<?php
namespace Misuzu;

use stdClass;
use RuntimeException;

if(!isset($msz) || !($msz instanceof \Misuzu\MisuzuContext))
    die('Script must be called through the Misuzu route dispatcher.');

$postId = !empty($_GET['p']) && is_string($_GET['p']) ? (int)$_GET['p'] : 0;
$topicId = !empty($_GET['t']) && is_string($_GET['t']) ? (int)$_GET['t'] : 0;
$categoryId = null;

$currentUser = $msz->authInfo->userInfo;
$currentUserId = $currentUser === null ? '0' : $currentUser->id;

if($topicId < 1 && $postId > 0) {
    try {
        $postInfo = $msz->forumCtx->posts->getPost(postId: (string)$postId);
    } catch(RuntimeException $ex) {
        Template::throwError(404);
    }

    $categoryId = (int)$postInfo->categoryId;
    $perms = $msz->authInfo->getPerms('forum', $postInfo->categoryId);
    $canDeleteAny = $perms->check(Perm::F_POST_DELETE_ANY);

    if($postInfo->deleted && !$canDeleteAny)
        Template::throwError(404);

    $topicId = $postInfo->topicId;
    $preceedingPostCount = $msz->forumCtx->posts->countPosts(
        topicInfo: $topicId,
        upToPostInfo: $postInfo,
        deleted: $canDeleteAny ? null : false
    );
}

try {
    $topicIsNuked = $topicIsDeleted = $canDeleteAny = false;
    $topicInfo = $msz->forumCtx->topics->getTopic(topicId: $topicId);
} catch(RuntimeException $ex) {
    $topicIsNuked = true;
}

if(!$topicIsNuked) {
    $topicIsDeleted = $topicInfo->deleted;

    if($categoryId !== (int)$topicInfo->categoryId) {
        $categoryId = (int)$topicInfo->categoryId;
        $perms = $msz->authInfo->getPerms('forum', $topicInfo->categoryId);
    }

    if($msz->usersCtx->hasActiveBan($currentUser))
        $perms = $perms->apply(fn($calc) => $calc & (Perm::F_CATEGORY_LIST | Perm::F_CATEGORY_VIEW));

    $canDeleteAny = $perms->check(Perm::F_POST_DELETE_ANY);
}

if($topicIsNuked || $topicIsDeleted) {
    if($msz->forumCtx->topicRedirects->hasTopicRedirect($topicId)) {
        $topicRedirectInfo = $msz->forumCtx->topicRedirects->getTopicRedirect($topicId);
        Template::set('topic_redir_info', $topicRedirectInfo);

        if($topicIsNuked || !$canDeleteAny) {
            header('Location: ' . $topicRedirectInfo->linkTarget);
            return;
        }
    }

    if(empty($topicRedirectInfo) && !$canDeleteAny)
        Template::throwError(404);
}

if(!$perms->check(Perm::F_CATEGORY_VIEW))
    Template::throwError(403);

// Maximum amount of posts a topic may contain to still be deletable by the author
// this should be in the config
$deletePostThreshold = 1;

$categoryInfo = $msz->forumCtx->categories->getCategory(topicInfo: $topicInfo);
$topicIsLocked = $topicInfo->locked;
$topicIsArchived = $categoryInfo->archived;
$topicPostsTotal = $topicInfo->totalPostsCount;
$topicIsFrozen = $topicIsArchived || $topicIsDeleted;
$canDeleteOwn = !$topicIsFrozen && !$topicIsLocked && $perms->check(Perm::F_POST_DELETE_OWN);
$canBumpTopic = !$topicIsFrozen && $perms->check(Perm::F_TOPIC_BUMP);
$canLockTopic = !$topicIsFrozen && $perms->check(Perm::F_TOPIC_LOCK);
$canNukeOrRestore = $canDeleteAny && $topicIsDeleted;
$canDelete = !$topicIsDeleted && (
    $canDeleteAny || (
        $topicPostsTotal > 0
        && $topicPostsTotal <= $deletePostThreshold
        && $canDeleteOwn
        && $topicInfo->userId === (string)$currentUserId
    )
);

$topicPosts = $topicInfo->postsCount;
if($canDeleteAny)
    $topicPosts += $topicInfo->deletedPostsCount;

if(isset($preceedingPostCount))
    $pagination = Pagination::fromPage($topicPosts, (int)floor($preceedingPostCount / 10), 10, 0);
else
    $pagination = Pagination::fromInput($topicPosts, 10, 'page');

if(!$pagination->validOffset)
    Template::throwError(404);

$postInfos = $msz->forumCtx->posts->getPosts(
    topicInfo: $topicInfo,
    deleted: $perms->check(Perm::F_POST_DELETE_ANY) ? null : false,
    pagination: $pagination,
);

if(empty($postInfos))
    Template::throwError(404);

try {
    $originalPostInfo = $msz->forumCtx->posts->getPost(topicInfo: $topicInfo);
} catch(RuntimeException $ex) {
    Template::throwError(404);
}

$posts = [];

foreach($postInfos as $postInfo) {
    $posts[] = $post = new stdClass;
    $post->info = $postInfo;

    if($postInfo->userId !== null) {
        $post->user = $msz->usersCtx->getUserInfo($postInfo->userId);
        $post->colour = $msz->usersCtx->getUserColour($post->user);
        $post->postsCount = $msz->forumCtx->countTotalUserPosts($post->user);
    }

    $post->isOriginalPost = $originalPostInfo->id == $postInfo->id;
    $post->isOriginalPoster = $originalPostInfo->userId !== null && $postInfo->userId !== null
        && $originalPostInfo->userId === $postInfo->userId;
}

$canReply = !$topicIsArchived && !$topicIsLocked && !$topicIsDeleted && $perms->check(Perm::F_POST_CREATE);

if(!$msz->forumCtx->topics->checkUserHasReadTopic($currentUser, $topicInfo))
    $msz->forumCtx->topics->incrementTopicViews($topicInfo);

$msz->forumCtx->topics->updateUserReadTopic($currentUser, $topicInfo);

$perms = $perms->checkMany([
    'can_create_post' => Perm::F_POST_CREATE,
    'can_edit_post' => Perm::F_POST_EDIT_OWN,
    'can_edit_any_post' => Perm::F_POST_EDIT_ANY,
    'can_delete_post' => Perm::F_POST_DELETE_OWN,
    'can_delete_any_post' => Perm::F_POST_DELETE_ANY,
]);

Template::render('forum.topic', [
    'topic_breadcrumbs' => iterator_to_array($msz->forumCtx->categories->getCategoryAncestry($topicInfo)),
    'global_accent_colour' => $msz->forumCtx->categories->getCategoryColour($topicInfo),
    'topic_info' => $topicInfo,
    'category_info' => $categoryInfo,
    'topic_posts' => $posts,
    'can_reply' => $canReply,
    'topic_pagination' => $pagination,
    'topic_can_delete' => $canDelete,
    'topic_can_delete_any' => $canDeleteAny,
    'topic_can_nuke_or_restore' => $canNukeOrRestore,
    'topic_can_bump' => $canBumpTopic,
    'topic_can_lock' => $canLockTopic,
    'topic_user_id' => $currentUserId,
    'topic_perms' => $perms,
]);