//! \file       GarOperation.cs
//! \date       Fri Feb 03 19:06:52 2017
//! \brief      Base class for GARbro file operation.
//
// Copyright (C) 2017 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//

using System;
using System.IO;
using GARbro.GUI.Strings;

namespace GARbro.GUI
{
    internal class GarOperation
    {
        internal MainWindow             m_main;
        internal ProgressDialog         m_progress_dialog;
        internal Exception              m_pending_error;
        internal FileExistsDialogResult m_duplicate_action;
        internal string                 m_title;

        const int MaxRenameAttempts = 100;

        protected GarOperation (MainWindow parent, string dialog_title)
        {
            m_main = parent;
            m_title = dialog_title;
        }

        protected Stream CreateNewFile (string filename)
        {
            FileMode open_mode = FileMode.CreateNew;
            if (m_duplicate_action.ApplyToAll &&
                m_duplicate_action.Action == ExistingFileAction.Overwrite)
                open_mode = FileMode.Create;
            try
            {
                return File.Open (filename, open_mode);
            }
            catch (IOException) // file already exists?
            {
                if (!File.Exists (filename) || FileMode.Create == open_mode) // some unforseen I/O error, give up
                    throw;
            }
            if (!m_duplicate_action.ApplyToAll)
            {
                var msg_text = string.Format (guiStrings.TextFileAlreadyExists, Path.GetFileName (filename));
                m_duplicate_action = m_main.Dispatcher.Invoke (() => m_main.ShowFileExistsDialog (m_title, msg_text, m_progress_dialog.GetWindowHandle()));
            }
            switch (m_duplicate_action.Action)
            {
            default:
            case ExistingFileAction.Abort:
                throw new OperationCanceledException();
            case ExistingFileAction.Skip:
                throw new SkipExistingFileException();
            case ExistingFileAction.Rename:
                return CreateRenamedFile (filename);
            case ExistingFileAction.Overwrite:
                return File.Open (filename, FileMode.Create);
            }
        }

        /// <summary>
        /// Creates new file with specified filename, or, if it's already exists, tries to open
        /// files named "FILENAME.1.EXT", "FILENAME.2.EXT" and so on.
        /// <exception cref="System.IOException">Throws exception after 100th failed attempt.</exception>
        /// </summary>

        public static Stream CreateRenamedFile (string filename)
        {
            var ext = Path.GetExtension (filename);
            for (int attempt = 1; ; ++attempt)
            {
                var name = Path.ChangeExtension (filename, attempt.ToString()+ext);
                try
                {
                    return File.Open (name, FileMode.CreateNew);
                }
                catch (IOException) // file already exists
                {
                    if (MaxRenameAttempts == attempt) // limit number of attempts
                        throw;
                }
            }
        }

        protected FileErrorDialogResult ShowErrorDialog (string error_text)
        {
            return m_main.Dispatcher.Invoke (() => m_main.ShowErrorDialog (m_title, error_text, m_progress_dialog.GetWindowHandle()));
        }
    }

    internal class SkipExistingFileException : ApplicationException
    {
    }
}