<?php
header('Content-Type: application/json');
require_once 'auth/session.php';
require_once 'includes/permissions.php';
requireLogin();

if ($_SERVER['REQUEST_METHOD'] === 'GET') {
    $server_id = $_GET['server_id'] ?? 0;
    if (!$server_id) {
        echo json_encode([]);
        exit;
    }
    $stmt = db()->prepare("SELECT * FROM channels WHERE server_id = ?");
    $stmt->execute([$server_id]);
    echo json_encode($stmt->fetchAll());
    exit;
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $action = $_POST['action'] ?? 'create';
    $server_id = $_POST['server_id'] ?? 0;
    $user_id = $_SESSION['user_id'];

    if ($action === 'update') {
        $channel_id = $_POST['channel_id'] ?? 0;
        $name = $_POST['name'] ?? '';
        $type = $_POST['type'] ?? 'chat';
        $status = $_POST['status'] ?? null;
        $allow_file_sharing = isset($_POST['allow_file_sharing']) ? 1 : 0;
        $message_limit = !empty($_POST['message_limit']) ? (int)$_POST['message_limit'] : null;
        $theme_color = $_POST['theme_color'] ?? null;
        if ($theme_color === '') $theme_color = null;

        // Check if user has permission to manage channels
        $stmt = db()->prepare("SELECT server_id FROM channels WHERE id = ?");
        $stmt->execute([$channel_id]);
        $chan = $stmt->fetch();
        
        if ($chan && Permissions::hasPermission($user_id, $chan['server_id'], Permissions::MANAGE_CHANNELS)) {
            $name = strtolower(preg_replace('/[^a-zA-Z0-9\-]/', '-', $name));
            $stmt = db()->prepare("UPDATE channels SET name = ?, type = ?, status = ?, allow_file_sharing = ?, theme_color = ?, message_limit = ? WHERE id = ?");
            $stmt->execute([$name, $type, $status, $allow_file_sharing, $theme_color, $message_limit, $channel_id]);
        }
        header('Location: index.php?server_id=' . $server_id . '&channel_id=' . $channel_id);
        exit;
    }

    if ($action === 'delete') {
        $channel_id = $_POST['channel_id'] ?? 0;
        $stmt = db()->prepare("SELECT server_id FROM channels WHERE id = ?");
        $stmt->execute([$channel_id]);
        $chan = $stmt->fetch();

        if ($chan && Permissions::hasPermission($user_id, $chan['server_id'], Permissions::MANAGE_CHANNELS)) {
            $stmt = db()->prepare("DELETE FROM channels WHERE id = ?");
            $stmt->execute([$channel_id]);
        }
        header('Location: index.php?server_id=' . ($chan['server_id'] ?? ''));
        exit;
    }

    $name = $_POST['name'] ?? '';
    $type = $_POST['type'] ?? 'text';
    $user_id = $_SESSION['user_id'];
    
    // Check if user has permission to manage channels
    if (Permissions::hasPermission($user_id, $server_id, Permissions::MANAGE_CHANNELS) && $name) {
        try {
            // Basic sanitization for channel name
            $name = strtolower(preg_replace('/[^a-zA-Z0-9\-]/', '-', $name));
            $allow_file_sharing = isset($_POST['allow_file_sharing']) ? 1 : 0;
            $message_limit = !empty($_POST['message_limit']) ? (int)$_POST['message_limit'] : null;
            $theme_color = $_POST['theme_color'] ?? null;
            if ($theme_color === '') $theme_color = null;
            
            $stmt = db()->prepare("INSERT INTO channels (server_id, name, type, allow_file_sharing, theme_color, message_limit) VALUES (?, ?, ?, ?, ?, ?)");
            $stmt->execute([$server_id, $name, $type, $allow_file_sharing, $theme_color, $message_limit]);
            $channel_id = db()->lastInsertId();
            
            header('Location: index.php?server_id=' . $server_id . '&channel_id=' . $channel_id);
            exit;
        } catch (Exception $e) {
            die("Error creating channel: " . $e->getMessage());
        }
    }
}
header('Location: index.php');