using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;
using ZXing;
using Microsoft.Win32;

/*
 * Copyright (c) 2014 Brad Greco <brad@bgreco.net>
 */
namespace QuickQR
{
    public partial class QRForm : Form
    {
        const int WM_HOTKEY = 786;

        private BarcodeWriter writer;
        private KeyBinding keyBinding;
        private String currentText;
        private Settings settings;

        [DllImport("user32.dll")]
        private static extern int RegisterHotKey(IntPtr hwnd, int id, int fsModifiers, int vk);
        [DllImport("user32.dll")]
        private static extern int UnregisterHotKey(IntPtr hwnd, int id);

        public QRForm()
        {
            InitializeComponent();
        }

        private void QRForm_Load(object sender, EventArgs e)
        {
            settings = new Settings();
            loadSettings();
            registerHotkey(keyBinding);
            writer = new BarcodeWriter { Format = BarcodeFormat.QR_CODE };
            writer.Options.Margin = 2;
            fileHide.ShortcutKeyDisplayString = "Esc";
            reset();
            notifyIcon.Icon = new System.Drawing.Icon(this.Icon, 16, 16);
        }

        private void notifyIcon_DoubleClick(object sender, EventArgs e)
        {
            this.Show();
            this.Activate();
            generateFromClipboard();
        }

        private void generateFromClipboard()
        {
            if (Clipboard.ContainsText())
            {
                inputTextBox.Text = Clipboard.GetText();
                generate(Clipboard.GetText());
            }
            else
            {
                reset();
            }
        }

        private void generateFromTextBox()
        {
            if (inputTextBox.Text.Length > 0)
                generate(inputTextBox.Text);
            else
                reset();
        }

        private void generate(String text)
        {
            System.Diagnostics.Debug.WriteLine("Generating: " + text);
            currentText = text;
            draw();
        }

        private void draw()
        {
            writer.Options.Width = QRImage.Width;
            writer.Options.Height = QRImage.Height;
            try
            {
                QRImage.Image = writer.Write(currentText);
            }
            catch (Exception e)
            {
                System.Diagnostics.Debug.WriteLine(e.Message);
                showError(e.Message);
                return;
            }
            finally
            {
                inputTextBox.SelectAll();
                inputTextBox.Focus();
            }
            if (QRLabel.ForeColor != Color.Black)
                QRLabel.ForeColor = Color.Black;
            QRLabel.Text = currentText;
            fileSaveAs.Enabled = true;
            QRImage.ContextMenuStrip = imageMenu;
        }

        private void registerHotkey(KeyBinding hotkey)
        {
            settings.setHotkey(hotkey);
            unregisterHotkey();
            if (hotkey.key > 0)
                RegisterHotKey(this.Handle, hotkey.getID(), hotkey.sum(), hotkey.key);
            keyBinding = hotkey;
        }

        private void unregisterHotkey()
        {
            if (keyBinding.key > 0)
                UnregisterHotKey(this.Handle, keyBinding.getID());
        }

        private void showHotkeyForm()
        {
            unregisterHotkey();
            SetHotkey form = new SetHotkey(keyBinding);
            if (form.ShowDialog() == DialogResult.OK)
                registerHotkey(form.keyBinding);
            form.Dispose();
        }

        private void loadSettings()
        {
            optionWinStart.Checked = menuAutorun.Checked = settings.autostart;
            optionBackground.Checked = settings.background;
            keyBinding = new KeyBinding(settings.hotkey);
            registerAutostart();
        }

        private void registerAutostart()
        {
            RegistryKey key = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);
            if (settings.autostart)
                key.SetValue("QuickQR", Application.ExecutablePath.ToString());
            else
                key.DeleteValue("QuickQR", false);
        }

        private void showError(String message)
        {
            QRLabel.ForeColor = Color.Red;
            QRLabel.Text = message;
        }

        private void reset()
        {
            inputTextBox.Text = string.Empty;
            QRImage.Image = null;
            QRLabel.Text = String.Empty;
            inputTextBox.Focus();
            currentText = string.Empty;
            fileSaveAs.Enabled = false;
            QRImage.ContextMenuStrip = null;
        }

        private void toggleBackground()
        {
            settings.setBackground(!settings.background);
            optionBackground.Checked = settings.background;
        }

        private void toggleAutorun()
        {
            settings.setAutostart(!settings.autostart);
            optionWinStart.Checked = menuAutorun.Checked = settings.autostart;
            registerAutostart();
        }

        private void saveImage()
        {
            SaveFileDialog dialog = new SaveFileDialog();
            dialog.DefaultExt = "png";
            dialog.Filter = "PNG images (*.png)|*.png|All files (*.*)|*.*";
            String fileName = currentText;
            foreach (char c in Path.GetInvalidFileNameChars())
            {
                fileName = fileName.Replace(c.ToString(), "");
            }
            dialog.FileName = fileName;
            if (dialog.ShowDialog() == DialogResult.OK)
            {
                QRImage.Image.Save(dialog.FileName, ImageFormat.Png);
            }
            dialog.Dispose();
        }

        [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")]
        protected override void WndProc(ref Message m)
        {
            // Listen for operating system messages.
            switch (m.Msg)
            {
                case WM_HOTKEY:
                    System.Diagnostics.Debug.WriteLine(m.WParam.ToString());
                    if (m.WParam.ToInt32() == keyBinding.getID())
                    {
                        System.Diagnostics.Debug.WriteLine("Our hotkey received");
                        this.Show();
                        this.Activate();
                        generateFromClipboard();
                    }
                    break;
            }
            base.WndProc(ref m);
        }

        protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (keyData == Keys.Escape)
            {
                if (settings.background)
                    this.Hide();
                else
                    Application.Exit();
                return true;
            }
            return base.ProcessCmdKey(ref msg, keyData);
        }

        private void QRForm_Resize(object sender, EventArgs e)
        {
            if (currentText != string.Empty)
                draw();
        }

        private void inputTextBox_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter)
                generateFromTextBox();
        }

        private void generateButton_Click(object sender, EventArgs e)
        {
            generateFromTextBox();
        }

        private void fileHide_Click(object sender, EventArgs e)
        {
            this.Hide();
        }

        private void fileExit_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void menuGenerateClipboard_Click(object sender, EventArgs e)
        {
            this.Show();
            generateFromClipboard();
        }

        private void menuNew_Click(object sender, EventArgs e)
        {
            this.Show();
            reset();
        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void QRForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("Reason: " + e.CloseReason);
            if (settings.background && (e.CloseReason == CloseReason.None || e.CloseReason == CloseReason.UserClosing))
            {
                this.Hide();
                e.Cancel = true;
            }
        }

        private void optionHotkey_Click(object sender, EventArgs e)
        {
            showHotkeyForm();
        }

        private void menuAutorun_Click(object sender, EventArgs e)
        {
            toggleAutorun();
        }

        private void menuHotkey_Click(object sender, EventArgs e)
        {
            showHotkeyForm();
        }

        private void optionWinStart_Click(object sender, EventArgs e)
        {
            toggleAutorun();
        }

        private void optionBackground_Click(object sender, EventArgs e)
        {
            toggleBackground();
        }

        private void imageCopy_Click(object sender, EventArgs e)
        {
            Clipboard.SetImage(QRImage.Image);
        }

        private void fileSaveAs_Click(object sender, EventArgs e)
        {
            saveImage();
        }

        private void imageSaveAs_Click(object sender, EventArgs e)
        {
            saveImage();
        }

        private void helpAbout_Click(object sender, EventArgs e)
        {
            AboutForm form = new AboutForm();
            form.ShowDialog();
            form.Dispose();
        }
    }
}