using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Shapes;

namespace Signal_Generator
{
    public class ProcedureModel : ICommand, INotifyPropertyChanged
    {
        public DrawTask currentTask;
        Canvas targetCanvas;

        public ProcedureModel()
        {
        }

        public event EventHandler CanExecuteChanged;
        
        public void RaiseCanExecuteChanged()
        {
            CanExecuteChanged?.Invoke(this, new EventArgs());
        }

        private void RaiseCanExecuteChanged(object o, PropertyChangedEventArgs e)
        {
            Action a = () =>
            {
                RaiseCanExecuteChanged();
            };
            targetCanvas.Dispatcher.Invoke(a);
        }

        public bool CanExecute(object parameter)
        {
            if (parameter == null) return false;
            var parameters = parameter as object[];
            var btn = parameters[0] as Button;
            var ms = MultiSignal.getInstance();

            if ((ms == null) || (ms.count() == 0))
                return false;
            switch (btn.Name)
            {
                case "start_Button":
                    btn.Content = updateStartButtonContent();
                    return true;
                default:
                    btn.Content = updatePauseButtonContent().Item2;
                    if (!updatePauseButtonContent().Item1)
                        return false;
                    return true;
            }
        }

        private string updateStartButtonContent()
        {
            if (currentTask == null) return "Запустить";
            switch (currentTask.state)
            {
                case DrawTask.State.Created:
                    return "Запустить";
                case DrawTask.State.Running:
                    return "Завершить";
                case DrawTask.State.Paused:
                    goto case DrawTask.State.Running;
                default:
                    goto case DrawTask.State.Created;
            }
        }

        private Tuple<bool, string> updatePauseButtonContent()
        {
            if (currentTask == null) return new Tuple<bool, string>(false, "Пауза");
            switch (currentTask.state)
            {
                case DrawTask.State.Created:
                    return new Tuple<bool, string>(false, "Пауза");
                case DrawTask.State.Running:
                    return new Tuple<bool, string>(true, "Пауза");
                case DrawTask.State.Paused:
                    return new Tuple<bool, string>(true, "Возобновить");
                default:
                    goto case DrawTask.State.Created;
            }
        }

        public void Execute(object parameter)
        {
            var parameters = parameter as object[];
            var btn = parameters[0] as Button;
            targetCanvas = parameters[1] as Canvas;


            switch (btn.Name)
            {
                case "start_Button":
                    startOrCancelTask();
                    break;
                case "pause_Button":
                    pauseOrResumeTask();
                    break;
            }

        }

        private void startOrCancelTask ()
        {
            targetCanvas.Children.Clear();
            if (currentTask != null)
                switch (currentTask.state)
                {
                    case DrawTask.State.Paused:
                        goto case DrawTask.State.Running;
                    case DrawTask.State.Running:
                        currentTask.state = DrawTask.State.Canceled;
                        return;
                }
            Action newAction = () =>
            {
                currentTask.PropertyChanged += RaiseCanExecuteChanged;
                currentTask.buildTask(this, targetCanvas);
            };
            currentTask = new DrawTask(newAction);
            currentTask.Start();
        }

        private void pauseOrResumeTask()
        {
            switch (currentTask.state)
            {
                case DrawTask.State.Paused:
                    currentTask.state = DrawTask.State.Running;
                    break;
                case DrawTask.State.Running:
                    currentTask.state = DrawTask.State.Paused;
                    break;
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        private string currentAmplitude;
        public string CurrentAmplitude
        {
            get { return currentAmplitude; }
            set
            {
                currentAmplitude = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("CurrentAmplitude"));
            }
        }
        
        private string currentTime;
        public string CurrentTime
        {
            get { return currentTime; }
            set
            {
                currentTime = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("CurrentTime"));
            }
        }
    }
}