using System.Net;
using System.Runtime.InteropServices;
using System.Text;

namespace System
{
    internal class WinInet
    {
        // For PInvoke: Initiates the enumeration of the cache groups in the Internet cache
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindFirstUrlCacheGroup",
            CallingConvention = CallingConvention.StdCall)]
        public static extern IntPtr FindFirstUrlCacheGroup(
            int dwFlags,
            int dwFilter,
            IntPtr lpSearchCondition,
            int dwSearchCondition,
            ref long lpGroupId,
            IntPtr lpReserved);

        // For PInvoke: Retrieves the next cache group in a cache group enumeration
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindNextUrlCacheGroup",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool FindNextUrlCacheGroup(
            IntPtr hFind,
            ref long lpGroupId,
            IntPtr lpReserved);

        // For PInvoke: Releases the specified GROUPID and any associated state in the cache index file
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "DeleteUrlCacheGroup",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool DeleteUrlCacheGroup(
            long groupId,
            int dwFlags,
            IntPtr lpReserved);

        // For PInvoke: Begins the enumeration of the Internet cache
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindFirstUrlCacheEntryA",
            CallingConvention = CallingConvention.StdCall)]
        public static extern IntPtr FindFirstUrlCacheEntry(
            [MarshalAs(UnmanagedType.LPWStr)] string lpszUrlSearchPattern,
            IntPtr lpFirstCacheEntryInfo,
            ref int lpdwFirstCacheEntryInfoBufferSize);

        // For PInvoke: Retrieves the next entry in the Internet cache
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "FindNextUrlCacheEntryA",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool FindNextUrlCacheEntry(
            IntPtr hFind,
            IntPtr lpNextCacheEntryInfo,
            ref int lpdwNextCacheEntryInfoBufferSize);

        // For PInvoke: Removes the file that is associated with the source name from the cache, if the file exists
        [DllImport(@"wininet",
            SetLastError = true,
            CharSet = CharSet.Auto,
            EntryPoint = "DeleteUrlCacheEntryA",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool DeleteUrlCacheEntry(
            IntPtr lpszUrlName);

        [DllImport("wininet.dll",
            SetLastError = true,
CharSet = CharSet.Unicode,
            EntryPoint = "InternetGetCookieEx",
            CallingConvention = CallingConvention.StdCall)]
        public static extern bool InternetGetCookieEx(
            string url,
            string? cookieName,
            StringBuilder cookieData,
            ref int size,
            int dwFlags,
            IntPtr lpReserved);

        //Read HTTP Only
        const int InternetCookieHttponly = 0x2000;

        public static CookieContainer? GetUriCookieContainer(Uri uri)
        {
            // First, create a null cookie container
            CookieContainer? cookies = null;

            // Determine the size of the cookie
            var datasize = 8192 * 16;
            var cookieData = new StringBuilder(datasize);

            // Call InternetGetCookieEx from wininet.dll
            if (!InternetGetCookieEx(uri.ToString(), null, cookieData, ref datasize, InternetCookieHttponly, IntPtr.Zero))
            {
                if (datasize < 0)
                    return null;
                // Allocate stringbuilder large enough to hold the cookie
                cookieData = new StringBuilder(datasize);
                if (!InternetGetCookieEx(
                    uri.ToString(),
                    null, cookieData,
                    ref datasize,
                    InternetCookieHttponly,
                    IntPtr.Zero))
                    return null;
            }

            // If the cookie contains data, add it to the cookie container
            if (cookieData.Length > 0)
            {
                cookies = new CookieContainer();
                cookies.SetCookies(uri, cookieData.ToString().Replace(';', ','));
            }

            // Return the cookie container
            return cookies;
        }
    }
}