/* Ceres Solver - A fast non-linear least squares minimizer
 * Copyright 2013 Google Inc. All rights reserved.
 * http://code.google.com/p/ceres-solver/
 *
 * 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: mierle@gmail.com (Keir Mierle)
 *
 * A minimal C API for Ceres. Not all functionality is included. This API is
 * not intended for clients of Ceres, but is instead intended for easing the
 * process of binding Ceres to other languages.
 *
 * Currently this is a work in progress.
 */

#ifndef CERES_PUBLIC_C_API_H_
#define CERES_PUBLIC_C_API_H_

#ifdef __cplusplus
extern "C" {
#endif

/* Init the Ceres private data. Must be called before anything else. */
void ceres_init();

/* Equivalent to CostFunction::Evaluate() in the C++ API.
 *
 * The user is may keep private information inside the opaque user_data object.
 * The pointer here is the same one passed in the ceres_add_residual_block(). */
typedef int (*ceres_cost_function_t)(void* user_data,
                                     double** parameters,
                                     double* residuals,
                                     double** jacobians);

/* Equivalent to LossFunction::Evaluate() from the C++ API. */
typedef int (*ceres_loss_function_t)(void* user_data,
                                     double squared_norm,
                                     double out[3]);

/* Equivalent to Problem from the C++ API. */
struct ceres_problem_s;
typedef struct ceres_problem_s ceres_problem_t;

struct ceres_residual_block_id_s;
typedef struct ceres_residual_block_id_s ceres_residual_block_id_t;

/* Create and destroy a problem */
/* TODO(keir): Add options for the problem. */
ceres_problem_t* ceres_create_problem();
void ceres_free_problem(ceres_problem_t* problem);

/* Add a residual block. */
/* TODO(keir): Add support for loss functions */
ceres_residual_block_id_t* ceres_problem_add_residual_block(
    ceres_problem_t* problem,
    ceres_cost_function_t cost_function,
    ceres_loss_function_t loss_function,
    void* user_data,
    int num_residuals,
    int num_parameter_blocks,
    int* parameter_block_sizes,
    double** parameters);

void ceres_solve(ceres_problem_t* problem);

/* TODO(keir): Figure out a way to pass a config in. */

#ifdef __cplusplus
}
#endif

#endif  /* CERES_PUBLIC_C_API_H_ */