<?php
session_start();
require_once __DIR__ . '/../db/config.php';

$action = $_GET['action'] ?? '';

if ($action === 'upload_image' || (isset($_POST['action']) && $_POST['action'] === 'upload_image')) {
    if (!isset($_FILES['file'])) {
        echo json_encode(['success' => false, 'error' => 'No file uploaded']);
        exit;
    }

    $file = $_FILES['file'];
    $ext = pathinfo($file['name'], PATHINFO_EXTENSION);
    $allowed = ['jpg', 'jpeg', 'png', 'gif', 'webp'];
    
    if (!in_array(strtolower($ext), $allowed)) {
        echo json_encode(['success' => false, 'error' => 'Invalid file type']);
        exit;
    }

    $filename = time() . '_' . uniqid() . '.' . $ext;
    $targetDir = __DIR__ . '/../assets/images/chat/';
    if (!is_dir($targetDir)) {
        mkdir($targetDir, 0777, true);
    }
    
    $targetPath = $targetDir . $filename;
    if (move_uploaded_file($file['tmp_name'], $targetPath)) {
        $imageUrl = '/assets/images/chat/' . $filename;
        
        $message = '<img src="' . $imageUrl . '" class="img-fluid rounded cursor-pointer" style="max-width: 200px; max-height: 200px;" onclick="window.open(\'' . $imageUrl . '\')">';
        
        if (isset($_SESSION['admin_id'])) {
            $user_id = $_POST['user_id'] ?? 0;
            $ip = $_POST['ip_address'] ?? '';
            $sender = 'admin';
            $admin_id = $_SESSION['admin_id'];
            $stmt = db()->prepare("INSERT INTO messages (user_id, admin_id, sender, message, ip_address) VALUES (?, ?, ?, ?, ?)");
            $stmt->execute([$user_id, $admin_id, $sender, $message, $ip]);
        } else {
            $user_id = $_SESSION['user_id'] ?? 0;
            $ip = getRealIP();
            $stmt = db()->prepare("INSERT INTO messages (user_id, sender, message, ip_address) VALUES (?, ?, ?, ?)");
            $stmt->execute([$user_id, 'user', $message, $ip]);
        }
        
        echo json_encode(['success' => true, 'url' => $imageUrl]);
    } else {
        echo json_encode(['success' => false, 'error' => 'Failed to move uploaded file']);
    }
    exit;
}

if ($action === 'get_messages') {
    $user_id = $_SESSION['user_id'] ?? 0;
    $target_user_id = $_GET['user_id'] ?? $user_id;
    $target_ip = $_GET['ip'] ?? getRealIP();
    
    // If admin is requesting, we use the provided user_id and ip
    if (isset($_SESSION['admin_id'])) {
        $stmt = db()->prepare("SELECT * FROM messages WHERE (user_id = ? AND user_id != 0) OR (user_id = 0 AND ip_address = ?) ORDER BY created_at ASC");
        $stmt->execute([$target_user_id, $target_ip]);
    } else {
        // User requesting their own messages
        $stmt = db()->prepare("SELECT * FROM messages WHERE (user_id = ? AND user_id != 0) OR (user_id = 0 AND ip_address = ?) ORDER BY created_at ASC");
        $stmt->execute([$user_id, getRealIP()]);
    }
    
    $messages = $stmt->fetchAll();
    echo json_encode($messages);
    exit;
}

if ($action === 'send_message') {
    $message = $_POST['message'] ?? '';
    if (!$message) exit(json_encode(['success' => false]));

    $user_id = $_SESSION['user_id'] ?? 0;
    $ip = getRealIP();

    $stmt = db()->prepare("INSERT INTO messages (user_id, sender, message, ip_address) VALUES (?, ?, ?, ?)");
    $stmt->execute([$user_id, 'user', $message, $ip]);
    $newId = db()->lastInsertId();
    echo json_encode(['success' => true, 'id' => $newId]);
    exit;
}

if ($action === 'admin_send') {
    $message = $_POST['message'] ?? '';
    $user_id = $_POST['user_id'] ?? 0;
    $target_ip = $_POST['ip_address'] ?? '';
    
    if (!$message) exit(json_encode(['success' => false]));

    $admin_id = $_SESSION['admin_id'] ?? 1; 
    $sender = 'admin';

    $stmt = db()->prepare("INSERT INTO messages (user_id, admin_id, sender, message, ip_address) VALUES (?, ?, ?, ?, ?)");
    $stmt->execute([$user_id, $admin_id, $sender, $message, $target_ip]);
    $newId = db()->lastInsertId();
    echo json_encode(['success' => true, 'id' => $newId]);
    exit;
}

if ($action === 'ping') {
    $user_id = $_SESSION['user_id'] ?? 0;
    $ip = getRealIP();
    $stmt = db()->prepare("INSERT INTO chat_visitors (user_id, ip_address) VALUES (?, ?) ON DUPLICATE KEY UPDATE last_ping = CURRENT_TIMESTAMP");
    $stmt->execute([$user_id, $ip]);
    echo json_encode(['success' => true]);
    exit;
}

if ($action === 'admin_get_all') {
    // Get distinct users/IPs who have messaged or pinged
    // Combine messages and visitors to show even those who haven't messaged yet
    $stmt = db()->query("
        SELECT 
            combined.user_id, 
            combined.ip_address, 
            COALESCE(m.message, '用户已进入聊天室') as message, 
            COALESCE(m.created_at, combined.last_activity) as created_at,
            u.username, 
            u.uid, 
            r.remark
        FROM (
            SELECT user_id, ip_address, MAX(created_at) as last_activity FROM messages GROUP BY user_id, ip_address
            UNION
            SELECT user_id, ip_address, last_ping as last_activity FROM chat_visitors
        ) combined
        LEFT JOIN (
            SELECT user_id, ip_address, message, created_at FROM messages WHERE id IN (SELECT MAX(id) FROM messages GROUP BY user_id, ip_address)
        ) m ON (combined.user_id = m.user_id AND combined.ip_address = m.ip_address)
        LEFT JOIN users u ON combined.user_id = u.id
        LEFT JOIN chat_remarks r ON (combined.user_id = r.user_id AND combined.ip_address = r.ip_address)
        WHERE combined.last_activity > DATE_SUB(NOW(), INTERVAL 24 HOUR)
        ORDER BY created_at DESC
    ");
    echo json_encode($stmt->fetchAll());
    exit;
}

if ($action === 'save_remark') {
    if (!isset($_SESSION['admin_id'])) exit(json_encode(['success' => false, 'error' => 'Unauthorized']));
    
    $user_id = $_POST['user_id'] ?? 0;
    $ip = $_POST['ip_address'] ?? '';
    $remark = $_POST['remark'] ?? '';
    
    $stmt = db()->prepare("INSERT INTO chat_remarks (user_id, ip_address, remark) VALUES (?, ?, ?) ON DUPLICATE KEY UPDATE remark = ?");
    $stmt->execute([$user_id, $ip, $remark, $remark]);
    
    echo json_encode(['success' => true]);
    exit;
}

if ($action === 'get_remark') {
    if (!isset($_SESSION['admin_id'])) exit(json_encode(['success' => false, 'error' => 'Unauthorized']));
    
    $user_id = $_GET['user_id'] ?? 0;
    $ip = $_GET['ip'] ?? '';
    
    $stmt = db()->prepare("SELECT remark FROM chat_remarks WHERE user_id = ? AND ip_address = ?");
    $stmt->execute([$user_id, $ip]);
    $remark = $stmt->fetchColumn() ?: '';
    
    echo json_encode(['success' => true, 'remark' => $remark]);
    exit;
}