/*
 * Copyright (c) 2017 Samsung Electronics Co., Ltd
 *
 * Licensed under the Flora License, Version 1.1 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://floralicense.org/license/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace LibTVRefCommonPortable.Utils
{
    /// <summary>
    /// A class for file system control function.
    /// </summary>
    class FileSystemUtils
    {
        /// <summary>
        /// A instance of file system port layer
        /// </summary>
        private static IFileSystemAPIs fileSystemAPIs;

        /// <summary>
        /// A instance of FileSystemUtils
        /// </summary>
        private static readonly FileSystemUtils instance = new FileSystemUtils();

        /// <summary>
        /// A property of FileSystemUtils instance
        /// </summary>
        public static FileSystemUtils Instance
        {
            get
            {
                return instance;
            }
        }

        /// <summary>
        /// A unit test stub for FileSystemUtils
        /// </summary>
        private class TestStub : IFileSystemAPIs
        {
            /// <summary>
            /// A directory path which should be used for app data storing.
            /// </summary>
            public string AppDataStorage
            {
                get
                {
                    return "test_app_data_path/";
                }
            }

            /// <summary>
            /// A directory path which should be used for app resource storing.
            /// </summary>
            public string AppResourceStorage
            {
                get
                {
                    return "test_app_resource_path/";
                }
            }

            /// <summary>
            /// A directory path which should be used for sharing between apps.
            /// </summary>
            public string PlatformShareStorage
            {
                get
                {
                    return "test_platform_share_path/";
                }
            }

            /// <summary>
            /// A method closes the file.
            /// </summary>
            /// <param name="stream">A file descriptor</param>
            public void CloseFile(Stream stream)
            {
            }

            /// <summary>
            /// A method flushing the stream to write remains.
            /// </summary>
            /// <param name="stream">A file descriptor</param>
            public void Flush(Stream stream)
            {
            }

            /// <summary>
            /// A method checks if a file existence in the file system.
            /// </summary>
            /// <param name="filePath">A file path</param>
            /// <returns>An existence of the file</returns>
            public bool IsFileExist(string filePath)
            {
                return true;
            }

            /// <summary>
            /// A method checks if file is read to use.
            /// </summary>
            /// <param name="filePath">A file path</param>
            /// <returns>A status of ready</returns>
            public bool IsFileReady(string filePath)
            {
                return true;
            }

            /// <summary>
            /// A method opens a file on the given mode.
            /// </summary>
            /// <param name="filePath">A file path</param>
            /// <param name="mode">An opening mode</param>
            /// <returns>A file descriptor</returns>
            public Stream OpenFile(string filePath, UtilFileMode mode)
            {
                throw new NotImplementedException();
            }
        }

        /// <summary>
        /// A constructor
        /// </summary>
        private FileSystemUtils()
        {
            fileSystemAPIs = new TestStub();

            try
            {
                if (DependencyService.Get<IFileSystemAPIs>() != null)
                {
                    fileSystemAPIs = DependencyService.Get<IFileSystemAPIs>();
                }
            }
            catch (InvalidOperationException e)
            {
                DebuggingUtils.Err(e.Message);
            }
        }

        /// <summary>
        /// A directory path which should be used for app data storing.
        /// </summary>
        public string AppDataStorage
        {
            get
            {
                return fileSystemAPIs.AppDataStorage;
            }
        }

        /// <summary>
        /// A directory path which should be used for app resource storing.
        /// </summary>
        public string AppResourceStorage
        {
            get
            {
                return fileSystemAPIs.AppResourceStorage;
            }
        }

        /// <summary>
        /// A directory path which should be used for sharing between apps.
        /// </summary>
        public string PlatformShareStorage
        {
            get
            {
                return fileSystemAPIs.PlatformShareStorage;
            }
        }

        /// <summary>
        /// A method opens a file on the given mode.
        /// </summary>
        /// <param name="filePath">A file path</param>
        /// <param name="mode">An opening mode</param>
        /// <returns>A file descriptor</returns>
        public Stream OpenFile(string filePath, UtilFileMode mode)
        {
            return fileSystemAPIs.OpenFile(filePath, mode);
        }

        /// <summary>
        /// A method flushing the stream to write remains.
        /// </summary>
        /// <param name="stream">A file descriptor</param>
        public void Flush(Stream stream)
        {
            fileSystemAPIs.Flush(stream);
        }

        /// <summary>
        /// A method closes the file.
        /// </summary>
        /// <param name="stream">A file descriptor</param>
        public void CloseFile(Stream stream)
        {
            fileSystemAPIs.CloseFile(stream);
        }

        /// <summary>
        /// A method checks if a file existence in the file system.
        /// </summary>
        /// <param name="filePath">A file path</param>
        /// <returns>An existence of the file</returns>
        public bool IsFileExist(String filePath)
        {
            return fileSystemAPIs.IsFileExist(filePath);
        }

        /// <summary>
        /// A method checks if file is read to use.
        /// </summary>
        /// <param name="filePath">A file path</param>
        /// <returns>A status of ready</returns>
        public bool IsFileReady(String filePath)
        {
            return fileSystemAPIs.IsFileReady(filePath);
        }


    }
}