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.Logging;
using Tango.PPC.Common;
using Tango.PPC.Technician.Dialogs;

namespace Tango.PPC.Technician.ViewModels
{
    public class LoggingViewVM : PPCViewModel
    {
        private const int MAX_LOGS = 1000;
        private List<LogItemBase> paused_logs;

        public SynchronizedObservableCollection<LogItemBase> ApplicationLogs { get; set; }

        public SynchronizedObservableCollection<LogItemBase> EmbeddedLogs { get; set; }

        private LogItemBase _selectedLog;
        public LogItemBase SelectedLog
        {
            get { return _selectedLog; }
            set { _selectedLog = value; RaisePropertyChangedAuto(); OnSelectedLogChanged(); }
        }

        private ICollectionView _applicationLogsViewSource;
        public ICollectionView ApplicationLogsViewSource
        {
            get { return _applicationLogsViewSource; }
            set { _applicationLogsViewSource = value; RaisePropertyChangedAuto(); }
        }

        private String _filter;
        public String Filter
        {
            get { return _filter; }
            set
            {
                _filter = value;
                RaisePropertyChangedAuto();
                ApplicationLogsViewSource.Refresh();
            }
        }

        private bool _isPaused;
        public bool IsPaused
        {
            get { return _isPaused; }
            set { _isPaused = value; RaisePropertyChangedAuto(); OnIsPausedChanged(); }
        }

        public RelayCommand ClearCommand { get; set; }

        public LoggingViewVM()
        {
            ApplicationLogs = new SynchronizedObservableCollection<LogItemBase>();
            EmbeddedLogs = new SynchronizedObservableCollection<LogItemBase>();
            ApplicationLogsViewSource = CollectionViewSource.GetDefaultView(ApplicationLogs);
            paused_logs = new List<LogItemBase>();
            LogManager.NewLog += LogManager_NewLog;
            ClearCommand = new RelayCommand(ClearLogs);

            Filter = "error";

            ApplicationLogsViewSource.Filter = (x) =>
            {
                try
                {
                    LogItemBase log = x as LogItemBase;
                    return String.IsNullOrWhiteSpace(Filter) || log.Category.ToString().ToLower().Contains(Filter.ToLower()) || log.Message.ToLower().Contains(Filter.ToLower());
                }
                catch
                {
                    return false;
                }
            };
        }

        private void OnIsPausedChanged()
        {
            foreach (var log in paused_logs)
            {
                LogManager_NewLog(this, log);
            }

            paused_logs.Clear();
        }

        private void LogManager_NewLog(object sender, LogItemBase log)
        {
            if (!IsPaused)
            {
                InvokeUI(() =>
                {
                    ApplicationLogs.Insert(0, log);

                    try
                    {
                        if (ApplicationLogs.Count > MAX_LOGS)
                        {
                            ApplicationLogs.Remove(ApplicationLogs.Last());
                        }
                    }
                    catch
                    {
                        //I don't know if this will cause an exception but I'm tired.
                    }
                });
            }
            else
            {
                paused_logs.Add(log);
            }
        }

        private void ClearLogs()
        {
            ApplicationLogs.Clear();
            paused_logs.Clear();
        }

        private async void OnSelectedLogChanged()
        {
            if (SelectedLog != null)
            {
                await NotificationProvider.ShowDialog<LogItemDetailsViewVM>(new LogItemDetailsViewVM()
                {
                    Log = SelectedLog,
                });

                SelectedLog = null;
            }
        }

        public override void OnApplicationStarted()
        {

        }
    }
}