using System;
using System.Collections.Generic;
using UnityEngine;

namespace ConformalDecals.MaterialModifiers {
    public class MaterialPropertyCollection : ScriptableObject {
        private static readonly int OpacityId = Shader.PropertyToID("_Opacity");
        private static readonly int CutoffId  = Shader.PropertyToID("_Cutoff");

        public MaterialTextureProperty MainMaterialTextureProperty { get; set; }

        private List<MaterialProperty>        _materialProperties;
        private List<MaterialTextureProperty> _textureMaterialProperties;

        public Material DecalMaterial {
            get {
                if (_protoDecalMaterial == null) {
                    _protoDecalMaterial = MakeMaterial(_decalShader);
                }

                return _protoDecalMaterial;
            }
        }

        private Shader   _decalShader;
        private Material _protoDecalMaterial;

        public void Initialize() {
            _materialProperties = new List<MaterialProperty>();
            _textureMaterialProperties = new List<MaterialTextureProperty>();
        }

        public void AddProperty(MaterialProperty property) {
            foreach (var p in _materialProperties) {
                if (p.PropertyName == property.PropertyName) {
                    _materialProperties.Remove(property);
                }
            }

            _materialProperties.Add(property);

            if (property is MaterialTextureProperty textureProperty) {
                foreach (var p in _textureMaterialProperties) {
                    if (p.PropertyName == textureProperty.PropertyName) {
                        _textureMaterialProperties.Remove(textureProperty);
                    }
                }

                _textureMaterialProperties.Add(textureProperty);

                if (textureProperty.IsMain) MainMaterialTextureProperty ??= textureProperty;
            }
        }

        public void SetShader(string shaderName) {
            if (_decalShader == null && string.IsNullOrEmpty(shaderName)) {
                throw new FormatException("Shader name not provided");
            }

            var shader = Shabby.Shabby.FindShader(shaderName);
            
            if (shader == null) throw new FormatException($"Unable to find specified shader '{shaderName}'");

            _decalShader = shader;
        }

        public void SetScale(Material material, Vector2 scale) {
            foreach (var textureProperty in _textureMaterialProperties) {
                textureProperty.UpdateScale(material, scale);
            }
        }

        public void SetOpacity(Material material, float opacity) {
            material.SetFloat(OpacityId, opacity);
        }

        public void SetCutoff(Material material, float cutoff) {
            material.SetFloat(CutoffId, cutoff);
        }

        private Material MakeMaterial(Shader shader) {
            var material = new Material(shader);
            foreach (MaterialProperty property in _materialProperties) {
                property.Modify(material);
            }

            return material;
        }
    }
}