using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.IO.Compression;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace HexToFileConverter
{
    public partial class frmMain : Form
    {
        public frmMain()
        {
            InitializeComponent();
        }

        private void textBox1_TextChanged(object sender, EventArgs e) { }

        private void btnWriteToFile_Click(object sender, EventArgs e)
        {
            string fileHex = txtHexCode.Text;

			// Should refactor this to extract message box to single method.
            if (cmbFileType.Text == "Document")
            {
                string dialogueMessage = WriteDocumentToFile(fileHex);
                MessageBox.Show(dialogueMessage);
            }
            if (cmbFileType.Text == "Message")
            {
                string dialogueMessage = WriteMessageToFile(fileHex);
                MessageBox.Show(dialogueMessage);
            }
            if (cmbFileType.Text == "PDF")
            {
                string dialogueMessage = WriteHexToPDF(fileHex);
                MessageBox.Show(dialogueMessage);
            }
            if (cmbFileType.Text == "Image")
            {
                string dialogueMessage = WriteHexToJPG(fileHex);
                MessageBox.Show(dialogueMessage);
            }
            if (cmbFileType.Text != "Message" && cmbFileType.Text != "Document" && cmbFileType.Text != "PDF" && cmbFileType.Text != "Image")
            {
                MessageBox.Show("Please select a file type.");
            }
        }

        static string WriteDocumentToFile(string fileHex)
        {
            string fileName = DateTime.Now.ToString("dd-MM-yyyy-HH-mm-ss");
            byte[] fileBytes = HexStringToBytes(fileHex);

            // Write to .doc file
            File.WriteAllBytes(@"C:\\Users\\Public\\Documents\" + fileName + ".doc", fileBytes);
            return "File saved as " + fileName + ".doc";
        }

        static string WriteMessageToFile(string fileHex)
        {
            string fileName = DateTime.Now.ToString("dd-MM-yyyy-HH-mm-ss");
            byte[] fileBytes = HexStringToBytes(fileHex);

            // Write to .doc file
            File.WriteAllBytes(@"C:\\Users\\Public\\Documents\" + fileName + ".msg", fileBytes);
            return "File saved as " + fileName + ".msg";
        }

        static string WriteHexToPDF(string fileHex)
        {
            string fileName = DateTime.Now.ToString("dd-MM-yyyy-HH-mm-ss");

            // Remove "0x" prefix if present
            if (fileHex.StartsWith("0x"))
                fileHex = fileHex.Substring(2);

            // Convert hex to bytes
            byte[] pdfBytes = HexStringToPDF(fileHex);
            File.WriteAllBytes(@"C:\\Users\\Public\\Documents\" + fileName + ".pdf", pdfBytes);
            return "File saved as " + fileName + ".pdf";
        }

        static string WriteHexToJPG(string fileHex)
        {
            string fileName = DateTime.Now.ToString("dd-MM-yyyy-HH-mm-ss");
            byte[] fileBytes = HexStringToBytes(fileHex);

            // Write to .doc file
            File.WriteAllBytes(@"C:\\Users\\Public\\Documents\" + fileName + ".jpg", fileBytes);
            return "File saved as " + fileName + ".jpg";
        }

        static byte[] HexStringToBytes(string hex)
        {
            if (string.IsNullOrWhiteSpace(hex))
                throw new ArgumentException("Hex string is null or empty.");

            // Remove 0x prefix if present
            if (hex.StartsWith("0x", StringComparison.OrdinalIgnoreCase))
            hex = hex.Substring(2);

            // Remove whitespace, newlines, etc.
            hex = hex.Replace(" ", "").Replace("\n", "").Replace("\r", "");

            // If odd length, pad with a '0' at the end
            if (hex.Length % 2 != 0)
            {
                Console.WriteLine("Warning: Odd-length hex string detected. Padding with 0.");
                hex += "0";
            }

            int length = hex.Length;
            byte[] result = new byte[length / 2];

            for (int i = 0; i < length; i += 2)
            {
                result[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
            }
            return result;
        }

        static byte[] HexStringToPDF(string hex)
        {
            if (hex.StartsWith("<")) hex = hex.Substring(1);
            if (hex.EndsWith(">")) hex = hex.Substring(0, hex.Length - 1);

            byte[] bytes = new byte[hex.Length / 2];
            for (int i = 0; i < bytes.Length; i++)
                bytes[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);

            return bytes;
        }


        static byte[] HexStringToByteArray(string hex)
        {
            byte[] data = new byte[hex.Length / 2];
            for (int i = 0; i < data.Length; i++)
            {
                data[i] = Convert.ToByte(hex.Substring(i * 2, 2), 16);
            }
            return data;
        }

        public static string WriteToFile()
        {
            return "Success";
        }

        private void frmMain_Load(object sender, EventArgs e) { }
		
    }
}