/*
    Copyright (C) 2014-2019 de4dot@gmail.com

    This file is part of dnSpy

    dnSpy 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 3 of the License, or
    (at your option) any later version.

    dnSpy 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 dnSpy.  If not, see <http://www.gnu.org/licenses/>.
*/

using System;
using System.ComponentModel.Composition;
using System.IO;
using System.Windows.Forms;

namespace dnSpy.Contracts.MVVM {
	/// <summary>
	/// Asks the user to pick a filename
	/// </summary>
	public interface IPickFilename {
		/// <summary>
		/// Lets the user pick a new filename. Returns null if the user didn't pick a new filename.
		/// </summary>
		/// <param name="currentFileName">Current filename or null</param>
		/// <param name="defaultExtension">Default extension. It must not contain a period. Eg. valid
		/// extensions are "exe" and "dll" but not ".exe"</param>
		/// <param name="filter">Filename filter or null</param>
		/// <returns></returns>
		string? GetFilename(string? currentFileName, string? defaultExtension, string? filter = null);

		/// <summary>
		/// Lets the user pick filenames. Returns an empty array if the user canceled the dialog box.
		/// </summary>
		/// <param name="currentFileName">Current filename or null</param>
		/// <param name="defaultExtension">Default extension. It must not contain a period. Eg. valid
		/// extensions are "exe" and "dll" but not ".exe"</param>
		/// <param name="filter">Filename filter or null</param>
		/// <returns></returns>
		string[] GetFilenames(string? currentFileName, string? defaultExtension, string? filter = null);
	}

	/// <summary>
	/// Implements <see cref="IPickFilename"/>
	/// </summary>
	[Export(typeof(IPickFilename))]
	public sealed class PickFilename : IPickFilename {
		/// <inheritdoc/>
		public string? GetFilename(string? currentFileName, string? defaultExtension, string? filter) {
			var dialog = new OpenFileDialog() {
				Filter = string.IsNullOrEmpty(filter) ? PickFilenameConstants.AnyFilenameFilter : filter,
				RestoreDirectory = true,
				DefaultExt = defaultExtension,
				ValidateNames = true,
			};
			if (File.Exists(currentFileName))
				dialog.InitialDirectory = Path.GetDirectoryName(currentFileName)!;

			if (dialog.ShowDialog() != DialogResult.OK)
				return null;

			return dialog.FileName;
		}

		/// <inheritdoc/>
		public string[] GetFilenames(string? currentFileName, string? defaultExtension, string? filter = null) {
			var dialog = new OpenFileDialog() {
				Filter = string.IsNullOrEmpty(filter) ? PickFilenameConstants.AnyFilenameFilter : filter,
				RestoreDirectory = true,
				DefaultExt = defaultExtension,
				ValidateNames = true,
				Multiselect = true,
			};
			if (File.Exists(currentFileName))
				dialog.InitialDirectory = Path.GetDirectoryName(currentFileName)!;

			if (dialog.ShowDialog() != DialogResult.OK)
				return Array.Empty<string>();

			return dialog.FileNames;
		}
	}
}