# Ceres Solver - A fast non-linear least squares minimizer
# Copyright 2023 Google Inc. All rights reserved.
# http://ceres-solver.org/
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
#   this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
# * Neither the name of Google Inc. nor the names of its contributors may be
#   used to endorse or promote products derived from this software without
#   specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# Author: sameeragarwal@google.com (Sameer Agarwal)
#
# Script for explicitly generating template specialization of the
# SchurEliminator class. It is a rather large class
# and the number of explicit instantiations is also large. Explicitly
# generating these instantiations in separate .cc files breaks the
# compilation into separate compilation unit rather than one large cc
# file which takes 2+GB of RAM to compile.
#
# This script creates three sets of files.
#
# 1. schur_eliminator_x_x_x.cc and partitioned_matrix_view_x_x_x.cc
# where, the x indicates the template parameters and
#
# 2. schur_eliminator.cc & partitioned_matrix_view.cc
#
# that contains a factory function for instantiating these classes
# based on runtime parameters.
#
# 3. schur_templates.cc
#
# that contains a function which can be queried to determine what
# template specializations are available.
#
# The following list of tuples, specializations indicates the set of
# specializations that is generated.
SPECIALIZATIONS = [(2, 2, 2),
                   (2, 2, 3),
                   (2, 2, 4),
                   (2, 2, "Eigen::Dynamic"),
                   (2, 3, 3),
                   (2, 3, 4),
                   (2, 3, 6),
                   (2, 3, 9),
                   (2, 3, "Eigen::Dynamic"),
                   (2, 4, 3),
                   (2, 4, 4),
                   (2, 4, 6),
                   (2, 4, 8),
                   (2, 4, 9),
                   (2, 4, "Eigen::Dynamic"),
                   (2, "Eigen::Dynamic", "Eigen::Dynamic"),
                   (3, 3, 3),
                   (4, 4, 2),
                   (4, 4, 3),
                   (4, 4, 4),
                   (4, 4, "Eigen::Dynamic")]

import schur_eliminator_template
import partitioned_matrix_view_template
import os
import glob

def SuffixForSize(size):
  if size == "Eigen::Dynamic":
    return "d"
  return str(size)

def SpecializationFilename(prefix, row_block_size, e_block_size, f_block_size):
  return "_".join([prefix] + list(map(SuffixForSize, (row_block_size,
                                                 e_block_size,
                                                 f_block_size))))

def GenerateFactoryConditional(row_block_size, e_block_size, f_block_size):
  conditionals = []
  if (row_block_size != "Eigen::Dynamic"):
    conditionals.append("(options.row_block_size == %s)" % row_block_size)
  if (e_block_size != "Eigen::Dynamic"):
    conditionals.append("(options.e_block_size == %s)" % e_block_size)
  if (f_block_size != "Eigen::Dynamic"):
    conditionals.append("(options.f_block_size == %s)" % f_block_size)
  if (len(conditionals) == 0):
    return "%s"

  if (len(conditionals) == 1):
    return "  if " + conditionals[0] + " {\n  %s\n  }\n"

  return "  if (" + " &&\n     ".join(conditionals) + ") {\n  %s\n  }\n"

def Specialize(name, data):
  """
  Generate specialization code and the conditionals to instantiate it.
  """

  # Specialization files
  for row_block_size, e_block_size, f_block_size in SPECIALIZATIONS:
      output = SpecializationFilename("generated/" + name,
                                      row_block_size,
                                      e_block_size,
                                      f_block_size) + ".cc"

      with open(output, "w") as f:
        f.write(data["HEADER"])
        f.write(data["SPECIALIZATION_FILE"] %
                  (row_block_size, e_block_size, f_block_size))

  # Generate the _d_d_d specialization.
  output = SpecializationFilename("generated/" + name,
                                   "Eigen::Dynamic",
                                   "Eigen::Dynamic",
                                   "Eigen::Dynamic") + ".cc"
  with open(output, "w") as f:
    f.write(data["HEADER"])
    f.write(data["DYNAMIC_FILE"] %
              ("Eigen::Dynamic", "Eigen::Dynamic", "Eigen::Dynamic"))

  # Factory
  with open(name + ".cc", "w") as f:
    f.write(data["HEADER"])
    f.write(data["FACTORY_FILE_HEADER"])
    for row_block_size, e_block_size, f_block_size in SPECIALIZATIONS:
        factory_conditional = GenerateFactoryConditional(
            row_block_size, e_block_size, f_block_size)
        factory = data["FACTORY"] % (row_block_size, e_block_size, f_block_size)
        f.write(factory_conditional % factory);
    f.write(data["FACTORY_FOOTER"])

QUERY_HEADER = """// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
// * Neither the name of Google Inc. nor the names of its contributors may be
//   used to endorse or promote products derived from this software without
//   specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Author: sameeragarwal@google.com (Sameer Agarwal)
//
// What template specializations are available.
//
// ========================================
// THIS FILE IS AUTOGENERATED. DO NOT EDIT.
// THIS FILE IS AUTOGENERATED. DO NOT EDIT.
// THIS FILE IS AUTOGENERATED. DO NOT EDIT.
// THIS FILE IS AUTOGENERATED. DO NOT EDIT.
//=========================================
//
// This file is generated using generate_template_specializations.py.
"""

QUERY_FILE_HEADER = """
#include "ceres/internal/eigen.h"
#include "ceres/schur_templates.h"

namespace ceres {
namespace internal {

void GetBestSchurTemplateSpecialization(int* row_block_size,
                                        int* e_block_size,
                                        int* f_block_size) {
  LinearSolver::Options options;
  options.row_block_size = *row_block_size;
  options.e_block_size = *e_block_size;
  options.f_block_size = *f_block_size;
  *row_block_size = Eigen::Dynamic;
  *e_block_size = Eigen::Dynamic;
  *f_block_size = Eigen::Dynamic;
#ifndef CERES_RESTRICT_SCHUR_SPECIALIZATION
"""

QUERY_FOOTER = """
#endif
  return;
}

}  // namespace internal
}  // namespace ceres
"""

QUERY_ACTION = """  *row_block_size = %s;
    *e_block_size = %s;
    *f_block_size = %s;
    return;"""

def GenerateQueryFile():
  """
  Generate file that allows querying for available template specializations.
  """

  with open("schur_templates.cc", "w") as f:
    f.write(QUERY_HEADER)
    f.write(QUERY_FILE_HEADER)
    for row_block_size, e_block_size, f_block_size in SPECIALIZATIONS:
      factory_conditional = GenerateFactoryConditional(
        row_block_size, e_block_size, f_block_size)
      action = QUERY_ACTION % (row_block_size, e_block_size, f_block_size)
      f.write(factory_conditional % action)
    f.write(QUERY_FOOTER)


if __name__ == "__main__":
  for f in glob.glob("generated/*"):
    os.remove(f)

  Specialize("schur_eliminator",
               schur_eliminator_template.__dict__)
  Specialize("partitioned_matrix_view",
               partitioned_matrix_view_template.__dict__)
  GenerateQueryFile()