XCEngine/editor/src/Core/ProjectRootResolver.h

#pragma once

#include "Platform/Win32Utf8.h"

#include <shellapi.h>

#include <filesystem>
#include <optional>
#include <string>
#include <system_error>

namespace XCEngine {
namespace Editor {

namespace fs = std::filesystem;

namespace detail {

inline fs::path NormalizePath(const fs::path& path, const fs::path& basePath = {}) {
    if (path.empty()) {
        return {};
    }

    fs::path absolutePath = path;
    std::error_code ec;
    if (absolutePath.is_relative()) {
        absolutePath = basePath.empty()
            ? fs::absolute(absolutePath, ec)
            : fs::absolute(basePath / absolutePath, ec);
        if (ec) {
            absolutePath = basePath.empty() ? absolutePath : (basePath / path);
        }
    }

    ec.clear();
    const fs::path canonicalPath = fs::weakly_canonical(absolutePath, ec);
    if (!ec) {
        return canonicalPath.lexically_normal();
    }

    return absolutePath.lexically_normal();
}

inline bool IsWorkspaceRoot(const fs::path& candidate) {
    std::error_code ec;
    return fs::exists(candidate / L"CMakeLists.txt", ec) &&
        fs::is_directory(candidate / L"editor", ec) &&
        fs::is_directory(candidate / L"engine", ec);
}

inline bool IsEditorProjectRoot(const fs::path& candidate) {
    std::error_code ec;
    return fs::exists(candidate / L"Project.xcproject", ec) ||
        fs::is_directory(candidate / L"Assets", ec);
}

inline fs::path ResolveWorkspaceDefaultProjectRoot(const fs::path& workspaceRoot) {
    if (workspaceRoot.empty()) {
        return {};
    }

    const fs::path preferredProjectRoot = workspaceRoot / L"project";
    if (IsEditorProjectRoot(preferredProjectRoot)) {
        return NormalizePath(preferredProjectRoot);
    }

    if (IsEditorProjectRoot(workspaceRoot)) {
        return NormalizePath(workspaceRoot);
    }

    return NormalizePath(preferredProjectRoot);
}

inline std::optional<fs::path> FindWorkspaceRoot(fs::path start) {
    if (start.empty()) {
        return std::nullopt;
    }

    start = NormalizePath(start);
    for (fs::path current = start; !current.empty(); ) {
        if (IsWorkspaceRoot(current)) {
            return current;
        }

        const fs::path parent = current.parent_path();
        if (parent == current) {
            break;
        }
        current = parent;
    }

    return std::nullopt;
}

inline std::optional<fs::path> ParseCommandLineProjectOverride(const fs::path& workingDirectory) {
    int argc = 0;
    LPWSTR* argv = CommandLineToArgvW(GetCommandLineW(), &argc);
    if (!argv || argc <= 1) {
        if (argv) {
            LocalFree(argv);
        }
        return std::nullopt;
    }

    std::optional<fs::path> projectOverride;
    for (int i = 1; i < argc; ++i) {
        const std::wstring arg = argv[i] ? argv[i] : L"";
        if ((arg == L"--project" || arg == L"-p") && i + 1 < argc) {
            projectOverride = NormalizePath(fs::path(argv[++i]), workingDirectory);
            break;
        }

        static const std::wstring kProjectArgPrefix = L"--project=";
        if (arg.rfind(kProjectArgPrefix, 0) == 0) {
            projectOverride = NormalizePath(fs::path(arg.substr(kProjectArgPrefix.size())), workingDirectory);
            break;
        }
    }

    LocalFree(argv);
    return projectOverride;
}

inline std::string PathToUtf8(const fs::path& path) {
    return Platform::WideToUtf8(path.wstring());
}

} // namespace detail

inline std::string ResolveEditorProjectRootUtf8() {
    std::error_code ec;
    const fs::path workingDirectory = detail::NormalizePath(fs::current_path(ec));
    const fs::path executableDirectory = detail::NormalizePath(fs::path(Platform::Utf8ToWide(Platform::GetExecutableDirectoryUtf8())));

    if (const auto projectOverride = detail::ParseCommandLineProjectOverride(workingDirectory.empty() ? executableDirectory : workingDirectory)) {
        return detail::PathToUtf8(*projectOverride);
    }

    if (const auto workspaceRoot = detail::FindWorkspaceRoot(workingDirectory)) {
        return detail::PathToUtf8(detail::ResolveWorkspaceDefaultProjectRoot(*workspaceRoot));
    }

    if (const auto workspaceRoot = detail::FindWorkspaceRoot(executableDirectory)) {
        return detail::PathToUtf8(detail::ResolveWorkspaceDefaultProjectRoot(*workspaceRoot));
    }

    if (!workingDirectory.empty()) {
        return detail::PathToUtf8(workingDirectory);
    }

    return detail::PathToUtf8(executableDirectory);
}

inline bool SetEditorWorkingDirectory(const std::string& projectRootUtf8) {
    if (projectRootUtf8.empty()) {
        return false;
    }

    std::error_code ec;
    fs::current_path(fs::path(Platform::Utf8ToWide(projectRootUtf8)), ec);
    return !ec;
}

} // namespace Editor
} // namespace XCEngine