// <copyright file="UpdateShaderGraphAssemblyInfo.cs" company="BovineLabs">
// Copyright (c) BovineLabs. All rights reserved.
// </copyright>
 
namespace BovineLabs.Vision.Editor.ShaderGraph
{
    using System;
    using System.IO;
    using System.Linq;
    using UnityEditor;
    using UnityEditor.Compilation;
 
    /// <summary>
    /// Adds our assembly to the shader graph AssemblyInfo to give us internal access. A nasty hack required for now.
    /// </summary>
    [InitializeOnLoad]
    public static class UpdateShaderGraphAssemblyInfo
    {
        private const string ShaderGraphAssemblyName = "Unity.ShaderGraph.Editor";
        private const string AssemblyInfoName = "AssemblyInfo.cs";
        
        // This line should refer to your own assembly
        private const string VisibleLine = "[assembly: InternalsVisibleTo(\"BovineLabs.Vision.Editor\")]";
 
        static UpdateShaderGraphAssemblyInfo()
        {
            CompilationPipeline.assemblyCompilationStarted += OnAssemblyCompilationStarted;
        }
 
        private static void OnAssemblyCompilationStarted(string assemblyName)
        {
            var asmdef = CompilationPipeline.GetAssemblyDefinitionFilePathFromAssemblyName(assemblyName);
            var name = Path.GetFileNameWithoutExtension(asmdef);
 
            if (name == null || !name.Equals(ShaderGraphAssemblyName))
            {
                return;
            }
 
            var directory = Path.GetDirectoryName(asmdef);
            var assemblyInfoPath = Path.Combine(directory ?? throw new NullReferenceException(), AssemblyInfoName);
 
            var assemblyInfo = File.ReadAllLines(assemblyInfoPath);
 
            // Already setup
            if (assemblyInfo.Contains(VisibleLine))
            {
                return;
            }
 
            TurnOffReadOnly(assemblyInfoPath);
            File.AppendAllText(assemblyInfoPath, VisibleLine);
        }
 
        private static void TurnOffReadOnly(string file)
        {
            File.SetAttributes(file, File.GetAttributes(file) & ~FileAttributes.ReadOnly);
        }
    }
}