Extract new Flarum\Discussion namespace

src/Discussion/Discussion.php

@@ -0,0 +1,464 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion;
+
+use Flarum\Core\DiscussionState;
+use Flarum\Post\MergeableInterface;
+use Flarum\Foundation\EventGeneratorTrait;
+use Flarum\Database\ScopeVisibilityTrait;
+use Flarum\Database\AbstractModel;
+use Flarum\Discussion\Event\Deleted;
+use Flarum\Discussion\Event\Hidden;
+use Flarum\Discussion\Event\Renamed;
+use Flarum\Discussion\Event\Restored;
+use Flarum\Discussion\Event\Started;
+use Flarum\Post\Event\Deleted;
+use Flarum\Event\ScopePostVisibility;
+use Flarum\Post\Post;
+use Flarum\User\Guest;
+use Flarum\User\User;
+use Flarum\Util\Str;
+
+/**
+ * @property int $id
+ * @property string $title
+ * @property string $slug
+ * @property int $comments_count
+ * @property int $participants_count
+ * @property int $number_index
+ * @property \Carbon\Carbon $start_time
+ * @property int|null $start_user_id
+ * @property int|null $start_post_id
+ * @property \Carbon\Carbon|null $last_time
+ * @property int|null $last_user_id
+ * @property int|null $last_post_id
+ * @property int|null $last_post_number
+ * @property \Carbon\Carbon|null $hide_time
+ * @property int|null $hide_user_id
+ * @property DiscussionState|null $state
+ * @property \Illuminate\Database\Eloquent\Collection $posts
+ * @property \Illuminate\Database\Eloquent\Collection $comments
+ * @property \Illuminate\Database\Eloquent\Collection $participants
+ * @property Post|null $startPost
+ * @property User|null $startUser
+ * @property Post|null $lastPost
+ * @property User|null $lastUser
+ * @property \Illuminate\Database\Eloquent\Collection $readers
+ * @property bool $is_private
+ */
+class Discussion extends AbstractModel
+{
+    use EventGeneratorTrait;
+    use ScopeVisibilityTrait;
+
+    /**
+     * {@inheritdoc}
+     */
+    protected $table = 'discussions';
+
+    /**
+     * An array of posts that have been modified during this request.
+     *
+     * @var array
+     */
+    protected $modifiedPosts = [];
+
+    /**
+     * {@inheritdoc}
+     */
+    protected $dates = ['start_time', 'last_time', 'hide_time'];
+
+    /**
+     * Casts properties to a specific type.
+     *
+     * @var array
+     */
+    protected $casts = [
+        'is_private' => 'boolean'
+    ];
+
+    /**
+     * The user for which the state relationship should be loaded.
+     *
+     * @var User
+     */
+    protected static $stateUser;
+
+    /**
+     * Boot the model.
+     *
+     * @return void
+     */
+    public static function boot()
+    {
+        parent::boot();
+
+        static::deleted(function ($discussion) {
+            $discussion->raise(new Deleted($discussion));
+
+            // Delete all of the posts in the discussion. Before we delete them
+            // in a big batch query, we will loop through them and raise a
+            // PostWasDeleted event for each post.
+            $posts = $discussion->posts()->allTypes();
+
+            foreach ($posts->get() as $post) {
+                $discussion->raise(new Deleted($post));
+            }
+
+            $posts->delete();
+
+            // Delete all of the 'state' records for all of the users who have
+            // read the discussion.
+            $discussion->readers()->detach();
+        });
+    }
+
+    /**
+     * Start a new discussion. Raises the DiscussionWasStarted event.
+     *
+     * @param string $title
+     * @param User $user
+     * @return static
+     */
+    public static function start($title, User $user)
+    {
+        $discussion = new static;
+
+        $discussion->title = $title;
+        $discussion->start_time = time();
+        $discussion->start_user_id = $user->id;
+
+        $discussion->setRelation('startUser', $user);
+
+        $discussion->raise(new Started($discussion));
+
+        return $discussion;
+    }
+
+    /**
+     * Rename the discussion. Raises the DiscussionWasRenamed event.
+     *
+     * @param string $title
+     * @return $this
+     */
+    public function rename($title)
+    {
+        if ($this->title !== $title) {
+            $oldTitle = $this->title;
+            $this->title = $title;
+
+            $this->raise(new Renamed($this, $oldTitle));
+        }
+
+        return $this;
+    }
+
+    /**
+     * Hide the discussion.
+     *
+     * @param User $actor
+     * @return $this
+     */
+    public function hide(User $actor = null)
+    {
+        if (! $this->hide_time) {
+            $this->hide_time = time();
+            $this->hide_user_id = $actor ? $actor->id : null;
+
+            $this->raise(new Hidden($this));
+        }
+
+        return $this;
+    }
+
+    /**
+     * Restore the discussion.
+     *
+     * @return $this
+     */
+    public function restore()
+    {
+        if ($this->hide_time !== null) {
+            $this->hide_time = null;
+            $this->hide_user_id = null;
+
+            $this->raise(new Restored($this));
+        }
+
+        return $this;
+    }
+
+    /**
+     * Set the discussion's start post details.
+     *
+     * @param Post $post
+     * @return $this
+     */
+    public function setStartPost(Post $post)
+    {
+        $this->start_time = $post->time;
+        $this->start_user_id = $post->user_id;
+        $this->start_post_id = $post->id;
+
+        return $this;
+    }
+
+    /**
+     * Set the discussion's last post details.
+     *
+     * @param Post $post
+     * @return $this
+     */
+    public function setLastPost(Post $post)
+    {
+        $this->last_time = $post->time;
+        $this->last_user_id = $post->user_id;
+        $this->last_post_id = $post->id;
+        $this->last_post_number = $post->number;
+
+        return $this;
+    }
+
+    /**
+     * Refresh a discussion's last post details.
+     *
+     * @return $this
+     */
+    public function refreshLastPost()
+    {
+        if ($lastPost = $this->comments()->latest('time')->first()) {
+            $this->setLastPost($lastPost);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Refresh the discussion's comments count.
+     *
+     * @return $this
+     */
+    public function refreshCommentsCount()
+    {
+        $this->comments_count = $this->comments()->count();
+
+        return $this;
+    }
+
+    /**
+     * Refresh the discussion's participants count.
+     *
+     * @return $this
+     */
+    public function refreshParticipantsCount()
+    {
+        $this->participants_count = $this->participants()->count('users.id');
+
+        return $this;
+    }
+
+    /**
+     * Save a post, attempting to merge it with the discussion's last post.
+     *
+     * The merge logic is delegated to the new post. (As an example, a
+     * DiscussionRenamedPost will merge if adjacent to another
+     * DiscussionRenamedPost, and delete if the title has been reverted
+     * completely.)
+     *
+     * @param \Flarum\Post\MergeableInterface $post The post to save.
+     * @return Post The resulting post. It may or may not be the same post as
+     *     was originally intended to be saved. It also may not exist, if the
+     *     merge logic resulted in deletion.
+     */
+    public function mergePost(MergeableInterface $post)
+    {
+        $lastPost = $this->posts()->latest('time')->first();
+
+        $post = $post->saveAfter($lastPost);
+
+        return $this->modifiedPosts[] = $post;
+    }
+
+    /**
+     * Get the posts that have been modified during this request.
+     *
+     * @return array
+     */
+    public function getModifiedPosts()
+    {
+        return $this->modifiedPosts;
+    }
+
+    /**
+     * Define the relationship with the discussion's posts.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function posts()
+    {
+        return $this->hasMany('Flarum\Post\Post');
+    }
+
+    /**
+     * Define the relationship with the discussion's posts, but only ones which
+     * are visible to the given user.
+     *
+     * @param User $user
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function postsVisibleTo(User $user)
+    {
+        $relation = $this->posts();
+
+        static::$dispatcher->fire(
+            new ScopePostVisibility($this, $relation->getQuery(), $user)
+        );
+
+        return $relation;
+    }
+
+    /**
+     * Define the relationship with the discussion's publicly-visible comments.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\HasMany
+     */
+    public function comments()
+    {
+        return $this->postsVisibleTo(new Guest)->where('type', 'comment');
+    }
+
+    /**
+     * Query the discussion's participants (a list of unique users who have
+     * posted in the discussion).
+     *
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function participants()
+    {
+        return User::join('posts', 'posts.user_id', '=', 'users.id')
+            ->where('posts.discussion_id', $this->id)
+            ->select('users.*')
+            ->distinct();
+    }
+
+    /**
+     * Define the relationship with the discussion's first post.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function startPost()
+    {
+        return $this->belongsTo('Flarum\Post\Post', 'start_post_id');
+    }
+
+    /**
+     * Define the relationship with the discussion's author.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function startUser()
+    {
+        return $this->belongsTo('Flarum\User\User', 'start_user_id');
+    }
+
+    /**
+     * Define the relationship with the discussion's last post.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function lastPost()
+    {
+        return $this->belongsTo('Flarum\Post\Post', 'last_post_id');
+    }
+
+    /**
+     * Define the relationship with the discussion's most recent author.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function lastUser()
+    {
+        return $this->belongsTo('Flarum\User\User', 'last_user_id');
+    }
+
+    /**
+     * Define the relationship with the discussion's readers.
+     *
+     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
+     */
+    public function readers()
+    {
+        return $this->belongsToMany('Flarum\User\User', 'users_discussions');
+    }
+
+    /**
+     * Define the relationship with the discussion's state for a particular
+     * user.
+     *
+     * If no user is passed (i.e. in the case of eager loading the 'state'
+     * relation), then the static `$stateUser` property is used.
+     *
+     * @see Discussion::setStateUser()
+     *
+     * @param User|null $user
+     * @return \Illuminate\Database\Eloquent\Relations\HasOne
+     */
+    public function state(User $user = null)
+    {
+        $user = $user ?: static::$stateUser;
+
+        return $this->hasOne('Flarum\Core\DiscussionState')->where('user_id', $user ? $user->id : null);
+    }
+
+    /**
+     * Get the state model for a user, or instantiate a new one if it does not
+     * exist.
+     *
+     * @param User $user
+     * @return \Flarum\Core\DiscussionState
+     */
+    public function stateFor(User $user)
+    {
+        $state = $this->state($user)->first();
+
+        if (! $state) {
+            $state = new DiscussionState;
+            $state->discussion_id = $this->id;
+            $state->user_id = $user->id;
+        }
+
+        return $state;
+    }
+
+    /**
+     * Set the user for which the state relationship should be loaded.
+     *
+     * @param User $user
+     */
+    public static function setStateUser(User $user)
+    {
+        static::$stateUser = $user;
+    }
+
+    /**
+     * Set the discussion title.
+     *
+     * This automatically creates a matching slug for the discussion.
+     *
+     * @param string $title
+     */
+    protected function setTitleAttribute($title)
+    {
+        $this->attributes['title'] = $title;
+        $this->slug = Str::slug($title);
+    }
+}

src/Discussion/DiscussionMetadataUpdater.php

@@ -0,0 +1,104 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion;
+
+use Flarum\Post\Post;
+use Flarum\Post\Event\Deleted;
+use Flarum\Post\Event\Hidden;
+use Flarum\Post\Event\Posted;
+use Flarum\Post\Event\Restored;
+use Illuminate\Contracts\Events\Dispatcher;
+
+class DiscussionMetadataUpdater
+{
+    /**
+     * @param Dispatcher $events
+     */
+    public function subscribe(Dispatcher $events)
+    {
+        $events->listen(Posted::class, [$this, 'whenPostWasPosted']);
+        $events->listen(Deleted::class, [$this, 'whenPostWasDeleted']);
+        $events->listen(Hidden::class, [$this, 'whenPostWasHidden']);
+        $events->listen(Restored::class, [$this, 'whenPostWasRestored']);
+    }
+
+    /**
+     * @param Posted $event
+     */
+    public function whenPostWasPosted(Posted $event)
+    {
+        $discussion = $event->post->discussion;
+
+        if ($discussion && $discussion->exists) {
+            $discussion->refreshCommentsCount();
+            $discussion->refreshLastPost();
+            $discussion->refreshParticipantsCount();
+            $discussion->save();
+        }
+    }
+
+    /**
+     * @param \Flarum\Post\Event\Deleted $event
+     */
+    public function whenPostWasDeleted(Deleted $event)
+    {
+        $this->removePost($event->post);
+
+        $discussion = $event->post->discussion;
+
+        if ($discussion && $discussion->posts()->count() === 0) {
+            $discussion->delete();
+        }
+    }
+
+    /**
+     * @param \Flarum\Post\Event\Hidden $event
+     */
+    public function whenPostWasHidden(Hidden $event)
+    {
+        $this->removePost($event->post);
+    }
+
+    /**
+     * @param Restored $event
+     */
+    public function whenPostWasRestored(Restored $event)
+    {
+        $discussion = $event->post->discussion;
+
+        if ($discussion && $discussion->exists) {
+            $discussion->refreshCommentsCount();
+            $discussion->refreshParticipantsCount();
+            $discussion->refreshLastPost();
+            $discussion->save();
+        }
+    }
+
+    /**
+     * @param Post $post
+     */
+    protected function removePost(Post $post)
+    {
+        $discussion = $post->discussion;
+
+        if ($discussion && $discussion->exists) {
+            $discussion->refreshCommentsCount();
+            $discussion->refreshParticipantsCount();
+
+            if ($discussion->last_post_id == $post->id) {
+                $discussion->refreshLastPost();
+            }
+
+            $discussion->save();
+        }
+    }
+}

src/Discussion/DiscussionPolicy.php

@@ -0,0 +1,130 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion;
+
+use Carbon\Carbon;
+use Flarum\Discussion\Discussion;
+use Flarum\Event\ScopeHiddenDiscussionVisibility;
+use Flarum\Event\ScopePrivateDiscussionVisibility;
+use Flarum\Settings\SettingsRepositoryInterface;
+use Flarum\User\AbstractPolicy;
+use Flarum\User\Gate;
+use Flarum\User\User;
+use Illuminate\Contracts\Events\Dispatcher;
+use Illuminate\Database\Eloquent\Builder;
+
+class DiscussionPolicy extends AbstractPolicy
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected $model = Discussion::class;
+
+    /**
+     * @var SettingsRepositoryInterface
+     */
+    protected $settings;
+
+    /**
+     * @var Gate
+     */
+    protected $gate;
+
+    /**
+     * @var Dispatcher
+     */
+    protected $events;
+
+    /**
+     * @param SettingsRepositoryInterface $settings
+     * @param Gate $gate
+     * @param Dispatcher $events
+     */
+    public function __construct(SettingsRepositoryInterface $settings, Gate $gate, Dispatcher $events)
+    {
+        $this->settings = $settings;
+        $this->gate = $gate;
+        $this->events = $events;
+    }
+
+    /**
+     * @param User $actor
+     * @param string $ability
+     * @return bool|null
+     */
+    public function after(User $actor, $ability)
+    {
+        if ($actor->hasPermission('discussion.'.$ability)) {
+            return true;
+        }
+    }
+
+    /**
+     * @param User $actor
+     * @param Builder $query
+     */
+    public function find(User $actor, Builder $query)
+    {
+        // Hide private discussions per default.
+        $query->where(function ($query) use ($actor) {
+            $query->where('discussions.is_private', false);
+
+            $this->events->fire(
+                new ScopePrivateDiscussionVisibility($query, $actor)
+            );
+        });
+
+        if ($actor->cannot('viewDiscussions')) {
+            $query->whereRaw('FALSE');
+        } elseif (! $actor->hasPermission('discussion.hide')) {
+            $query->where(function ($query) use ($actor) {
+                $query->whereNull('discussions.hide_time')
+                    ->where('comments_count', '>', 0)
+                    ->orWhere('start_user_id', $actor->id);
+
+                $this->events->fire(
+                    new ScopeHiddenDiscussionVisibility($query, $actor, 'discussion.hide')
+                );
+            });
+        }
+    }
+
+    /**
+     * @param User $actor
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @return bool|null
+     */
+    public function rename(User $actor, Discussion $discussion)
+    {
+        if ($discussion->start_user_id == $actor->id) {
+            $allowRenaming = $this->settings->get('allow_renaming');
+
+            if ($allowRenaming === '-1'
+                || ($allowRenaming === 'reply' && $discussion->participants_count <= 1)
+                || ($discussion->start_time->diffInMinutes(new Carbon) < $allowRenaming)) {
+                return true;
+            }
+        }
+    }
+
+    /**
+     * @param User $actor
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @return bool|null
+     */
+    public function hide(User $actor, Discussion $discussion)
+    {
+        if ($discussion->start_user_id == $actor->id && $discussion->participants_count <= 1) {
+            return true;
+        }
+    }
+}

src/Discussion/DiscussionRenamedNotifier.php

@@ -0,0 +1,67 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion;
+
+use Flarum\Core\Notification\DiscussionRenamedBlueprint;
+use Flarum\Core\Notification\NotificationSyncer;
+use Flarum\Post\DiscussionRenamedPost;
+use Flarum\Discussion\Event\Renamed;
+use Illuminate\Contracts\Events\Dispatcher;
+
+class DiscussionRenamedNotifier
+{
+    /**
+     * @var NotificationSyncer
+     */
+    protected $notifications;
+
+    /**
+     * @param NotificationSyncer $notifications
+     */
+    public function __construct(NotificationSyncer $notifications)
+    {
+        $this->notifications = $notifications;
+    }
+
+    /**
+     * @param Dispatcher $events
+     */
+    public function subscribe(Dispatcher $events)
+    {
+        $events->listen(Renamed::class, [$this, 'whenDiscussionWasRenamed']);
+    }
+
+    /**
+     * @param \Flarum\Discussion\Event\Renamed $event
+     */
+    public function whenDiscussionWasRenamed(Renamed $event)
+    {
+        $post = DiscussionRenamedPost::reply(
+            $event->discussion->id,
+            $event->actor->id,
+            $event->oldTitle,
+            $event->discussion->title
+        );
+
+        $post = $event->discussion->mergePost($post);
+
+        if ($event->discussion->start_user_id !== $event->actor->id) {
+            $blueprint = new DiscussionRenamedBlueprint($post);
+
+            if ($post->exists) {
+                $this->notifications->sync($blueprint, [$event->discussion->startUser]);
+            } else {
+                $this->notifications->delete($blueprint);
+            }
+        }
+    }
+}

src/Discussion/DiscussionRepository.php

@@ -0,0 +1,75 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion;
+
+use Flarum\User\User;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Query\Expression;
+
+class DiscussionRepository
+{
+    /**
+     * Get a new query builder for the discussions table.
+     *
+     * @return Builder
+     */
+    public function query()
+    {
+        return Discussion::query();
+    }
+
+    /**
+     * Find a discussion by ID, optionally making sure it is visible to a
+     * certain user, or throw an exception.
+     *
+     * @param int $id
+     * @param User $user
+     * @return \Flarum\Discussion\Discussion
+     */
+    public function findOrFail($id, User $user = null)
+    {
+        $query = Discussion::where('id', $id);
+
+        return $this->scopeVisibleTo($query, $user)->firstOrFail();
+    }
+
+    /**
+     * Get the IDs of discussions which a user has read completely.
+     *
+     * @param User $user
+     * @return array
+     */
+    public function getReadIds(User $user)
+    {
+        return Discussion::leftJoin('users_discussions', 'users_discussions.discussion_id', '=', 'discussions.id')
+            ->where('user_id', $user->id)
+            ->where('read_number', '>=', new Expression('last_post_number'))
+            ->lists('id')
+            ->all();
+    }
+
+    /**
+     * Scope a query to only include records that are visible to a user.
+     *
+     * @param Builder $query
+     * @param User $user
+     * @return Builder
+     */
+    protected function scopeVisibleTo(Builder $query, User $user = null)
+    {
+        if ($user !== null) {
+            $query->whereVisibleTo($user);
+        }
+
+        return $query;
+    }
+}

src/Discussion/DiscussionValidator.php

@@ -0,0 +1,25 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion;
+
+use Flarum\Foundation\AbstractValidator;
+
+class DiscussionValidator extends AbstractValidator
+{
+    protected $rules = [
+        'title' => [
+            'required',
+            'min:3',
+            'max:80'
+        ]
+    ];
+}

src/Discussion/Event/Deleted.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Deleted
+{
+    /**
+     * @var \Flarum\Discussion\Discussion
+     */
+    public $discussion;
+
+    /**
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @param User $actor
+     */
+    public function __construct(Discussion $discussion, User $actor = null)
+    {
+        $this->discussion = $discussion;
+        $this->actor = $actor;
+    }
+}

src/Discussion/Event/Deleting.php

@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Deleting
+{
+    /**
+     * The discussion that is going to be deleted.
+     *
+     * @var Discussion
+     */
+    public $discussion;
+
+    /**
+     * The user who is performing the action.
+     *
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * Any user input associated with the command.
+     *
+     * @var array
+     */
+    public $data;
+
+    /**
+     * @param Discussion $discussion
+     * @param User $actor
+     * @param array $data
+     */
+    public function __construct(Discussion $discussion, User $actor, array $data = [])
+    {
+        $this->discussion = $discussion;
+        $this->actor = $actor;
+        $this->data = $data;
+    }
+}

src/Discussion/Event/Hidden.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Hidden
+{
+    /**
+     * @var \Flarum\Discussion\Discussion
+     */
+    public $discussion;
+
+    /**
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @param User $actor
+     */
+    public function __construct(Discussion $discussion, User $actor = null)
+    {
+        $this->discussion = $discussion;
+        $this->actor = $actor;
+    }
+}

src/Discussion/Event/Renamed.php

@@ -0,0 +1,45 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Renamed
+{
+    /**
+     * @var Discussion
+     */
+    public $discussion;
+
+    /**
+     * @var string
+     */
+    public $oldTitle;
+
+    /**
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @param User $actor
+     * @param string $oldTitle
+     */
+    public function __construct(Discussion $discussion, $oldTitle, User $actor = null)
+    {
+        $this->discussion = $discussion;
+        $this->oldTitle = $oldTitle;
+        $this->actor = $actor;
+    }
+}

src/Discussion/Event/Restored.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Restored
+{
+    /**
+     * @var \Flarum\Discussion\Discussion
+     */
+    public $discussion;
+
+    /**
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @param User $actor
+     */
+    public function __construct(Discussion $discussion, User $actor = null)
+    {
+        $this->discussion = $discussion;
+        $this->actor = $actor;
+    }
+}

src/Discussion/Event/Saving.php

@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Saving
+{
+    /**
+     * The discussion that will be saved.
+     *
+     * @var \Flarum\Discussion\Discussion
+     */
+    public $discussion;
+
+    /**
+     * The user who is performing the action.
+     *
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * Any user input associated with the command.
+     *
+     * @var array
+     */
+    public $data;
+
+    /**
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @param User $actor
+     * @param array $data
+     */
+    public function __construct(Discussion $discussion, User $actor, array $data = [])
+    {
+        $this->discussion = $discussion;
+        $this->actor = $actor;
+        $this->data = $data;
+    }
+}

src/Discussion/Event/Started.php

@@ -0,0 +1,38 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Discussion\Discussion;
+use Flarum\User\User;
+
+class Started
+{
+    /**
+     * @var \Flarum\Discussion\Discussion
+     */
+    public $discussion;
+
+    /**
+     * @var User
+     */
+    public $actor;
+
+    /**
+     * @param \Flarum\Discussion\Discussion $discussion
+     * @param User $actor
+     */
+    public function __construct(Discussion $discussion, User $actor = null)
+    {
+        $this->discussion = $discussion;
+        $this->actor = $actor;
+    }
+}

src/Discussion/Event/UserDataSaving.php

@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Core\DiscussionState;
+
+class UserDataSaving
+{
+    /**
+     * @var DiscussionState
+     */
+    public $state;
+
+    /**
+     * @param DiscussionState $state
+     */
+    public function __construct(DiscussionState $state)
+    {
+        $this->state = $state;
+    }
+}

src/Discussion/Event/UserRead.php

@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Event;
+
+use Flarum\Core\DiscussionState;
+
+class UserRead
+{
+    /**
+     * @var DiscussionState
+     */
+    public $state;
+
+    /**
+     * @param DiscussionState $state
+     */
+    public function __construct(DiscussionState $state)
+    {
+        $this->state = $state;
+    }
+}

src/Discussion/Search/DiscussionSearch.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search;
+
+use Flarum\Core\Search\AbstractSearch;
+
+/**
+ * An object which represents the internal state of a search for discussions:
+ * the search query, the user performing the search, the fallback sort order,
+ * relevant post information, and a log of which gambits have been used.
+ */
+class DiscussionSearch extends AbstractSearch
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected $defaultSort = ['lastTime' => 'desc'];
+
+    /**
+     * @var array
+     */
+    protected $relevantPostIds = [];
+
+    /**
+     * Get the related IDs for each result.
+     *
+     * @return int[]
+     */
+    public function getRelevantPostIds()
+    {
+        return $this->relevantPostIds;
+    }
+
+    /**
+     * Set the relevant post IDs for the results.
+     *
+     * @param array $relevantPostIds
+     * @return void
+     */
+    public function setRelevantPostIds(array $relevantPostIds)
+    {
+        $this->relevantPostIds = $relevantPostIds;
+    }
+}

src/Discussion/Search/DiscussionSearcher.php

@@ -0,0 +1,138 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search;
+
+use Flarum\Discussion\Discussion;
+use Flarum\Discussion\DiscussionRepository;
+use Flarum\Discussion\Search\DiscussionSearch;
+use Flarum\Post\PostRepository;
+use Flarum\Core\Search\ApplySearchParametersTrait;
+use Flarum\Core\Search\GambitManager;
+use Flarum\Core\Search\SearchCriteria;
+use Flarum\Core\Search\SearchResults;
+use Flarum\Event\ConfigureDiscussionSearch;
+use Illuminate\Database\Eloquent\Collection;
+
+/**
+ * Takes a DiscussionSearchCriteria object, performs a search using gambits,
+ * and spits out a DiscussionSearchResults object.
+ */
+class DiscussionSearcher
+{
+    use ApplySearchParametersTrait;
+
+    /**
+     * @var GambitManager
+     */
+    protected $gambits;
+
+    /**
+     * @var DiscussionRepository
+     */
+    protected $discussions;
+
+    /**
+     * @var PostRepository
+     */
+    protected $posts;
+
+    /**
+     * @param GambitManager $gambits
+     * @param DiscussionRepository $discussions
+     * @param PostRepository $posts
+     */
+    public function __construct(
+        GambitManager $gambits,
+        DiscussionRepository $discussions,
+        PostRepository $posts
+    ) {
+        $this->gambits = $gambits;
+        $this->discussions = $discussions;
+        $this->posts = $posts;
+    }
+
+    /**
+     * @param SearchCriteria $criteria
+     * @param int|null $limit
+     * @param int $offset
+     * @param array $load An array of relationships to load on the results.
+     * @return SearchResults
+     */
+    public function search(SearchCriteria $criteria, $limit = null, $offset = 0, array $load = [])
+    {
+        $actor = $criteria->actor;
+
+        $query = $this->discussions->query()->whereVisibleTo($actor);
+
+        // Construct an object which represents this search for discussions.
+        // Apply gambits to it, sort, and paging criteria. Also give extensions
+        // an opportunity to modify it.
+        $search = new DiscussionSearch($query->getQuery(), $actor);
+
+        $this->gambits->apply($search, $criteria->query);
+        $this->applySort($search, $criteria->sort);
+        $this->applyOffset($search, $offset);
+        $this->applyLimit($search, $limit + 1);
+
+        // TODO: inject dispatcher
+        event(new ConfigureDiscussionSearch($search, $criteria));
+
+        // Execute the search query and retrieve the results. We get one more
+        // results than the user asked for, so that we can say if there are more
+        // results. If there are, we will get rid of that extra result.
+        $discussions = $query->get();
+
+        $areMoreResults = $limit > 0 && $discussions->count() > $limit;
+
+        if ($areMoreResults) {
+            $discussions->pop();
+        }
+
+        // The relevant posts relationship isn't a typical Eloquent
+        // relationship; rather, we need to extract that information from our
+        // search object. We will delegate that task and prevent Eloquent
+        // from trying to load it.
+        if (in_array('relevantPosts', $load)) {
+            $this->loadRelevantPosts($discussions, $search);
+
+            $load = array_diff($load, ['relevantPosts', 'relevantPosts.discussion', 'relevantPosts.user']);
+        }
+
+        Discussion::setStateUser($actor);
+        $discussions->load($load);
+
+        return new SearchResults($discussions, $areMoreResults);
+    }
+
+    /**
+     * Load relevant posts onto each discussion using information from the
+     * search.
+     *
+     * @param Collection $discussions
+     * @param DiscussionSearch $search
+     */
+    protected function loadRelevantPosts(Collection $discussions, DiscussionSearch $search)
+    {
+        $postIds = [];
+        foreach ($search->getRelevantPostIds() as $relevantPostIds) {
+            $postIds = array_merge($postIds, array_slice($relevantPostIds, 0, 2));
+        }
+
+        $posts = $postIds ? $this->posts->findByIds($postIds, $search->getActor())->load('user')->all() : [];
+
+        foreach ($discussions as $discussion) {
+            $discussion->relevantPosts = array_filter($posts, function ($post) use ($discussion) {
+                return $post->discussion_id == $discussion->id;
+            });
+        }
+    }
+}

src/Discussion/Search/Fulltext/DriverInterface.php

@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Fulltext;
+
+interface DriverInterface
+{
+    /**
+     * Return an array of arrays of post IDs, grouped by discussion ID, which
+     * match the given string.
+     *
+     * @param string $string
+     * @return array
+     */
+    public function match($string);
+}

src/Discussion/Search/Fulltext/MySqlFulltextDriver.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Fulltext;
+
+use Flarum\Core\Post;
+
+class MySqlFulltextDriver implements DriverInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function match($string)
+    {
+        $discussionIds = Post::where('type', 'comment')
+            ->whereRaw('MATCH (`content`) AGAINST (? IN BOOLEAN MODE)', [$string])
+            ->orderByRaw('MATCH (`content`) AGAINST (?) DESC', [$string])
+            ->lists('discussion_id', 'id');
+
+        $relevantPostIds = [];
+
+        foreach ($discussionIds as $postId => $discussionId) {
+            $relevantPostIds[$discussionId][] = $postId;
+        }
+
+        return $relevantPostIds;
+    }
+}

src/Discussion/Search/Gambit/AuthorGambit.php

@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Gambit;
+
+use Flarum\User\UserRepository;
+use Flarum\Core\Search\AbstractRegexGambit;
+use Flarum\Core\Search\AbstractSearch;
+use Flarum\Discussion\Search\DiscussionSearch;
+use LogicException;
+
+class AuthorGambit extends AbstractRegexGambit
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected $pattern = 'author:(.+)';
+
+    /**
+     * @var \Flarum\User\UserRepository
+     */
+    protected $users;
+
+    /**
+     * @param \Flarum\User\UserRepository $users
+     */
+    public function __construct(UserRepository $users)
+    {
+        $this->users = $users;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function conditions(AbstractSearch $search, array $matches, $negate)
+    {
+        if (! $search instanceof DiscussionSearch) {
+            throw new LogicException('This gambit can only be applied on a DiscussionSearch');
+        }
+
+        $usernames = trim($matches[1], '"');
+        $usernames = explode(',', $usernames);
+
+        $ids = [];
+        foreach ($usernames as $username) {
+            $ids[] = $this->users->getIdForUsername($username);
+        }
+
+        $search->getQuery()->whereIn('start_user_id', $ids, 'and', $negate);
+    }
+}

src/Discussion/Search/Gambit/CreatedGambit.php

@@ -0,0 +1,45 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Gambit;
+
+use Flarum\Core\Search\AbstractRegexGambit;
+use Flarum\Core\Search\AbstractSearch;
+use Flarum\Discussion\Search\DiscussionSearch;
+use LogicException;
+
+class CreatedGambit extends AbstractRegexGambit
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected $pattern = 'created:(\d{4}\-\d\d\-\d\d)(\.\.(\d{4}\-\d\d\-\d\d))?';
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function conditions(AbstractSearch $search, array $matches, $negate)
+    {
+        if (! $search instanceof DiscussionSearch) {
+            throw new LogicException('This gambit can only be applied on a DiscussionSearch');
+        }
+
+        // If we've just been provided with a single YYYY-MM-DD date, then find
+        // discussions that were started on that exact date. But if we've been
+        // provided with a YYYY-MM-DD..YYYY-MM-DD range, then find discussions
+        // that were started during that period.
+        if (empty($matches[3])) {
+            $search->getQuery()->whereDate('start_time', $negate ? '!=' : '=', $matches[1]);
+        } else {
+            $search->getQuery()->whereBetween('start_time', [$matches[1], $matches[3]], 'and', $negate);
+        }
+    }
+}

src/Discussion/Search/Gambit/FulltextGambit.php

@@ -0,0 +1,54 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Gambit;
+
+use Flarum\Core\Search\AbstractSearch;
+use Flarum\Discussion\Search\DiscussionSearch;
+use Flarum\Discussion\Search\Fulltext\DriverInterface;
+use Flarum\Core\Search\GambitInterface;
+use LogicException;
+
+class FulltextGambit implements GambitInterface
+{
+    /**
+     * @var \Flarum\Discussion\Search\Fulltext\DriverInterface
+     */
+    protected $fulltext;
+
+    /**
+     * @param \Flarum\Discussion\Search\Fulltext\DriverInterface $fulltext
+     */
+    public function __construct(DriverInterface $fulltext)
+    {
+        $this->fulltext = $fulltext;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function apply(AbstractSearch $search, $bit)
+    {
+        if (! $search instanceof DiscussionSearch) {
+            throw new LogicException('This gambit can only be applied on a DiscussionSearch');
+        }
+
+        $relevantPostIds = $this->fulltext->match($bit);
+
+        $discussionIds = array_keys($relevantPostIds);
+
+        $search->setRelevantPostIds($relevantPostIds);
+
+        $search->getQuery()->whereIn('id', $discussionIds);
+
+        $search->setDefaultSort(['id' => $discussionIds]);
+    }
+}

src/Discussion/Search/Gambit/HiddenGambit.php

@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Gambit;
+
+use Flarum\Core\Search\AbstractRegexGambit;
+use Flarum\Core\Search\AbstractSearch;
+use Flarum\Discussion\Search\DiscussionSearch;
+use LogicException;
+
+class HiddenGambit extends AbstractRegexGambit
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected $pattern = 'is:hidden';
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function conditions(AbstractSearch $search, array $matches, $negate)
+    {
+        if (! $search instanceof DiscussionSearch) {
+            throw new LogicException('This gambit can only be applied on a DiscussionSearch');
+        }
+
+        $search->getQuery()->where(function ($query) use ($negate) {
+            if ($negate) {
+                $query->whereNull('hide_time')->where('comments_count', '>', 0);
+            } else {
+                $query->whereNotNull('hide_time')->orWhere('comments_count', 0);
+            }
+        });
+    }
+}

src/Discussion/Search/Gambit/UnreadGambit.php

@@ -0,0 +1,63 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Discussion\Search\Gambit;
+
+use Flarum\Discussion\DiscussionRepository;
+use Flarum\Core\Search\AbstractRegexGambit;
+use Flarum\Core\Search\AbstractSearch;
+use Flarum\Discussion\Search\DiscussionSearch;
+use LogicException;
+
+class UnreadGambit extends AbstractRegexGambit
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected $pattern = 'is:unread';
+
+    /**
+     * @var \Flarum\Discussion\DiscussionRepository
+     */
+    protected $discussions;
+
+    /**
+     * @param \Flarum\Discussion\DiscussionRepository $discussions
+     */
+    public function __construct(DiscussionRepository $discussions)
+    {
+        $this->discussions = $discussions;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function conditions(AbstractSearch $search, array $matches, $negate)
+    {
+        if (! $search instanceof DiscussionSearch) {
+            throw new LogicException('This gambit can only be applied on a DiscussionSearch');
+        }
+
+        $actor = $search->getActor();
+
+        if ($actor->exists) {
+            $readIds = $this->discussions->getReadIds($actor);
+
+            $search->getQuery()->where(function ($query) use ($readIds, $negate, $actor) {
+                if (! $negate) {
+                    $query->whereNotIn('id', $readIds)->where('last_time', '>', $actor->read_time ?: 0);
+                } else {
+                    $query->whereIn('id', $readIds)->orWhere('last_time', '<=', $actor->read_time ?: 0);
+                }
+            });
+        }
+    }
+}