/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2015 Thomas Braun, Jens Klingen, Robin Krom
 *
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using Greenshot.IniFile;
using Greenshot.Plugin;
using GreenshotPlugin.UnmanagedHelpers;
using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

namespace GreenshotPlugin.Core
{
    /// <summary>
    /// Description of PluginUtils.
    /// </summary>
    public static class PluginUtils
    {
        private static readonly CoreConfiguration conf = IniConfig.GetIniSection<CoreConfiguration>();
        private const string PATH_KEY = @"SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\";
        private static readonly IDictionary<string, Image> exeIconCache = new Dictionary<string, Image>();

        static PluginUtils()
        {
            conf.PropertyChanged += OnIconSizeChanged;
        }

        /// <summary>
        /// Simple global property to get the Greenshot host
        /// </summary>
        public static IGreenshotHost Host
        {
            get;
            set;
        }

        /// <summary>
        /// Clear icon cache
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void OnIconSizeChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == "IconSize")
            {
                List<Image> cachedImages = new List<Image>();
                lock (exeIconCache)
                {
                    foreach (string key in exeIconCache.Keys)
                    {
                        cachedImages.Add(exeIconCache[key]);
                    }
                    exeIconCache.Clear();
                }
                foreach (Image cachedImage in cachedImages)
                {
                    if (cachedImage != null)
                    {
                        cachedImage.Dispose();
                    }
                }
            }
        }

        /// <summary>
        /// Get the path of an executable
        /// </summary>
        /// <param name="exeName">e.g. cmd.exe</param>
        /// <returns>Path to file</returns>
        public static string GetExePath(string exeName)
        {
            using (RegistryKey key = Registry.LocalMachine.OpenSubKey(PATH_KEY + exeName, false))
            {
                if (key != null)
                {
                    // "" is the default key, which should point to the requested location
                    return (string)key.GetValue("");
                }
            }
            foreach (string pathEntry in (Environment.GetEnvironmentVariable("PATH") ?? "").Split(';'))
            {
                try
                {
                    string path = pathEntry.Trim();
                    if (!String.IsNullOrEmpty(path) && File.Exists(path = Path.Combine(path, exeName)))
                    {
                        return Path.GetFullPath(path);
                    }
                }
                catch (Exception)
                {
                    LOG.WarnFormat("Problem with path entry '{0}'.", pathEntry);
                }
            }
            return null;
        }

        /// <summary>
        /// Get icon for executable, from the cache
        /// </summary>
        /// <param name="path">path to the exe or dll</param>
        /// <param name="index">index of the icon</param>
        /// <returns>Bitmap with the icon or null if something happended</returns>
        public static Image GetCachedExeIcon(string path, int index)
        {
            string cacheKey = string.Format("{0}:{1}", path, index);
            Image returnValue;
            lock (exeIconCache)
            {
                if (!exeIconCache.TryGetValue(cacheKey, out returnValue))
                {
                    lock (exeIconCache)
                    {
                        if (!exeIconCache.TryGetValue(cacheKey, out returnValue))
                        {
                            returnValue = GetExeIcon(path, index);
                            if (returnValue != null)
                            {
                                exeIconCache.Add(cacheKey, returnValue);
                            }
                        }
                    }
                }
            }
            return returnValue;
        }

        /// <summary>
        /// Get icon for executable
        /// </summary>
        /// <param name="path">path to the exe or dll</param>
        /// <param name="index">index of the icon</param>
        /// <returns>Bitmap with the icon or null if something happended</returns>
        private static Bitmap GetExeIcon(string path, int index)
        {
            if (!File.Exists(path))
            {
                return null;
            }
            try
            {
                using (Icon appIcon = ImageHelper.ExtractAssociatedIcon(path, index, conf.UseLargeIcons))
                {
                    if (appIcon != null)
                    {
                        return appIcon.ToBitmap();
                    }
                }
                using (Icon appIcon = Shell32.GetFileIcon(path, conf.UseLargeIcons ? Shell32.IconSize.Large : Shell32.IconSize.Small, false))
                {
                    if (appIcon != null)
                    {
                        return appIcon.ToBitmap();
                    }
                }
            }
            catch (Exception exIcon)
            {
                LOG.Error("error retrieving icon: ", exIcon);
            }
            return null;
        }

        /// <summary>
        /// Helper method to add a MenuItem to the File MenuItem of an ImageEditor
        /// </summary>
        /// <param name="image">Image to display in the menu</param>
        /// <param name="text">Text to display in the menu</param>
        /// <param name="tag">The TAG value</param>
        /// <param name="shortcutKeys">Keys which can be used as shortcut</param>
        /// <param name="handler">The onclick handler</param>
        public static void AddToFileMenu(IImageEditor imageEditor, Image image, string text, object tag, Keys? shortcutKeys, EventHandler handler)
        {
            ToolStripMenuItem item = new ToolStripMenuItem();
            item.Image = image;
            item.Text = text;
            item.Tag = tag;
            if (shortcutKeys.HasValue)
            {
                item.ShortcutKeys = shortcutKeys.Value;
            }
            item.Click += handler;
            AddToFileMenu(imageEditor, item);
        }

        /// <summary>
        /// Helper method to add a MenuItem to the File MenuItem of an ImageEditor
        /// </summary>
        /// <param name="imageEditor"></param>
        /// <param name="item"></param>
        public static void AddToFileMenu(IImageEditor imageEditor, ToolStripMenuItem item)
        {
            ToolStripMenuItem toolStripMenuItem = imageEditor.GetFileMenuItem();
            bool added = false;
            for (int i = 0; i < toolStripMenuItem.DropDownItems.Count; i++)
            {
                if (toolStripMenuItem.DropDownItems[i].GetType() == typeof(ToolStripSeparator))
                {
                    toolStripMenuItem.DropDownItems.Insert(i, item);
                    added = true;
                    break;
                }
            }
            if (!added)
            {
                toolStripMenuItem.DropDownItems.Add(item);
            }
        }

        /// <summary>
        /// Helper method to add a MenuItem to the Plugin MenuItem of an ImageEditor
        /// </summary>
        /// <param name="imageEditor"></param>
        /// <param name="item"></param>
        public static void AddToPluginMenu(IImageEditor imageEditor, ToolStripMenuItem item)
        {
            ToolStripMenuItem toolStripMenuItem = imageEditor.GetPluginMenuItem();
            bool added = false;
            for (int i = 0; i < toolStripMenuItem.DropDownItems.Count; i++)
            {
                if (toolStripMenuItem.DropDownItems[i].GetType() == typeof(ToolStripSeparator))
                {
                    toolStripMenuItem.DropDownItems.Insert(i, item);
                    added = true;
                    break;
                }
            }
            if (!added)
            {
                toolStripMenuItem.DropDownItems.Add(item);
            }
        }

        /// <summary>
        /// Helper method to add a plugin MenuItem to the Greenshot context menu
        /// </summary>
        /// <param name="imageEditor"></param>
        /// <param name="item"></param>
        public static void AddToContextMenu(IGreenshotHost host, ToolStripMenuItem item)
        {
            // Here we can hang ourselves to the main context menu!
            ContextMenuStrip contextMenu = host.MainMenu;
            bool addedItem = false;

            // Try to find a separator, so we insert ourselves after it
            for (int i = 0; i < contextMenu.Items.Count; i++)
            {
                if (contextMenu.Items[i].GetType() == typeof(ToolStripSeparator))
                {
                    // Check if we need to add a new separator, which is done if the first found has a Tag with the value "PluginsAreAddedBefore"
                    if ("PluginsAreAddedBefore".Equals(contextMenu.Items[i].Tag))
                    {
                        ToolStripSeparator separator = new ToolStripSeparator();
                        separator.Tag = "PluginsAreAddedAfter";
                        separator.Size = new Size(305, 6);
                        contextMenu.Items.Insert(i, separator);
                    }
                    else if (!"PluginsAreAddedAfter".Equals(contextMenu.Items[i].Tag))
                    {
                        continue;
                    }
                    contextMenu.Items.Insert(i + 1, item);
                    addedItem = true;
                    break;
                }
            }
            // If we didn't insert the item, we just add it...
            if (!addedItem)
            {
                contextMenu.Items.Add(item);
            }
        }
    }
}