#include <migraphx/onnx/op_parser.hpp>
#include <migraphx/instruction.hpp>
#include <migraphx/ranges.hpp>
#include <migraphx/make_op.hpp>

namespace migraphx {
inline namespace MIGRAPHX_INLINE_NS {
namespace onnx {

struct parse_split : op_parser<parse_split>
{
    std::vector<op_desc> operators() const { return {{"Split"}}; }

    std::vector<instruction_ref> parse(const op_desc& /*opd*/,
                                       const onnx_parser& parser,
                                       onnx_parser::node_info info,
                                       std::vector<instruction_ref> args) const
    {
        int64_t axis = 0;
        if(contains(info.attributes, "axis"))
        {
            axis = parser.parse_value(info.attributes.at("axis")).at<int>();
        }

        auto lens      = args[0]->get_shape().lens();
        int64_t n_rank = static_cast<int64_t>(lens.size());
        if((axis < -n_rank) || (axis >= n_rank))
        {
            MIGRAPHX_THROW("PARSE_SPLIT: axis attribute out of rank!");
        }
        int64_t tuned_axis = (axis < 0) ? axis + n_rank : axis;

        std::vector<int64_t> vec_splits;
        if(contains(info.attributes, "split"))
        {
            literal s = parser.parse_value(info.attributes.at("split"));
            s.visit([&](auto v) { vec_splits.assign(v.begin(), v.end()); });

            if(std::accumulate(vec_splits.begin(), vec_splits.end(), int64_t(0)) !=
               static_cast<int64_t>(lens[tuned_axis]))
            {
                MIGRAPHX_THROW("PARSE_SPLIT: sum of split attribute unequal to dim size of axis!");
            }
        }
        // no split attribute, input is equally divided
        else
        {
            if((lens[tuned_axis] % info.num_outputs) != 0)
            {
                MIGRAPHX_THROW("PARSE_SPLIT: input cannot be equally divided into " +
                               std::to_string(info.num_outputs) + " splits!");
            }
            auto dl = lens[tuned_axis] / info.num_outputs;
            vec_splits.resize(info.num_outputs, dl);
        }

        std::vector<instruction_ref> ret_ins;
        int64_t start = 0;
        for(auto sl : vec_splits)
        {
            ret_ins.push_back(info.add_instruction(
                make_op("slice", {{"axes", {axis}}, {"starts", {start}}, {"ends", {start + sl}}}),
                args[0]));
            start += sl;
        }

        return ret_ins;
    }
};

} // namespace onnx
} // namespace MIGRAPHX_INLINE_NS
} // namespace migraphx
