using System.Collections;
using System.Collections.Generic;
using System.Linq;
#if UNITY_EDITOR
using UnityEditor;
#endif
using UnityEngine;

namespace Gaia
{
    public enum LoadMode { Disabled, EditorSelected, EditorAlways, RuntimeAlways }
    [ExecuteInEditMode]
    public class TerrainLoader : MonoBehaviour
    {
        public BoundsDouble m_loadingBounds = new BoundsDouble();
        [SerializeField]
        [HideInInspector]
        private LoadMode m_loadMode = LoadMode.EditorSelected;
        public LoadMode LoadMode {
                                    get {
                                            return m_loadMode;
                                        }
                                    set {
                                            m_loadMode = value;
                                            UpdateTerrains();
                                        }
                                    }
        [HideInInspector]
        public bool m_isSelected = false;
        [HideInInspector]
        public bool m_beingDragged = false;
        public float m_minRefreshDistance = 100f;
        public float m_maxRefreshDistance = 2000f;
        public float m_minRefreshMS = 100f;
        public float m_maxRefreshMS = 5000f;
        public bool m_followTransform = true;

        private BoundsDouble m_shiftedBounds = new BoundsDouble();

        private GaiaSessionManager m_sessionManager;
        private GaiaSessionManager SessionManager
        {
            get
            {
                if (m_sessionManager == null)
                {
                    m_sessionManager = GaiaSessionManager.GetSessionManager(false);
                }
                return m_sessionManager;
            }
        }

        private void OnDrawGizmos()
        {
#if UNITY_EDITOR
            if (TerrainLoaderManager.Instance.ShowLocalTerrain && ((m_loadMode == LoadMode.EditorSelected && m_isSelected) || m_loadMode == LoadMode.EditorAlways || (m_loadMode == LoadMode.RuntimeAlways && (Application.isPlaying ||  m_isSelected))))
            {
                if (m_loadMode == LoadMode.RuntimeAlways && !Application.isPlaying)
                {
                    Gizmos.color = Color.black;
                }
                else
                {
                    Gizmos.color = Color.magenta;
                }
                //m_loadingBounds.center = transform.position;
                if (m_followTransform)
                {
                    m_loadingBounds.center = transform.position;
                }
                Gizmos.DrawWireCube(m_loadingBounds.center, m_loadingBounds.size);
            }
#endif
        }

        private void Update()
        {
            if (m_loadMode == LoadMode.RuntimeAlways)
            {
                if (m_followTransform)
                {
                    m_loadingBounds.center = transform.position;
                }
                UpdateTerrains();
            }
        }

        public void Start()
        {
#if UNITY_EDITOR
            if (EditorApplication.isPlaying)
            {
                //Display Error when Loaders are not activated in the Loader Manager
                if (m_loadMode == LoadMode.RuntimeAlways && !TerrainLoaderManager.Instance.TerrainSceneStorage.m_terrainLoadingEnabled)
                {
                    Debug.LogError("Terrain Loaders are currently disabled under Gaia Runtime > Terrain Loader. The Terrain Loader on the object '" + transform.name + "' will not be able to load any terrains.");
                }
            }
#endif
        }

        public void Awake()
        {
#if UNITY_EDITOR
            if (EditorApplication.isPlayingOrWillChangePlaymode && !EditorApplication.isPlaying)
            {
                //Auto-Deselect non runtime loaders on entering playmode
                //otherwise the tool might interfere with runtime loading
                if(m_loadMode!=LoadMode.RuntimeAlways && m_isSelected)
                {
                    Selection.objects = new Object[1] { GaiaUtils.GetGaiaGameObject()};
                }
            }
            UpdateTerrains();
#endif
        }

        public void UnloadTerrains()
        {
            if (this!=null && gameObject != null)
            {
                foreach (TerrainScene terrainScene in TerrainLoaderManager.TerrainScenes)
                {
                    if (terrainScene.HasReference(gameObject))
                    {
                        terrainScene.RemoveReference(gameObject);
                    }
                }
            }
        }

        public void UpdateTerrains()
        {
            if (m_loadMode == LoadMode.Disabled || (m_loadMode == LoadMode.EditorSelected && !m_isSelected) || (m_loadMode==LoadMode.RuntimeAlways && !Application.isPlaying))
            {
                UnloadTerrains();
                return;
            }
            //shave off a tiny little bit of the loading size. - when a tool such as a spawner has a range that lies directly
            //on the edge of the terrain border, this leads to up to 9 additional terrains being loaded that are not required.
            //This results in slower spawning speeds, spawn issues, etc.
            m_shiftedBounds.extents = m_loadingBounds.extents - new Vector3Double(0.001, 0.001, 0.001); 
            m_shiftedBounds.center = m_loadingBounds.center + TerrainLoaderManager.Instance.GetOrigin();

            TerrainLoaderManager.Instance.UpdateTerrainLoadState(m_shiftedBounds, gameObject, m_minRefreshDistance, m_maxRefreshDistance, m_minRefreshMS, m_maxRefreshMS);
        }
    }
}