PageLoader.razor

@using Microsoft.Extensions.Logging;
@inject ILogger<PageLoader> Logger;

@code {

    public Dictionary<string, string> PageStyles { get; set; } = new();
    public Dictionary<string, AppPage> Pages { get; set; } = new();
    private AppPage? autoLoadPage;
    private string? currentPage;
    private string? previousPage;
    private string? currentInnerPage;
    private string? previousInnerPage;

    public void Load(string identifier)
    {
        Load(identifier, false);
    }

    public void Load(string identifier, bool inner)
    {
        if (currentInnerPage != null && !inner)
        {
            PageStyles[currentInnerPage] = "";
        }
        string? page = inner ? currentInnerPage : currentPage;
        if (page != null)
        {
            if (Pages[identifier].PreviousAnimationOut != null)
            {
                if (!Pages[identifier].PreviousAnimationOut.Equals(AnimationType.NONE))
                {
                    PageStyles[page] = "display: block; animation-name: " + Pages[identifier].PreviousAnimationOut;
                }
            }
            else if(Pages[page].AnimationOut != null)
            {
                PageStyles[page] = "display: block; animation-name: " + Pages[page].AnimationOut;
            }
            if(!inner)
            {
                previousPage = currentPage;
            } else
            {
                previousInnerPage = currentInnerPage;
            }
        }
        Logger.LogInformation("Loading page: " + identifier + (inner ? " (Inner page)" : ""));
        PageStyles[identifier] = "display: block; animation-name: " + Pages[identifier].AnimationIn;
        if(!inner)
        {
            if (currentInnerPage != null)
            {
                PageStyles[currentInnerPage] = "";
            }
            if (previousInnerPage != null)
            {
                PageStyles[previousInnerPage] = "";
            }
            currentInnerPage = null;
            previousInnerPage = null;
            currentPage = identifier;
        } else
        {
            currentInnerPage = identifier;
        }
        StateHasChanged();
    }

    public void UnloadLatest()
    {
        if(currentPage == null || previousPage == null)
        {
            return;
        }
        if(Pages[currentPage].AnimationOut != null)
        {
            PageStyles[currentPage] = "display: block; animation-name: " + Pages[currentPage].AnimationOut;
        } else
        {
            PageStyles[currentPage] = "";
        }
        string temp = previousPage;
        previousPage = currentPage;
        currentPage = temp;
        StateHasChanged();
    }

    public void ExitInner()
    {
        if (currentInnerPage == null)
        {
            return;
        }
        if (Pages[currentInnerPage].AnimationOut != null)
        {
            PageStyles[currentInnerPage] = "display: block; animation-name: " + Pages[currentInnerPage].AnimationOut;
        }
        currentInnerPage = null;
        previousInnerPage = null;
        StateHasChanged();
    }

    public void UnloadLatestInner()
    {
        if (currentInnerPage == null || previousInnerPage == null)
        {
            return;
        }
        if (Pages[currentInnerPage].AnimationOut != null)
        {
            PageStyles[currentInnerPage] = "display: block; animation-name: " + Pages[currentInnerPage].AnimationOut;
        }
        else
        {
            PageStyles[currentInnerPage] = "";
        }
        string temp = previousInnerPage;
        previousInnerPage = currentInnerPage;
        currentInnerPage = temp;
        PageStyles[currentInnerPage] = "display: block;";
        StateHasChanged();
    }

    public void UnloadAll()
    {
        foreach (string key in PageStyles.Keys)
        {
            PageStyles[key] = "";
        }
        currentInnerPage = null;
        previousInnerPage = null;
        if (autoLoadPage != null)
        {
            Load(autoLoadPage.GetType().Name);
        } else
        {
            currentPage = null;
            previousPage = null;
        }
    }

    public void RegisterPage(AppPage page)
    {
        string identifier = page.GetType().Name;
        Pages[identifier] = page;
        PageStyles[identifier] = "";
        if (page.AutoLoad)
        {
            Load(identifier);
            autoLoadPage = page;
        }
    }

    public enum AnimationType
    {
        SLIDE_TO_RIGHT,
        SLIDE_FROM_RIGHT,
        SLIDE_TO_LEFT,
        SLIDE_FROM_LEFT,
        SLIDE_TO_TOP,
        SLIDE_FROM_TOP,
        SLIDE_TO_BOTTOM,
        SLIDE_FROM_BOTTOM,
        FADE_IN,
        FADE_OUT,
        NONE,
    }

}