<?php
require_once __DIR__ . '/../helpers.php';
runAuth();

/**
 * Get chat messages for a task
 * POST: { TaskID, AfterMessageID? }
 */

$data = readJsonBody();
$taskID = (int) ($data['TaskID'] ?? 0);
$afterMessageID = (int) ($data['AfterMessageID'] ?? 0);

if ($taskID <= 0) {
    apiAbort(['OK' => false, 'ERROR' => 'missing_params', 'MESSAGE' => 'TaskID is required']);
}

try {
    if ($afterMessageID > 0) {
        $qMessages = queryTimed("
            SELECT
                m.ID, m.TaskID, m.SenderUserID, m.SenderType,
                m.MessageBody, m.IsRead, m.CreatedOn,
                u.FirstName as SenderName
            FROM ChatMessages m
            LEFT JOIN Users u ON u.ID = m.SenderUserID
            WHERE m.TaskID = ? AND m.ID > ?
            ORDER BY m.CreatedOn ASC
        ", [$taskID, $afterMessageID]);
    } else {
        $qMessages = queryTimed("
            SELECT
                m.ID, m.TaskID, m.SenderUserID, m.SenderType,
                m.MessageBody, m.IsRead, m.CreatedOn,
                u.FirstName as SenderName
            FROM ChatMessages m
            LEFT JOIN Users u ON u.ID = m.SenderUserID
            WHERE m.TaskID = ?
            ORDER BY m.CreatedOn ASC
        ", [$taskID]);
    }

    $messages = [];
    foreach ($qMessages as $msg) {
        $senderName = !empty(trim($msg['SenderName'] ?? ''))
            ? $msg['SenderName']
            : ($msg['SenderType'] === 'customer' ? 'Customer' : 'Staff');

        $messages[] = [
            'MessageID' => (int) $msg['ID'],
            'TaskID' => (int) $msg['TaskID'],
            'SenderUserID' => (int) $msg['SenderUserID'],
            'SenderType' => $msg['SenderType'],
            'SenderName' => $senderName,
            'Text' => $msg['MessageBody'],
            'IsRead' => ((int) $msg['IsRead']) === 1,
            'CreatedOn' => toISO8601($msg['CreatedOn']),
        ];
    }

    // Check if chat/task is closed
    $qTask = queryOne("SELECT CompletedOn FROM Tasks WHERE ID = ?", [$taskID]);
    $chatClosed = ($qTask && !empty(trim($qTask['CompletedOn'] ?? '')));

    jsonResponse([
        'OK' => true,
        'MESSAGES' => $messages,
        'COUNT' => count($messages),
        'CHAT_CLOSED' => $chatClosed,
    ]);

} catch (Exception $e) {
    jsonResponse(['OK' => false, 'ERROR' => 'server_error', 'MESSAGE' => $e->getMessage()]);
}