using Sirenix.OdinInspector;
using UnityEngine;
using UnityEngine.Splines;
#if UNITY_EDITOR
using System.IO;
using UnityEditor;
#endif

namespace DanieleMarotta.RiversongCodeShowcase
{
    [RequireComponent(typeof(SplineContainer))]
    public class WaterFlowMapBaker : MonoBehaviour
    {
#if UNITY_EDITOR
        public int WorldSize = 100;

        public int MapSize = 512;

        public float InfluenceRadius = 10;

        public Texture2D OutputTexture;

        [Button(ButtonSizes.Large)]
        [GUIColor("cyan")]
        public void BakeFlowMap()
        {
            var splineContainer = GetComponent<SplineContainer>();

            var texture = new Texture2D(MapSize, MapSize, TextureFormat.RGBA32, false, true)
            {
                wrapMode = TextureWrapMode.Clamp,
                filterMode = FilterMode.Bilinear
            };

            for (var y = 0; y < MapSize; y++)
            for (var x = 0; x < MapSize; x++)
            {
                var c = new Color(0.5f, 0.5f, 0, 0);

                var uv = new Vector2((x + 0.5f) / MapSize, (y + 0.5f) / MapSize);
                var world = new Vector3(uv.x * WorldSize, 0, uv.y * WorldSize);

                var distance = SplineUtility.GetNearestPoint(splineContainer.Spline, world, out _, out var t);
                if (distance <= InfluenceRadius)
                {
                    var tangent = splineContainer.Spline.EvaluateTangent(t);

                    var direction = new Vector2(tangent.x, tangent.z);
                    if (direction.sqrMagnitude > 0.0001f) direction.Normalize();

                    var influence = Mathf.Clamp01(1 - distance / InfluenceRadius);

                    c.r = direction.x * 0.5f + 0.5f;
                    c.g = direction.y * 0.5f + 0.5f;
                    c.b = influence;
                }

                texture.SetPixel(x, y, c);
            }

            texture.Apply(false, false);

            var textureDirty = false;
            if (!OutputTexture)
            {
                var path = EditorUtility.SaveFilePanelInProject("Save Flow Map", "WaterFlowMap", "asset", string.Empty);

                if (!string.IsNullOrEmpty(path))
                {
                    texture.name = Path.GetFileNameWithoutExtension(path);
                    AssetDatabase.CreateAsset(texture, path);
                    OutputTexture = AssetDatabase.LoadAssetAtPath<Texture2D>(path);
                    textureDirty = true;
                }
            }
            else
            {
                texture.name = OutputTexture.name;
                EditorUtility.CopySerialized(texture, OutputTexture);
                textureDirty = true;
            }

            if (textureDirty)
            {
                EditorUtility.SetDirty(OutputTexture);
                AssetDatabase.SaveAssets();
            }
        }
#endif
    }
}