#! /bin/sh
#!perl -w # --*- Perl -*--
eval 'exec perl -x $0 ${1+"$@"}'
    if 0;
#------------------------------------------------------------------------------
#$Author: antanas $
#$Date: 2021-04-28 23:13:31 +0300 (Wed, 28 Apr 2021) $
#$Revision: 8746 $
#$URL: svn+ssh://www.crystallography.net/home/coder/svn-repositories/cod-tools/tags/v3.8.0/scripts/cif_Fcalc $
#------------------------------------------------------------------------------
#*
#* Compute the structure factors from CIF files.
#*
#* USAGE:
#*    $0 --options input1.cif input*.cif
#**

# The implementation in this program follows the principles published in:

# (Yvon1977) Yvon, K.; Jeitschko, W. & Parthé, E. it LAZY PULVERIX, a
# computer program, for calculating X-ray and neutron diffraction
# powder patterns Journal of Applied Crystallography, 1977, 10, 73-74
# http://dx.doi.org/10.1107/S0021889877012898

# Exponential form of the structure factor was expanded how in
# (Wallwork, S. C., Introduction to the calculation of structure factors,
# published Cardiff [Wales] : Published for the International Union of
# Crystallography by University College Cardiff Press, 1980.)
# http://www.iucr.org/__data/assets/pdf_file/0015/13083/3.pdf

use strict;
use warnings;
use Math::Trig qw( deg2rad rad2deg pi );
use List::MoreUtils qw( any );
use COD::CIF::Parser qw( parse_cif );
use COD::CIF::Data::AtomList qw( atom_array_from_cif );
use COD::CIF::Data qw( get_cell );
use COD::Algebra::Vector qw( distance );
use COD::Spacegroups::Symop::Algebra qw( symop_vector_mul );
use COD::Spacegroups::Symop::Parse qw( modulo_1
                                       symop_from_string );
use COD::Precision qw( unpack_cif_number );
use COD::CromerMann;
use COD::CIF::Data qw( get_symmetry_operators );
use COD::Fractional qw( symop_ortho_from_fract );
use COD::SOptions qw( getOptions );
use COD::SUsage qw( usage options );
use COD::ErrorHandler qw( process_warnings
                          process_errors
                          process_parser_messages
                          report_message );
use COD::ToolsVersion qw( get_version_string );

my $use_parser = 'c';

my $die_on_error_level = {
    'ERROR'   => 1,
    'WARNING' => 0,
    'NOTE'    => 0
};

my $iso_temperature_factor = 0;
my $max_resolution = 1.5; # angstrom
my @hkl_limits = (10, -10, 10, -10, 10, -10); # hmax, hmin, k..., l...
my $miller_indexes;
my $max_number_print_of_F;
my $use_external_CR_table = 0;
my $hkl_file;

my $dump_atoms_and_neighbors = 0;

#* OPTIONS:
#*   --max-Fhkl-number
#*                     Selection of sorted (numerically and Friedel's law)
#*                     Fhkl number.
#*   --external_CR_table
#*                     Use Cromer Mann coefficients from external
#*                     source: table 6.1.1.4.
#*   --max-resolution
#*                     Selection of resolution.
#*   --isotropic-Tf
#*                     Use isotropic temperature factor for structure
#*                     factor calculations.
#*   --Miller-indexes "5 6 7 -1 2 -6"
#*                     Provide limits on the Miller indices
#*                     (hmax, hmin, kmax, kmin, lmax, lmin).
#*                     Default: '10 -10 10 -10 10 -10'.
#*   --get-hkl-data
#*                     Providing of a path to COD file which contains
#*                     hkl data.
#*
#*   --use-perl-parser
#*                     Use development CIF parser written in Perl.
#*   --use-c-parser
#*                     Use faster C/Yacc CIF parser (default).
#*
#*   --help, --usage
#*                     Output a short usage message (this message) and exit.
#*   --version
#*                     Output version information and exit.
#**
@ARGV = getOptions(
    '--max-resolution'             => \$max_resolution,
    '--max-Fhkl-number'            => \$max_number_print_of_F,
    '--isotropic-Tf'               => sub { $iso_temperature_factor = 1 },
    '--external_CR_table'          => sub { $use_external_CR_table = 1 },
    '--Miller-indexes'             => \$miller_indexes,
    '--get-hkl-data'               => \$hkl_file,
    '--use-perl-parser'            => sub{ $use_parser = 'perl' },
    '--use-c-parser'               => sub{ $use_parser = 'c' },

    '--options'      => sub { options; exit },
    '--help,--usage' => sub { usage; exit },
    '--version'      => sub { print get_version_string(), "\n"; exit }
);

binmode STDOUT, ':encoding(UTF-8)';
binmode STDERR, ':encoding(UTF-8)';

# tests for options
# --provide-Miller-indexes
if ( $miller_indexes ) {
    @hkl_limits = split /\s+/, $miller_indexes;
    for my $limit ( @hkl_limits ) {
        if ( $limit !~ /^[+-]?[0-9]+$/ ) {
            print "@hkl_limits\n";
            report_message( {
                'program'   => $0,
                'err_level' => 'ERROR',
                'message'   => 'the option \'--provide-Miller-indexes\' '
                             . 'contains incorrect argument'
            }, $die_on_error_level->{'ERROR'} );
        }
    }
}

@ARGV = ( '-' ) unless @ARGV;

my $hkl_and_F_sorted;
for my $filename (@ARGV) {

    my $options = { 'parser' => $use_parser, 'no_print' => 1 };
    my ( $data, $err_count, $messages ) = parse_cif( $filename, $options );
    process_parser_messages( $messages, $die_on_error_level );

    if( !@{$data} || !defined $data->[0] || !defined $data->[0]{name} ) {
        report_message( {
            'program'   => $0,
            'filename'  => $filename,
            'err_level' => 'WARNING',
            'message'   => 'file seems to be empty'
        }, $die_on_error_level->{'WARNING'} );
        next;
    }

    for my $datablock (@{$data}) {
        my $dataname = 'data_' . $datablock->{'name'};
        my $values = $datablock->{'values'};

        local $SIG{__WARN__} =  sub {
            process_warnings( {
                'message'       => @_,
                'program'       => $0,
                'filename'      => $filename,
                'add_pos'       => $dataname
            }, $die_on_error_level )
        };

        my @hkl_and_F;
        eval {

        my $cell_parameters = get_unit_cell_parameters( $values );
        my $atoms = atoms_from_cif( $datablock );

        my %atom_index; # contains a index in $atoms using 'label' key.
        foreach (@{$atoms}) {
            $atom_index{$_->{'site_label'}} = $_->{'index'};
        }

        # Test of aniso coefficients: if not all atoms (except H and D)
        # contains aniso coeff. than isotropic coeff. are used.
        if( !$iso_temperature_factor ) {
            foreach my $atom (@{$atoms}) {
                if( !defined $atom->{aniso_value_Uij}[0] &&
                    $atom->{'site_label'} !~ /[H|D][0-9]+/ ) {
                    warn 'WARNING, the CIF file does not contain the full '
                       . 'data of the standard anisotropic atomic displacement '
                       . 'components' . "\n";
                    if( $atom->{U_value_of_B_factor} !~ /[0-9]\.[0-9]+/ &&
                        $atom->{B_factor} !~ /[0-9]\.[0-9]+/) {
                        die 'ERROR, the CIF does not contain the correct '
                          . 'values for temperature factor calculation' . "\n";
                        }
                    $iso_temperature_factor = 1;
                    last;
                }
            }
        }

        my $atom_type_scattering = get_atom_type_scattering( $values );
        if ( $use_external_CR_table ) {
            for my $atom_type ( keys %{$atom_type_scattering} ) {
                delete $atom_type_scattering->{$atom_type}{'Cromer_Mann'};
            }
        }

        my @chemical_types = map { $_->{'chemical_type'} } @{$atoms};
        for my $chemical_type (@chemical_types) {
            next if defined $atom_type_scattering->{$chemical_type}{'Cromer_Mann'}[0];
            if ( !exists $COD::CromerMann::atoms{$chemical_type} ) {
                die 'ERROR, the Cromer-Mann coefficients are not '
                  . 'defined external source/CIF file for element '
                  . "'$chemical_type'\n";
            }
            $atom_type_scattering->{$chemical_type}{'Cromer_Mann'} =
                                    $COD::CromerMann::atoms{$chemical_type};

            print "External CR $chemical_type: ";
            print "@{$atom_type_scattering->{$chemical_type}{'Cromer_Mann'}}\n";
        }


        if( !defined $atom_type_scattering->{$atoms->[0]{'chemical_type'}}
                                            {'scat_dispersion_real'} ) {
            die 'ERROR, the CIF file does not contain the data ' .
                'of anomalous-dispersion scattering factor' . "\n";
        }

        my @abc_star = @{$cell_parameters->{reciprocal_cell_radians}}[0..2];

        my ($h_max, $h_min, $k_max, $k_min, $l_max, $l_min) = @hkl_limits;
        foreach my $h_limit ( $h_min..$h_max ) {
        foreach my $k_limit ( $k_min..$k_max ) {
        foreach my $l_limit ( $l_min..$l_max ) {
            next if( $h_limit == 0 && $k_limit == 0 && $l_limit == 0 );
            my @hkl = ($h_limit, $k_limit, $l_limit);
            my $resolution_hkl = spacing_d_hkl(
                @hkl,
                @{$cell_parameters->{reciprocal_cell_radians}} );
            next if($resolution_hkl < $max_resolution);

            my ( $F_cos_comp_w_Tf_and_cor,
                 $F_sin_comp_w_Tf_and_cor,
                 $F_cos_comp_w_cor,
                 $F_sin_comp_w_cor,
                 $F_cos_comp,
                 $F_sin_comp ) = ( 0, 0, 0, 0, 0, 0 );

            foreach my $atom (@{$atoms}) {
                my $atom_type = $atom->{'chemical_type'};

                my $Cromer_Mann_coeff =
                    $atom_type_scattering->{$atom_type}{'Cromer_Mann'};

                my $atom_structure_factor =
                    atom_structure_factor_from_coefficients(
                        $Cromer_Mann_coeff, $resolution_hkl );

                my $scat_dispersion_real =
                    $atom_type_scattering->{$atom_type}{'scat_dispersion_real'};

                my $atom_structure_factor_corrected =
                    sqrt( ( $atom_structure_factor +
                            $scat_dispersion_real )**2 +
                            $scat_dispersion_real**2 );

                foreach my $sym_xyz (@{$atom->{symmetrical_xyz_fract}}) {
                    my $atom_hkl_phase = atom_phase_hkl_rad( @hkl, @{$sym_xyz} );

                    my $temperature_factor;
                    if( !$iso_temperature_factor ) {
                    # calculation of aniso temperature factor;
                    # !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

                        if( $atom->{chemical_type} eq 'H' ) {
                            if( defined $atom->{neighbors}[0] ) {
                                my $H_neighbor_label = $atom->{neighbors}[0];
                                my $H_neighbor_index = $atom_index{$H_neighbor_label};
                                ## print "$H_neighbor_index $H_neighbor_label\n";
                                $temperature_factor =
                                    temperature_factor_aniso(
                                        @{$atoms->[$H_neighbor_index]->{aniso_value_Uij}},
                                        @hkl, @abc_star );
                                ## print "$temperature_factor\n";
                            } else {
                                $temperature_factor = 1;
                            }
                        } else {
                            $temperature_factor =
                                temperature_factor_aniso(
                                    @{$atom->{aniso_value_Uij}},
                                    @hkl, @abc_star );
                        }
                    } else { # calculation of iso temperature factor;
                        $temperature_factor =
                            exp( ( -$atom->{B_factor}/4 ) *
                                 ( 1/$resolution_hkl )**2 );
                    }

                    $F_cos_comp_w_Tf_and_cor +=
                        $atom->{atom_site_occupancy} *
                        $atom_structure_factor * cos( $atom_hkl_phase );
                    $F_sin_comp_w_Tf_and_cor +=
                        $atom->{atom_site_occupancy} *
                        $atom_structure_factor * sin( $atom_hkl_phase );
                    # structure factor components without corrections;
                    $F_cos_comp_w_cor +=
                        $atom->{atom_site_occupancy} * $atom_structure_factor *
                        $temperature_factor * cos( $atom_hkl_phase );
                    $F_sin_comp_w_cor +=
                        $atom->{atom_site_occupancy} * $atom_structure_factor *
                        $temperature_factor * sin( $atom_hkl_phase );

                    $F_cos_comp +=
                        $atom->{atom_site_occupancy} *
                        $atom_structure_factor_corrected *
                        $temperature_factor * cos( $atom_hkl_phase );
                    $F_sin_comp +=
                        $atom->{atom_site_occupancy} *
                        $atom_structure_factor_corrected *
                        $temperature_factor * sin( $atom_hkl_phase );
                } # foreach of cell atoms;
            } # foreach of asymmetric unit atoms;

            my $F_hkl_without_Tf_and_cor =
                sqrt( $F_cos_comp_w_Tf_and_cor**2 +
                      $F_sin_comp_w_Tf_and_cor**2 );
            my $F_hkl_iso_without_cor =
                sqrt( $F_cos_comp_w_cor**2 + $F_sin_comp_w_cor**2 );
            my $F_hkl_squared =
                $F_cos_comp ** 2 + $F_sin_comp ** 2;

            push @hkl_and_F, [ $F_hkl_squared, \@hkl ];

        }}} # end for

        # Sorting by F (descending):
        $hkl_and_F_sorted = [ sort { $b->[0] <=> $a->[0] } @hkl_and_F ];

        # ----------------------------------------------------

        my $search_equal_intensities = sort_Friedel( $hkl_and_F_sorted );
        if( defined $max_number_print_of_F ) {
            if( $max_number_print_of_F > @{$search_equal_intensities} ) {
                warn 'WARNING, the value of --max-Fhkl-number is larger'
                   . 'than the number of calculated structure factors -- '
                   . "printing out all structure factors\n";
            } else {
                $search_equal_intensities =
                    [ @{$search_equal_intensities}[0..($max_number_print_of_F - 1)] ];
            }
        }
        if( !defined $hkl_file ) {
            foreach my $Fri_Fhkl (@{$search_equal_intensities}) {
                my $adding_field = (' %3s %3s %3s')x$#{$Fri_Fhkl};
                printf '%0.3f'.$adding_field."\n",
                $Fri_Fhkl->[0], map{ @{$_} } @{$Fri_Fhkl}[1..$#{$Fri_Fhkl}];
            }
        }
        }; # end eval
        if ($@) {
            process_errors( {
              'message'       => $@,
              'program'       => $0,
              'filename'      => $filename,
              'add_pos'       => $dataname
            }, $die_on_error_level->{'ERROR'} )
        };
    } # end foreach data block
} # end foreach file

# for hkl data extracting from CIF.hkl and comparison with my calculated
# values;
if( defined $hkl_file ) {
    my $hkl_options = { 'parser' => $use_parser, 'no_print' => 1 };
    my ( $hkl_data, $hkl_err_count, $messages ) = parse_cif( $hkl_file,
                                                             $hkl_options );
    process_parser_messages( $messages, $die_on_error_level );
    next if ( $hkl_err_count > 0 );

    # take a top segment of calculated and sorted structure factors;
    if( defined $max_number_print_of_F ) {
        if( $max_number_print_of_F > @{$hkl_and_F_sorted} ) {
            report_message( {
                'program'   => $0,
                'filename'  => $hkl_file,
                'err_level' => 'WARNING',
                'message'   => 'the value of --max-Fhkl-number is larger '
                             . 'than the number of calculated structure '
                             . 'factors -- printing out all structure '
                             . 'factors'
            }, $die_on_error_level->{'WARNING'} );
        } else {
            $hkl_and_F_sorted =
                [ @{$hkl_and_F_sorted}[0..($max_number_print_of_F - 1)] ];
        }
    }

    for my $hkl_datablock (@{$hkl_data}) {
        my $values = $hkl_datablock->{'values'};
        my( $h_values, $k_values, $l_values,
            $F_squared_meas,
            $F_squared_calc,
            $F_squared_sigma_meas ) =
                ( $values->{_refln_index_h},
                  $values->{_refln_index_k},
                  $values->{_refln_index_l},
                  $values->{_refln_f_squared_meas},
                  $values->{_refln_f_squared_calc},
                  $values->{_refln_f_squared_sigma} );

        foreach my $calculated (@{$hkl_and_F_sorted}) {
            for my $i (0..$#{$values->{_refln_index_h}}) {
                if( $calculated->[1][0] == $h_values->[$i] &&
                    $calculated->[1][1] == $k_values->[$i] &&
                    $calculated->[1][2] == $l_values->[$i] ) {
                    if(
                        ($calculated->[0] >
                         ($F_squared_meas->[$i] - $F_squared_sigma_meas->[$i])) &&
                        ($calculated->[0] <
                         ($F_squared_meas->[$i] + $F_squared_sigma_meas->[$i]))
                        ) {
                        print 'Y ';
                    } else {
                        print 'N ';
                    }
                    my $error_squared =
                        ( abs( $F_squared_meas->[$i] - $calculated->[0] ) /
                          $F_squared_meas->[$i] ) * 100 ;
                    print  "My Calc: $calculated->[0] "
                         . "Meas: $F_squared_meas->[$i] "
                         . "Their Calc: $F_squared_calc->[$i] "
                         . "Sigma: $F_squared_sigma_meas->[$i] "
                         . " My Error: $error_squared\n";
                    last;
                }
            } # end for
        } # end foreach
    } # end for data blocks
}

#--------------------------------------------------------------------#
# Function of extracting atom information from the CIF file.
#
# Parameters:
#   $datablock
#               A reference to an array of hashes where the data from the CIF
#               file is stored.
#
# Returns:
# $atoms = [
#           # [0]
#           {
#               site_label => 'O10',
#               chemical_type => 'O',
#               coordinates_fract" => [0.1, 0.2, 0.3],
#               coordinates_ortho => [10, 20.5, 25.2],
#               atom_site_occupancy => 0.5,
#               B_factor => 0.78,
#               U_value_of_B_factor => 0.03,
#               aniso_value_Uij => [0.01, 0.002, 0.003,..,0.006] # 6 values,
# a1, a2, .., b1, b2.., b4, c.
#               symmetrical_xyz_fract => [\@xyz1, \@xyz2, .. ],
#               symmetrical_xyz_ortho => [\@xyz1, \@xyz2, .. ],
#               count_of_cell_atoms => 10, # only for first atom;
#               neighbors => [C23, C25],
#           },
#           # [1]
#           {
#             ...
#           },
#  ];
sub atoms_from_cif
{
    my( $datablock ) = @_;
    my $values = $datablock->{values};

    my @cell = get_cell( $values );
    my $f2o = symop_ortho_from_fract( @cell );

    my $themal_coefficients = get_thermal( $values );
    my $sym_atoms_and_their_count = cell_filling_sym( $values, $f2o );
    my $atoms_neighbors = get_neighbors( $values );

    my $atoms = atom_array_from_cif( $datablock, {} );

    foreach my $atom ( @{$atoms} ) {
        my $index = $atom->{'index'};
        %{$atom} = (%{$atom}, %{$themal_coefficients->[$index]});
        %{$atom} = (%{$atom}, %{$sym_atoms_and_their_count->[$index]});
        %{$atom} = (%{$atom}, %{$atoms_neighbors->[$index]});
    }

    return $atoms;
}

#--------------------------------------------------------------------#
# Function of extracting atoms Crommer-Mann coefficients the CIF file.
#
# Parameters:
#    values - a reference to array of hashes where a data from the CIF
#    file is stored
#
# Returns:
# \@ = (
#           # [0]
#           {
#               Crommer_Mann_coefficients => [1.10, .., .., ] # 9 values;
# a1, a2, .., b1, b2.., b4, c.
#           },
#           # [1]
#           {
#               Crommer_Mann_coefficients => [1.10, .., .., ]
#           },
#  );
sub get_atom_type_scattering
{
    my( $values ) = @_;

    return {} if !exists $values->{'_atom_type_symbol'};

    my %scattering;
    for my $i (0..$#{$values->{_atom_type_symbol}}) {
        # correction of chemical element to standard record;
        my $chemical_type =
            ucfirst( lc( substr( $values->{'_atom_type_symbol'}[$i], 0, 2 ) ) );
        $chemical_type =~ s/\s//g;
        $scattering{$chemical_type} = {
            'Cromer_Mann' => [
                $values->{'_atom_type_scat_cromer_mann_a1'}[$i],
                $values->{'_atom_type_scat_cromer_mann_a2'}[$i],
                $values->{'_atom_type_scat_cromer_mann_a3'}[$i],
                $values->{'_atom_type_scat_cromer_mann_a4'}[$i],
                $values->{'_atom_type_scat_cromer_mann_b1'}[$i],
                $values->{'_atom_type_scat_cromer_mann_b2'}[$i],
                $values->{'_atom_type_scat_cromer_mann_b3'}[$i],
                $values->{'_atom_type_scat_cromer_mann_b4'}[$i],
                $values->{'_atom_type_scat_cromer_mann_c'}[$i] ],
            'scat_dispersion_real' =>
                $values->{'_atom_type_scat_dispersion_real'}[$i],
            'scat_dispersion_imag' =>
                $values->{'_atom_type_scat_dispersion_imag'}[$i],
        };
    }

    return \%scattering;
}

#--------------------------------------------------------------------#
# Function of extracting atoms anisotropic and isotropic
# thermal parameters the CIF file.
#
# Parameters:
#    values - a reference to array of hashes where a data from the CIF
#    file is stored
#
# Returns:
# \@ = (
#           # [0]
#           {
#               B_factor => 0.78,
#               U_value_of_B_factor => 0.03,
#               aniso_value_Uij => [0.01, 0.002, 0.003,..,0.006] # 6 values,
#           },
#           # [1]
#           {
#               B_factor => 0.78,
#               U_value_of_B_factor => 0.03,
#               aniso_value_Uij => [0.01, 0.002, 0.003,..,0.006] # 6 values,
#           },
#  );
sub get_thermal
{
    my( $values ) = @_;

    my @atoms_thermal_coefficients;

    my $thermal_parameter_B =
        [ map { ( unpack_cif_number( $_ ) )[0] }
              @{$values->{'_atom_site_b_iso_or_equiv'}} ];
    my $squared_displacement_U =
        [ map { ( unpack_cif_number( $_ ) )[0] }
              @{$values->{'_atom_site_u_iso_or_equiv'}} ];
    my @anisotropic_U_ij_values =
        ( [ map { ( unpack_cif_number( $_ ) )[0] }
                @{$values->{'_atom_site_aniso_u_11'}} ],
          [ map { ( unpack_cif_number( $_ ) )[0] }
                @{$values->{'_atom_site_aniso_u_22'}} ],
          [ map { ( unpack_cif_number( $_ ) )[0] }
                @{$values->{'_atom_site_aniso_u_33'}} ],
          [ map { ( unpack_cif_number( $_ ) )[0] }
                @{$values->{'_atom_site_aniso_u_23'}} ],
          [ map { ( unpack_cif_number( $_ ) )[0] }
                @{$values->{'_atom_site_aniso_u_13'}} ],
          [ map { ( unpack_cif_number( $_ ) )[0] }
                @{$values->{'_atom_site_aniso_u_12'}} ] );
    # _atom_site_aniso_label needs for extracting of anisotropic values;
    my %temporary_aniso_data;
    for my $i (0..$#{$values->{_atom_site_aniso_label}}) {
        my $atom_aniso_label =
            $values->{'_atom_site_aniso_label'}[$i];
        $temporary_aniso_data{$atom_aniso_label} =
            [ $anisotropic_U_ij_values[0]->[$i],
              $anisotropic_U_ij_values[1]->[$i],
              $anisotropic_U_ij_values[2]->[$i],
              $anisotropic_U_ij_values[3]->[$i],
              $anisotropic_U_ij_values[4]->[$i],
              $anisotropic_U_ij_values[5]->[$i] ];
    }

    for my $i (0..$#{$values->{_atom_site_label}}) {
        my $atom_label = $values->{'_atom_site_label'}[$i];
        my %thermal_info = (
            'B_factor' => ($thermal_parameter_B->[$i] ||
                         $squared_displacement_U->[$i] !~ /[0-9]\.[0-9]+/ ?
                         $thermal_parameter_B->[$i] :
                         8 * (pi**2) * $squared_displacement_U->[$i]
            ),
            'U_value_of_B_factor' => $squared_displacement_U->[$i],
            'aniso_value_Uij'     => $temporary_aniso_data{$atom_label}
            );
        push @atoms_thermal_coefficients, \%thermal_info;
    }
    return \@atoms_thermal_coefficients;
}

#--------------------------------------------------------------------#
# Function of extracting unit-cell parameters of the CIF file.
#
# Parameters:
#    values - a reference to array of hashes where a data from the CIF
#    file is stored
#
# Return
# $a = {
#        crystal_cell_degrees => [a, b, c, alpha, beta, gamma ],
#        crystal_cell_radians => [a, b, c, alpha_rad, beta_rad, gamma_rad ],
#        cell_volume => 14.055,
#        reciprocal_cell_degrees => [a*, b*, c*, alpha*, beta*, gamma*],
#        reciprocal_cell_radians => [a*,b*,c*,alpha_rad*,beta_rad*,gamma_rad*],
#      }
sub get_unit_cell_parameters
{
    my( $values ) = @_;

    my @crystal_lattice = get_cell( $values );
    my $cell_volume = unpack_cif_number( $values->{_cell_volume}[0] );
    my( $a, $b, $c, $alpha, $beta, $gamma ) = @crystal_lattice;
    my @crystal_cell_radians =
        ( $a, $b, $c, deg2rad( $alpha ), deg2rad( $beta ), deg2rad( $gamma ) );
    # alpha between b and c; beta between a and c; gamma between a and b.
    # @star_crystal_lattice = ( a*[0], b*[1], c*[2], alpha*, beta*, gamma*[5] );
    my @abc_star_values = (
        d2r_length( $b, $c, deg2rad( $alpha ), $cell_volume ), # a*
        d2r_length( $a, $c, deg2rad( $beta ), $cell_volume ), # b*
        d2r_length( $a, $b, deg2rad( $gamma ), $cell_volume )  # c*
        );
    my @alpha_beta_gamma_star_radians = (
        d2r_angle( deg2rad( $beta ), deg2rad( $gamma ), deg2rad( $alpha ) ), # alpha*
        d2r_angle( deg2rad( $alpha ), deg2rad( $gamma ), deg2rad( $beta ) ), # beta*
        d2r_angle( deg2rad( $alpha ), deg2rad( $beta ), deg2rad( $gamma ) ), # gamma*
    );
    my  @alpha_beta_gamma_star_degrees =
        map { rad2deg($_) } @alpha_beta_gamma_star_radians;
    my @star_crystal_cell_parameters_degrees =
        (@abc_star_values, @alpha_beta_gamma_star_degrees);
    my @star_crystal_cell_parameters_radians =
        (@abc_star_values, @alpha_beta_gamma_star_radians);
    my $crystal_par = {
        crystal_cell_degrees => \@crystal_lattice,
        crystal_cell_radians => \@crystal_cell_radians,
        cell_volume => $cell_volume,
        reciprocal_cell_degrees => \@star_crystal_cell_parameters_degrees,
        reciprocal_cell_radians => \@star_crystal_cell_parameters_radians
    };
    return $crystal_par;
}

#--------------------------------------------------------------------#
# Function of converting lattice parameters (length of cell edges):
# from direct space to reciprocal.
#
# Parameters:
# for example  c* = d2r_length( a, b, angle(a,b), cell_volume );
# Return:
# for example 0.554 [angstrom**-1]
sub d2r_length
{
    my( $a, $b, $gamma, $cell_vol ) = @_;
    return $a * $b * sin( $gamma ) / $cell_vol;
}

#--------------------------------------------------------------------#
# Function of converting lattice parameters (cell angles):
# from direct space to reciprocal.
#
# Parameters and return:
# gamma* = d2r_angle( alpha, beta, GAMMA );
# beta* = d2r_angle( alpha, gamma, BETA );
# alpha* = d2r_angle( beta, gamma, ALPHA );
sub d2r_angle
{
    my( $alpha, $beta, $GAMMA ) = @_;
    use POSIX;
    return POSIX::acos(
        (cos( $alpha ) * cos( $beta ) - cos( $GAMMA )) /
        (sin( $alpha ) * sin( $beta )) );
}

#----------------------------------------------------------------------#
# Function for calculation the distance(resolution) between hkl layers.
#
# Parameters:
# hkl (index of reflection), reciprocal lattice.
# for ex.: spacing_d_hkl( h, k, l, a*, b*, c*, alpha*, beta*, gamma* )
# Return
# hkl resolution (in angstrom): 5.
sub spacing_d_hkl
{
    my( $h, $k, $l, $a_star, $b_star, $c_star,
         $alpha_star, $beta_star, $gamma_star ) = @_;
    return 1 /
        sqrt( $h**2 * $a_star**2 +
              $k**2 * $b_star**2 +
              $l**2 * $c_star**2 +
              2 * $h * $k * $a_star * $b_star * cos( $gamma_star ) +
              2 * $h * $l * $a_star * $c_star * cos( $beta_star ) +
              2 * $k * $l * $b_star * $c_star * cos( $alpha_star ) );
}

#----------------------------------------------------------------------#
# Function for atom structure factor calculation.
#
# Parameters:
# [ Cromer_Mann coefficients: a1, .., a4, b1, .., b4, c ], diff. wavelength,
# sin(teta_hkl);
#
# Return:
# Value of atom structure factor which depends on wavelength and sin(teta_hkl)
# for ex.:
# atom_structure_factor_from_coefficient([a1,..,c],1.54, 0.33) = 1.4;
sub atom_structure_factor_from_coefficients
{
    my( $Cromer_Mann, $resolution ) = @_;
    my( $a1, $a2, $a3, $a4, $b1, $b2, $b3, $b4, $c ) = @{$Cromer_Mann};
    my $sin_teta_div_wavelength = 1 / (2 * $resolution);
    return
        $a1 * exp( -$b1 * $sin_teta_div_wavelength**2 ) +
        $a2 * exp( -$b2 * $sin_teta_div_wavelength**2 ) +
        $a3 * exp( -$b3 * $sin_teta_div_wavelength**2 ) +
        $a4 * exp( -$b4 * $sin_teta_div_wavelength**2 ) +
        $c;
}

#----------------------------------------------------------------------#
# Function for calculation of atom hkl_phase.
#
# Parameters:
# phase_hkl( @hkl, @xyz_fract, @cell_length_abc);
# Return:
# phase(in radians)
# for ex.:
# phase_hkl( @hkl, @xyz_fract, @cell_length_abc) = 1.12;
sub atom_phase_hkl_rad
{
    my( $h, $k, $l, $fract_x, $fract_y, $fract_z ) = @_;
    return 2 * pi * ( $h * $fract_x + $k * $fract_y + $l * $fract_z );
}

# Function for temperature factor calculation (anisotropic);
# equation from "Principles of protein X-ray crystallography",
# Jan Drenth, page 94; T(aniso; hkl)=..
#
# Parameters:
# temperature_factor_aniso( U11, U22, U33, U23, U13, U12, h, k, l, a*, b*, c* );
# Return:
# T(aniso, hkl).
sub temperature_factor_aniso
{
    my( $U_11, $U_22, $U_33, $U_23, $U_13, $U_12,
        $h, $k, $l, $repro_length_a, $repro_length_b, $repro_length_c ) = @_;
    return exp( (-2 * pi**2) *
                ($U_11 * ($h**2) * ($repro_length_a**2) +
                 $U_22 * ($k**2) * ($repro_length_b**2) +
                 $U_33 * ($l**2) * ($repro_length_c**2) +
                 2 * $U_12 * $h * $k * $repro_length_a * $repro_length_b +
                 2 * $U_13 * $h * $l * $repro_length_a * $repro_length_c +
                 2 * $U_23 * $k * $l * $repro_length_b * $repro_length_c ) );
}

# Function for symmetric transformations of atom positions for receiving of
# symmetrical atoms.
#
# Parameters:
# 1. values - a reference to array of hashes where a data from the CIF
# file is stored; 2. reference to orthogonalization matrix
# for orthogonal coordinates calculation.
# f.e.: cell_filling_sym( \[\%1, \%2, ..], "0022254", \matrix );
#
# Return:
# \@sym_atom_info = (
#           # [0]
#           {
#               symmetrical_xyz_fract => [\@xyz1, \@xyz2, .. ],
#               symmetrical_xyz_ortho => [\@xyz1, \@xyz2, .. ],
#            },
#        .. )
sub cell_filling_sym
{
    my( $values, $f2o ) = @_;

    my $sym_data = get_symmetry_operators( { 'values' => $values } );

    my @sym_operators = map { symop_from_string($_) } @{$sym_data};

    my @sym_atom_info;
    foreach my $i (0..$#{$values->{_atom_site_label}}) {
        my %sym_atom_coordinates;

        my $x = unpack_cif_number( $values->{'_atom_site_fract_x'}[$i] );
        my $y = unpack_cif_number( $values->{'_atom_site_fract_y'}[$i] );
        my $z = unpack_cif_number( $values->{'_atom_site_fract_z'}[$i] );

        my $fract_xyz = [ $x, $y, $z ];
        my $ortho_xyz = symop_vector_mul( $f2o, $fract_xyz );

        foreach my $symop ( @sym_operators ) {
            my $new_xyz_fract = symop_apply( [@{$fract_xyz}, 1], $symop);
            $new_xyz_fract = [ @{$new_xyz_fract}[0..2] ];
            my $new_xyz_ortho = symop_vector_mul( $f2o, $new_xyz_fract );

            push @{$sym_atom_coordinates{'symmetrical_xyz_fract'}},
                                                        $new_xyz_fract;
            push @{$sym_atom_coordinates{'symmetrical_xyz_ortho'}},
                                                        $new_xyz_ortho;
        }
        push @sym_atom_info, \%sym_atom_coordinates;
    }

    # searching of symmetric atom twins;
    my @temporary_sym_all;
    foreach my $ref (@sym_atom_info) {
        my $sym_atoms_ortho = $ref->{'symmetrical_xyz_ortho'};
        ## print "$sym_atoms_ortho\n";
        my $sym_atoms_without_twins = [];
        my $length_of_ref = $#{$sym_atoms_ortho};
        for my $i (0..$length_of_ref) { # symmetric atoms
            for my $k ($i+1..$length_of_ref) {
                next if distance( $sym_atoms_ortho->[$i],
                                  $sym_atoms_ortho->[$k] ) >= 0.01;
                next if any { $_ eq $k } @{$sym_atoms_without_twins};
                push @{$sym_atoms_without_twins}, $k;
            } # for 3
        } # for 2
        push @temporary_sym_all, $sym_atoms_without_twins;
    } # for 1

    # deleting of symmetric atom twins;
    for my $i (0..$#temporary_sym_all) {
        next if !defined $temporary_sym_all[$i]->[0];
        for my $del_position (reverse sort @{$temporary_sym_all[$i]}) {
            splice @{$sym_atom_info[$i]->{symmetrical_xyz_ortho}},
                   $del_position, 1;
            splice @{$sym_atom_info[$i]->{symmetrical_xyz_fract}},
                   $del_position, 1;
        }
    }

    # only for first element adding the atoms full count of crystal cell;
    my $atoms_number_of_cell = 0;
    foreach my $ref (@sym_atom_info) {
        $atoms_number_of_cell += scalar @{$ref->{symmetrical_xyz_ortho}};
    }
    $sym_atom_info[0]{'count_of_cell_atoms'} = $atoms_number_of_cell;

    return \@sym_atom_info;
}


#---------------------------------------------------------------
# Subroutine symop_apply() was copied from 'cif_fillcell' script. rev. 1440;
#===============================================================#
sub symop_apply
{
    my($atom_xyz, $symop) = @_;
    my @new_atom_xyz;

    for (my $i = 0; $i < @{$symop}; $i++) {
        $new_atom_xyz[$i] = 0;
        for(my $j = 0; $j < @{$symop}; $j++) {
            ${$atom_xyz}[$j] =~ s/\([0-9]+\)$//;
            $new_atom_xyz[$i] += ${$atom_xyz}[$j] * ${$symop}[$i][$j];
        }
        $new_atom_xyz[$i] = modulo_1($new_atom_xyz[$i]);
    }

    return \@new_atom_xyz;
}

#------------------------------------------------------------------------------
# Function for Fhkl sorting against Friedel's laws.
#
# Parameters:
# sort_Fhkl() outputs.
#
# Return:
# \@array = (
#           # [0]
#           [F_value1, [h1,k1,l1], [h1,k1,l1], .. ],
#           # [1]
#           [F_value2, [h2,k2,l2], [h2,k2,l2], .. ]
sub sort_Friedel
{
    my( $ref_to_sorted_Fhkl ) = @_;

    my %pairs;
    foreach (@{$ref_to_sorted_Fhkl}) {
        my $F = sprintf '%.4f', $_->[0];
        push @{$pairs{$F}}, $_;
    }

    my @output;
    for my $F (sort { $b <=> $a } keys %pairs) {
        push @output,
             [ $pairs{$F}->[0][0],
                    sort {
                        $a->[0] <=> $b->[0] ||
                        $a->[1] <=> $b->[1] ||
                        $a->[2] <=> $b->[2]
                    } map { $_->[1] } @{$pairs{$F}} ];
    }

    return \@output;
}

#------------------------------------------------------------------------------
# Function for extracting of data details about
# covalent bonds
#
# Parameters:
#    values - a reference to array of hashes where a data from the CIF
#    file is stored
#
# Returns:
# \@ = (
#           # [0]
#           {
#               neighbors => [H134,H135],
#           },
#           # [1]
#           {
#               neighbors => [C13,C15],
#           },
#
sub get_neighbors
{
    my( $values ) = @_;

    my $bond_atoms_1 = $values->{'_geom_bond_atom_site_label_1'};
    my $bond_atoms_2 = $values->{'_geom_bond_atom_site_label_2'};

    my @neighbors;
    foreach my $label ( @{ $values->{'_atom_site_label'} } ) {

        my %atom_info;
        $atom_info{'neighbors'} = [];
        for my $i (0..$#{$bond_atoms_1}) {

            my $atom1_label = $bond_atoms_1->[$i];
            my $atom2_label = $bond_atoms_2->[$i];

            if( $label eq $atom1_label ) {
                push @{$atom_info{'neighbors'}}, $atom2_label;
            } elsif( $label eq $atom2_label ) {
                push @{$atom_info{'neighbors'}}, $atom1_label;
            }
        }
        push @neighbors, \%atom_info;
    }

    return \@neighbors;
}
