<?php

/**
 * Adding a comment to a ticket: validation, access check, reply-parent check,
 * @mention extraction (audit-logged, and notified only to mentioned users who
 * can see the ticket), comment + watcher notifications.
 *
 * Shared by the web UI (api/add_comment.php) and the MCP add_comment tool so
 * both run one code path (tinker_tickets#111). Extracted verbatim from
 * add_comment.php. Returns result arrays; on validation failure the array
 * carries 'http_status' for HTTP callers. Callers own sessions/CSRF/responses.
 */

require_once dirname(__DIR__) . '/models/TicketModel.php';
require_once dirname(__DIR__) . '/models/CommentModel.php';
require_once dirname(__DIR__) . '/models/AuditLogModel.php';
require_once dirname(__DIR__) . '/helpers/NotificationHelper.php';
require_once dirname(__DIR__) . '/helpers/SynapseHelper.php';

class CommentService
{
    /**
     * @param array $currentUser Authenticated user row (user_id, username, display_name, groups, is_admin)
     * @param array $data        ticket_id, comment_text, optional markdown_enabled / parent_comment_id
     */
    public static function addComment(mysqli $conn, array $currentUser, array $data): array
    {
        $userId = $currentUser['user_id'];

        $ticketId = isset($data['ticket_id']) ? trim((string)$data['ticket_id']) : '';
        if (!ctype_digit($ticketId) || (int)$ticketId <= 0) {
            return ['success' => false, 'error' => 'Invalid ticket ID', 'http_status' => 400];
        }

        // Reject empty/whitespace-only comments
        $commentTextRaw = isset($data['comment_text']) ? trim((string)$data['comment_text']) : '';
        if ($commentTextRaw === '') {
            return ['success' => false, 'error' => 'Comment text cannot be empty', 'http_status' => 400];
        }

        // Persist the trimmed text (not the raw client value) — matches update_comment.php
        // and keeps stored comment_text free of leading whitespace that could shift a
        // markdown-enabled comment's first line out of column 0 on reload.
        $data['comment_text'] = $commentTextRaw;

        // Never trust a client-supplied display name — always attribute the comment to
        // the authenticated user.
        $data['user_name'] = $currentUser['display_name'] ?? $currentUser['username'] ?? 'User';

        // Verify user can access the ticket before allowing a comment
        $ticketModel = new TicketModel($conn);
        $ticket = $ticketModel->getTicketById($ticketId);
        if (!$ticket) {
            return ['success' => false, 'error' => 'Ticket not found', 'http_status' => 404];
        }
        if (!$ticketModel->canUserAccessTicket($ticket, $currentUser)) {
            return ['success' => false, 'error' => 'Access denied', 'http_status' => 403];
        }

        // Initialize models
        $commentModel = new CommentModel($conn);
        $auditLog = new AuditLogModel($conn);

        // If replying, the parent comment must belong to this same (accessible) ticket.
        if (isset($data['parent_comment_id']) && $data['parent_comment_id'] !== null && $data['parent_comment_id'] !== '') {
            $parentComment = $commentModel->getCommentById((int)$data['parent_comment_id']);
            if (!$parentComment || (string)$parentComment['ticket_id'] !== (string)$ticketId) {
                return ['success' => false, 'error' => 'Invalid parent comment', 'http_status' => 400];
            }
        }

        // Extract @mentions from comment text
        $mentions = $commentModel->extractMentions($data['comment_text'] ?? '');
        $mentionedUsers = [];
        if (!empty($mentions)) {
            $mentionedUsers = $commentModel->getMentionedUsers($mentions);
        }

        // Add comment with user tracking
        $result = $commentModel->addComment($ticketId, $data, $userId);

        // Log comment creation to audit log
        if ($result['success'] && isset($result['comment_id'])) {
            $auditLog->logCommentCreate($userId, $result['comment_id'], $ticketId);

            // Log mentions to audit log
            foreach ($mentionedUsers as $mentionedUser) {
                $auditLog->log(
                    $userId,
                    'mention',
                    'user',
                    (string)$mentionedUser['user_id'],
                    [
                        'ticket_id' => $ticketId,
                        'comment_id' => $result['comment_id'],
                        'mentioned_username' => $mentionedUser['username']
                    ]
                );
            }

            // Matrix notifications
            $authorDisplay = $currentUser['display_name'] ?? $currentUser['username'] ?? null;
            $commentText   = $data['comment_text'] ?? '';
            $ticketTitle   = $ticket['title'] ?? "Ticket #{$ticketId}";
            $ticketVisibility = $ticket['visibility'] ?? 'public';

            // @mention notifications — resolve usernames → Matrix IDs via Synapse Admin API.
            // Only notify mentioned users who actually have access to this ticket;
            // otherwise a mention would DM them the ticket's title and comment text
            // even though canUserAccessTicket() would deny them the ticket itself.
            $accessibleMentionedUsers = array_filter(
                $mentionedUsers,
                fn($u) => $ticketModel->canUserAccessTicket($ticket, $u)
            );
            if (!empty($accessibleMentionedUsers)) {
                $mentionedUsernames = array_column($accessibleMentionedUsers, 'username');
                $mentionedMatrixIds = SynapseHelper::resolveUsernames($mentionedUsernames);
                if (!empty($mentionedMatrixIds)) {
                    NotificationHelper::sendMentionNotification($ticketId, $ticketTitle, $commentText, $authorDisplay, $mentionedMatrixIds);
                }
            }

            // General comment notification (opt-in via MATRIX_NOTIFY_COMMENTS)
            if (!empty($GLOBALS['config']['MATRIX_NOTIFY_COMMENTS'])) {
                NotificationHelper::sendCommentNotification(
                    $ticketId,
                    $ticketTitle,
                    $commentText,
                    $authorDisplay,
                    $ticketVisibility !== 'public',
                    $ticketVisibility
                );
            }

            // Notify watchers of the new comment
            NotificationHelper::notifyWatchers(
                $conn,
                $ticketId,
                $ticketTitle,
                'comment_added',
                ['author' => $authorDisplay, 'preview' => mb_strimwidth($commentText, 0, 200, '…')],
                (int)$userId,
                $ticketVisibility
            );

            // Add mentioned users to result for frontend
            $result['mentions'] = array_map(function ($u) {
                return $u['username'];
            }, $mentionedUsers);
        }

        // Add user info to result for frontend avatar rendering
        if ($result['success']) {
            $result['user_name'] = $currentUser['display_name'] ?? $currentUser['username'];
            $result['user_id']   = $userId;
        }

        return $result;
    }
}