using System.Collections.Generic;
using Engine.Core;

using SDL3;

namespace Engine.Integration.SDL3;

public class Sdl3WindowManager : Behaviour, IUpdate, IEnterUniverse, IExitUniverse
{
    private readonly BehaviourCollector<Sdl3Window> windows = new();
    private readonly BehaviourCollector<ISdl3EventProcessor> eventProcessors = new();
    private readonly Dictionary<nint, Sdl3Window> windowsDictionary = [];

    public Sdl3WindowManager()
    {
        windows.OnCollected.AddListener(OnWindowCollected);
        windows.OnRemoved.AddListener(OnWindowRemoved);
    }

    private void OnWindowCollected(IBehaviourCollector<Sdl3Window> sender, IBehaviourCollector<Sdl3Window>.BehaviourCollectedArguments args)
        => windowsDictionary.Add(args.BehaviourCollected.Window, args.BehaviourCollected);

    private void OnWindowRemoved(IBehaviourCollector<Sdl3Window> sender, IBehaviourCollector<Sdl3Window>.BehaviourRemovedArguments args)
    {
        windowsDictionary.Remove(args.BehaviourRemoved.Window);
        if (windowsDictionary.Count == 0)
            SDL.Quit();
    }

    public void EnterUniverse(IUniverse universe)
    {
        windows.Assign(universe);
        eventProcessors.Assign(universe);
    }

    public void ExitUniverse(IUniverse universe)
    {
        windows.Unassign();
        eventProcessors.Unassign();
    }

    public void Update()
    {
        while (SDL.PollEvent(out SDL.Event e))
            ProcessInternalEvents(e);
    }

    private void ProcessInternalEvents(SDL.Event sdlEvent)
    {
        if (!windowsDictionary.TryGetValue(SDL.GetWindowFromID(sdlEvent.Window.WindowID), out Sdl3Window? window))
            return;

        for (int i = 0; i < eventProcessors.Count; i++)
            eventProcessors[i].Process(sdlEvent);

        SDL.EventType eventType = (SDL.EventType)sdlEvent.Type;

        switch (eventType)
        {
            case SDL.EventType.WindowRestored: window.ShowState = WindowShowState.Normal; break;
            case SDL.EventType.WindowMaximized: window.ShowState = WindowShowState.Maximized; break;
            case SDL.EventType.WindowMinimized: window.ShowState = WindowShowState.Minimized; break;

            case SDL.EventType.WindowFocusGained: window.FocusState = WindowFocusState.Focused; break;
            case SDL.EventType.WindowFocusLost: window.FocusState = WindowFocusState.Unfocused; break;

            case SDL.EventType.WindowCloseRequested:
            case SDL.EventType.Quit: Universe.Remove(window.UniverseObject); break;
        }
    }
}