using System;
using System.IO;
using System.Text;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Security.Cryptography;

// The 'text' parameter will contain the text from the:
//   - Current Clipboard when run by HotKey
//   - History Item when run from the History Menu
// The returned string will be:
//   - Placed directly on the Clipboard
//   - Ignored by ClipboardFusion if it is 'null'
public static class ClipboardFusionHelper
{
    delegate byte[] ComputeHash(Stream s);

    private static uint[] crcTable =
    {
        0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
        0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
        0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
        0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
        0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
        0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
        0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
        0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
        0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
        0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
        0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
        0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
        0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
        0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
        0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
        0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
        0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
        0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
        0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
        0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
        0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
        0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
        0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
        0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
        0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
        0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
        0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
        0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
        0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
        0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
        0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
        0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
        0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
        0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
        0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
        0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
        0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
        0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
        0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
        0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
        0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
        0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
        0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
        0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
        0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
        0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
        0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
        0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
        0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
        0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
        0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
        0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
        0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
        0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
        0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
        0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
        0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
        0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
        0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
        0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
        0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
        0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
        0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
        0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
    };

    private static uint crc32(byte[] buf, int num, uint crc)
    {
        for (int i = 0; i < num; ++i)
        {
            crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >> 8);
        }
        return crc;
    }

    private static byte[] GetCRC32(Stream s)
    {
        byte[] array = new byte[4096];
        uint crc = 0xFFFFFFFF;
        int num = 0;
        do
        {
            num = s.Read(array, 0, 4096);
            if (num > 0)
            {
                crc = crc32(array, num, crc);
            }
        }
        while (num > 0);

        crc = crc ^ 0xFFFFFFFF;

        var res = BitConverter.GetBytes(crc);
        Array.Reverse(res);

        return res;
    }

    private static Dictionary<string, ComputeHash> map = new Dictionary<string, ComputeHash>()
    {
        { "MD5", MD5.Create().ComputeHash },
        { "SHA1", SHA1.Create().ComputeHash },
        { "SHA256", SHA256.Create().ComputeHash },
        { "SHA384", SHA384 .Create().ComputeHash },
        { "SHA512", SHA512.Create().ComputeHash },
        { "CRC32", GetCRC32 }
    };

    public static string ProcessText(string text)
    {
        // your code goes here
        if (Clipboard.ContainsFileDropList())
        {
            ComputeHash compute;
            string aloname = BFS.Dialog.GetUserInputListViewWithFilter("Choose a hash algorithm", new string[] { "MD5", "SHA1", "SHA256", "SHA384", "SHA512", "CRC32" });

            if (map.TryGetValue(aloname, out compute))
            {
                StringBuilder builder = new StringBuilder();

                foreach (string file in Clipboard.GetFileDropList())
                {
                    try
                    {
                        using (FileStream stream = File.OpenRead(file))
                        {
                            builder.Append("*" + Path.GetFileName(file) + " ");
                            byte[] hash = compute(stream);
                            for (int i = 0; i < hash.Length; i++)
                            {
                                builder.Append(hash[i].ToString("x2"));
                            }
                            builder.Append("\n");
                        }
                    }
                    catch (Exception ex)
                    {

                    }
                }

                if (builder.Length != 0)
                {
                    string copyAll = "Copy all the hash values above";
                    builder.Append(copyAll);
                    string res = BFS.Dialog.GetUserInputListViewWithFilter(aloname + " checksum: FileNames at left, checksums at right, you can copy a checksum to clipboard by clicking it!", builder.ToString().Split('\n'));

                    if (res == copyAll)
                    {
                        return builder.Replace("\n", Environment.NewLine).ToString().Substring(0, builder.Length - copyAll.Length);
                    }
                    else if (res != "")
                    {
                        return res.Split(' ')[1];
                    }
                }
            }


        }
        return null;
    }
}