using System;
using System.Windows.Forms;
using nsoftware.SecureBlackbox;

/// <summary>
/// Summary description for SignForm.
/// </summary>
public class DecryptPropsForm : System.Windows.Forms.Form
{
    private System.Windows.Forms.Button btnCancel;
    private System.Windows.Forms.Button btnOK;
    private System.Windows.Forms.OpenFileDialog dlgOpen;
    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.Container components = null;
    private GroupBox gbGeneralEnc;
    private GroupBox gbKeyInfo;
    private Label lbCertificate;
    private Button btnBrowseCert;
    private TextBox edCertPassword;
    private TextBox edCert;
    private Label lbCertPassword;
    private TextBox edPassphrase;
    private Label lbPassphrase;
    private Label label1;
    private TextBox textInfo;
    private XMLDecryptor decryptor = null;

    public DecryptPropsForm(XMLDecryptor _decryptor)
    {
        //
        // Required for Windows Form Designer support
        //
        InitializeComponent();

        //
        // TODO: Add any constructor code after InitializeComponent call
        //
        decryptor = _decryptor;

        String t = "";
        if (_decryptor.UseGCM)
            t = "-GCM";
        String s = "Encryption method: " + _decryptor.EncryptionMethod + t + Environment.NewLine;

        if (_decryptor.EncryptedDataType == XMLDecryptorEncryptedDataTypes.cxedtElement)
            t = "Element";
        else if (_decryptor.EncryptedDataType == XMLDecryptorEncryptedDataTypes.cxedtContent)
            t = "Content";
        else
            t = "External";
        s = s + "Encrypted data type: " + t + Environment.NewLine;

        bool certRequired = false;

        if (_decryptor.EncryptKey)
        {
            s = s + "EncryptKey: true" + Environment.NewLine;
            if (_decryptor.KeyEncryptionType == XMLDecryptorKeyEncryptionTypes.cxetKeyTransport)
            {
                s = s + "Key encryption type: transport" + Environment.NewLine;
                if (_decryptor.KeyTransportMethod == XMLDecryptorKeyTransportMethods.cxktRSA15)
                    t = "RSA v1.5";
                else
                    t = "RSA-OAEP";

                s = s + "Key transport method: " + t + Environment.NewLine;
                certRequired = true;
            }
            else
            {
                s = s + "Key encryption type: wrap" + Environment.NewLine;
                s = s + "Key wrap method: " + _decryptor.KeyWrapMethod + Environment.NewLine;
            }
        }
        else
            s = s + "EncryptKey: false" + Environment.NewLine;

        t = _decryptor.Config("KeyName");
        if (t.Length > 0)
            s = s + "Key name: " + t + Environment.NewLine;

        t = _decryptor.Config("MimeType");
        if (t.Length > 0)
            s = s + "Mime type: " + t + Environment.NewLine;

        textInfo.Text = s;

        edPassphrase.Enabled = !certRequired;
        lbPassphrase.Enabled = !certRequired;
        edCert.Enabled = certRequired;
        lbCertificate.Enabled = certRequired;
        edCertPassword.Enabled = certRequired;
        lbCertPassword.Enabled = certRequired;
        btnBrowseCert.Enabled = certRequired;
    }

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            if (components != null)
            {
                components.Dispose();
            }
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code
    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
            this.btnCancel = new System.Windows.Forms.Button();
            this.btnOK = new System.Windows.Forms.Button();
            this.dlgOpen = new System.Windows.Forms.OpenFileDialog();
            this.gbGeneralEnc = new System.Windows.Forms.GroupBox();
            this.textInfo = new System.Windows.Forms.TextBox();
            this.gbKeyInfo = new System.Windows.Forms.GroupBox();
            this.lbCertificate = new System.Windows.Forms.Label();
            this.btnBrowseCert = new System.Windows.Forms.Button();
            this.edCertPassword = new System.Windows.Forms.TextBox();
            this.edCert = new System.Windows.Forms.TextBox();
            this.lbCertPassword = new System.Windows.Forms.Label();
            this.edPassphrase = new System.Windows.Forms.TextBox();
            this.lbPassphrase = new System.Windows.Forms.Label();
            this.label1 = new System.Windows.Forms.Label();
            this.gbGeneralEnc.SuspendLayout();
            this.gbKeyInfo.SuspendLayout();
            this.SuspendLayout();
            // 
            // btnCancel
            // 
            this.btnCancel.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
            this.btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel;
            this.btnCancel.Location = new System.Drawing.Point(272, 329);
            this.btnCancel.Name = "btnCancel";
            this.btnCancel.Size = new System.Drawing.Size(75, 25);
            this.btnCancel.TabIndex = 7;
            this.btnCancel.Text = "Cancel";
            // 
            // btnOK
            // 
            this.btnOK.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
            this.btnOK.Location = new System.Drawing.Point(185, 329);
            this.btnOK.Name = "btnOK";
            this.btnOK.Size = new System.Drawing.Size(75, 25);
            this.btnOK.TabIndex = 6;
            this.btnOK.Text = "OK";
            this.btnOK.Click += new System.EventHandler(this.btnOK_Click);
            // 
            // gbGeneralEnc
            // 
            this.gbGeneralEnc.Controls.Add(this.textInfo);
            this.gbGeneralEnc.Controls.Add(this.gbKeyInfo);
            this.gbGeneralEnc.Location = new System.Drawing.Point(7, 55);
            this.gbGeneralEnc.Name = "gbGeneralEnc";
            this.gbGeneralEnc.Size = new System.Drawing.Size(340, 265);
            this.gbGeneralEnc.TabIndex = 18;
            this.gbGeneralEnc.TabStop = false;
            this.gbGeneralEnc.Text = "General";
            // 
            // textInfo
            // 
            this.textInfo.Location = new System.Drawing.Point(8, 16);
            this.textInfo.Multiline = true;
            this.textInfo.Name = "textInfo";
            this.textInfo.ScrollBars = System.Windows.Forms.ScrollBars.Both;
            this.textInfo.Size = new System.Drawing.Size(325, 83);
            this.textInfo.TabIndex = 19;
            // 
            // gbKeyInfo
            // 
            this.gbKeyInfo.Controls.Add(this.lbCertificate);
            this.gbKeyInfo.Controls.Add(this.btnBrowseCert);
            this.gbKeyInfo.Controls.Add(this.edCertPassword);
            this.gbKeyInfo.Controls.Add(this.edCert);
            this.gbKeyInfo.Controls.Add(this.lbCertPassword);
            this.gbKeyInfo.Controls.Add(this.edPassphrase);
            this.gbKeyInfo.Controls.Add(this.lbPassphrase);
            this.gbKeyInfo.Location = new System.Drawing.Point(8, 105);
            this.gbKeyInfo.Name = "gbKeyInfo";
            this.gbKeyInfo.Size = new System.Drawing.Size(325, 150);
            this.gbKeyInfo.TabIndex = 16;
            this.gbKeyInfo.TabStop = false;
            this.gbKeyInfo.Text = "Key/certificate properties  ";
            // 
            // lbCertificate
            // 
            this.lbCertificate.AutoSize = true;
            this.lbCertificate.Location = new System.Drawing.Point(7, 75);
            this.lbCertificate.Name = "lbCertificate";
            this.lbCertificate.Size = new System.Drawing.Size(109, 13);
            this.lbCertificate.TabIndex = 65;
            this.lbCertificate.Text = "Encryption certificate:";
            // 
            // btnBrowseCert
            // 
            this.btnBrowseCert.Location = new System.Drawing.Point(244, 89);
            this.btnBrowseCert.Name = "btnBrowseCert";
            this.btnBrowseCert.Size = new System.Drawing.Size(75, 25);
            this.btnBrowseCert.TabIndex = 64;
            this.btnBrowseCert.Text = "Browse ...";
            this.btnBrowseCert.Click += new System.EventHandler(this.btnBrowseCert_Click);
            // 
            // edCertPassword
            // 
            this.edCertPassword.Location = new System.Drawing.Point(118, 123);
            this.edCertPassword.Name = "edCertPassword";
            this.edCertPassword.PasswordChar = '*';
            this.edCertPassword.Size = new System.Drawing.Size(201, 20);
            this.edCertPassword.TabIndex = 63;
            // 
            // edCert
            // 
            this.edCert.Location = new System.Drawing.Point(10, 92);
            this.edCert.Name = "edCert";
            this.edCert.Size = new System.Drawing.Size(228, 20);
            this.edCert.TabIndex = 62;
            // 
            // lbCertPassword
            // 
            this.lbCertPassword.AutoSize = true;
            this.lbCertPassword.Location = new System.Drawing.Point(7, 126);
            this.lbCertPassword.Name = "lbCertPassword";
            this.lbCertPassword.Size = new System.Drawing.Size(105, 13);
            this.lbCertPassword.TabIndex = 61;
            this.lbCertPassword.Text = "Certificate password:";
            // 
            // edPassphrase
            // 
            this.edPassphrase.Location = new System.Drawing.Point(10, 41);
            this.edPassphrase.Name = "edPassphrase";
            this.edPassphrase.Size = new System.Drawing.Size(309, 20);
            this.edPassphrase.TabIndex = 1;
            // 
            // lbPassphrase
            // 
            this.lbPassphrase.AutoSize = true;
            this.lbPassphrase.Location = new System.Drawing.Point(7, 25);
            this.lbPassphrase.Name = "lbPassphrase";
            this.lbPassphrase.Size = new System.Drawing.Size(79, 13);
            this.lbPassphrase.TabIndex = 0;
            this.lbPassphrase.Text = "Key/Password:";
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.ForeColor = System.Drawing.SystemColors.Highlight;
            this.label1.Location = new System.Drawing.Point(4, 9);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(319, 39);
            this.label1.TabIndex = 22;
            this.label1.Text = "The XML document is encrypted. Depending on the document\'s \r\nencryption type you " +
    "would need to provide a decryption password \r\nor decryption certificate.";
            // 
            // DecryptPropsForm
            // 
            this.AcceptButton = this.btnOK;
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.CancelButton = this.btnCancel;
            this.ClientSize = new System.Drawing.Size(354, 361);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.gbGeneralEnc);
            this.Controls.Add(this.btnCancel);
            this.Controls.Add(this.btnOK);
            this.Cursor = System.Windows.Forms.Cursors.Default;
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
            this.MaximizeBox = false;
            this.Name = "DecryptPropsForm";
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterParent;
            this.Text = "Encryption properties";
            this.gbGeneralEnc.ResumeLayout(false);
            this.gbGeneralEnc.PerformLayout();
            this.gbKeyInfo.ResumeLayout(false);
            this.gbKeyInfo.PerformLayout();
            this.ResumeLayout(false);
            this.PerformLayout();

    }
    #endregion

    public Certificate LoadCertificate(string file, string password)
    {
        Certificate cert = null;

        if (file.Length > 0)
        {
            try
            {
                CertificateManager certmanager = new CertificateManager();

                certmanager.ImportFromFile(file, password);

                cert = certmanager.Certificate;
            }
            catch (Exception e)
            {
                MessageBox.Show("Cannot load certificate!");
            }
        }

        return cert;
    }

    private byte[] getKey(string algorithm)
    {
        int len = 0;

        if (algorithm.Equals("AES128", StringComparison.OrdinalIgnoreCase))
            len = 16;
        else if (algorithm.Equals("AES192", StringComparison.OrdinalIgnoreCase))
            len = 24;
        else if (algorithm.Equals("AES256", StringComparison.OrdinalIgnoreCase))
            len = 32;
        else if (algorithm.Equals("Camellia128", StringComparison.OrdinalIgnoreCase))
            len = 16;
        else if (algorithm.Equals("Camellia192", StringComparison.OrdinalIgnoreCase))
            len = 24;
        else if (algorithm.Equals("Camellia256", StringComparison.OrdinalIgnoreCase))
            len = 32;
        else if (algorithm.Equals("DES", StringComparison.OrdinalIgnoreCase))
            len = 8;
        else if (algorithm.Equals("3DES", StringComparison.OrdinalIgnoreCase))
            len = 24;
        else if (algorithm.Equals("RC4", StringComparison.OrdinalIgnoreCase))
            len = 16;
        else if (algorithm.Equals("SEED", StringComparison.OrdinalIgnoreCase))
            len = 16;

        // simple key derivation function from a Passphrase
        // TODO: replace with SHA256 hash or KDF
        string s = edPassphrase.Text;
        while (s.Length < len)
            s = s + "/" + edPassphrase.Text;

        byte[] res = new byte[len];
        for (int i = 0; i < len; i++)
            res[i] = (byte)s[i];

        return res;
    }

    private void btnBrowseCert_Click(object sender, EventArgs e)
    {
        dlgOpen.Title = "Select certificate file";
        dlgOpen.Filter = "PEM-encoded certificate (*.pem)|*.PEM|DER-encoded certificate (*.cer)|*.CER|PFX-encoded certificate (*.pfx)|*.PFX";
        if (dlgOpen.ShowDialog() == DialogResult.OK)
            edCert.Text = dlgOpen.FileName;
    }

    private void btnOK_Click(object sender, EventArgs e)
    {
        if (decryptor.EncryptKey)
        {
            if (decryptor.KeyEncryptionType == XMLDecryptorKeyEncryptionTypes.cxetKeyTransport)
            {
                try
                {
                    decryptor.KeyDecryptionCertificate = LoadCertificate(edCert.Text, edCertPassword.Text);
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
            else
            {
                decryptor.KeyDecryptionKey = getKey(decryptor.KeyWrapMethod);
            }
        }
        else
        {
            decryptor.DecryptionKey = getKey(decryptor.EncryptionMethod);
        }

        this.DialogResult = DialogResult.OK;
    }
}