using System.Reflection;
using System.Text;
using System.Text.Json;

namespace Nerfed.Compiler;

public static class Generator
{
    public const string AssemblyDefinitionExtensionName = ".asmdef";
    public const string CSProjectExtensionName = ".csproj";
    public const string SolutionExtensionName = ".sln";

    public static void GenerateSolution(string projectDirectory, Project project, out string solutionFilePath)
    {
        // Clear files.
        ClearCSProjectFiles(projectDirectory);

        // Generate projects.
        string[] assemblyDefinitionFilePaths = Directory.GetFiles(projectDirectory, AssemblyDefinitionExtensionName, SearchOption.AllDirectories);
        foreach (string assemblyDefinitionFilePath in assemblyDefinitionFilePaths)
        {
            GenerateCSProject(assemblyDefinitionFilePath, projectDirectory, out string csProjectFilePath);
        }

        // Generate solution.
        string[] csProjectPaths = Directory.GetFiles(projectDirectory, $"*{CSProjectExtensionName}", SearchOption.TopDirectoryOnly);
        string[] csProjectGuids = new string[csProjectPaths.Length];
        for (int i = 0; i < csProjectPaths.Length; i++)
        {
            csProjectGuids[i] = Guid.NewGuid().ToString("B").ToUpper();
        }

        StringBuilder content = new StringBuilder();

        // Write the solution file header
        content.AppendLine("Microsoft Visual Studio Solution File, Format Version 12.00");
        content.AppendLine("# Visual Studio Version 17");
        content.AppendLine("VisualStudioVersion = 17.10.35013.160");
        content.AppendLine("MinimumVisualStudioVersion = 10.0.40219.1");

        // Add each project to the solution file
        for (int i = 0; i < csProjectPaths.Length; i++)
        {
            string csProjectPath = csProjectPaths[i];
            string csProjectGuid = csProjectGuids[i];
            string csProjectName = Path.GetFileNameWithoutExtension(csProjectPath);
            string csProjectRelativePath = Path.GetRelativePath(projectDirectory, csProjectPath);
            // FAE04EC0-301F-11D3-BF4B-00C04F79EFBC for C# projects.
            content.AppendLine($"Project(\"{{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}}\") = \"{csProjectName}\", \"{csProjectRelativePath}\", \"{csProjectGuid}\"");
            content.AppendLine("EndProject");
        }

        // Add global sections (these can be extended as needed)
        content.AppendLine("Global");
        content.AppendLine("	GlobalSection(SolutionConfigurationPlatforms) = preSolution");
        content.AppendLine("		Test|x64 = Test|x64");
        content.AppendLine("		Release|x64 = Release|x64");
        content.AppendLine("		Debug|x64 = Debug|x64");
        content.AppendLine("	EndGlobalSection");
        content.AppendLine("	GlobalSection(ProjectConfigurationPlatforms) = postSolution");

        for (int i = 0; i < csProjectPaths.Length; i++)
        {
            string projectGuid = csProjectGuids[i];
            content.AppendLine($"		{projectGuid}.Test|x64.ActiveCfg = Test|x64");
            content.AppendLine($"		{projectGuid}.Test|x64.Build.0 = Test|x64");
            content.AppendLine($"		{projectGuid}.Release|x64.ActiveCfg = Release|x64");
            content.AppendLine($"		{projectGuid}.Release|x64.Build.0 = Release|x64");
            content.AppendLine($"		{projectGuid}.Debug|x64.ActiveCfg = Debug|x64");
            content.AppendLine($"		{projectGuid}.Debug|x64.Build.0 = Debug|x64");
        }

        content.AppendLine("	EndGlobalSection");
        content.AppendLine("	GlobalSection(SolutionProperties) = preSolution");
        content.AppendLine("		HideSolutionNode = FALSE");
        content.AppendLine("	EndGlobalSection");
        content.AppendLine("EndGlobal");

        // Write the solution file content to disk
        string solutionName = project.Name + SolutionExtensionName;
        solutionFilePath = Path.Combine(projectDirectory, solutionName);
        File.WriteAllText(solutionFilePath, content.ToString());
    }

    private static bool GenerateCSProject(string assemblyDefinitionFilePath, string projectPath, out string csProjectFilePath)
    {
        if (!File.Exists(assemblyDefinitionFilePath))
        {
            csProjectFilePath = string.Empty;
            return false;
        }

        string jsonString = File.ReadAllText(assemblyDefinitionFilePath);
        AssemblyDefinition assemblyDefinition = JsonSerializer.Deserialize(jsonString, AssemblyDefinitionContext.Default.AssemblyDefinition);

        Assembly[] loadedAssemblies = AppDomain.CurrentDomain.GetAssemblies();
        Assembly runtimeAssembly = loadedAssemblies.FirstOrDefault(assembly => assembly.GetName().Name == "Nerfed.Runtime") ?? throw new Exception("Failed to find Runtime Assembly!");

        // TODO: get all dependencies.
        // TODO: properly get assemblies.

        StringBuilder content = new StringBuilder();

        content.AppendLine("<Project Sdk=\"Microsoft.NET.Sdk\">");

        content.AppendLine(" <PropertyGroup>");
        content.AppendLine("     <TargetFramework>net8.0</TargetFramework>");
        content.AppendLine("     <ImplicitUsings>enable</ImplicitUsings>");
        content.AppendLine("     <Nullable>disable</Nullable>");
        content.AppendLine("     <PublishAot>true</PublishAot>");
        content.AppendLine("     <InvariantGlobalization>true</InvariantGlobalization>");
        content.AppendLine("     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>");
        content.AppendLine("     <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>");
        content.AppendLine("     <IsPackable>false</IsPackable>");
        content.AppendLine("     <Configurations>Debug;Test;Release</Configurations>");
        content.AppendLine("     <Platforms>x64</Platforms>");
        content.AppendLine(" </PropertyGroup>");

        content.AppendLine(" <PropertyGroup Condition=\" '$(Configuration)|$(Platform)' == 'Debug|x64' \">");
        content.AppendLine("     <DefineConstants>TRACE;LOG_INFO;PROFILING</DefineConstants>");
        content.AppendLine(" </PropertyGroup>");

        content.AppendLine(" <PropertyGroup Condition=\" '$(Configuration)|$(Platform)' == 'Test|x64' \">");
        content.AppendLine("     <DefineConstants>TRACE;LOG_ERROR;PROFILING</DefineConstants>");
        content.AppendLine("     <Optimize>true</Optimize>");
        content.AppendLine(" </PropertyGroup>");

        content.AppendLine(" <PropertyGroup Condition=\" '$(Configuration)|$(Platform)' == 'Release|x64' \">");
        content.AppendLine("     <DefineConstants>TRACE;LOG_ERROR</DefineConstants>");
        content.AppendLine("     <Optimize>true</Optimize>");
        content.AppendLine(" </PropertyGroup>");

        content.AppendLine(" <ItemGroup>");
        content.AppendLine($"     <Compile Include=\"{assemblyDefinitionFilePath}/**/*.cs\"/>");
        content.AppendLine(" </ItemGroup>");

        content.AppendLine(" <ItemGroup>");
        content.AppendLine("     <Reference Include=\"Nerfed.Runtime\">");
        content.AppendLine($"         <HintPath>{runtimeAssembly.Location}</HintPath>");
        content.AppendLine("         <Private>false</Private>");
        content.AppendLine("     </Reference>");
        content.AppendLine(" </ItemGroup>");

        content.AppendLine("</Project>");

        string csProjectName = assemblyDefinition.Name + CSProjectExtensionName;
        csProjectFilePath = Path.Combine(projectPath, csProjectName);
        File.WriteAllText(csProjectFilePath, content.ToString());

        return true;
    }

    private static void ClearCSProjectFiles(string projectPath)
    {
        string[] csProjectFiles = Directory.GetFiles(projectPath, $"*{CSProjectExtensionName}", SearchOption.TopDirectoryOnly);
        foreach (string csProjectFile in csProjectFiles)
        {
            File.Delete(csProjectFile);
        }
    }
}