#include <iostream>
#include <stdexcept>
#include <optional>
#include <filesystem>
#include <senseApis/senseApiManager.h>
#include <senseApis/senseApiLib.h>
#include <opts.h>
#include <user/senseApiDesc.h>

namespace fs = std::filesystem;

namespace hk {
namespace sense_api {

static std::optional<std::string> findLibraryPath(
    const std::string& libraryPath)
{
    std::vector<std::string> searchPaths = {
        OptionParser::getOptions().senseApiLibPath,
        fs::current_path().string(),
        fs::path("/proc/self/exe").parent_path().string()
    };

    for (const auto& path : searchPaths)
    {
        fs::path fullPath = fs::path(path) / libraryPath;
        if (fs::exists(fullPath))
        {
            return fullPath.string();
        }
    }

    std::cerr << std::string(__func__) + ": library '"
              + libraryPath + "' isn't in search bespoke search paths: ";
    for (const auto& path : searchPaths)
    {
        std::cerr << path << " ";
    }
    std::cerr << std::endl;
    std::cerr << "Trying to load " + libraryPath + " from system default search "
        "paths\n";

    return std::nullopt;
}

SenseApiLib& SenseApiManager::loadSenseApiLib(const std::string& libraryPath)
{
    std::optional<std::string> fullPath = findLibraryPath(libraryPath);
    auto lib = std::make_unique<SenseApiLib>(fullPath.value_or(libraryPath));

    // Clear any existing error
    dlerror();
    lib->handle.reset(dlopen(lib->libraryPath.c_str(), RTLD_LAZY));
    if (!lib->handle && fullPath.has_value())
    {
        // Fallback to using the supplied libraryPath
        dlerror();
        lib->handle.reset(dlopen(libraryPath.c_str(), RTLD_LAZY));
    }

    if (!lib->handle)
    {
        std::string error = dlerror()
            ? dlerror()
            : "Unknown error while opening shlib";
        throw std::runtime_error(
            std::string(__func__) + " - Cannot load library '"
            + libraryPath + "': "
            + error);
    }

    // Initialize getSenseApiDescriptor
    auto func = reinterpret_cast<SenseApiLib::SenseApiDescGetterFn*>(
        dlsym(lib->handle.get(), HK_SENSE_API_DESC_GETTER_FN_NAME));
    if (!func)
    {
        throw std::runtime_error(
            std::string(__func__) + ": dlsym("
            HK_SENSE_API_DESC_GETTER_FN_NAME ") failed for library '"
            + lib->libraryPath + "'");
    }
    lib->getSenseApiDescriptor = func;

    senseApiLibs.push_back(std::move(lib));
    return *senseApiLibs.back();
}

std::optional<std::reference_wrapper<SenseApiLib>>
SenseApiManager::getSenseApiLib(const std::string& libraryPath)
{
    auto it = std::find_if(senseApiLibs.begin(), senseApiLibs.end(),
        [&libPath = libraryPath](const std::unique_ptr<SenseApiLib>& lib) {
            return lib->libraryPath == libPath;
        }
    );

    if (it != senseApiLibs.end()) { return **it; }
    return std::nullopt;
}

void SenseApiManager::unloadSenseApiLib(const std::string& libraryPath)
{
    auto it = std::find_if(senseApiLibs.begin(), senseApiLibs.end(),
        [&lpath = libraryPath](const std::unique_ptr<SenseApiLib>& lib) {
            return lib->libraryPath == lpath;
        }
    );

    if (it != senseApiLibs.end())
    {
        senseApiLibs.erase(it);
        return;
    }

    std::cerr << std::string(__func__) + ": Library not found: "
        << libraryPath << '\n';
}

} // namespace sense_api
} // namespace hk