJsonRequest = is_api_request();

        if (!$isJsonRequest && $posts->count() === 0) {
            if ($skipLayout) {
                return response(null, 204);
            } else {
                // make sure topic has posts at all otherwise this will be a redirect loop
                if ($topic->posts()->showDeleted($showDeleted)->exists()) {
                    return ujs_redirect(route('forum.topics.show', $topic));
                } else {
                    abort(404);
                }
            }
        }

        if ($isJsonRequest || $skipLayout) {
            $jumpTo = null;
        } else {
            $firstPost = $posts->first();
            $jumpTo = $firstPost->getKey();

            if ($cursorHelper->getSortName() === 'id_asc') {
                if ($jumpTo !== $topic->topic_first_post_id) {
                    $extraSort = 'id_desc';
                }
            } else {
                $extraSort = 'id_asc';
            }
            if (isset($extraSort)) {
                $extraPosts = (clone $postsQueryBase)->cursorSort($extraSort, ['id' => $jumpTo])->get()->reverse();

                $posts = $extraPosts->concat($posts);
            }
        }

        $posts->each(fn ($item) => $item
            ->setRelation('forum', $topic->forum)
            ->setRelation('topic', $topic));

        $nextCursor = $cursorHelper->next($posts);

        if ($isJsonRequest) {
            return array_merge([
                'posts' => json_collection($posts, 'Forum\Post', ['body']),
                'search' => ['limit' => $params['limit'], 'sort' => $cursorHelper->getSortName()],
                'topic' => json_item($topic, 'Forum\Topic'),
            ], cursor_for_response($nextCursor));
        }

        $posts->load([
            'lastEditor',
            'user.country',
            'user.rank',
            'user.supporterTagPurchases',
            'user.team',
            'user.userGroups',
        ]);

        $navigatingBackwards = $cursorHelper->getSortName() === 'id_desc';
        if ($navigatingBackwards) {
            $posts = $posts->reverse();
        }

        $navUrls = [
            'next' => static::nextUrl($topic, 'id_asc', $nextCursor, $showDeleted),
            'previous' => static::nextUrl(
                $topic,
                'id_desc',
                $cursorHelper->next([$posts->first()]),
                $showDeleted
            ),
        ];

        $firstShownPostId = $posts->first()->getKey();
        // position of the first post, incremented in the view
        // to generate positions of further posts
        $firstPostPosition = $topic->postPosition($firstShownPostId);

        if ($skipLayout) {
            return [
                'content' => view('forum.topics._posts', compact('posts', 'firstPostPosition', 'topic'))->render(),
                'next_url' => $navigatingBackwards ? $navUrls['previous'] : $navUrls['next'],
            ];
        }

        $poll = $topic->poll();
        if ($poll->exists()) {
            $topic->load([
                'pollOptions.votes',
                'pollOptions.post',
            ]);
            $canEditPoll = $poll->canEdit() && priv_check('ForumTopicPollEdit', $topic)->can();
        } else {
            $canEditPoll = false;
        }

        $pollSummary = PollOption::summary($topic, $currentUser);

        $topic->incrementViewCount($currentUser, \Request::ip());
        $posts->last()->markRead($currentUser);

        // Instantiate new cover model separately to prevent it from getting used by opengraph
        $coverModel = $topic->cover ?? new TopicCover(['topic_id' => $topic->getKey()]);
        $coverModel->setRelation('topic', $topic);
        $cover = json_item($coverModel, new TopicCoverTransformer());

        $watch = TopicWatch::lookup($topic, $currentUser);

        $featureVotes = $this->groupFeatureVotes($topic);
        $noindex = !$topic->forum->enable_indexing;

        set_opengraph($topic);

        return ext_view('forum.topics.show', compact(
            'canEditPoll',
            'cover',
            'watch',
            'jumpTo',
            'pollSummary',
            'posts',
            'featureVotes',
            'firstPostPosition',
            'navUrls',
            'noindex',
            'topic',
            'userCanModerate',
            'showDeleted'
        ));
    }


    /**
     * Create Topic
     *
     * Create a new topic.
     *
     * ---
     *
     * ### Response Format
     *
     * Field  | Type                       | Includes
     * ------ | -------------------------- | --------
     * topic  | [ForumTopic](#forum-topic) | |
     * post   | [ForumPost](#forum-post)   | body
     *
     * @bodyParam body string required Content of the topic. Example: hello
     * @bodyParam forum_id integer required Forum to create the topic in. Example: 1
     * @bodyParam title string required Title of the topic. Example: untitled
     * @bodyParam with_poll boolean Enable this to also create poll in the topic (default: false). Example: 1
     * @bodyParam forum_topic_poll[hide_results] boolean Enable this to hide result until voting period ends (default: false). No-example
     * @bodyParam forum_topic_poll[length_days] integer Number of days for voting period. 0 means the voting will never ends (default: 0). This parameter is required if `hide_results` option is enabled. No-example
     * @bodyParam forum_topic_poll[max_options] integer Maximum number of votes each user can cast (default: 1). No-example
     * @bodyParam forum_topic_poll[options] string required Newline-separated list of voting options. BBCode is supported. Example: item A...
     * @bodyParam forum_topic_poll[title] string required Title of the poll. Example: my poll
     * @bodyParam forum_topic_poll[vote_change] boolean Enable this to allow user to change their votes (default: false). No-example
     */
    public function store()
    {
        $params = get_params(request()->all(), null, [
            'body:string',
            'cover_id:int',
            'forum_id:int',
            'title:string',
            'with_poll:bool',
        ], ['null_missing' => true]);

        $forum = Forum::findOrFail($params['forum_id']);
        $user = auth()->user();

        priv_check('ForumTopicStore', $forum)->ensureCan();

        if ($params['with_poll']) {
            $poll = (new TopicPoll())->fill($this->getPollParams());

            if (!$poll->isValid()) {
                return error_popup($poll->validationErrors()->toSentence());
            }
        }

        $topicParams = [
            'title' => $params['title'],
            'user' => $user,
            'body' => $params['body'],
            'cover' => TopicCover::findForUse($params['cover_id'], $user),
        ];

        $topic = Topic::createNew($forum, $topicParams, $poll ?? null);

        if ($user->user_notify || $forum->isHelpForum()) {
            TopicWatch::setState($topic, $user, 'watching_mail');
        }

        $post = $topic->posts->last();
        $post->markRead($user);

        if (is_api_request()) {
            return [
                'topic' => json_item($topic, 'Forum\Topic'),
                'post' => json_item($post, 'Forum\Post', ['body']),
            ];
        } else {
            return ujs_redirect(route('forum.topics.show', $topic));
        }
    }

    /**
     * Edit Topic
     *
     * Edit topic. Only title can be edited through this endpoint.
     *
     * ---
     *
     * ### Response Format
     *
     * The edited [ForumTopic](#forum-topic).
     *
     * @urlParam topic integer required Id of the topic. Example: 1
     * @bodyParam forum_topic[topic_title] string New topic title. Example: titled
     */
    public function update($id)
    {
        $topic = Topic::withTrashed()->findOrFail($id);

        if (!priv_check('ForumTopicEdit', $topic)->can()) {
            abort(403);
        }

        $params = get_params(request()->all(), 'forum_topic', ['topic_title']);

        if ($topic->update($params)) {
            if ((Auth::user()->user_id ?? null) !== $topic->topic_poster) {
                $this->logModerate(
                    'LOG_EDIT_TOPIC',
                    [$topic->topic_title],
                    $topic
                );
            }

            if (is_api_request()) {
                return json_item($topic, 'Forum\Topic');
            } else {
                return response(null, 204);
            }
        } else {
            return error_popup($topic->validationErrors()->toSentence());
        }
    }

    public function vote($topicId)
    {
        $topic = Topic::findOrFail($topicId);

        priv_check('ForumTopicVote', $topic)->ensureCan();

        $params = get_params(Request::input(), 'forum_topic_vote', ['option_ids:int[]']);
        $params['user_id'] = Auth::user()->user_id;
        $params['ip'] = Request::ip();

        if ($topic->vote()->fill($params)->save()) {
            return ujs_redirect(route('forum.topics.show', $topic->topic_id));
        } else {
            return error_popup($topic->vote()->validationErrors()->toSentence());
        }
    }

    public function voteFeature($topicId)
    {
        $star = FeatureVote::createNew([
            'user_id' => Auth::user()->user_id,
            'topic_id' => $topicId,
        ]);

        if ($star->getKey() !== null) {
            return ujs_redirect(route('forum.topics.show', $topicId));
        } else {
            return error_popup($star->validationErrors()->toSentence());
        }
    }

    private function getIndexParams($topic, $currentUser, $userCanModerate)
    {
        $rawParams = request()->all();
        $params = get_params($rawParams, null, [
            'start', // either number or "unread" or "latest"
            'end:int',
            'n:int',

            'skip_layout:bool',
            'with_deleted:bool',

            'sort:string',
            'limit:int',
        ], ['null_missing' => true]);

        $params['skip_layout'] = $params['skip_layout'] ?? false;
        $params['limit'] = \Number::clamp($params['limit'] ?? Post::PER_PAGE, 1, 50);

        if ($userCanModerate) {
            $params['with_deleted'] ??= UserProfileCustomization::forUser($currentUser)['forum_posts_show_deleted'];
        } else {
            $params['with_deleted'] = false;
        }

        $params['cursor'] = cursor_from_params($rawParams);

        if (!is_array($params['cursor'])) {
            $params['start'] = match ($params['start']) {
                'latest' => $topic->topic_last_post_id,
                'unread' => Post::lastUnreadByUser($topic, $currentUser),
                default => get_int($params['start']),
            };

            if ($params['n'] !== null && $params['n'] > 0) {
                $post = $topic->nthPost($params['n']) ?? $topic->posts()->last();
                if ($post !== null) {
                    $params['cursor'] = ['id' => $post->getKey() - 1];
                    $params['sort'] = 'id_asc';
                }
            } elseif ($params['start'] !== null) {
                $params['cursor'] = ['id' => $params['start'] - 1];
                $params['sort'] = 'id_asc';
            } elseif ($params['end'] !== null) {
                $params['cursor'] = ['id' => $params['end'] + 1];
                $params['sort'] = 'id_desc';
            }
        }

        return $params;
    }

    private function getPollParams()
    {
        return get_params(request()->all(), 'forum_topic_poll', [
            'hide_results:bool',
            'length_days:int',
            'max_options:int',
            'options:string_split',
            'title',
            'vote_change:bool',
        ]);
    }

    private function groupFeatureVotes($topic)
    {
        if (!$topic->isFeatureTopic()) {
            return [];
        }

        $ret = [];

        foreach ($topic->featureVotes()->with('user')->get() as $vote) {
            $username = optional($vote->user)->username;
            $ret[$username] ?? ($ret[$username] = 0);
            $ret[$username] += $vote->voteIncrement();
        }

        arsort($ret);

        return $ret;
    }
}