/*
 * ECOS - Embedded Conic Solver.
 * Copyright (C) 2012-2015 A. Domahidi [domahidi@embotech.com],
 * Automatic Control Lab, ETH Zurich & embotech GmbH, Zurich, Switzerland.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


/*
 * The branch and bound module is (c) Han Wang, Stanford University, 
 * [hanwang2@stanford.edu] 
 */

#ifndef __ecos_bb_H__
#define __ecos_bb_H__

#include "ecos.h"
#include "spla.h"
#include "glblopts.h"

/* Print verbosity */
#define MI_PRINTLEVEL (1)

/* ecos_bb configuration settings */
#define MI_ABS_EPS (1E-6)
#define MI_REL_EPS (1E-3)
#define MI_MAXITER (1000)
#define MI_INT_TOL (FTOL_INACC)

/* Flags */
#define MI_SOLVED_NON_BRANCHABLE (3)
#define MI_SOLVED_BRANCHABLE (2)
#define MI_NOT_SOLVED (1)
#define MI_FREE (0)

#define MI_ONE (1)
#define MI_ZERO (0)
#define MI_STAR (-1)

/*** Exit flags ***/
/*ECOS_BB found optimal solution*/
#define MI_OPTIMAL_SOLN (ECOS_OPTIMAL) 
/*ECOS_BB proved problem is infeasible*/
#define MI_INFEASIBLE (ECOS_PINF)	   
/*ECOS_BB proved problem is unbounded*/
#define MI_UNBOUNDED (ECOS_DINF)	   
/*ECOS_BB hit maximum iterations but a feasible solution was found and the best seen feasible solution was returned*/
#define MI_MAXITER_FEASIBLE_SOLN (ECOS_OPTIMAL + ECOS_INACC_OFFSET) 
/*ECOS_BB hit maximum iterations without finding a feasible solution*/
#define MI_MAXITER_NO_SOLN (ECOS_PINF + ECOS_INACC_OFFSET)
/*ECOS_BB hit maximum iterations without finding a feasible solution that was unbounded*/
#define MI_MAXITER_UNBOUNDED (ECOS_DINF + ECOS_INACC_OFFSET)

/* Max integer and all smaller integer representable by single precision */
#define MAX_FLOAT_INT (8388608)

/* define INFINITY and isinf for MSFT */
#ifdef _MSC_VER
#include "float.h"
#define INFINITY (DBL_MAX+DBL_MAX)
/* this will also return true if x is nan, but we don't check that anyway */
#define isinf(x) (!_finite(x))
#endif

#ifdef __cplusplus
extern "C" {
#endif

typedef struct settings_bb{
	idxint maxit;               /* maximum number of iterations         */
    idxint verbose;             /* verbosity bool for PRINTLEVEL < 3    */
	pfloat abs_tol_gap;			/* termination criteria |U-L|    		*/
	pfloat rel_tol_gap;			/* termination criteria for |U-L|/|L| < 3    */
	pfloat integer_tol; 		/* integer rounding tolerance */
} settings_bb;

typedef struct node {
	char status;
	pfloat L;
	pfloat U;
	idxint split_idx;
	pfloat split_val;
} node;

/* Wrapper for mixed integer module */
typedef struct ecos_bb_pwork{
	/* Mixed integer data */
	idxint num_bool_vars;
	idxint num_int_vars;

	node* nodes;
	char* bool_node_ids;
	pfloat* int_node_ids;

	idxint* bool_vars_idx;
	idxint* int_vars_idx;

	/* ECOS data */
	pwork* ecos_prob;

	/* Modified pointers to ecos internals */
	/* Use these to edit or reset the h variables */
	spmat* A;
	spmat* G;
	pfloat* c;
	pfloat* b;
	pfloat* h;

	/* best iterate seen so far */
    /* variables */
    pfloat* x;  /* primal variables                    */
    pfloat* y;  /* multipliers for equality constaints */
    pfloat* z;  /* multipliers for conic inequalities  */
    pfloat* s;  /* slacks for conic inequalities       */
    pfloat kap; /* kappa (homogeneous embedding)       */
	pfloat tau; /* tau (homogeneous embedding)         */
    stats* info; /* info of best iterate               */
	pfloat global_U;
	pfloat global_L;

	/* Tmp data */
	char* tmp_bool_node_id;
	pfloat* tmp_int_node_id;
	idxint iter;

	/* Stored pointers to prevent memory leaks */
	pfloat* Gpr_new;
	idxint* Gjc_new;
	idxint* Gir_new;
	pfloat* h_new;

	/* settings struct */
	settings* ecos_stgs;
	settings_bb* stgs;
	idxint default_settings;

} ecos_bb_pwork;

ecos_bb_pwork* ECOS_BB_setup(
    idxint n, idxint m, idxint p,
    idxint l, idxint ncones, idxint* q, idxint nex,
    pfloat* Gpr, idxint* Gjc, idxint* Gir,
    pfloat* Apr, idxint* Ajc, idxint* Air,
    pfloat* c, pfloat* h, pfloat* b,
    idxint num_bool_vars, idxint* bool_vars_idx,
    idxint num_int_vars, idxint* int_vars_idx,
    settings_bb* stgs);

idxint ECOS_BB_solve(ecos_bb_pwork* prob);

void ECOS_BB_cleanup(ecos_bb_pwork* prob, idxint num_vars_keep);

void updateDataEntry_h(ecos_bb_pwork* w, idxint idx, pfloat value);

void updateDataEntry_c(ecos_bb_pwork* w, idxint idx, pfloat value);

settings_bb* get_default_ECOS_BB_settings();

/* Calculate the offset into the node_id array */
static inline char* get_bool_node_id(idxint idx, ecos_bb_pwork* prob){
    return &prob->bool_node_ids[prob->num_bool_vars * idx];
}

static inline pfloat* get_int_node_id(idxint idx, ecos_bb_pwork* prob){
    return &prob->int_node_ids[prob->num_int_vars * idx * 2];
}

static inline pfloat abs_2(pfloat number){
	return number < 0.0 ? -number : number;
}

static inline pfloat pfloat_round(pfloat number){
    return (number >= 0) ? (int)(number + 0.5) : (int)(number - 0.5);
}

static inline pfloat pfloat_ceil(pfloat number, pfloat integer_tol){
	return (pfloat) (number < 0 ? (int) number : (int) (number+(1-integer_tol)) );
}

static inline pfloat pfloat_floor(pfloat number, pfloat integer_tol){
    return (pfloat) (number < 0 ? (int) (number-(1-integer_tol)) : (int) number);
}

static inline idxint float_eqls(pfloat a, pfloat b, pfloat integer_tol){
	return abs_2(a - b) < integer_tol;
}

#ifdef __cplusplus
}
#endif

#endif