#  You may distribute under the terms of the GNU General Public License
#
#  (C) Paul Evans, 2008-2017 -- leonerd@leonerd.org.uk

package Circle::GlobalRules;

use strict;
use warnings;

our $VERSION = '0.173320';

use Text::Balanced qw( extract_delimited extract_quotelike );

use base qw( Circle::Rule::Store ); # for the attributes

use Circle::TaggedString;

sub unquote_qr
{
   my $re = shift;

   $re = "$re";

   # Perl tries to put (?-xism:RE) around our pattern. Lets attempt to remove
   # it if we can
   # Recent perls use (?^:RE) instead
   $re =~ s/^\(\?-xism:(.*)\)$/$1/;
   $re =~ s/^\(\?\^:(.*)\)$/$1/;

   return ( $2, $1 ) if $re =~ m/^\(\?([ixsm]*)-?[xism]*:(.*)\)$/;
   return ( $2, $1 ) if $re =~ m/^\(\?\^([ixsm]*):(.*)\)$/;

   # Failed. Lets just be safe then
   return ( $re, "" );
}

# Not an object class. Instead, just a store of rule subs

sub register
{
   my ( $rulestore ) = @_;

   $rulestore->register_cond( matches => __PACKAGE__ );

   $rulestore->register_action( rewrite => __PACKAGE__ );
   $rulestore->register_action( format => __PACKAGE__ );
   $rulestore->register_action( unformat => __PACKAGE__ );
   $rulestore->register_action( level => __PACKAGE__ );
   $rulestore->register_action( highlight => __PACKAGE__ );
}

###### CONDITIONS

### MATCHES

sub parse_cond_matches
   : Rule_description("Look for regexp or substring matches in the text")
   : Rule_format('/regexp/ or "literal"')
{
   shift; # class
   my ( $spec ) = @_;

   if( $spec =~ m{^/} ) {
      # Try to pull the flags
      my ( $content, $flags ) = $spec =~ m{^/(.*)/([i]*)$} or die "Unrecognised regexp string $spec\n";

      return qr/$content/i if $flags eq "i";
      return qr/$content/;
   }
   elsif( $spec =~ m{^"} ) {
      my ( $content ) = $spec =~ m{^"(.*)"$} or die "Unrecognised literal string $spec\n";

      return qr/\Q$content/;
   }
   else {
      die "Unrecognised string type $spec";
   }
}

sub deparse_cond_matches
{
   shift; # class
   my ( $re ) = @_;

   my ( $pattern, $flags ) = unquote_qr( $re );
   return "/$pattern/$flags";
}

sub eval_cond_matches
{
   shift; # class
   my ( $event, $results, $re ) = @_;

   defined( my $text = $event->{text} ) or return 0;
   $text = "$text";  # stringify a String::Tagged

   pos( $text ) = 0;

   my $matched;

   while( $text =~ m/$re/g ) {
      my @matchgroups;
      for ( 0 .. $#+ ) {
         my ( $start, $end ) = ( $-[$_], $+[$_] );
         my $len = $end - $start;

         push @matchgroups, [ $start, $len ];
      }

      $results->push_result( "matchgroups", \@matchgroups );
      $matched = 1;
   }

   return $matched;
}

###### ACTIONS

### REWRITE

sub parse_action_rewrite
   : Rule_description("Rewrite text of the line or matched parts")
   : Rule_format('line|matches|match(number) "string"|s/pattern/replacement/')
{
   shift; # class
   my ( $spec ) = @_;

   $spec =~ s/^(\w+)\s*// or die "Expected type as first argument\n";
   my $type = $1;

   my $groupnum;

   if( $type eq "line" ) {
      $groupnum = -1;
   }
   elsif( $type eq "matches" ) {
      $groupnum = 0;
   }
   elsif( $type eq "match" ) {
      $spec =~ s/^\((\d+)\)\s*// or die "Expected match group number\n";
      $groupnum = $1;
   }
   else {
      die "Unrecognised format type $type\n";
   }

   my ( undef, $remains, undef, $op, $delim, $lhs, undef, undef, $rhs, undef, $mods ) = extract_quotelike( $spec )
      or die 'Expected "string" or s/pattern/replacement/';
   $spec = $remains;
   $op = $delim if $op eq "";

   if( $op eq '"' ) {
      # Literal
      return ( $groupnum, literal => $lhs );
   }
   elsif( $op eq "s" ) {
      # s/foo/bar/
      my $global = $mods =~ s/g//;
      # TODO: Range check that mods contains only /ism
      return ( $groupnum, subst => qr/(?$mods:$lhs)/, $rhs, $global );
   }
   else {
      die 'Expected "string" or s/pattern/replacement/';
   }
}

sub deparse_action_rewrite
{
   shift; # class
   my ( $groupnum, $kind, $lhs, $rhs, $global ) = @_;

   my $type = $groupnum == -1 ? "line" :
              $groupnum ==  0 ? "matches" :
                                "match($groupnum)";

   if( $kind eq "literal" ) {
      return "$type \"$lhs\"";
   }
   elsif( $kind eq "subst" ) {
      my ( $pattern, $flags ) = unquote_qr( $lhs );
      return "$type s/$pattern/$rhs/$flags" . ( $global ? "g" : "" );
   }
}

sub eval_action_rewrite
{
   shift; # class
   my ( $event, $results, $groupnum, $kind, $lhs, $rhs, $global ) = @_;

   my @location;
   if( $groupnum == -1 ) {
      @location = ( 0, -1 );
   }
   else {
      foreach my $groups ( @{ $results->get_result( "matchgroups" ) } ) {
         my $group = $groups->[$groupnum] or next;
         @location = @$group;
         last; # can only do the first one
      }
   }

   ref $event->{text} or $event->{text} = Circle::TaggedString->new( $event->{text} );
   my $text = $event->{text}->substr( $location[0], $location[1] );

   if( $kind eq "literal" ) {
      $text = $lhs;
   }
   elsif( $kind eq "subst" ) {
      $text =~ s/$lhs/$rhs/  if !$global;
      $text =~ s/$lhs/$rhs/g if  $global;
   }

   $event->{text}->set_substr( $location[0], $location[1], $text );
}

### FORMAT

sub parse_action_format
   : Rule_description("Apply formatting to the line or matched parts")
   : Rule_format('line|matches|match(number) key="value" [key="value" ...]')
{
   shift; # class
   my ( $spec ) = @_;

   $spec =~ s/^(\w+)\s*// or die "Expected type as first argument\n";
   my $type = $1;

   my $groupnum;

   if( $type eq "line" ) {
      $groupnum = -1;
   }
   elsif( $type eq "matches" ) {
      $groupnum = 0;
   }
   elsif( $type eq "match" ) {
      $spec =~ s/^\((\d+)\)\s*// or die "Expected match group number\n";
      $groupnum = $1;
   }
   else {
      die "Unrecognised format type $type\n";
   }

   my %format;
   while( $spec =~ s/^(\w+)=// ) {
      my $name = $1;

      my $value = extract_delimited( $spec, q{"'} );
      s/^["']//, s/["']$// for $value;

      $format{$name} = $value;

      $spec =~ s/^\s+//;
   }

   if( length $spec ) {
      die "Unrecognised format spec $spec\n";
   }

   return ( $groupnum, \%format );
}

sub deparse_action_format
{
   shift; # class
   my ( $groupnum, $formathash ) = @_;

   return unless %$formathash;

   my $type = $groupnum == -1 ? "line" :
              $groupnum ==  0 ? "matches" :
                                "match($groupnum)";

   return "$type ".join( " ", map { qq($_="$formathash->{$_}") } sort keys %$formathash );
}

sub eval_action_format
{
   shift; # class
   my ( $event, $results, $groupnum, $formathash ) = @_;

   my $str = $event->{text};
   ref $str or $str = Circle::TaggedString->new( $str );

   if( $groupnum == -1 ) {
      $str->apply_tag( 0, -1, $_, $formathash->{$_} ) for keys %$formathash;
   }
   else {
      foreach my $groups ( @{ $results->get_result( "matchgroups" ) } ) {
         my $group = $groups->[$groupnum] or next;
         my ( $start, $len ) = @$group;

         $str->apply_tag( $start, $len, $_, $formathash->{$_} ) for keys %$formathash;
      }
   }
}

### UNFORMAT

sub parse_action_unformat
   : Rule_description("Remove formatting from the line or matched parts")
   : Rule_format('line|matches|match(number) key [key ...]')
{
   shift; # class
   my ( $spec ) = @_;

   $spec =~ s/^(\w+)\s*// or die "Expected type as first argument\n";
   my $type = $1;

   my $groupnum;

   if( $type eq "line" ) {
      $groupnum = -1;
   }
   elsif( $type eq "matches" ) {
      $groupnum = 0;
   }
   elsif( $type eq "match" ) {
      $spec =~ s/^\((\d+)\)\s*// or die "Expected match group number\n";
      $groupnum = $1;
   }
   else {
      die "Unrecognised format type $type\n";
   }

   my @tags;
   while( $spec =~ s/^(\w+)// ) {
      my $name = $1;

      push @tags, $name;

      $spec =~ s/^\s+//;
   }

   if( length $spec ) {
      die "Unrecognised format spec $spec\n";
   }

   return ( $groupnum, \@tags );
}

sub deparse_action_unformat
{
   shift; # class
   my ( $groupnum, $taglist ) = @_;

   my $type = $groupnum == -1 ? "line" :
              $groupnum ==  0 ? "matches" :
                                "match($groupnum)";

   my $ret = $type;
   $ret .= " $_" for @$taglist;

   return $ret;
}

my @alltags = qw( fg bg b u i );

sub eval_action_unformat
{
   shift; # class
   my ( $event, $results, $groupnum, $taglist ) = @_;

   $taglist = \@alltags unless @$taglist;

   my $str = $event->{text};
   ref $str or $str = Circle::TaggedString->new( $str );

   if( $groupnum == -1 ) {
      $str->unapply_tag( 0, -1, $_ ) for @$taglist;
   }
   else {
      foreach my $groups ( @{ $results->get_result( "matchgroups" ) } ) {
         my $group = $groups->[$groupnum] or next;
         my ( $start, $len ) = @$group;

         $str->unapply_tag( $start, $len, $_ ) for @$taglist;
      }
   }
}

### LEVEL

sub parse_action_level
   : Rule_description("Set the activity level for the targetted item")
   : Rule_format('$level')
{
   shift; # class
   my ( $spec ) = @_;

   $spec =~ s/^(\d)// or die "Expected level number as first argument\n";
   my $level = $1;

   $level >= 0 and $level <= 3 or die "Expected 'level' between 0 and 3\n";

   return ( $level );
}

sub deparse_action_level
{
   shift; # class
   my ( $level ) = @_;

   return "$level";
}

sub eval_action_level
{
   shift; # class
   my ( $event, $results, $level ) = @_;

   $event->{level} = $level;
}

## HIGHLIGHT

sub parse_action_highlight
   : Rule_description("Highlight matched regions and set activity level to 3")
   : Rule_format('')
{
   my $self = shift;
   return;
}

sub deparse_action_highlight
{
   my $self = shift;
   return;
}

sub eval_action_highlight
{
   my $self = shift;
   my ( $event, $results ) = @_;

   my $str = $event->{text};
   ref $str or $str = Circle::TaggedString->new( $str );

   foreach my $matchgroup ( @{ $results->get_result( "matchgroups" ) } ) {
      my ( $start, $len ) = @{$matchgroup->[0]}[0,1];

      $str->apply_tag( $start, $len, b => 1 );
      $str->apply_tag( $start, $len, fg => "highlight" );
   }

   $event->{level} = 3;
}

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