using OctoCore;
using UnityEngine;
using UnityEngine.SocialPlatforms;

[ExecuteInEditMode, DefaultExecutionOrder(0)]
public class PortalManager : MonoBehaviour
{
    public static PortalManager Instance { get; private set; }

    [System.Serializable]
    public class State
    {
        public bool PlayerInside;
        public Portal[] Portals;
    }

    [SerializeField, OctoReadOnly] private State _state;
    
    void OnEnable()
    {
        _state = new State();
        _state.Portals = new Portal[3];

        if (!Instance)
            Instance = this;

        ResetMasks();
    }

    void OnDisable()
    {
        if (Instance == this)
            Instance = null;

        ResetMasks();
    }

    void Update()
    {
        UpdateMasks();
    }

    public void SetInside(bool inside)
    {
        _state.PlayerInside = inside;

        UpdateMasks();
    }

    public void RegisterPortal(Portal portal)
    {
        _state.Portals[portal.ID] = portal;

        ManageMask(portal, true);
    }

    public void UnregisterPortal(Portal portal)
    {
        ManageMask(portal, false);

        _state.Portals[portal.ID] = null;
    }

    public void ManageMask(Portal portal, bool active)
    {
        if (!portal)
            return;

        if (_state.Portals[portal.ID] != portal)
        {
            RegisterPortal(portal);
            return;
        }

        Vector3 camPos = Camera.main ? Camera.main.transform.position : Vector3.zero;

        Matrix4x4 m = new Matrix4x4();
        m.SetRow(0, new Vector4(camPos.x, camPos.y, camPos.z, !active || _state.PlayerInside ? 0 : 1));
        m.SetRow(1, new Vector4(portal.transform.position.x, portal.transform.position.y, portal.transform.position.z, portal.Oval));
        m.SetRow(2, new Vector4(portal.transform.up.x, portal.transform.up.y, portal.transform.up.z, portal.transform.localScale.x));
        m.SetRow(3, new Vector4(portal.transform.forward.x, portal.transform.forward.y, portal.transform.forward.z, portal.transform.localScale.y));

        SetMask(portal.ID, m);
    }

    private void UpdateMasks()
    {
        for (int i = 0; i < _state.Portals.Length; i++)
            ManageMask(_state.Portals[i], true);
    }

    private void ResetMasks()
    {
        for (int i = 0; i < _state.Portals.Length; i++)
        {
            Matrix4x4 m = new Matrix4x4();
            m.SetRow(0, Vector4.zero);
            m.SetRow(1, Vector4.zero);
            m.SetRow(2, Vector4.zero);
            m.SetRow(3, Vector4.zero);

            SetMask(i, m);
        }
    }

    private void SetMask(int id, Matrix4x4 m)
    {
        Shader.SetGlobalMatrix($"_Mask{id}", m);
    }
}