#include "path_utils.hpp"
#include <iostream>
#include <optional>
#include <filesystem>
#ifdef _WIN32
# include <windows.h>
# include <tchar.h>
#endif

std::optional<std::filesystem::path> engine::path_utils::exe() noexcept {
#if defined(_WIN32)
    TCHAR filename[MAX_PATH];
    if (!GetModuleFileName(NULL, filename, MAX_PATH))
        return {};
    return std::filesystem::path(filename);
#elif defined(linux)
    return std::filesystem::canonical("/proc/self/exe");
#else
# error "operating system not supported"
#endif
}

engine::path_utils::Paths::Paths() noexcept {
    const auto exe_opt = engine::path_utils::exe();
    if (!exe_opt) {
        std::cerr << "cannot find path of executable" << std::endl;
        exit(1);
    }
    m_exe = *exe_opt;

    const auto files_root = m_exe.parent_path();
    const auto bin = std::filesystem::weakly_canonical(BINDIR);
    const std::filesystem::path pkgdata { PKGDATADIR };
    const auto assets = pkgdata / "assets";

    m_assets_objs     = std::filesystem::canonical(files_root / std::filesystem::weakly_canonical(assets / "objs")    .lexically_relative(bin));
    m_assets_textures = std::filesystem::canonical(files_root / std::filesystem::weakly_canonical(assets / "textures").lexically_relative(bin));
    m_spvshaders      = std::filesystem::canonical(files_root / std::filesystem::weakly_canonical(SPVSHADERSDIR)      .lexically_relative(bin));
}