File Coverage

blib/lib/Term/Form.pm

Criterion	Covered	Total	%
statement	45	753	5.9
branch	3	310	0.9
condition	0	89	0.0
subroutine	14	63	22.2
pod	2	2	100.0
total	64	1217	5.2

package Term::Form;

use warnings;
use strict;
use 5.10.0;

our $VERSION = '0.554';
use Exporter 'import';
our @EXPORT_OK = qw( fill_form );

use Carp       qw( croak );
use List::Util qw( any );

use Term::Choose::LineFold        qw( line_fold print_columns cut_to_printwidth );
use Term::Choose::Constants       qw( :all );
use Term::Choose::Screen          qw( :all );
use Term::Choose::Util            qw( unicode_sprintf get_term_size );
use Term::Choose::ValidateOptions qw( validate_options );

my $Plugin;

BEGIN {
    if ( $^O eq 'MSWin32' ) {
        require Term::Choose::Win32;
        require Win32::Console::ANSI;
        $Plugin = 'Term::Choose::Win32';
    }
    else {
        require Term::Choose::Linux;
        $Plugin = 'Term::Choose::Linux';
    }
}


sub new {
    my $class = shift;
    croak "new: called with " . @_ . " arguments - 0 or 1 arguments expected." if @_ > 1;
    my ( $opt ) = @_;
    my $instance_defaults = _defaults();
    if ( defined $opt ) {
        croak "new: The (optional) argument is not a HASH reference." if ref $opt ne 'HASH';
        my $caller = 'new';
        validate_options( _valid_options( $caller ), $opt, $caller );
        for my $key ( keys %$opt ) {
            $instance_defaults->{$key} = $opt->{$key} if defined $opt->{$key};
        }
    }
    my $self = bless $instance_defaults, $class;
    $self->{backup_instance_defaults} = { %$instance_defaults };
    $self->{plugin} = $Plugin->new();
    return $self;
}


sub _valid_options {
    return {
        codepage_mapping   => '[ 0 1 ]',
        auto_up            => '[ 0 1 2 ]',
        clear_screen       => '[ 0 1 2 ]',
        color              => '[ 0 1 2 ]',         # hide_cursor == 2 # documentation
        hide_cursor        => '[ 0 1 2 ]',
        page               => '[ 0 1 2 ]',         # undocumented
        keep               => '[ 1-9 ][ 0-9 ]*',   # undocumented
        read_only          => 'Array_Int',
        skip_items         => 'Regexp',            # undocumented
                                                   # only keys are checked, passed values are ignored
                                                   # it's up to the user to remove the skipped items from the returned array
        back               => 'Str',
        confirm            => 'Str',
        footer             => 'Str',               # undocumented
        info               => 'Str',
        prompt             => 'Str',
    };
}


sub _defaults {
    return {
        auto_up            => 0,
        back               => '   BACK',
        clear_screen       => 0,
        codepage_mapping   => 0,
        color              => 0,
        confirm            => 'CONFIRM',
        footer             => '',
        hide_cursor        => 1,
        info               => '',
        keep               => 5,
        page               => 1,
        prompt             => '',
        read_only          => [],
        skip_items         => undef,
    };
}


sub __init_term {
    my ( $self ) = @_;
    $self->{plugin}->__set_mode( { mode => 'cbreak', hide_cursor => 0 } );
}


sub __reset_term {
    my ( $self, $up ) = @_;
    if ( defined $self->{plugin} ) {
        $self->{plugin}->__reset_mode( { hide_cursor => 0 } );
    }
    if ( $up ) {
        print up( $up );
    }
    if ( $self->{clear_screen} == 2 ) { # readline
        print "\r" . clear_to_end_of_line();
    }
    else {
        print "\r" . clear_to_end_of_screen();
    }
    if ( $self->{hide_cursor} == 1 ) {
        print show_cursor();
    }
    elsif ( $self->{hide_cursor} == 2 ) {
        print hide_cursor();
    }
}


sub __reset {
    my ( $self, $up ) = @_;
    $self->__reset_term( $up );
    if ( exists $self->{backup_instance_defaults} ) {
        my $instance_defaults = $self->{backup_instance_defaults};
        for my $key ( keys %$self ) {
            if ( $key eq 'plugin' || $key eq 'backup_instance_defaults' ) {
                next;
            }
            elsif ( exists $instance_defaults->{$key} ) {
                $self->{$key} = $instance_defaults->{$key};
            }
            else {
                delete $self->{$key};
            }
        }
    }
}


sub __get_list {
    my ( $self, $orig_list ) = @_;
    my $list;
    if ( $self->{color} ) {
        $list = [ @{$self->{i}{pre}} ];
        my $count = @{$self->{i}{pre}};
        for my $entry ( @$orig_list ) {
            my ( $key, $value ) = @$entry;
            my @color;
            $key =~ s/\x{feff}//g;
            $key =~ s/(\e\[[\d;]*m)/push( @color, $1 ) && "\x{feff}"/ge;
            $self->{i}{key_colors}[$count++] = [ @color ];
            push @$list, [ $self->__sanitized_string( $key ), $value ];
        }
    }
    else {
        $list = [ @{$self->{i}{pre}}, map { [ $self->__sanitized_string( $_->[0] ), $_->[1] ] } @$orig_list ];
    }
    return $list;
}


sub __limit_key_w {
    my ( $self, $term_w ) = @_;
    if ( $self->{i}{max_key_w} > $term_w / 3 ) {
        $self->{i}{max_key_w} = int( $term_w / 3 );
    }
}


sub __available_width {
    my ( $self, $term_w ) = @_;
    $self->{i}{avail_w} = $term_w - ( $self->{i}{max_key_w} + length( $self->{i}{sep} ) + $self->{i}{arrow_w} );
    # Subtract $self->{i}{arrow_w} for the '<' before the string.
    # In each case where no '<'-prefix is required (diff==0) $self->{i}{arrow_w} is added again.
    # Routins where $self->{i}{arrow_w} is added:  __left, __bspace, __home, __ctrl_u, __delete
    # The required space (1) for the cursor (or the '>') behind the string is already subtracted in get_term_size
}


sub __threshold_width {
    my ( $self ) = @_;
    $self->{i}{th} = int( $self->{i}{avail_w} / 5 );
    $self->{i}{th} = 40 if $self->{i}{th} > 40; ##
}


sub __sanitized_string {
    my ( $self, $str ) = @_;
    if ( defined $str ) {
        $str =~ s/\t/ /g;
        $str =~ s/\v+/\ \ /g;
        $str =~ s/[\p{Cc}\p{Noncharacter_Code_Point}\p{Cs}]//g;
    }
    else {
        $str = '';
    }
    return $str;
}


sub __threshold_char_count {
    my ( $self, $m ) = @_;
    $m->{th_l} = 0;
    $m->{th_r} = 0;
    my ( $tmp_w, $count ) = ( 0, 0 );
    for ( @{$m->{p_str}} ) {
        $tmp_w += $_->[1];
        ++$count;
        if ( $tmp_w > $self->{i}{th} ) {
            $m->{th_l} = $count;
            last;
        }
    }
    ( $tmp_w, $count ) = ( 0, 0 );
    for ( reverse @{$m->{p_str}} ) {
        $tmp_w += $_->[1];
        ++$count;
        if ( $tmp_w > $self->{i}{th} ) {
            $m->{th_r} = $count;
            last;
        }
    }
}


sub __string_and_pos {
    my ( $self, $list ) = @_;
    my $default = $list->[$self->{i}{curr_row}][1];
    if ( ! defined $default ) {
        $default = '';
    }
    my $m = {
        avail_w => $self->{i}{avail_w},
        th_l    => 0,
        th_r    => 0,
        str     => [],
        str_w   => 0,
        pos     => 0,
        p_str   => [],
        p_str_w => 0,
        p_pos   => 0,
        diff    => 0,
    };
    for ( $default =~ /\X/g ) {
        my $char_w = print_columns( $_ );
        push @{$m->{str}}, [ $_, $char_w ];
        $m->{str_w} += $char_w;
    }
    $m->{pos}  = @{$m->{str}};
    $m->{diff} = $m->{pos};
    _unshift_till_avail_w( $m, [ 0 .. $#{$m->{str}} ] );
    return $m;
}


sub __left {
    my ( $self, $m ) = @_;
    if ( $m->{pos} ) {
        $m->{pos}--;
        # '<=' and not '==' because th_l could change and fall behind p_pos
        while ( $m->{p_pos} <= $m->{th_l} && $m->{diff} ) {
            _unshift_element( $m, $m->{pos} - $m->{p_pos} );
        }
        if ( ! $m->{diff} ) { # no '<'
            $m->{avail_w} = $self->{i}{avail_w} + $self->{i}{arrow_w};
            _push_till_avail_w( $m, [ $#{$m->{p_str}} + 1 .. $#{$m->{str}} ] );
        }
        $m->{p_pos}--;
    }
    else {
        $self->{i}{beep} = 1;
    }
}


sub __right {
    my ( $self, $m ) = @_;
    if ( $m->{pos} < $#{$m->{str}} ) {
        $m->{pos}++;
        # '>=' and not '==' because th_r could change and fall in front of p_pos
        while ( $m->{p_pos} >= $#{$m->{p_str}} - $m->{th_r} && $#{$m->{p_str}} + $m->{diff} != $#{$m->{str}} ) {
            _push_element( $m );
        }
        $m->{p_pos}++;
    }
    elsif ( $m->{pos} == $#{$m->{str}} ) {
        #rec w if vw
        $m->{pos}++;
        $m->{p_pos}++;
        # cursor now behind the string at the end position
    }
    else {
        $self->{i}{beep} = 1;
    }
}

sub __bspace {
    my ( $self, $m ) = @_;
    if ( $m->{pos} ) {
        $m->{pos}--;
        # '<=' and not '==' because th_l could change and fall behind p_pos
        while ( $m->{p_pos} <= $m->{th_l} && $m->{diff} ) {
            _unshift_element( $m, $m->{pos} - $m->{p_pos} );
        }
        $m->{p_pos}--;
        if ( ! $m->{diff} ) { # no '<'
            $m->{avail_w} = $self->{i}{avail_w} + $self->{i}{arrow_w};
        }
        _remove_pos( $m );
    }
    else {
        $self->{i}{beep} = 1;
    }
}

sub __delete {
    my ( $self, $m ) = @_;
    if ( $m->{pos} < @{$m->{str}} ) {
        if ( ! $m->{diff} ) { # no '<'
            $m->{avail_w} = $self->{i}{avail_w} + $self->{i}{arrow_w};
        }
        _remove_pos( $m );
    }
    else {
        return;
    }
}

sub __ctrl_u {
    my ( $self, $m ) = @_;
    if ( $m->{pos} ) {
        for my $removed ( splice ( @{$m->{str}}, 0, $m->{pos} ) ) {
            $m->{str_w} -= $removed->[1];
        }
        # diff always 0     # never '<'
        $m->{avail_w} = $self->{i}{avail_w} + $self->{i}{arrow_w};
        _fill_from_begin( $m );
    }
    else {
        $self->{i}{beep} = 1;
    }
}

sub __ctrl_k {
    my ( $self, $m ) = @_;
    if ( $m->{pos} < @{$m->{str}} ) {
        for my $removed ( splice ( @{$m->{str}}, $m->{pos}, @{$m->{str}} - $m->{pos} ) ) {
            $m->{str_w} -= $removed->[1];
        }
        _fill_from_end( $m );
    }
    else {
        $self->{i}{beep} = 1;
    }
}

sub __home {
    my ( $self, $m ) = @_;
    if ( $m->{pos} > 0 ) {
        # diff always 0     # never '<'
        $m->{avail_w} = $self->{i}{avail_w} + $self->{i}{arrow_w};
        _fill_from_begin( $m );
    }
    else {
        $self->{i}{beep} = 1;
    }
}

sub __end {
    my ( $self, $m ) = @_;
    if ( $m->{pos} < @{$m->{str}} ) {
        _fill_from_end( $m );
    }
    else {
        $self->{i}{beep} = 1;
    }
}

sub __add_char {
    my ( $self, $m, $char ) = @_;
    my $char_w = print_columns( $char );
    splice( @{$m->{str}}, $m->{pos}, 0, [ $char, $char_w ] );
    $m->{pos}++;
    splice( @{$m->{p_str}}, $m->{p_pos}, 0, [ $char, $char_w ] );
    $m->{p_pos}++;
    $m->{p_str_w} += $char_w;
    $m->{str_w}   += $char_w;
    # no '<' if:
    if ( ! $m->{diff} && $m->{p_pos} < $self->{i}{avail_w} + $self->{i}{arrow_w} ) {
        $m->{avail_w} = $self->{i}{avail_w} + $self->{i}{arrow_w};
    }
    while ( $m->{p_pos} < $#{$m->{p_str}} ) {
        if ( $m->{p_str_w} <= $m->{avail_w} ) {
            last;
        }
        my $tmp = pop @{$m->{p_str}};
        $m->{p_str_w} -= $tmp->[1];
    }
    while ( $m->{p_str_w} > $m->{avail_w} ) {
        my $tmp = shift @{$m->{p_str}};
        $m->{p_str_w} -= $tmp->[1];
        $m->{p_pos}--;
        $m->{diff}++;
    }
}

sub _unshift_element {
    my ( $m, $pos ) = @_;
    my $tmp = $m->{str}[$pos];
    unshift @{$m->{p_str}}, $tmp;
    $m->{p_str_w} += $tmp->[1];
    $m->{diff}--;
    $m->{p_pos}++;
    while ( $m->{p_str_w} > $m->{avail_w} ) {
        my $tmp = pop @{$m->{p_str}};
        $m->{p_str_w} -= $tmp->[1];
    }
}

sub _push_element {
    my ( $m ) = @_;
    my $tmp = $m->{str}[$#{$m->{p_str}} + $m->{diff} + 1];
    push @{$m->{p_str}}, $tmp;
    if ( defined $tmp->[1] ) {
        $m->{p_str_w} += $tmp->[1];
    }
    while ( $m->{p_str_w} > $m->{avail_w} ) {
        my $tmp = shift @{$m->{p_str}};
        $m->{p_str_w} -= $tmp->[1];
        $m->{diff}++;
        $m->{p_pos}--;
    }
}

sub _unshift_till_avail_w {
    my ( $m, $idx ) = @_;
    for ( @{$m->{str}}[reverse @$idx] ) {
        if ( $m->{p_str_w} + $_->[1] > $m->{avail_w} ) {
            last;
        }
        unshift @{$m->{p_str}}, $_;
        $m->{p_str_w} += $_->[1];
        $m->{p_pos}++;  # p_pos stays on the last element of the p_str
        $m->{diff}--;   # diff: difference between p_pos and pos; pos is always bigger or equal p_pos
    }
}

sub _push_till_avail_w {
    my ( $m, $idx ) = @_;
    for ( @{$m->{str}}[@$idx] ) {
        if ( $m->{p_str_w} + $_->[1] > $m->{avail_w} ) {
            last;
        }
        push @{$m->{p_str}}, $_;
        $m->{p_str_w} += $_->[1];
    }
}

sub _remove_pos {
    my ( $m ) = @_;
    splice( @{$m->{str}}, $m->{pos}, 1 );
    my $tmp = splice( @{$m->{p_str}}, $m->{p_pos}, 1 );
    $m->{p_str_w} -= $tmp->[1];
    $m->{str_w}   -= $tmp->[1];
    _push_till_avail_w( $m, [ ( $#{$m->{p_str}} + $m->{diff} + 1 ) .. $#{$m->{str}} ] );
}

sub _fill_from_end {
    my ( $m ) = @_;
    $m->{pos}     = @{$m->{str}};
    $m->{p_str}   = [];
    $m->{p_str_w} = 0;
    $m->{diff}    = @{$m->{str}};
    $m->{p_pos}   = 0;
    _unshift_till_avail_w( $m, [ 0 .. $#{$m->{str}} ] );
}

sub _fill_from_begin {
    my ( $m ) = @_;
    $m->{pos}     = 0;
    $m->{p_pos}   = 0;
    $m->{diff}    = 0;
    $m->{p_str}   = [];
    $m->{p_str_w} = 0;
    _push_till_avail_w( $m, [ 0 .. $#{$m->{str}} ] );
}


sub __print_readline {
    my ( $self, $m ) = @_;
    my $i = $self->{i}{curr_row};
    print "\r" . clear_to_end_of_line();
    print $self->{i}{keys}[$i] . $self->{i}{seps}[$i];
    if ( $self->{no_echo} && $self->{no_echo} == 2 ) {
        return;
    }
    my $print_str = '';
    # left arrow:
    if ( $m->{diff} ) {
        $print_str .= $self->{i}{arrow_left};
    }
    # input text:
    if ( $self->{no_echo} ) {
        $print_str .= ( '*' x @{$m->{p_str}} );
    }
    else {
        $print_str .= join( '', map { $_->[0] } @{$m->{p_str}} );
    }
    # right arrow:
    if ( @{$m->{p_str}} + $m->{diff} != @{$m->{str}} ) {
        $print_str .= $self->{i}{arrow_right};
    }
    my $back_to_pos = 0;
    for ( @{$m->{p_str}}[$m->{p_pos} .. $#{$m->{p_str}}] ) {
        $back_to_pos += $_->[1];
    }
    if ( $self->{hide_cursor} ) {
        print show_cursor();
    }
    print $print_str;
    if ( $back_to_pos ) {
        print left( $back_to_pos );
    }
}


sub __unicode_trim {
    my ( $self, $str, $len ) = @_;
    return $str if print_columns( $str ) <= $len;
    return cut_to_printwidth( $str, $len - 3, 0 ) . '...';
}


sub __length_longest_key {
    my ( $self, $list ) = @_;
    my $longest = 0;
    for my $i ( 0 .. $#$list ) {
        if ( $i < @{$self->{i}{pre}} ) {
            next;
        }
        if ( any { $_ == $i } @{$self->{i}{keys_to_skip}} ) {
            next;
        }
        my $len = print_columns( $list->[$i][0] );
        $longest = $len if $len > $longest;
    }
    $self->{i}{max_key_w} = $longest;
}


sub __prepare_hight {
    my ( $self, $list, $term_w, $term_h ) = @_;
    $self->{i}{avail_h} = $term_h;
    if ( length $self->{i}{info_prompt} ) {
        my $info_w = $term_w;
        if ( $^O ne 'MSWin32' && $^O ne 'cygwin' ) {
            $info_w += WIDTH_CURSOR;
        }
        my @info_prompt = line_fold( $self->{i}{info_prompt}, $info_w, { color => $self->{color}, join => 0 } );
        $self->{i}{info_prompt_row_count} = @info_prompt;
        $self->{i}{info_prompt} = join "\n", @info_prompt;
        $self->{i}{avail_h} -= $self->{i}{info_prompt_row_count};
        my $min_avail_h = $self->{keep};
        if (  $term_h < $min_avail_h ) {
            $min_avail_h = $term_h;
        }
        if ( $self->{i}{avail_h} < $min_avail_h ) {
            $self->{i}{avail_h} = $min_avail_h;
        }
    }
    else {
        $self->{i}{info_prompt_row_count} = 0;
    }
    if ( @$list > $self->{i}{avail_h} ) {
        $self->{i}{page_count} = int @$list / ( $self->{i}{avail_h} - 1 );
        if ( @$list % ( $self->{i}{avail_h} - 1 ) ) {
            $self->{i}{page_count}++;
        }
    }
    else {
        $self->{i}{page_count} = 1;
    }
    if ( $self->{page} == 2 || ( $self->{page} == 1 && $self->{i}{page_count} > 1) ) {
        $self->{i}{print_footer} = 1;
        $self->{i}{avail_h}--;
    }
    else {
        $self->{i}{print_footer} = 0;
    }
    return;
}


sub __print_current_row {
    my ( $self, $list, $m ) = @_;
    print "\r" . clear_to_end_of_line();
    if ( $self->{i}{curr_row} < @{$self->{i}{pre}} ) {
        print reverse_video();
        print $list->[$self->{i}{curr_row}][0];
        print normal();
    }
    else {
        $self->__print_readline( $m );
        $list->[$self->{i}{curr_row}][1] = join( '', map { defined $_->[0] ? $_->[0] : '' } @{$m->{str}} );
    }
}


sub __prepare_skip_row {
    my ( $self, $list, $idx ) = @_;
    my $remainder = '';
    my $val = '';
    ( $self->{i}{keys}[$idx], $remainder ) = cut_to_printwidth( $list->[$idx][0], $self->{i}{max_key_w}, 1 );
    if ( length $remainder ) {
        ( $self->{i}{seps}[$idx], $remainder ) = cut_to_printwidth( $remainder, 2, 1 );
        if ( length $remainder ) {
            $val = cut_to_printwidth( $remainder, $self->{i}{avail_w}, 0 );
        }
    }
    if ( ! length $self->{i}{seps}[$idx] ) {
        $self->{i}{seps}[$idx] = '  ';
    }
    elsif ( length $self->{i}{seps}[$idx] == 1 ) {
        $self->{i}{seps}[$idx] .= ' ';
    }
    my $row = $self->{i}{keys}[$idx] . $self->{i}{seps}[$idx] . $val;
    if ( exists $self->{i}{key_colors} && @{$self->{i}{key_colors}[$idx]} ) {
        my @key_colors = @{$self->{i}{key_colors}[$idx]};
        $row =~ s/\x{feff}/shift @key_colors/ge;
        $row .= normal();
    }
    return $row;
}


sub __get_row {
    my ( $self, $list, $idx ) = @_;
    if ( $idx < @{$self->{i}{pre}} ) {
        return $list->[$idx][0];
    }
    if ( any { $_ == $idx } @{$self->{i}{keys_to_skip}} ) {
        return $self->__prepare_skip_row( $list, $idx );
    }
    if ( ! defined $self->{i}{keys}[$idx] ) {
        my $key = $list->[$idx][0];
        $self->{i}{keys}[$idx] = unicode_sprintf( $key, $self->{i}{max_key_w} );
    }
    if ( ! defined $self->{i}{seps}[$idx] ) {
        if ( any { $_ == $idx } @{$self->{i}{read_only}} ) {
            $self->{i}{seps}[$idx] = $self->{i}{sep_ro};
        }
        else {
            $self->{i}{seps}[$idx] = $self->{i}{sep};
        }
    }
    if ( exists $self->{i}{key_colors} && @{$self->{i}{key_colors}[$idx]} ) {
        my @key_colors = @{$self->{i}{key_colors}[$idx]};
        $self->{i}{keys}[$idx] =~ s/\x{feff}/shift @key_colors/ge;
        $self->{i}{keys}[$idx] .= normal();
    }
    if ( defined $list->[$idx][1] ) {
        my $val = $self->__unicode_trim( $list->[$idx][1], $self->{i}{avail_w} );
        return $self->{i}{keys}[$idx] . $self->{i}{seps}[$idx] . $val;
    }
    else {
        return $self->{i}{keys}[$idx] . $self->{i}{seps}[$idx];
    }
}


sub __write_screen {
    my ( $self, $list ) = @_;
    my @rows;
    for my $idx ( $self->{i}{begin_row} .. $self->{i}{end_row} ) {
        push @rows, $self->__get_row( $list, $idx );
    }
    print join "\n", @rows;
    $self->{i}{curr_page} = int( $self->{i}{end_row} / $self->{i}{avail_h} ) + 1;
    my $up = 0;
    if ( $self->{i}{print_footer} ) {
        my $trailing_empty_page_rows = $self->{i}{avail_h} - ( $self->{i}{end_row} - $self->{i}{begin_row} );
        if ( $trailing_empty_page_rows > 1 ) {
            print "\n" x ( $trailing_empty_page_rows - 1 );
        }
        print "\n", sprintf $self->{i}{footer_fmt}, $self->{i}{curr_page};
        $up += $trailing_empty_page_rows;
    }
    $up += $self->{i}{end_row} - $self->{i}{curr_row};
    if ( $up ) {
        print up( $up );
    }
}


sub __prepare_footer_fmt {
    my ( $self, $term_w ) = @_;
    if ( ! $self->{i}{print_footer} ) {
        return;
    }
    my $width_p_count = length $self->{i}{page_count};
    my $p_count = $self->{i}{page_count};
    my $footer_fmt = '--- %0' . $width_p_count . 'd/' . $p_count . ' ---';
    if ( $self->{footer} ) {
        $footer_fmt .= $self->{footer};
    }
    if ( print_columns( sprintf $footer_fmt, $p_count ) > $term_w ) { # color
        $footer_fmt = '%0' . $width_p_count . 'd/' . $p_count;
        if ( length( sprintf $footer_fmt, $p_count ) > $term_w ) {
            if ( $width_p_count > $term_w ) {
                $width_p_count = $term_w;
            }
            $footer_fmt = '%0' . $width_p_count . '.' . $width_p_count . 's';
        }
    }
    $self->{i}{footer_fmt} = $footer_fmt;
}


sub __write_first_screen {
    my ( $self, $list ) = @_;
    $self->{i}{curr_row} = $self->{auto_up} ? 0 : @{$self->{i}{pre}};
    $self->{i}{begin_row} = 0;
    $self->{i}{end_row}  = ( $self->{i}{avail_h} - 1 );
    if ( $self->{i}{end_row} > $#$list ) {
        $self->{i}{end_row} = $#$list;
    }
    $self->{i}{seps} = [];
    $self->{i}{keys} = [];
    if ( $self->{clear_screen} == 1 ) {
        print clear_screen();
    }
    else {
        print "\r" . clear_to_end_of_screen();
    }
    if ( $self->{hide_cursor} ) {
        print hide_cursor();
    }
    if ( length $self->{i}{info_prompt} ) {
        print $self->{i}{info_prompt} . "\n"; #
    }
    $self->__write_screen( $list );
}


sub __prepare_meta_menu_elements {
    my ( $self, $term_w ) = @_;
    my @meta_menu_elements = ( 'back', 'confirm' );
    $self->{i}{pre} = [];
    for my $meta_menu_element ( @meta_menu_elements ) {
        my @color;
        my $tmp = $self->{i}{$meta_menu_element . '_orig'};
        if ( $self->{color} ) {
            $tmp =~ s/\x{feff}//g;
            $tmp =~ s/(\e\[[\d;]*m)/push( @color, $1 ) && "\x{feff}"/ge;
        }
        $tmp = $self->__sanitized_string( $tmp );
        if ( print_columns( $tmp ) > $term_w ) {
            $tmp = cut_to_printwidth( $tmp, $term_w, 0 );
        }
        if ( @color ) {
            $tmp =~ s/\x{feff}/shift @color/ge;
            $tmp .= normal();
        }
        $self->{$meta_menu_element} = $tmp;
        push @{$self->{i}{pre}}, [ $self->{$meta_menu_element}, ];
    }
}


sub __modify_fill_form_options {
    my ( $self ) = @_;
    if ( $self->{clear_screen} == 2 ) {
        $self->{clear_screen} = 0;
    }
    if ( length $self->{footer} && $self->{page} != 2 ) {
        $self->{page} = 2;
    }
    if ( $self->{page} == 2 && ! $self->{clear_screen} ) {
        $self->{clear_screen} = 1;
    }
}


sub fill_form {
    if ( ref $_[0] ne __PACKAGE__ ) {
        my $ob = __PACKAGE__->new();
        delete $ob->{backup_instance_defaults};
        return $ob->fill_form( @_ );
    }
    my ( $self, $orig_list, $opt ) = @_;
    croak "'fill_form' called with no argument." if ! defined $orig_list;
    croak "'fill_form' requires an ARRAY reference as its argument." if ref $orig_list ne 'ARRAY';
    $opt = {} if ! defined $opt;
    croak "'fill_form': the (optional) second argument must be a HASH reference" if ref $opt ne 'HASH';
    return [] if ! @$orig_list; ##
    if ( %$opt ) {
        my $caller = 'fill_form';
        validate_options( _valid_options( $caller ), $opt, $caller );
        for my $key ( keys %$opt ) {
            $self->{$key} = $opt->{$key} if defined $opt->{$key};
        }
    }
    $self->__modify_fill_form_options();
    if ( $^O eq "MSWin32" ) {
        print $self->{codepage_mapping} ? "\e(K" : "\e(U";
    }
    my @tmp;
    if ( length $self->{info} ) {
        push @tmp, $self->{info};
    }
    if ( length $self->{prompt} ) {
        push @tmp, $self->{prompt};
    }
    $self->{i}{info_prompt} = join "\n", @tmp;
    $self->{i}{sep}    = ': ';
    $self->{i}{sep_ro} = '| ';
    die if length $self->{i}{sep} != length $self->{i}{sep_ro};
    $self->{i}{arrow_left}  = '<';
    $self->{i}{arrow_right} = '>';
    $self->{i}{arrow_w} = 1;
    local $| = 1;
    local $SIG{INT} = sub {
        $self->__reset(); #
        print "^C\n";
        exit;
    };
    $self->__init_term();
    my ( $term_w, $term_h ) = get_term_size();
    $self->{i}{back_orig}    = $self->{back};
    $self->{i}{confirm_orig} = $self->{confirm};
    $self->__prepare_meta_menu_elements( $term_w );
    $self->{i}{read_only} = [];
    if ( @{$self->{read_only}} ) {
        $self->{i}{read_only} = [ map { $_ + @{$self->{i}{pre}} } @{$self->{read_only}} ];
    }

    $self->{i}{keys_to_skip} = [];
    if ( defined $self->{skip_items} ) {
        for my $i ( 0 .. $#$orig_list ) {
            if ( defined $orig_list->[$i][0] && $orig_list->[$i][0] =~ $self->{skip_items} ) {
                push @{$self->{i}{keys_to_skip}}, $i + @{$self->{i}{pre}};
            }
            else {
                $self->{i}{end_down} = $i;
            }
        }
        $self->{i}{end_down} += @{$self->{i}{pre}};
    }
    else {
        $self->{i}{end_down} = $#$orig_list + @{$self->{i}{pre}};
    }
    my $list = $self->__get_list( $orig_list );
    $self->__length_longest_key( $list );
    $self->__limit_key_w( $term_w );
    $self->__available_width( $term_w );
    $self->__threshold_width();
    $self->__prepare_hight( $list, $term_w, $term_h );
    $self->__prepare_footer_fmt( $term_w );
    $self->__write_first_screen( $list );
    my $m = $self->__string_and_pos( $list );
    my $k = 0;

    CHAR: while ( 1 ) {
        my $locked = 0;
        if ( any { $_ == $self->{i}{curr_row} } @{$self->{i}{read_only}} ) {
            $locked = 1;
        }
        if ( $self->{i}{beep} ) {
            print bell();
            $self->{i}{beep} = 0;
        }
        else {
            if ( $self->{hide_cursor} ) {
                print hide_cursor();
            }
            $self->__print_current_row( $list, $m );
        }
        my $char;
        if ( any { $_ == $self->{i}{curr_row} } @{$self->{i}{keys_to_skip}} ) {
            if ( $self->{i}{direction} eq 'up' || $self->{i}{curr_row} >= $self->{i}{end_down} ) {
                $char = VK_UP;
            }
            else {
                $char = VK_DOWN;
            }
        }
        else {
            $char = $self->{plugin}->__get_key_OS();
        }
        $self->{i}{direction} = 'down';
        if ( ! defined $char ) {
            $self->__reset();
            warn "EOT: $!";
            return;
        }
        next CHAR if $char == NEXT_get_key;
        next CHAR if $char == KEY_TAB;
        my ( $tmp_term_w, $tmp_term_h ) = get_term_size();
        if ( $tmp_term_w != $term_w || $tmp_term_h != $term_h && $tmp_term_h < ( @$list + 1 ) ) {
            my $up = $self->{i}{curr_row} + $self->{i}{info_prompt_row_count};
            print up( $up ) if $up;
            ( $term_w, $term_h ) = ( $tmp_term_w, $tmp_term_h );
            $self->__prepare_meta_menu_elements( $term_w );
            $self->__length_longest_key( $list );
            $self->__limit_key_w( $term_w );
            $self->__available_width( $term_w );
            $self->__threshold_width();
            $self->__prepare_hight( $list, $term_w, $term_h );
            $self->__prepare_footer_fmt( $term_w );
            $self->__write_first_screen( $list );
            $m = $self->__string_and_pos( $list );
        }
        # reset $m->{avail_w} to default:
        $m->{avail_w} = $self->{i}{avail_w};
        $self->__threshold_char_count( $m );
        if ( $char == KEY_BSPACE || $char == CONTROL_H ) {
            $k = 1;
            if ( $locked ) {    # read_only
                $self->{i}{beep} = 1;
            }
            else {
                $self->__bspace( $m );
            }
        }
        elsif ( $char == CONTROL_U ) {
            $k = 1;
            if ( $locked ) {
                $self->{i}{beep} = 1;
            }
            else {
                $self->__ctrl_u( $m );
            }
        }
        elsif ( $char == CONTROL_K ) {
            $k = 1;
            if ( $locked ) {
                $self->{i}{beep} = 1;
            }
            else {
                $self->__ctrl_k( $m );
            }
        }
        elsif ( $char == VK_DELETE || $char == CONTROL_D ) {
            $k = 1;
            $self->__delete( $m );
        }
        elsif ( $char == VK_RIGHT || $char == CONTROL_F ) {
            $k = 1;
            $self->__right( $m );
        }
        elsif ( $char == VK_LEFT || $char == CONTROL_B ) {
            $k = 1;
            $self->__left( $m );
        }
        elsif ( $char == VK_END || $char == CONTROL_E ) {
            $k = 1;
            $self->__end( $m );
        }
        elsif ( $char == VK_HOME || $char == CONTROL_A ) {
            $k = 1;
            $self->__home( $m );
        }
        elsif ( $char == VK_UP || $char == CONTROL_S ) {
            $k = 1;
            if ( $self->{i}{curr_row} == 0 ) {
                $self->{i}{beep} = 1;
            }
            else {
                $self->{i}{curr_row}--;
                $m = $self->__string_and_pos( $list );
                if ( $self->{i}{curr_row} >= $self->{i}{begin_row} ) {
                    $self->__reset_previous_row( $list, $self->{i}{curr_row} + 1 );
                    print up( 1 );
                }
                else {
                    $self->__print_previous_page( $list );
                }
            }
        }
        elsif ( $char == VK_DOWN || $char == CONTROL_T ) {
            $k = 1;
            if ( $self->{i}{curr_row} == $#$list ) {
                $self->{i}{beep} = 1;
            }
            else {
                $self->{i}{curr_row}++;
                $m = $self->__string_and_pos( $list );
                if ( $self->{i}{curr_row} <= $self->{i}{end_row} ) {
                    $self->__reset_previous_row( $list, $self->{i}{curr_row} - 1 );
                    print down( 1 );
                }
                else {
                    print up( $self->{i}{end_row} - $self->{i}{begin_row} );
                    $self->__print_next_page( $list );
                }
            }
        }
        elsif ( $char == VK_PAGE_UP || $char == CONTROL_P ) {
            $k = 1;
            if ( $self->{i}{curr_page} == 1 ) {
                if ( $self->{i}{curr_row} == 0 ) {
                    $self->{i}{beep} = 1;
                }
                else {
                    $self->__reset_previous_row( $list, $self->{i}{curr_row} );
                    print up( $self->{i}{curr_row} );
                    $self->{i}{curr_row} = 0;
                    $m = $self->__string_and_pos( $list );
                }
            }
            else {
                my $up = $self->{i}{curr_row} - $self->{i}{begin_row};
                print up( $up ) if $up;
                $self->{i}{curr_row} = $self->{i}{begin_row} - $self->{i}{avail_h};
                $m = $self->__string_and_pos( $list );
                $self->__print_previous_page( $list );
            }
        }
        elsif ( $char == VK_PAGE_DOWN || $char == CONTROL_N ) {
            $k = 1;
            if ( $self->{i}{curr_page} == $self->{i}{page_count} ) {
                if ( $self->{i}{curr_row} == $#$list ) {
                    $self->{i}{beep} = 1;
                }
                else {
                    $self->__reset_previous_row( $list, $self->{i}{curr_row} );
                    my $rows = $self->{i}{end_row} - $self->{i}{curr_row};
                    print down( $rows );
                    $self->{i}{curr_row} = $self->{i}{end_row};
                    $m = $self->__string_and_pos( $list );
                }
            }
            else {
                my $up = $self->{i}{curr_row} - $self->{i}{begin_row};
                print up( $up ) if $up;
                $self->{i}{curr_row} = $self->{i}{end_row} + 1;
                $m = $self->__string_and_pos( $list );
                $self->__print_next_page( $list );
            }
        }
        elsif ( $char == CONTROL_X ) {
            if ( @{$m->{str}} ) {
                $list->[$self->{i}{curr_row}][1] = '';
                $m = $self->__string_and_pos( $list );
            }
            else {
                $self->{i}{beep} = 1;
            }
        }
        elsif ( $char == VK_INSERT ) {
            $self->{i}{beep} = 1;
        }
        elsif ( $char == LINE_FEED || $char == CARRIAGE_RETURN ) {
            # LINE_FEED == CONTROL_J, CARRIAGE_RETURN == CONTROL_M
            my $up = $self->{i}{curr_row} - $self->{i}{begin_row};
            if ( $self->{i}{info_prompt_row_count} ) {
                $up += $self->{i}{info_prompt_row_count};
            }
            if ( $list->[$self->{i}{curr_row}][0] eq $self->{back} ) {
                $self->__reset( $up );
                return;
            }
            elsif ( $list->[$self->{i}{curr_row}][0] eq $self->{confirm} ) {
                splice @$list, 0, @{$self->{i}{pre}};
                $self->__reset( $up );
                return [ map { [ $orig_list->[$_][0], $list->[$_][1] // '' ] } 0 .. $#{$list} ];
            }
            if ( $self->{auto_up} == 2 || $self->{i}{curr_row} == $#$list ) {
                print up( $up );
                print "\r" . clear_to_end_of_screen();
                $self->__write_first_screen( $list );
                $m = $self->__string_and_pos( $list );
            }
            else {
                $self->{i}{curr_row}++;
                $m = $self->__string_and_pos( $list );
                if ( $self->{i}{curr_row} <= $self->{i}{end_row} ) {
                    $self->__reset_previous_row( $list, $self->{i}{curr_row} - 1 );
                    print down( 1 );
                }
                else {
                    print up( $self->{i}{end_row} - $self->{i}{begin_row} );
                    $self->__print_next_page( $list );
                }
            }
        }
        else {
            $k = 1;
            if ( $locked ) {
                $self->{i}{beep} = 1;
            }
            else {
                $char = chr $char;
                utf8::upgrade $char;
                $self->__add_char( $m, $char );
            }
        }
    }
}


sub __reset_previous_row {
    my ( $self, $list, $idx ) = @_;
    print "\r" . clear_to_end_of_line();
    print $self->__get_row( $list, $idx );
    if ( $self->{i}{curr_row} < $idx ) {
        $self->{i}{direction} = 'up';
    }
}


sub __print_next_page {
    my ( $self, $list ) = @_;
    $self->{i}{begin_row} = $self->{i}{end_row} + 1;
    $self->{i}{end_row}   = $self->{i}{end_row} + $self->{i}{avail_h};
    $self->{i}{end_row}   = $#$list if $self->{i}{end_row} > $#$list;
    print "\r" . clear_to_end_of_screen();
    $self->__write_screen( $list );
    if ( $self->{i}{curr_row} == $self->{i}{end_row} ) {
        $self->{i}{direction} = 'up';
    }
}


sub __print_previous_page {
    my ( $self, $list ) = @_;
    $self->{i}{end_row}   = $self->{i}{begin_row} - 1;
    $self->{i}{begin_row} = $self->{i}{begin_row} - $self->{i}{avail_h};
    $self->{i}{begin_row} = 0 if $self->{i}{begin_row} < 0;
    print "\r" . clear_to_end_of_screen();
    $self->__write_screen( $list );
    if ( $self->{i}{curr_row} > $self->{i}{begin_row} ) {
        $self->{i}{direction} = 'up';
    }
}


1;


__END__