using Blazor.Extensions.Canvas.Canvas2D;
using Blazor.Extensions;
using Microsoft.AspNetCore.Components.Web;
using Microsoft.AspNetCore.Components;
using Microsoft.JSInterop;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json;
using StackExchange.Redis;

namespace BlazorCanvas.Server.Components.Data;

// https://www.codeproject.com/Articles/5269947/Drawing-with-the-HTML-Canvas-Element-in-Blazor-Ser

public class CanvasService {
    private Canvas2DContext? _currentCanvasContext;
    private IJSRuntime _jsRuntime;
    private IConnectionMultiplexer _cache;
    private ChannelMessageQueue _channel;
    private CanvasCommand _lastCommand = new();
    private bool _is_started = false;

    public CanvasService(IJSRuntime jsRuntime, IConnectionMultiplexer cache) {
        _jsRuntime = jsRuntime;
        _cache = cache;
        _channel = _cache.GetSubscriber().Subscribe(RedisChannel.Literal("lol"));
    }

    public string currentColor { get; set; } = "Black";
    public int pointSize { get; set; } = 1;
    public bool snap { get; set; }
    public ElementReference divCanvas { get; set; }
    public BECanvasComponent myCanvas { get; set; } = new();

    public async void Consume() {
        CancellationToken cToken = new();
        
        while (!cToken.IsCancellationRequested) {
            var mess = await _channel.ReadAsync(cToken);
            var comm = JsonConvert.DeserializeObject<CanvasCommand>(mess.Message);
            if (comm is not null)
                Draw(comm);
        }
    }

    public async void Draw(IEnumerable<CanvasCommand> lsCommand) {
        if (_currentCanvasContext is null) {
            _currentCanvasContext = await myCanvas.CreateCanvas2DAsync();
            await _currentCanvasContext.ClearRectAsync(0, 0, 1920, 1080);
        }
        await _currentCanvasContext.BeginBatchAsync();
        foreach (CanvasCommand command in lsCommand) {
            await _currentCanvasContext.SetFillStyleAsync(command.Color);
            await _currentCanvasContext.FillRectAsync(command.X, command.Y, command.PointSize, command.PointSize);
        }
        await _currentCanvasContext.EndBatchAsync();
    }

    public async void Draw(CanvasCommand command) {
        if (_currentCanvasContext is null) {
            _currentCanvasContext = await myCanvas.CreateCanvas2DAsync();
            await _currentCanvasContext.ClearRectAsync(0, 0, 1920, 1080);
        }
        await _currentCanvasContext.SetFillStyleAsync(command.Color);
        await _currentCanvasContext.FillRectAsync(command.X, command.Y, command.PointSize, command.PointSize);
    }

    public async void HandleMouse(MouseEventArgs eventArgs) {
        double mouseX = 0, mouseY = 0;

        if (!_is_started) { 
            Consume();
            _is_started = true;
        }

        if (eventArgs.Buttons == 0 || eventArgs.Buttons > 2)
            return; // Rien faire si aucun bouton est appuyé ou si les deux boutons/ d'autres boutons sont appuyés.

        if (divCanvas.Id?.Length > 0) {
            string data = await _jsRuntime.InvokeAsync<string>("getDivCanvasOffsets",
                new object[] { divCanvas });
            string color = "White";
            CanvasCommand command = new();
            JObject? offsets = (JObject?)JsonConvert.DeserializeObject(data);

            if (offsets is not null && offsets.HasValues) { // Translation entre le canvas et la souris.
                mouseX = eventArgs.PageX - offsets.Value<double>("offsetLeft");
                mouseY = eventArgs.PageY - offsets.Value<double>("offsetTop");
            }

            if (eventArgs.Buttons == 1) // Couleur si bouton gauche, blanc si bouton droit
                color = currentColor;

            if (snap) { // Magnétisme boboche.
                mouseX -= mouseX % pointSize;
                mouseY -= mouseY % pointSize;
            }
        
            command.X = mouseX;
            command.Y = mouseY;
            command.Color = color;
            command.PointSize = pointSize;

            if (command.Equals(_lastCommand))
                return; // Pour pas spammer des commandes si c'est pas pertinent.
            
            // TODO: Shipper les commandes à Franz.
            _cache.GetSubscriber().Publish(RedisChannel.Literal("lol"), JsonConvert.SerializeObject(command));

            //Draw(command);

            _lastCommand = command;
        }
    }
}