using System.Collections.Generic;
using UnityEditor;
using UnityEngine;
using UnityEngine.Rendering;

namespace Module.ProjectValidator.Editor
{
    internal sealed class AssetValidatorMaterialShader : IAssetValidator<Material>
    {
        public void Validate(Material obj, List<ValidatorResult> results)
        {
            if (obj.shader == null)
                results.Add(ValidatorResult.Create(EValidatorSeverity.Error, "Shader is Null"));
            else if (!IsCompatible(obj.shader))
                results.Add(ValidatorResult.Create(EValidatorSeverity.Warning, $"Shader '{obj.shader.name}' is not compatible with render pipeline"));
            else if (!obj.shader.isSupported)
                results.Add(ValidatorResult.Create(EValidatorSeverity.Warning, $"Shader '{obj.shader.name}' is not supported"));
            else if (ShaderUtil.ShaderHasError(obj.shader))
                results.Add(ValidatorResult.Create(EValidatorSeverity.Error, $"Shader '{obj.shader.name}' has compile errors"));
        }

        private static bool IsCompatible(Shader shader)
        {
            var pipeline = GraphicsSettings.currentRenderPipeline;

            if (pipeline == null)
                return true;

            var tagSearch = new ShaderTagId("RenderPipeline");
            var tagPipeline = new ShaderTagId(pipeline.renderPipelineShaderTag);

            for (var i = 0; i < shader.passCount; i++)
            {
                var tagPass = shader.FindPassTagValue(i, tagSearch);

                if (tagPass == tagPipeline)
                    return true;
            }
            
            return false;
        }
    }
}