IkiWiki::Plugin::syntax - Add syntax highlighting to ikiwiki

    This is the example code 

    [[syntax language=perl text="""
    #!/usr/bin/perl

    print "Hello, world\n";
    """]]

    and this is my bash profile (using file type autodetection )

    [[syntax file="software/examples/mybash_profile" 
        description="My profile" ]]

    This is the syntax engine chart in this site:

    [[syntax ]]

package IkiWiki::Plugin::syntax;

use warnings;
use strict;
use Carp;
use utf8;
use Data::Dumper;

use IkiWiki 2.00;

use IkiWiki::Plugin::syntax::gettext;   # fake gettext for the IkiWiki old version
use IkiWiki::Plugin::syntax::Simple;    # the last option
use IkiWiki::Plugin::syntax::X;

our $VERSION    =   '0.25';
our $_syntax    =   undef;

my  %engine_parameters = (
    'Simple'    =>  undef,
    'Kate'      =>  undef,
    'Vim'       =>  undef,
);
my  $use_template   =   0;

# Module implementation here
sub import { #{{{
    ### Define the hooks into ikiwiki ...
    hook(type => 'checkconfig', id => 'syntax', call => \&checkconfig);
	hook(type => "preprocess", id => "syntax", call => \&preprocess);
} # }}}

sub checkconfig {
    
    ### select an engine from the global ikiwiki configuration
    #
    my  $engine = $IkiWiki::config{syntax_engine} || q(Simple);

    ### Read global parameters ...
    $use_template = $IkiWiki::config{syntax_use_template} || 0;

    # search for special parameters (unused)
    foreach my $engine_name (keys %engine_parameters) {
        my  $key    =  "syntax_" . lc($engine_name);
        if (exists $IkiWiki::config{$key}) {
            $engine_parameters{$engine_name} = $config{$key};
        }
    }

    _change_engine( $engine, %{ $engine_parameters{$engine} } );

    return;            
}

sub _change_engine {
    my  ($engine_name, %engine_params) = @_;

    # close the old engine 
    if (defined $_syntax) {
        undef $_syntax;
    }

    ## create a reusable object
    $_syntax = _new_engine( $engine_name );

    if ($_syntax) {
        $_syntax->logging( sprintf 'using the engine %s', $engine_name );
    }
    else {
        error 'could not create a IkiWiki::Plugin::syntax object';
    }
    
    return $_syntax;
}

sub _new_engine {
    my  $name       =   shift;
    my  $engine     =   sprintf 'IkiWiki::Plugin::syntax::%s', $name;
    my  $object     =   undef;

    eval "use ${engine}";

    if (not @_) {
        if (not $object = $engine->new( )) {
            $object = IkiWiki::Plugin::syntax::Simple->new();
        }
    }

    return $object;
}

sub preprocess (@) { #{{{
    my %params = (
        language        =>  undef,      ### plugin parameters
        description     =>  undef,      #
        text            =>  undef,      #
        file            =>  undef,      #
        linenumbers     =>  0,          #
        formatcomments  =>  0,          ###
        force_subpage   =>  0,          ###  Ikiwiki parameters
        page            =>  undef,      #
        destpage        =>  undef,      ###
        @_
    );

    #   engine change ? 
    if (defined( $params{engine} )) {
        _change_engine( $params{engine} );
    }

    #   check parameters
    eval {
        _clean_up_parameters( \%params );
    };

    if ($@) {
        if (my $ex = Syntax::X::Parameters::None->caught()) {
            # show the plugin info
            return _info_response();
        } else {
            return $_syntax->fail_response( $ex );
        }
    }

    $_syntax->logging( sprintf 'set language to %s', $params{language} );

    ### getting syntax highlight in html format ...  
    eval {
        $_syntax->syntax_highlight( %params );
        };

    if (my $ex = $@) {
        return $_syntax->fail_response( $ex );
    }        

    ### decode to utf-8 ...
    # utf8::decode( $syntax_html );

    ###     build the final text with a template named "syntax" or joining html
    #       blocks
    return _build_output( \%params, $_syntax->output() );
} # }}}

sub _build_output {
    my  $params_ref =   shift;
    my  $html_text  =   shift;
    my  %params     =   (
            language    =>  $_syntax->language(),
            title       =>  $params_ref->{title},
            description =>  $params_ref->{description},
            text        =>  $html_text,
            url         =>  defined $params_ref->{file} 
                            ? IkiWiki::urlto( $params_ref->{file}, 
                                              $params_ref->{page} )
                            : undef,
        );

    if ($use_template) {
        # take a template reference             
        my $tmpl = template('syntax.tmpl', default_escape => 0);
        
        # set substitutions variables            
        $tmpl->param( %params );

        # and process ..
        return $tmpl->output(); 
    }
    else {
        return _manual_output( %params );
    }
}

sub _manual_output {
    my  %params     =   @_;
    my  @html       =   ();

    if (defined $params{title}) {
        push(@html, $_syntax->css('title', $params{title}));
    }

    if (defined $params{url}) {
        push(@html, $params{url});
    }

    if (defined $params{text}) {
        push(@html, $_syntax->css('syntax', $params{text} ) );
    }

    if (defined $params{description}) {
        push(@html, $_syntax->css('description', $params{description}) );
    }

    return join("\n", @html);
}

sub _clean_up_parameters {
    my  $params_ref     =   shift;

    # check for the object availability	        
    if (not $_syntax) {
        Syntax::X->throw( 'syntax plugin not available' );
    }
    else {
        $_syntax->reset_engine();
    }

    ## save a selected group of parameters in the engine object
    $_syntax->page( $params_ref->{page} );
    if ($params_ref->{linenumbers}) {
        $_syntax->linenumbers( 1 );
        $_syntax->first_line_number( $params_ref->{linenumbers} );
    }
    if ($params_ref->{bars}) {
        $_syntax->bars( $params_ref->{bars} );
    }

    #   if defined a external source file ...
    if (defined($params_ref->{file})) {
        ### load file content: $params_ref->{file}
        $_syntax->source( readfile(srcfile($params_ref->{file})) );

        ### add depend from file ...
        add_depends($params_ref->{page}, $params_ref->{file});
    }
    elsif (defined($params_ref->{text})) {
        $_syntax->source( $params_ref->{text} );
    }
    else {
        Syntax::X::Parameters::None->throw( gettext(q(missing text or file parameters)) );
    }

    ## check the source language
    if (not $_syntax->detect_language( 
                    proposed => $params_ref->{language},
                    filename => $params_ref->{file},
                    content  => $_syntax->source() )) {
        Syntax::X::Parameters::Wrong->throw( 
            gettext( q(could not determine or manage the source language) ));
    }
    else {
        # save the language
        $params_ref->{language} = $_syntax->language();
    }

    return;
}

sub _info_response {
    my  %info       =   $_syntax->plugin_info();
    my $tmpl        =   template('syntax_info.tmpl');

    $tmpl->param( %info );

    return $tmpl->output();
}

1; 

__END__