#ifndef VIENNA_RNA_PACKAGE_EXTERIOR_LOOPS_H
#define VIENNA_RNA_PACKAGE_EXTERIOR_LOOPS_H

#include <ViennaRNA/data_structures.h>
#include <ViennaRNA/params.h>

/**
 *  @file     exterior_loops.h
 *  @ingroup  loops
 *  @brief    Energy evaluation of exterior loops for MFE and partition function calculations
 */

/**
 *  @{
 *  @ingroup   loops
 *
 */

/**
 *  @brief  Auxiliary helper arrays for fast exterior loop computations
 *
 *  @see vrna_exp_E_ext_fast_init(), vrna_exp_E_ext_fast_rotate(),
 *  vrna_exp_E_ext_fast_free(), vrna_exp_E_ext_fast()
 */
typedef struct {
  FLT_OR_DBL  *qq;
  FLT_OR_DBL  *qq1;

  int         qqu_size;
  FLT_OR_DBL  **qqu;
} vrna_mx_pf_aux_el_t;


/**
 *  <H2>Compute the Energy contribution of an Exterior loop stem</H2>
 *  This definition is a wrapper for the E_Stem() function.
 *  It is substituted by an E_Stem() function call with argument
 *  extLoop=1, so the energy contribution returned reflects a
 *  stem introduced in an exterior-loop.<BR>
 *  As for the parameters si1 and sj1 of the substituted
 *  E_Stem() function, you can inhibit to take 5'-, 3'-dangles
 *  or mismatch contributions to be taken into account by passing
 *  -1 to these parameters.
 * 
 *  @see    E_Stem()
 *  @param  type  The pair type of the stem-closing pair
 *  @param  si1   The 5'-mismatching nucleotide
 *  @param  sj1   The 3'-mismatching nucleotide
 *  @param  P     The data structure containing scaled energy parameters
 *  @return       The energy contribution of the introduced exterior-loop stem
 */
int E_ExtLoop(int type,
              int si1,
              int sj1,
              vrna_param_t *P);

/**
 *  This is the partition function variant of @ref E_ExtLoop()
 *  @see E_ExtLoop()
 *  @return The Boltzmann weighted energy contribution of the introduced exterior-loop stem
 */
FLT_OR_DBL exp_E_ExtLoop( int type,
                      int si1,
                      int sj1,
                      vrna_exp_param_t *P);

/**
 *  <H2>Compute the energy contribution of a stem branching off a loop-region</H2>
 *  This function computes the energy contribution of a stem that branches off
 *  a loop region. This can be the case in multiloops, when a stem branching off
 *  increases the degree of the loop but also <I>immediately interior base pairs</I>
 *  of an exterior loop contribute free energy.
 *  To switch the behavior of the function according to the evaluation of a multiloop-
 *  or exterior-loop-stem, you pass the flag 'extLoop'.
 *  The returned energy contribution consists of a TerminalAU penalty if the pair type
 *  is greater than 2, dangling end contributions of mismatching nucleotides adjacent to
 *  the stem if only one of the si1, sj1 parameters is greater than 0 and mismatch energies
 *  if both mismatching nucleotides are positive values.
 *  Thus, to avoid incorporating dangling end or mismatch energies just pass a negative number,
 *  e.g. -1 to the mismatch argument.
 * 
 *  This is an illustration of how the energy contribution is assembled:
 *  <PRE>
 *        3'  5'
 *        |   |
 *        X - Y
 *  5'-si1     sj1-3'
 *  </PRE>
 * 
 *  Here, (X,Y) is the base pair that closes the stem that branches off a loop region.
 *  The nucleotides si1 and sj1 are the 5'- and 3'- mismatches, respectively. If the base pair
 *  type of (X,Y) is greater than 2 (i.e. an A-U or G-U pair, the TerminalAU penalty will be
 *  included in the energy contribution returned. If si1 and sj1 are both nonnegative numbers,
 *  mismatch energies will also be included. If one of si1 or sj1 is a negative value, only
 *  5' or 3' dangling end contributions are taken into account. To prohibit any of these mismatch
 *  contributions to be incorporated, just pass a negative number to both, si1 and sj1.
 *  In case the argument extLoop is 0, the returned energy contribution also includes
 *  the <I>internal-loop-penalty</I> of a multiloop stem with closing pair type.
 * 
 *  @see    E_MLstem()
 *  @see    E_ExtLoop()
 *  @note   This function is threadsafe
 * 
 *  @param  type    The pair type of the first base pair un the stem
 *  @param  si1     The 5'-mismatching nucleotide
 *  @param  sj1     The 3'-mismatching nucleotide
 *  @param  extLoop A flag that indicates whether the contribution reflects the one of an exterior loop or not
 *  @param  P       The data structure containing scaled energy parameters
 *  @return         The Free energy of the branch off the loop in dcal/mol
 * 
 */
int E_Stem( int type,
            int si1,
            int sj1,
            int extLoop,
            vrna_param_t *P);

/**
 *  <H2>Compute the Boltzmann weighted energy contribution of a stem branching off a loop-region</H2>
 *  This is the partition function variant of @ref E_Stem()
 *  @see E_Stem()
 *  @note This function is threadsafe
 * 
 *  @return The Boltzmann weighted energy contribution of the branch off the loop
 */
FLT_OR_DBL exp_E_Stem(int type,
                  int si1,
                  int sj1,
                  int extLoop,
                  vrna_exp_param_t *P);


int
E_ext_loop( int i,
            int j,
            vrna_fold_compound_t *vc);

void
E_ext_loop_5( vrna_fold_compound_t *vc);

int
vrna_BT_ext_loop_f5(vrna_fold_compound_t *vc,
                    int *k,
                    int *i,
                    int *j,
                    vrna_bp_stack_t *bp_stack,
                    int *stack_count);


vrna_mx_pf_aux_el_t *
vrna_exp_E_ext_fast_init(vrna_fold_compound_t *vc);


void
vrna_exp_E_ext_fast_rotate( vrna_fold_compound_t  *vc,
                            vrna_mx_pf_aux_el_t   *aux_mx);


void
vrna_exp_E_ext_fast_free( vrna_fold_compound_t  *vc,
                          vrna_mx_pf_aux_el_t   *aux_mx);


FLT_OR_DBL
vrna_exp_E_ext_fast(vrna_fold_compound_t  *vc,
                    int                   i,
                    int                   j,
                    vrna_mx_pf_aux_el_t   *aux_mx);

/**
 * @}
 */


#endif