// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2023 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
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// modification, are permitted provided that the following conditions are met:
//
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//   this list of conditions and the following disclaimer.
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//   this list of conditions and the following disclaimer in the documentation
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/callbacks.h"

#include <algorithm>
#include <iostream>  // NO LINT
#include <string>

#include "ceres/program.h"
#include "ceres/stringprintf.h"
#include "glog/logging.h"

namespace ceres::internal {

StateUpdatingCallback::StateUpdatingCallback(Program* program,
                                             double* parameters)
    : program_(program), parameters_(parameters) {}

StateUpdatingCallback::~StateUpdatingCallback() = default;

CallbackReturnType StateUpdatingCallback::operator()(
    const IterationSummary& /*summary*/) {
  program_->StateVectorToParameterBlocks(parameters_);
  program_->CopyParameterBlockStateToUserState();
  return SOLVER_CONTINUE;
}

GradientProblemSolverStateUpdatingCallback::
    GradientProblemSolverStateUpdatingCallback(
        int num_parameters,
        const double* internal_parameters,
        double* user_parameters)
    : num_parameters_(num_parameters),
      internal_parameters_(internal_parameters),
      user_parameters_(user_parameters) {}

GradientProblemSolverStateUpdatingCallback::
    ~GradientProblemSolverStateUpdatingCallback() = default;

CallbackReturnType GradientProblemSolverStateUpdatingCallback::operator()(
    const IterationSummary& summary) {
  if (summary.step_is_successful) {
    std::copy_n(internal_parameters_, num_parameters_, user_parameters_);
  }
  return SOLVER_CONTINUE;
}

LoggingCallback::LoggingCallback(const MinimizerType minimizer_type,
                                 const bool log_to_stdout)
    : minimizer_type(minimizer_type), log_to_stdout_(log_to_stdout) {}

LoggingCallback::~LoggingCallback() = default;

CallbackReturnType LoggingCallback::operator()(
    const IterationSummary& summary) {
  std::string output;
  if (minimizer_type == LINE_SEARCH) {
    output = StringPrintf(
        "% 4d: f:% 8e d:% 3.2e g:% 3.2e h:% 3.2e s:% 3.2e e:% 3d it:% 3.2e "
        "tt:% 3.2e",
        summary.iteration,
        summary.cost,
        summary.cost_change,
        summary.gradient_max_norm,
        summary.step_norm,
        summary.step_size,
        summary.line_search_function_evaluations,
        summary.iteration_time_in_seconds,
        summary.cumulative_time_in_seconds);
  } else if (minimizer_type == TRUST_REGION) {
    // clang-format off
    if (summary.iteration == 0) {
      output = "iter      cost      cost_change  |gradient|   |step|    tr_ratio  tr_radius  ls_iter  iter_time  total_time\n";  // NOLINT
    }
    output += StringPrintf(
        "% 4d % 8e   % 3.2e   % 3.2e  % 3.2e  % 3.2e % 3.2e     % 4d   % 3.2e   % 3.2e",  // NOLINT
        // clang-format on
        summary.iteration,
        summary.cost,
        summary.cost_change,
        summary.gradient_max_norm,
        summary.step_norm,
        summary.relative_decrease,
        summary.trust_region_radius,
        summary.linear_solver_iterations,
        summary.iteration_time_in_seconds,
        summary.cumulative_time_in_seconds);
  } else {
    LOG(FATAL) << "Unknown minimizer type.";
  }

  if (log_to_stdout_) {
    std::cout << output << std::endl;
  } else {
    VLOG(1) << output;
  }
  return SOLVER_CONTINUE;
}

}  // namespace ceres::internal