#include "OutputWriter.hpp"

#include <opm/core/io/eclipse/EclipseWriter.hpp>
#include <opm/core/utility/parameters/Parameter.hpp>
#include <opm/core/utility/parameters/ParameterGroup.hpp>

#include <forward_list>
#include <map>
#include <memory> // unique_ptr

using namespace std;
using namespace Opm;
using namespace Opm::parameter;

namespace {

/// Multiplexer over a list of output writers
struct MultiWriter : public OutputWriter {
    /// Shorthand for a list of owned output writers
    typedef forward_list <unique_ptr <OutputWriter> > writers_t;
    typedef writers_t::iterator it_t;
    typedef unique_ptr <writers_t> ptr_t;

    /// Adopt a list of writers
    MultiWriter (ptr_t writers) : writers_ (std::move (writers)) { }

    /// Forward the call to all writers
    virtual void writeInit(const SimulatorTimer &timer,
                           const SimulatorState& reservoirState,
                           const WellState& wellState) {
        for (it_t it = writers_->begin (); it != writers_->end (); ++it) {
            (*it)->writeInit (timer, reservoirState, wellState);
        }
    }

    virtual void writeTimeStep(const SimulatorTimer& timer,
                                 const SimulatorState& reservoirState,
                                 const WellState& wellState) {
        for (it_t it = writers_->begin (); it != writers_->end(); ++it) {
            (*it)->writeTimeStep (timer, reservoirState, wellState);
        }
    }

private:
    ptr_t writers_;
};

/// Psuedo-constructor, can appear in template
template <typename Format> unique_ptr <OutputWriter>
create (const ParameterGroup& params,
        std::shared_ptr <const EclipseGridParser> parser,
        std::shared_ptr <const UnstructuredGrid> grid) {
    return unique_ptr <OutputWriter> (new Format (params, parser, grid));
}

/// Map between keyword in configuration and the corresponding
/// constructor function (type) that should be called when detected.
/// The writer must have a constructor which takes params and parser.
///
/// If you want to add more possible writer formats, just add them
/// to the list below!
typedef map <const char*, unique_ptr <OutputWriter> (*)(
        const ParameterGroup&,
        std::shared_ptr <const EclipseGridParser>,
        std::shared_ptr <const UnstructuredGrid>)> map_t;
map_t FORMATS = {
    { "output_ecl", &create <EclipseWriter> },
};

} // anonymous namespace

unique_ptr <OutputWriter>
OutputWriter::create (const ParameterGroup& params,
                      std::shared_ptr <const EclipseGridParser> parser,
                      std::shared_ptr <const UnstructuredGrid> grid) {
    // allocate a list which will be filled with writers. this list
    // is initially empty (no output).
    MultiWriter::ptr_t list (new MultiWriter::writers_t ());

    // loop through the map and see if we can find the key that is
    // specified there
    typedef map_t::iterator map_it_t;
    for (map_it_t it = FORMATS.begin (); it != FORMATS.end(); ++it) {
        // keyword which would indicate that this format should be used
        const std::string name (it->first);

        // invoke the constructor for the type if we found the keyword
        // and put the pointer to this writer onto the list
        if (params.getDefault <bool> (name, false)) {
            list->push_front (it->second (params, parser, grid));
        }
    }

    // create a multiplexer from the list of formats we found
    return unique_ptr <OutputWriter> (new MultiWriter (std::move (list)));
}