Connected.Framework/Connected.Caching/CachingService.cs

using System.Collections.Immutable;
using Connected.Caching.Net;
using Connected.Net.Server;

namespace Connected.Caching;

internal sealed class CachingService : MemoryCache, ICachingService, IDisposable, IAsyncDisposable
{
	public CachingService(IEndpointServer server, CacheServer state, CacheServerConnection backplaneClient)
	{
		if (server is null)
			throw new ArgumentException(null, nameof(server));

		if (state is null)
			throw new ArgumentException(null, nameof(state));

		BackplaneClient = backplaneClient;

		Server = server;
		BackplaneServer = state;

		server.Changed += OnServerChanged;
		server.Initialized += OnServerInitialized;
		BackplaneServer.Received += OnReceived;
		BackplaneClient.Received += OnReceived;
	}

	private CacheServerConnection BackplaneClient { get; set; }
	private CacheServer BackplaneServer { get; }
	private IEndpointServer Server { get; }

	private async void OnServerInitialized(object? sender, EventArgs e)
	{
		await Initialize();
	}

	public async Task Initialize()
	{
		await BackplaneClient.Disconnect();

		try
		{
			if (!await Server.IsServer())
			{
				await BackplaneClient.Initialize(Server.ServerUrl);
				await BackplaneClient.Connect();
			}
		}
		catch
		{
			// Server probably not initalized yet
		}
	}

	private async void OnReceived(object? sender, CacheNotificationArgs e)
	{
		if (string.Equals(e.Method, nameof(Clear), StringComparison.Ordinal))
			ClearCore(e.Key);
		else if (string.Equals(e.Method, nameof(Remove), StringComparison.Ordinal))
		{
			if (e.Ids is not null && e.Ids.Any())
			{
				foreach (var id in e.Ids)
					RemoveCore(e.Key, id);
			}
		}
		else if (string.Equals(e.Method, nameof(Invalidate), StringComparison.Ordinal))
		{
			if (e.Ids is not null && e.Ids.Any())
			{
				foreach (var id in e.Ids)
					await InvalidateCore(e.Key, id, true);
			}
		}
	}

	private async void OnServerChanged(object? sender, ServerChangedArgs e)
	{
		await Initialize();
	}

	public override async Task Clear(string key)
	{
		await base.Clear(key);

		var args = new CacheNotificationArgs(nameof(Clear)) { Key = key };

		if (await Server.IsServer())
			await BackplaneServer.Send(args);
		else
			await BackplaneClient.Notify(nameof(Clear), args);


	}
	protected internal override async Task OnInvalidating(CacheEventArgs e)
	{
		var args = new CacheNotificationArgs(nameof(Invalidate))
		{
			Ids = new List<string> { e.Id },
			Key = e.Key
		};

		if (await Server.IsServer())
			await BackplaneServer.Send(args);
		else
			await BackplaneClient.Notify(nameof(Invalidate), args);
	}

	protected override async Task OnRemove(string key, ImmutableList<string> ids)
	{
		await base.OnRemove(key, ids);

		var args = new CacheNotificationArgs(nameof(Remove))
		{
			Ids = ids.ToList(),
			Key = key
		};

		if (await Server.IsServer())
			await BackplaneServer.Send(args);
		else
			await BackplaneClient.Notify(nameof(Remove), args);
	}

	protected override async Task OnRemove(string key, object? id)
	{
		await base.OnRemove(key, id);

		var ids = new List<string>();

		if (id is not null)
			ids.Add(id.ToString());

		await OnRemove(key, ids.ToImmutableList());
	}

	public async ValueTask DisposeAsync()
	{
		Server.Changed -= OnServerChanged;
		Server.Initialized -= OnServerInitialized;
	}


	protected override void OnDisposing(bool disposing)
	{
		Server.Changed -= OnServerChanged;
		Server.Initialized -= OnServerInitialized;

		base.OnDisposing(disposing);
	}
}