using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;
using Tango.Core;
using Tango.Core.Commands;
using Tango.Core.DI;
using Tango.Core.Json;
using Tango.FSE.Common.FileSystem;
using Tango.Logging;
using Tango.PPC.Shared.Logs;
using Tango.SharedUI.Components;

namespace Tango.FSE.Common.Logging
{
    /// <summary>
    /// Represents a remote log file model.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <seealso cref="Tango.Core.ExtendedObject" />
    public class RemoteLogFileModel<T> : ExtendedObject where T : LogItemBase
    {
        private ILogFileParser<T> _parser;

        /// <summary>
        /// Occurs when the remote log file has downloaded successfully.
        /// </summary>
        public event EventHandler DownloadCompleted;

        [TangoInject]
        private ILoggingProvider LoggingProvider { get; set; }

        /// <summary>
        /// Gets or sets the remote log file.
        /// </summary>
        public RemoteLogFile RemoteLogFile { get; set; }

        /// <summary>
        /// Gets the duration of the remote log file.
        /// </summary>
        public TimeSpan Duration
        {
            get { return RemoteLogFile.DateModified - RemoteLogFile.DateCreated; }
        }

        private RemoteLogFileStatus _status;
        /// <summary>
        /// Gets or sets the remote log file status.
        /// </summary>
        public RemoteLogFileStatus Status
        {
            get { return _status; }
            set { _status = value; RaisePropertyChangedAuto(); }
        }

        private FileSystemHandler _handler;
        /// <summary>
        /// Gets or sets the remote log file download handler.
        /// </summary>
        public FileSystemHandler Handler
        {
            get { return _handler; }
            set { _handler = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets or sets the temporary file (where the actual log file is stored locally).
        /// </summary>
        public String TemporaryFile { get; set; }

        private ObservableCollection<T> _logItems;
        /// <summary>
        /// Gets or sets the log items.
        /// </summary>
        public ObservableCollection<T> LogItems
        {
            get { return _logItems; }
            set { _logItems = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets or sets the download command.
        /// </summary>
        public RelayCommand DownloadCommand { get; set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="RemoteLogFileModel{T}"/> class.
        /// </summary>
        /// <param name="parser">The parser.</param>
        public RemoteLogFileModel(ILogFileParser<T> parser)
        {
            TangoIOC.Default.Inject(this);
            _parser = parser;
            LogItems = new ObservableCollection<T>();
            DownloadCommand = new RelayCommand(DownloadLogFile);
        }

        /// <summary>
        /// Downloads the log file.
        /// </summary>
        public async void DownloadLogFile()
        {
            if (Status == RemoteLogFileStatus.None || Status == RemoteLogFileStatus.Failed)
            {
                Status = RemoteLogFileStatus.Downloading;
                String tempLogFile = TemporaryManager.CreateImaginaryFile(".log");
                Handler = await LoggingProvider.DownloadLogFile(RemoteLogFile, tempLogFile);
                Handler.StatusChanged += (x, status) =>
                {
                    if (status == FileSystemHandlerStatus.Completed)
                    {
                        TemporaryFile = tempLogFile;
                        LogItems = new ObservableCollection<T>(_parser.Parse(tempLogFile, RemoteLogFile.DateCreated.ToLocalTime()));
                        Status = RemoteLogFileStatus.Downloaded;
                        RemoteLogFile.DateModified = LogItems.Last().TimeStamp.ToUniversalTime();
                        RaisePropertyChanged(nameof(Duration));
                        DownloadCompleted?.Invoke(this, new EventArgs());
                    }
                    else if (status == FileSystemHandlerStatus.Failed)
                    {
                        Status = RemoteLogFileStatus.Failed;
                    }
                };
            }
        }
    }
}