#include "probing_client_platform_factory.h"
#include "mir/client_platform.h"
#include "mir/shared_library.h"
#include "mir/shared_library_prober.h"
#include "mir/shared_library_prober_report.h"

#include <boost/exception/all.hpp>
#include <stdexcept>

namespace mcl = mir::client;

mcl::ProbingClientPlatformFactory::ProbingClientPlatformFactory(
    std::shared_ptr<mir::SharedLibraryProberReport> const& rep,
    StringList const& force_libs,
    StringList const& lib_paths)
    : shared_library_prober_report{rep},
      platform_overrides{force_libs},
      platform_paths{lib_paths}
{
    if (platform_overrides.empty() && platform_paths.empty())
    {
        BOOST_THROW_EXCEPTION(
            std::runtime_error{"Attempted to create a ClientPlatformFactory with no platform paths or overrides"});
    }
}

std::shared_ptr<mcl::ClientPlatform>
mcl::ProbingClientPlatformFactory::create_client_platform(mcl::ClientContext* context)
{
    // Note we don't want to keep unused platform modules loaded any longer
    // than it takes to choose the right one. So this list is local:
    std::vector<std::shared_ptr<mir::SharedLibrary>> platform_modules;

    auto const module_selector = [context, &platform_modules](std::shared_ptr<mir::SharedLibrary> const& module)
    {
        try
        {
            auto probe = module->load_function<ClientPlatformProbe>("is_appropriate_module", CLIENT_PLATFORM_VERSION);
            if (probe(context))
            {
                platform_modules.push_back(module);
                return Selection::quit;
            }
        }
        catch (std::runtime_error const&)
        {
            // Assume we were handed a SharedLibrary that's not a client platform module of the correct vintage.
        }

        return Selection::persist;
    };

    if (!platform_overrides.empty())
    {
        // Even forcing a choice, platform is only loaded on demand. It's good
        // to not need to hold the module open when there are no connections.
        // Also, this allows you to swap driver binaries on disk at run-time,
        // if you really wanted to.

        for (auto const& platform : platform_overrides)
            module_selector(std::make_shared<mir::SharedLibrary>(platform));
    }
    else
    {
        for (auto const& path : platform_paths)
            select_libraries_for_path(path, module_selector, *shared_library_prober_report);
    }

    for (auto& module : platform_modules)
    {
        auto factory = module->load_function<CreateClientPlatform>("create_client_platform", CLIENT_PLATFORM_VERSION);
        return factory(context);
    }

    BOOST_THROW_EXCEPTION(std::runtime_error{"No appropriate client platform module found"});
}
