using System;
using System.ComponentModel;
using System.Windows;
using Microsoft.Extensions.DependencyInjection;
using Pf2e.Scrapper.Helpers;
using Pf2e.Scrapper.Processors;
using Pf2e.Scrapper.Processors.Collection;
using Pf2e.Scrapper.WPF.EntityViewer;
using Pf2e.Scrapper.WPF.ProgressForm;
using Pf2e.Scrapper.WPF.StartForm;
using Pf2e.Database;
using Slugify;

namespace Pf2e.Scrapper;

internal sealed class ImportApplication : Application
{
    public ImportApplication(
        IServiceProvider serviceProvider,
        ApplicationSettings settings,
        ProcessorCollection processors
    )
    {
        ServiceProvider = serviceProvider;
        Settings = settings;
        Processors = processors;

        CurrentStage = ApplicationStage.InitialSettings;
        //CurrentStage = ApplicationStage.Viewer;
    }

    #region "Поля"

    /// <summary>
    /// Текущий этап выполнения программы.
    /// </summary>
    public ApplicationStage CurrentStage
    {
        get => _currentStage;
        set
        {
            ApplicationStage oldValue = _currentStage;
            _currentStage = value;

            CloseStage(oldValue);
            StartStage(_currentStage);
        }
    }
    private ApplicationStage _currentStage = ApplicationStage.BootUp;

    #endregion

    #region "Жизненный цикл"

    private StartForm? _startFormWpf;

    private ProgressForm? _progressFormWpf;

    private EntityForm? _entityForm;

    private Window? CurrentWpfForm { get; set; }

    public delegate void ApplicationStateChangeDelegate(object sender, ApplicationStage nextStage);

    private void StartStage(ApplicationStage stage)
    {
        switch (stage)
        {
            case ApplicationStage.BootUp:
                throw new(
                    $"{CurrentStage} никогда не должен быть установлен через поле \"CurrentStage\"."
                );

            case ApplicationStage.InitialSettings:
                _startFormWpf = ActivatorUtilities.CreateInstance<StartForm>(ServiceProvider);
                _startFormWpf.WindowStartupLocation = WindowStartupLocation.CenterScreen;
                _startFormWpf.Closing += Wpf_HandleFormClosing;
                _startFormWpf.ApplicationStateChange += ApplicationStateChange;
                _startFormWpf.Show();

                CurrentWpfForm = _startFormWpf;
                break;

            case ApplicationStage.ImportProcess:
                ProcessorExecutor executor = ActivatorUtilities.CreateInstance<ProcessorExecutor>(
                    ServiceProvider
                );

                _progressFormWpf = ActivatorUtilities.CreateInstance<ProgressForm>(ServiceProvider);
                _progressFormWpf.WindowStartupLocation = WindowStartupLocation.CenterScreen;
                _progressFormWpf.Closing += Wpf_HandleFormClosing;
                _progressFormWpf.ApplicationStateChange += ApplicationStateChange;
                _progressFormWpf.Show();

                CurrentWpfForm = _progressFormWpf;

                executor.Start();
                break;

            case ApplicationStage.Viewer:
                _entityForm = ActivatorUtilities.CreateInstance<EntityForm>(ServiceProvider);
                _entityForm.WindowStartupLocation = WindowStartupLocation.CenterScreen;
                _entityForm.Closing += Wpf_HandleFormClosing;
                _entityForm.ApplicationStateChange += ApplicationStateChange;
                _entityForm.Show();

                CurrentWpfForm = _entityForm;
                break;

            default:
                throw new ArgumentOutOfRangeException();
        }
    }

    private void CloseStage(ApplicationStage stage)
    {
        CurrentWpfForm = null;

        switch (stage)
        {
            case ApplicationStage.BootUp:
                // Нечего закрывать
                break;

            case ApplicationStage.InitialSettings:
                _startFormWpf!.Hide();
                _startFormWpf!.Close();
                _startFormWpf = null;
                break;

            case ApplicationStage.ImportProcess:
                _progressFormWpf!.Hide();
                _progressFormWpf!.Close();
                _progressFormWpf = null;
                break;

            case ApplicationStage.Viewer:
                _entityForm!.Hide();
                _entityForm!.Close();
                _entityForm = null;
                break;

            default:
                throw new ArgumentOutOfRangeException(nameof(stage));
        }
    }

    #endregion

    #region "События"

    public void ApplicationStateChange(object sender, ApplicationStage nextStage)
    {
        if (sender?.Equals(CurrentWpfForm) ?? false)
        {
            CurrentStage = nextStage;
        }
    }

    private void Wpf_HandleFormClosing(object? sender, CancelEventArgs e)
    {
        if (sender?.Equals(CurrentWpfForm) ?? false)
        {
            Shutdown();
        }
        else
        {
            e.Cancel = true;
        }
    }
    #endregion

    #region "Внедрение зависимостей"

    public IServiceProvider ServiceProvider { get; }
    public ApplicationSettings Settings { get; }
    public ProcessorCollection Processors { get; }

    public static void RegisterServices(IServiceCollection services)
    {
        // Контекст базы данных
        services.AddEntityFrameworkNpgsql();

        services.AddDbContext<Pf2eDbContext>();
        //services.AddDbContextPool<Pf2eDbContext>(options =>
        //{
        //    options.Us
        //});

        // Основная программа
        services.AddSingleton<ImportApplication>();

        // Настройки программы
        services.AddSingleton<ApplicationSettings>();

        // Набор процессоров
        services.AddSingleton<ProcessorCollection>();

        // Помощник идентификации базы данных
        services.AddSingleton<DatabaseHelper>();

        // Помощник создание URL-совместимых названий
        services.AddTransient<SlugHelper>();

        // Счётчик прогресса
        services.AddSingleton<ProcessProgress>();
    }

    #endregion
}

internal enum ApplicationStage
{
    BootUp,
    InitialSettings,
    ImportProcess,
    Viewer,
    Rules,
}