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/*! \file
 * \brief Exports TPR I/O tools during Python module initialization.
 *
 * Provides _gmxapi.SimulationParameters and _gmxapi.TprFile classes, as well
 * as module functions read_tprfile, write_tprfile, copy_tprfile, and rewrite_tprfile.
 *
 * TprFile is a Python object that holds a gmxapicompat::TprReadHandle.
 *
 * SimulationParameters is the Python type for data sources providing the
 * simulation parameters aspect of input to simulation operations.
 *
 * \author M. Eric Irrgang <ericirrgang@gmail.com>
 * \ingroup module_python
 */

#include "gmxapi/exceptions.h"

#include "gmxapi/gmxapicompat.h"
#include "gmxapi/compat/mdparams.h"
#include "gmxapi/compat/tpr.h"

#include "module.h"

using gmxapi::GmxapiType;

namespace gmxpy
{


void detail::export_tprfile(pybind11::module& module)
{
    namespace py = pybind11;
    using gmxapicompat::GmxMdParams;
    using gmxapicompat::readTprFile;
    using gmxapicompat::TprReadHandle;

    py::class_<GmxMdParams> mdparams(module, "SimulationParameters");
    // We don't want Python users to create invalid params objects, so don't
    // export a constructor until we can default initialize a valid one.
    //    mdparams.def(py::init());
    mdparams.def("extract",
                 [](const GmxMdParams& self) {
                     py::dict dictionary;
                     for (const auto& key : gmxapicompat::keys(self))
                     {
                         try
                         {
                             // TODO: More complete typing and dispatching.
                             // This only handles the two types described in the initial implementation.
                             // Less trivial types (strings, maps, arrays) warrant additional
                             // design discussion before being exposed through an interface
                             // like this one.
                             // Also reference https://gitlab.com/gromacs/gromacs/-/issues/2993

                             // We can use templates and/or tag dispatch in a more complete
                             // future implementation.
                             const auto& paramType = gmxapicompat::mdParamToType(key);
                             if (paramType == GmxapiType::FLOAT64)
                             {
                                 dictionary[key.c_str()] = extractParam(self, key, double());
                             }
                             else if (paramType == GmxapiType::INT64)
                             {
                                 dictionary[key.c_str()] = extractParam(self, key, int64_t());
                             }
                         }
                         catch (const gmxapicompat::ValueError& e)
                         {
                             throw gmxapi::ProtocolError(std::string("Unknown parameter: ") + key);
                         }
                     }
                     return dictionary;
                 },
                 "Get a dictionary of the parameters.");

    // Overload a setter for each known type and None
    mdparams.def("set",
                 [](GmxMdParams* self, const std::string& key, int64_t value) {
                     gmxapicompat::setParam(self, key, value);
                 },
                 py::arg("key").none(false), py::arg("value").none(false),
                 "Use a dictionary to update simulation parameters.");
    mdparams.def("set",
                 [](GmxMdParams* self, const std::string& key, double value) {
                     gmxapicompat::setParam(self, key, value);
                 },
                 py::arg("key").none(false), py::arg("value").none(false),
                 "Use a dictionary to update simulation parameters.");
    mdparams.def("set",
                 [](GmxMdParams* self, const std::string& key, py::none) {
                     // unsetParam(self, key);
                 },
                 py::arg("key").none(false), py::arg("value"),
                 "Use a dictionary to update simulation parameters.");


    py::class_<TprReadHandle> tprfile(module, "TprFile");
    tprfile.def("params", [](const TprReadHandle& self) {
        auto params = gmxapicompat::getMdParams(self);
        return params;
    });

    module.def("read_tprfile", &readTprFile, py::arg("filename"),
               "Get a handle to a TPR file resource for a given file name.");

    module.def("write_tprfile",
               [](std::string filename, const GmxMdParams& parameterObject) {
                   auto tprReadHandle = gmxapicompat::getSourceFileHandle(parameterObject);
                   auto params        = gmxapicompat::getMdParams(tprReadHandle);
                   auto structure     = gmxapicompat::getStructureSource(tprReadHandle);
                   auto state         = gmxapicompat::getSimulationState(tprReadHandle);
                   auto topology      = gmxapicompat::getTopologySource(tprReadHandle);
                   gmxapicompat::writeTprFile(filename, *params, *structure, *state, *topology);
               },
               py::arg("filename").none(false), py::arg("parameters"),
               "Write a new TPR file with the provided data.");

    module.def("copy_tprfile",
               [](const gmxapicompat::TprReadHandle& input, std::string outFile) {
                   return gmxapicompat::copy_tprfile(input, outFile);
               },
               py::arg("source"), py::arg("destination"),
               "Copy a TPR file from ``source`` to ``destination``.");

    module.def("rewrite_tprfile",
               [](std::string input, std::string output, double end_time) {
                   return gmxapicompat::rewrite_tprfile(input, output, end_time);
               },
               py::arg("source"), py::arg("destination"), py::arg("end_time"),
               "Copy a TPR file from ``source`` to ``destination``, replacing `nsteps` with "
               "``end_time``.");
}

} // end namespace gmxpy
