/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2015-2023 Advanced Micro Devices, Inc. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <migraphx/split_single_dyn_dim.hpp>
#include <migraphx/module.hpp>
#include <migraphx/pass_manager.hpp>
#include <migraphx/functional.hpp>
#include <migraphx/make_op.hpp>
#include <migraphx/ranges.hpp>
#include <migraphx/matcher.hpp>

namespace migraphx {
inline namespace MIGRAPHX_INLINE_NS {

struct dynamic_dimensions_check
{
    std::string dyn_param_str;
    shape::dynamic_dimension dd;
};

/**
 * Returns value if the parameters contain one non-fixed dynamic_dimension that is the same between
 * all of the dynamic shape parameters.
 * Returns the parameters and the dynamic dimension in a vector of dynamic_dimensions_check objects.
 */
optional<std::vector<dynamic_dimensions_check>>
has_one_unique_dyn_dim(const std::unordered_map<std::string, shape>& param_shapes)
{
    if(param_shapes.empty())
    {
        return std::nullopt;
    }
    auto is_dynamic = [](const auto& p) { return p.second.dynamic(); };
    std::vector<std::decay_t<decltype(param_shapes)>::value_type> dyn_params{};
    std::copy_if(
        param_shapes.begin(), param_shapes.end(), std::back_inserter(dyn_params), is_dynamic);
    if(dyn_params.empty())
        return std::nullopt;
    std::vector<dynamic_dimensions_check> ret{};
    // get non-fixed dynamic_dimension from all parameters
    for(const auto& param : dyn_params)
    {
        const auto& dds   = param.second.dyn_dims();
        int num_non_fixed = 0;
        for(auto dds_it = dds.begin(); dds_it != dds.end(); ++dds_it)
        {
            if(not dds_it->is_fixed())
            {
                num_non_fixed += 1;
                // catch more than one non-fixed dynamic_dimension
                if(num_non_fixed > 1)
                {
                    return std::nullopt;
                }
                ret.push_back(dynamic_dimensions_check{param.first, *dds_it});
            }
        }
    }
    if(ret.empty())
    {
        return std::nullopt;
    }
    // check all the same dynamic_dimension
    bool same_dd =
        std::all_of(ret.begin() + 1, ret.end(), [&](auto ddc) { return ddc.dd == ret.at(0).dd; });
    if(same_dd)
    {
        return ret;
    }
    return std::nullopt;
}

/**
 * Check the parameters in std::vector<dynamic_dimensions_check> object to see if any of the
 * parameters outputs to a select_module operator.
 */
bool any_sm_next(const_module_ref mm, const std::vector<dynamic_dimensions_check>& ddcs)
{
    for(const auto& ddc : ddcs)
    {
        auto p_outputs  = mm->get_parameter(ddc.dyn_param_str)->outputs();
        bool is_sm_next = std::any_of(p_outputs.cbegin(), p_outputs.cend(), [](auto ins) {
            return ins->name() == "select_module";
        });
        if(is_sm_next)
        {
            return true;
        };
    }
    return false;
}

/**
 * Makes all the shapes in the dynamic_dimension range.  Probably won't work for `if`
 * and `loop` instructions, depending on how the submodules for those
 * work. Inserts select_module instruction to the top. Replaces return, bypassing other
 * instructions. Skips if the dynamic parameter outputs to a select_module operator.
 */
void split_single_dyn_dim::apply(module_pass_manager& mpm) const
{
    module_ref mm                               = &mpm.get_module();
    auto param_names                            = mm->get_parameter_names();
    auto param_shapes                           = mm->get_parameter_shapes();
    optional<std::vector<dynamic_dimensions_check>> dd_check_vec =
        has_one_unique_dyn_dim(param_shapes);
    if(dd_check_vec.has_value() and not any_sm_next(mm, dd_check_vec.value()))
    {
        // all dynamic dimension objects should be the same for all parameters in dd_check_vec
        auto dyn_dim = dd_check_vec->at(0).dd;
        // create submodules for each dimension size
        std::vector<module_ref> submodules;
        for(size_t dim_size : migraphx::range(dyn_dim.min, dyn_dim.max + 1))
        {
            auto* submod = mpm.create_module("dim_" + std::to_string(dim_size));
            // instruction map for new static shaped submodule parameters
            std::unordered_map<instruction_ref, instruction_ref> map_ins;
            for(const auto& dd_check : dd_check_vec.value())
            {
                // create static shape using dim_size
                const auto& dyn_param = mm->get_parameter(dd_check.dyn_param_str);
                auto dyn_param_shape  = mm->get_parameter_shape(dd_check.dyn_param_str);
                auto static_shape     = dyn_param_shape.to_static(dim_size);
                map_ins[dyn_param]    = submod->add_parameter(dd_check.dyn_param_str, static_shape);
            }
            auto outputs = submod->add_instructions(mm, map_ins);
            submod->add_return({outputs});
            submodules.push_back(submod);
        }
        // redirect to select_module operator and return
        std::vector<instruction_ref> sm_inputs;
        std::transform(param_names.cbegin(),
                       param_names.cend(),
                       std::back_inserter(sm_inputs),
                       [&](auto pn) { return mm->get_parameter(pn); });
        auto output_shapes       = mm->get_output_shapes();
        migraphx::shape out_attr = migraphx::shape{output_shapes};
        auto sm_ins              = mm->add_instruction(
            migraphx::make_op("select_module",
                              {{"output_dyn_shapes", migraphx::to_value(out_attr)}}),
            sm_inputs,
            submodules);
        std::vector<instruction_ref> outputs(output_shapes.size());
        for(size_t i = 0; i < output_shapes.size(); ++i)
        {
            outputs.at(i) =
                mm->add_instruction(migraphx::make_op("get_tuple_elem", {{"index", i}}), sm_ins);
        }
        mm->replace_return(outputs);
    }
}

} // namespace MIGRAPHX_INLINE_NS
} // namespace migraphx
