using System;
using System.IO;
using System.Collections.Generic;
using UnrealBuildTool;

public class UEBlueprintMCPEditor : ModuleRules
{
    public UEBlueprintMCPEditor(ReadOnlyTargetRules Target) : base(Target)
    {
        PCHUsage = ModuleRules.PCHUsageMode.UseExplicitOrSharedPCHs;

        PublicDependencyModuleNames.AddRange(new string[]
        {
            "Core",
            "CoreUObject",
            "Engine",
            "UMG",
        });

        PrivateDependencyModuleNames.AddRange(new string[]
        {
            "UnrealEd",
            "UMGEditor",
            "BlueprintGraph",
            "KismetCompiler",
            "Kismet",
            "GraphEditor",
            "InputCore",
            "Slate",
            "SlateCore",
            "EditorSubsystem",
            "ToolMenus",
            "AssetTools",
            "Projects",
            "Json",
            "JsonUtilities",
            "AssetRegistry",
            "HTTP",
            "Niagara",
            "NiagaraCore",
            "NiagaraEditor",
            "ImageWrapper",
            "RenderCore",
            "RHI",
            "MovieScene",
            "MovieSceneTracks",
        });

        // ---- Optional Voxel integration -----------------------------------
        // voxel_graph_op needs Voxel's editor modules. Voxel is a heavy third-party
        // plugin most projects don't have, so it is wired in ONLY when present. The
        // C++ side guards everything behind WITH_MCP_VOXEL and compiles to stubs at 0.
        //   env UE_MCP_WITH_VOXEL = "1" -> force on  (errors if the plugin is missing)
        //   env UE_MCP_WITH_VOXEL = "0" -> force off
        //   unset                       -> auto-detect
        string voxelEnv = Environment.GetEnvironmentVariable("UE_MCP_WITH_VOXEL");
        string voxelPrivate = (voxelEnv == "0") ? null : FindVoxelGraphEditorPrivate(Target);
        bool voxelEnabled = voxelPrivate != null && voxelEnv != "0";

        if (voxelEnabled)
        {
            // Reach a few VoxelGraphEditor private headers (node classes). We only use
            // inline/virtual members, so no private link symbols cross the boundary.
            PrivateIncludePaths.Add(voxelPrivate);
            PrivateDependencyModuleNames.AddRange(new string[]
            {
                "VoxelCore",
                "VoxelCoreEditor",
                "VoxelGraph",
                "VoxelGraphEditor",
            });
            PublicDefinitions.Add("WITH_MCP_VOXEL=1");
        }
        else
        {
            if (voxelEnv == "1")
            {
                throw new BuildException(
                    "UE_MCP_WITH_VOXEL=1 but the Voxel plugin (Source/VoxelGraphEditor/Private) " +
                    "could not be located. Install the Voxel plugin into this project or the engine, " +
                    "or unset UE_MCP_WITH_VOXEL.");
            }
            PublicDefinitions.Add("WITH_MCP_VOXEL=0");
        }
    }

    // Locate <Voxel>/Source/VoxelGraphEditor/Private by scanning the project's and
    // engine's plugin folders for Voxel.uplugin. Returns null if Voxel isn't installed.
    private string FindVoxelGraphEditorPrivate(ReadOnlyTargetRules Target)
    {
        var roots = new List<string>();
        if (Target.ProjectFile != null)
        {
            roots.Add(Path.Combine(Target.ProjectFile.Directory.FullName, "Plugins"));
        }
        // The Plugins folder this plugin itself lives in (covers <Project>/Plugins/Voxel).
        roots.Add(Path.GetFullPath(Path.Combine(ModuleDirectory, "..", "..", "..")));
        try { roots.Add(Path.Combine(EngineDirectory, "Plugins")); } catch { }

        foreach (string root in roots)
        {
            string hit = FindVoxelUnder(root, 0);
            if (hit != null) return hit;
        }
        return null;
    }

    // Bounded, fault-tolerant recursive search (GetFiles+AllDirectories aborts wholesale
    // on a single inaccessible subdir, so we walk manually and swallow per-dir errors).
    private string FindVoxelUnder(string dir, int depth)
    {
        if (depth > 5 || string.IsNullOrEmpty(dir) || !Directory.Exists(dir)) return null;
        try
        {
            string upl = Path.Combine(dir, "Voxel.uplugin");
            if (File.Exists(upl))
            {
                string priv = Path.Combine(dir, "Source", "VoxelGraphEditor", "Private");
                if (Directory.Exists(priv)) return priv;
            }
            foreach (string sub in Directory.GetDirectories(dir))
            {
                string hit = FindVoxelUnder(sub, depth + 1);
                if (hit != null) return hit;
            }
        }
        catch { }
        return null;
    }
}