#region Usings
using System;
using System.Runtime.InteropServices;

#endregion

namespace Utilities.Web.WebBrowserHelper
{
    /// <summary>
    /// Class for clearing the cache
    /// </summary>
    public static class WebBrowserHelper
    {
        #region Definitions/DLL Imports
        /// <summary>
        /// For PInvoke Contains information about an entry in the Internet cache
        /// </summary>
        [StructLayout(LayoutKind.Explicit, Size = 80)]
        public struct INTERNET_CACHE_ENTRY_INFOA
        {
            [FieldOffset(0)]
            public uint dwStructSize;
            [FieldOffset(4)]
            public IntPtr lpszSourceUrlName;
            [FieldOffset(8)]
            public IntPtr lpszLocalFileName;
            [FieldOffset(12)]
            public uint CacheEntryType;
            [FieldOffset(16)]
            public uint dwUseCount;
            [FieldOffset(20)]
            public uint dwHitRate;
            [FieldOffset(24)]
            public uint dwSizeLow;
            [FieldOffset(28)]
            public uint dwSizeHigh;
            [FieldOffset(32)]
            public System.Runtime.InteropServices.ComTypes.FILETIME LastModifiedTime;
            [FieldOffset(40)]
            public System.Runtime.InteropServices.ComTypes.FILETIME ExpireTime;
            [FieldOffset(48)]
            public System.Runtime.InteropServices.ComTypes.FILETIME LastAccessTime;
            [FieldOffset(56)]
            public System.Runtime.InteropServices.ComTypes.FILETIME LastSyncTime;
            [FieldOffset(64)]
            public IntPtr lpHeaderInfo;
            [FieldOffset(68)]
            public uint dwHeaderInfoSize;
            [FieldOffset(72)]
            public IntPtr lpszFileExtension;
            [FieldOffset(76)]
            public uint dwReserved;
            [FieldOffset(76)]
            public uint dwExemptDelta;
        }

        // 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.LPTStr)] 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);
        #endregion

        #region Public Static Functions

        public static void Main()
        {
            ClearCache();
        }

        /// <summary>
        /// Clears the cache of the web browser
        /// </summary>
        public static void ClearCache()
        {

            try
            {

                // No more items have been found.
                const int ERROR_NO_MORE_ITEMS = 259;

                // Local variables
                int cacheEntryInfoBufferSizeInitial = 0;
                int cacheEntryInfoBufferSize = 0;
                IntPtr cacheEntryInfoBuffer = IntPtr.Zero;
                INTERNET_CACHE_ENTRY_INFOA internetCacheEntry;
                IntPtr enumHandle = IntPtr.Zero;
                bool returnValue = false;

                // Start to delete URLs that do not belong to any group.
                enumHandle = FindFirstUrlCacheEntry(null, IntPtr.Zero, ref cacheEntryInfoBufferSizeInitial);
                if (enumHandle == IntPtr.Zero && ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error())
                    return;

                cacheEntryInfoBufferSize = cacheEntryInfoBufferSizeInitial;
                cacheEntryInfoBuffer = Marshal.AllocHGlobal(cacheEntryInfoBufferSize);
                enumHandle = FindFirstUrlCacheEntry(null, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);

                while (true)
                {
                    internetCacheEntry = (INTERNET_CACHE_ENTRY_INFOA)Marshal.PtrToStructure(cacheEntryInfoBuffer, typeof(INTERNET_CACHE_ENTRY_INFOA));

                    string sourceUrlName = Marshal.PtrToStringAnsi(internetCacheEntry.lpszSourceUrlName);
                    cacheEntryInfoBufferSizeInitial = cacheEntryInfoBufferSize;

                    if ((sourceUrlName.Contains("instagram.com") || sourceUrlName.Contains("facebook.com")) && sourceUrlName.ToLower().Contains("cookie"))
                    {
                        DeleteUrlCacheEntry(internetCacheEntry.lpszSourceUrlName);
                    }

                    returnValue = FindNextUrlCacheEntry(enumHandle, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);

                    if (!returnValue && ERROR_NO_MORE_ITEMS == Marshal.GetLastWin32Error())
                    {
                        break;
                    }
                    if (!returnValue && cacheEntryInfoBufferSizeInitial > cacheEntryInfoBufferSize)
                    {
                        cacheEntryInfoBufferSize = cacheEntryInfoBufferSizeInitial;
                        cacheEntryInfoBuffer = Marshal.ReAllocHGlobal(cacheEntryInfoBuffer, (IntPtr)cacheEntryInfoBufferSize);
                        returnValue = FindNextUrlCacheEntry(enumHandle, cacheEntryInfoBuffer, ref cacheEntryInfoBufferSizeInitial);
                    }
                }
                Marshal.FreeHGlobal(cacheEntryInfoBuffer);


            }
            catch
            {

                // error
            }

        }
        #endregion
    }
}