using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.Core.Commands;

namespace Tango.PPC.Common.Navigation
{
    /// <summary>
    /// Represents the PPC views navigation manager.
    /// </summary>
    public interface INavigationManager
    {
        /// <summary>
        /// Occurs when the current view model has changed.
        /// </summary>
        event EventHandler<PPCViewModel> CurrentVMChanged;

        /// <summary>
        /// Gets the current module.
        /// </summary>
        IPPCModule CurrentModule { get; }

        /// <summary>
        /// Gets the current view model.
        /// </summary>
        PPCViewModel CurrentVM { get; }

        /// <summary>
        /// Gets a value indicating whether the navigation system is able to navigate to the previous view.
        /// </summary>
        bool CanNavigateBack { get; }

        /// <summary>
        /// Gets a value indicating whether the back should be enabled.
        /// </summary>
        bool IsBackEnabled { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether the navigation system is currently navigating.
        /// </summary>
        bool IsNavigating { get; set; }

        /// <summary>
        /// Navigates to the previous view if <see cref="CanNavigateBack"/> is true.
        /// </summary>
        Task<bool> NavigateBack();

        /// <summary>
        /// Navigates to the previous view..
        /// </summary>
        RelayCommand NavigateBackCommand { get; }

        /// <summary>
        /// Navigates to the specified full path in command parameter.
        /// </summary>
        RelayCommand<String> NavigateToCommand { get; }

        /// <summary>
        /// Navigates to the specified PPC view.
        /// </summary>
        /// <param name="view">The view.</param>
        Task<bool> NavigateTo(NavigationView view, bool pushToHistory = true);

        /// <summary>
        /// Navigates to the specified PPC view with the specified receive object.
        /// </summary>
        /// <param name="view">The view.</param>
        Task<bool> NavigateWithObject<TPass>(NavigationView view, TPass obj, bool pushToHistory = true);

        /// <summary>
        /// Navigates to the specified module.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        Task<bool> NavigateTo<T>(bool pushToHistory = true) where T : IPPCModule;

        /// <summary>
        /// Navigates to the specified module using the view path (e.g MainView.JobsView).
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="viewPath">The view path.</param>
        Task<bool> NavigateTo<T>(String viewPath, bool pushToHistory = true) where T : IPPCModule;

        /// <summary>
        /// Navigates to the specified module using the view path (e.g MainView,JobsView).
        /// This method makes it easy to do stuff like NavigateTo(nameof(MainView),nameof(JobsView));
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="viewPath">The view path.</param>
        Task<bool> NavigateTo<T>(bool pushToHistory = true, params String[] viewPath) where T : IPPCModule;

        /// <summary>
        /// Navigates to the specified module and view by full path (e.g Jobs.JobsView).
        /// </summary>
        /// <param name="fullPath">The full path.</param>
        Task<bool> NavigateTo(String fullPath, bool pushToHistory = true, Action<PPCViewModel, PPCViewModel> onNavigating = null, Action<PPCViewModel, PPCViewModel> onNavigated = null);

        /// <summary>
        /// Navigates to the specified module and view with the specified object and expecting a return parameter.
        /// The view must be of type INavigationResultProvider<TResult>.
        /// </summary>
        /// <param name="fullPath">The full path.</param>
        Task<TResult> NavigateForResult<TModule, TView, TResult, TPass>(TPass obj, bool pushToHistory = true)
            where TModule : IPPCModule;

        /// <summary>
        /// Navigates to the specified module and view with the specified object.
        /// </summary>
        /// <typeparam name="TModule">The type of the module.</typeparam>
        /// <typeparam name="TView">The type of the view.</typeparam>
        /// <typeparam name="TPass">The type of the pass.</typeparam>
        /// <param name="obj">The object.</param>
        /// <param name="pushToHistory">if set to <c>true</c> [push to history].</param>
        /// <returns></returns>
        Task<bool> NavigateWithObject<TModule, TView, TPass>(TPass obj, bool pushToHistory = true)
               where TModule : IPPCModule;

        /// <summary>
        /// Clears the navigation back history.
        /// </summary>
        void ClearHistory();

        /// <summary>
        /// Clears the navigation back history except the specified view type.
        /// </summary>
        void ClearHistoryExcept<T>();
    }
}