package Config::Model::Itself ;

use Mouse ;
use Config::Model 2.141;
use 5.014; # for the /r modifier

use IO::File ;
use Log::Log4perl 1.11;
use Carp ;
use Data::Dumper ;
use Scalar::Util qw/weaken/;
use File::Find ;
use File::Path ;
use File::Basename ;
use Data::Compare ;
use Path::Tiny 0.125; # for mkdir
use Mouse::Util::TypeConstraints;

my $logger = Log::Log4perl::get_logger("Backend::Itself");

subtype 'ModelPathTiny' => as 'Object' => where { $_->isa('Path::Tiny') };

coerce 'ModelPathTiny'  => from 'Str'  => via {path($_)} ;

# find all .pl file in model_dir and load them...

around BUILDARGS => sub {
    my $orig  = shift;
    my $class = shift;
    my %args  = @_;

    my $legacy = delete $args{model_object};
    if ($legacy) {
        $args{config_model} = $legacy->instance->config_model;
        $args{meta_instance} = $legacy->instance;
        $args{meta_root} = $legacy;
    }
    return $class->$orig( %args );
};

has 'config_model' => (
    is => 'ro',
    isa => 'Config::Model',
    lazy_build => 1,
) ;


sub _build_config_model {
    my $self = shift;
    # don't trigger builders below
    if ($self->{meta_root}) {
        return $self->meta_root->instance->config_model;
    }
    elsif ($self->{meta_instance}) {
        return $self->meta_instance->config_model;
    }
    else {
        return Config::Model -> new ( ) ;
    }
}

has check        => (is =>'ro', isa => 'Bool', default => 1) ;

has 'meta_instance' => (
    is =>'ro',
    isa =>'Config::Model::Instance',
    lazy_build => 1,
) ;

sub _build_meta_instance {
    my $self = shift;

    # don't trigger builders below
    if ($self->{meta_root}) {
        return $self->meta_root->instance;
    }
    else {
        # load Config::Model model
        return $self->config_model->instance (
            root_class_name => 'Itself::Model' ,
            instance_name   => 'meta_model' ,
            check => $self->check,
        );
    }

}

has meta_root => (
    is =>'ro',
    isa =>'Config::Model::Node',
    lazy_build => 1,
) ;

sub _build_meta_root {
    my $self = shift;

    return $self->meta_instance -> config_root ;
}

has cm_lib_dir   => (
    is =>'ro',
    isa => 'ModelPathTiny',
    lazy_build => 1,
    coerce => 1
) ;

sub _build_cm_lib_dir {
    my $self = shift;
    my $p =  path('lib/Config/Model');
    if (! $p->is_dir) {
        $p->mkdir();
    }
    return $p;
}

has force_write  => (is =>'ro', isa => 'Bool', default => 0) ;
has root_model   => (is =>'ro', isa => 'str');

has modified_classes => (
    is =>'rw',
    isa =>'HashRef[Bool]',
    traits => ['Hash'],
    default => sub { {} } ,
    handles => {
        clear_classes => 'clear',
        set_class => 'set',
        class_was_changed => 'get' ,
        class_known => 'exists',
    }
) ;

has model_dir => (
    is => 'ro',
    isa => 'ModelPathTiny',
    lazy_build => 1,
);

sub _build_model_dir {
    my $self = shift;
    my $md = $self->cm_lib_dir->child('models');
    $md->mkdir;
    return $md;
}

sub BUILD {
    my $self = shift;

    # avoid memory cycle
    weaken($self);

    my $cb = sub {
        my %args = @_ ;
        my $p = $args{path} || '' ;
        return unless $p =~ /^class/ ;
        return unless $args{index}; # may be empty when class order is changed
        return if $self->class_was_changed($args{index}) ;
        $logger->info("class $args{index} was modified");

        $self->add_modified_class($args{index}) ;
    } ;
    $self->meta_instance -> on_change_cb($cb) ;

}

sub add_tracked_class {
    my $self = shift;
    $self->set_class(shift,0) ;
}

sub add_modified_class {
    my $self = shift;
    $self->set_class(shift,1) ;
}

sub class_needs_write {
    my $self = shift;
    my $name =  shift;
    return ($self->force_write or not $self->class_known($name) or $self->class_was_changed($name)) ;
}

sub read_app_files {
    my $self = shift;
    my $force_load = shift || 0;
    my $read_from =  shift ;
    my $application = shift ;

    my $app_dir = $read_from || $self->model_dir->parent;
    my %apps;
    my %map;
    $logger->info("reading app files from ".$app_dir);
    foreach my $dir ( $app_dir->children(qr/\.d$/) ) {

        $logger->info("reading app dir ".$dir);
        foreach my $file ( $dir->children() ) {
            next if $file =~ m!/README!;
            next if $file =~ /(~|\.bak|\.orig)$/;
            next if $application and $file->basename ne $application;

            # bad categories are filtered by the model
            my %data = ( category => $dir->basename('.d') );
            $logger->info("reading app file ".$file);

            foreach ($file->lines({ chomp => 1})) {
                s/^\s+//;
                s/\s+$//;
                s/#.*//;
                my ( $k, $v ) = split /\s*=\s*/;
                next unless $v;
                $data{$k} = $v;
            }

            my $appli = $file->basename;
            $apps{$appli} = $data{model} ;
            $map{$appli} = $file;

            $self->meta_root->load_data(
                data => { application => { $appli => \%data } },
                check => $force_load ? 'no' : 'yes'
            ) ;
        }
    }

    $self->{app_map} = \%map;

    return \%apps;
}

sub read_all {
    my $self = shift ;
    my %args = @_ ;

    my $force_load = delete $args{force_load} || 0 ;
    my $read_from ;
    my $model_dir ;
    if ($args{read_from}) {
        $read_from = path (delete $args{read_from});
        die "Cannot read from unknown dir ".$read_from unless $read_from->is_dir;
        $model_dir = $read_from->child('models');
        die "Cannot read from unknown dir ".$model_dir unless $model_dir->is_dir;
    }

    my $apps = $self-> read_app_files($force_load, $read_from, delete $args{application});

    my $root_model_arg = delete $args{root_model} || '';
    my $model = $apps->{$root_model_arg} || $root_model_arg ;
    my $legacy = delete $args{legacy} ;

    croak "read_all: unexpected parameters ",join(' ', keys %args) if %args ;

    my $dir = $self->model_dir;
    $dir->mkdir ;

    my $root_model_file = $model ;
    $root_model_file =~ s!::!/!g ;
    my $read_dir = $model_dir || $dir;
    $logger->info("searching model files in ".$read_dir);

    my @files ;
    my $wanted = sub {
        push @files, $_ if ( $_->is_file and /\.pl$/
                                 and m!$read_dir/$root_model_file\b!
                                 and not m!\.d/!
                           ) ;
    } ;
    $read_dir->visit($wanted, { recurse => 1} ) ;

    my %read_models ;
    my %class_file_map ;

    my @all_models = $self->load_model_files(
        $read_dir, \@files, $legacy, \%class_file_map, \%read_models
    );

    $self->{root_model} = $model || (sort @all_models)[0];

    # Create all classes listed in %read_models to avoid problems with
    # include statement while calling load_data
    my $root_obj = $self->meta_root ;
    my $class_element = $root_obj->fetch_element('class') ;
    foreach my $class (sort keys %read_models) {
        $class_element->fetch_with_id($class);
    }

    #require Tk::ObjScanner; Tk::ObjScanner::scan_object(\%read_models) ;

    $logger->info("loading all extracted data in Config::Model::Itself");
    # load with a array ref to avoid warnings about missing order
    $root_obj->load_data(
        data => {class => [ %read_models ] },
        check => $force_load ? 'no' : 'yes'
    ) ;

    $self->read_model_annotations( $dir, $root_obj, \@files);

    return $self->{map} = \%class_file_map ;
}

sub load_model_files {
    my ($self, $read_dir, $files, $legacy, $class_file_map, $read_models) = @_;

    my @all_models;
    for my $file (@$files) {
        $logger->info("loading config file $file");

        # now apply some translation to read model
        # - translate legacy warp parameters
        # - expand elements name
        my @legacy = $legacy ? ( legacy => $legacy ) : () ;
        my $tmp_model = Config::Model -> new( skip_include => 1, @legacy ) ;

        # @models order is important to write configuration class back in the same
        # order as the declaration
        my @models = $tmp_model -> load ( 'Tmp' , $file->absolute ) ;
        push @all_models, @models;

        my $rel_file = $file ;
        $rel_file =~ s/^$read_dir\/?//;
        die "wrong reg_exp" if $file eq $rel_file ;
        $class_file_map->{$rel_file} = \@models ;

        # - move experience, description and level status into parameter info.
        foreach my $model_name (@models) {
            $read_models->{$model_name} = $self->normalize_model($model_name, $tmp_model);
        }
    }
    return @all_models;
}

sub normalize_model {
    my ($self, $model_name, $tmp_model) = @_;

    # no need to dclone model as Config::Model object is temporary
    my $raw_model =  $tmp_model -> get_raw_model( $model_name ) ;
    my $new_model =  $tmp_model -> get_model_clone( $model_name ) ;

    $self->upgrade_model($model_name, $new_model);

    # track read class to identify later classes added by user
    $self->add_tracked_class($model_name);

    # some modifications may be done to cope with older model styles. If a modif
    # was done, mark the class as changed so it will be saved later
    $self->add_modified_class($model_name) unless Compare($raw_model, $new_model) ;

    foreach my $item (qw/description summary level experience status/) {
        foreach my $elt_name (keys %{$new_model->{element}}) {
            my $moved_data = delete $new_model->{$item}{$elt_name}  ;
            next unless defined $moved_data ;
            $new_model->{element}{$elt_name}{$item} = $moved_data ;
        }
        delete $new_model->{$item} ;
    }

    # Since accept specs and elements are stored in a ordered hash,
    # load_data expects a array ref instead of a hash ref.
    # Build this array ref taking the order into
    # account
    foreach my $what (qw/element accept/) {
        my $list  = delete $new_model -> {$what.'_list'} ;
        my $h     = delete $new_model -> {$what} ;
        $new_model -> {$what} = [] ;
        foreach my $name (@$list) {
            push @{$new_model->{$what}}, $name, $h->{$name}
        }
        ;
    }

    # remove hash key with undefined values
    foreach my $name (keys %$new_model) {
        if (not defined $new_model->{$name} or $new_model->{$name} eq '') {
            delete $new_model->{$name};
        }
    }
    return $new_model ;
}

sub read_model_annotations {
    my ($self, $dir, $root_obj, $files) = @_;

    # load annotations and comment header
    for my $file (@$files) {
        $logger->info("loading annotations from file $file");
        my $fh = IO::File->new($file) || die "Can't open $file: $!" ;
        my @lines = $fh->getlines ;
        $fh->close;
        $root_obj->load_pod_annotation(join('',@lines)) ;

        my @headers ;
        foreach my $l (@lines) {
            if ($l =~ /^\s*#/ or $l =~ /^\s*$/){
                push @headers, $l
            }
            else {
                last;
            }
        }
        my $rel_file = $file ;
        $rel_file =~ s/^$dir\/?//;
        $self->{header}{$rel_file} = \@headers;
    }
}

# can be removed end of 2019 (after buster is released)
sub upgrade_model {
    my ($self, $config_class_name, $model) = @_ ;

    my $multi_backend = 0;
    foreach my $config (qw/read_config write_config/) {
        my $ref = $model->{$config};
        if ($ref and ref($ref) eq 'ARRAY') {
            if (@$ref == 1) {
                $model->{$config} = $ref->[0];
            }
            elsif (@$ref > 1){
                $logger->warn("$config_class_name $config: cannot migrate multiple backends to rw_config");
                $multi_backend++;
            }
        }
    }

    if ($model->{read_config} and not $multi_backend) {
        say ("Model $config_class_name: moving read_config specification to rw_config");
        $model->{rw_config} = delete $model->{read_config};
    }

    if ($model->{write_config} and not $multi_backend) {
        say "Model $config_class_name: merging write_config specification in rw_config";
        if (not $multi_backend) {
            foreach my $spec ( keys %{$model->{write_config}} ) {
                $model->{rw_config}{$spec} = $model->{write_config}{$spec}
            } ;
            delete $model->{write_config};
        }
    }
}

# internal
sub get_perl_data_model{
    my $self = shift ;
    my %args = @_ ;
    my $root_obj = $self->{meta_root};
    my $class_name = $args{class_name}
      || croak __PACKAGE__," read: undefined class name";

    my $class_element = $root_obj->fetch_element('class') ;

    # skip if class was deleted during edition
    return unless $class_element->defined($class_name) ;

    my $class_elt = $class_element -> fetch_with_id($class_name) ;

    my $model = $class_elt->dump_as_data ;

    # now apply some translation to read model
    # - Do NOT translate legacy warp parameters
    # - Do not compact elements name

    # don't forget to add name
    $model->{name} = $class_name if keys %$model;

    return $model ;
}

sub write_app_files {
    my $self = shift;

    my $app_dir = $self->cm_lib_dir;
    my $app_obj = $self->meta_root->fetch_element('application');

    foreach my $app_name ( $app_obj->fetch_all_indexes ) {
        $logger->debug("writing $app_name...");
        my $app = $app_obj->fetch_with_id($app_name);
        my $cat_dir_name = $app->fetch_element_value( name =>'category' ).'.d';
        $app_dir->child($cat_dir_name)->mkdir();
        my $app_file = $app_dir->child($cat_dir_name)->child($app->index_value) ;

        my @lines ;
        foreach my $name ( $app->children ) {
            next if $name eq 'category'; # saved as directory above

            my $v = $app->fetch_element_value($name); # need to spit out 0 ?
            next unless defined $v;
            push @lines, "$name = $v\n";

        }
        $logger->info("writing file ".$app_file);
        $app_file->spew(@lines);
        delete $self->{app_map}{$app_name};
    }

    # prune removed app files
    foreach my $old_file ( values %{$self->{app_map}}) {
        $logger->debug("Removing $old_file.");
        $old_file->remove;
    }
}

sub write_all {
    my $self = shift ;
    my %args = @_ ;
    my $root_obj = $self->meta_root ;
    my $dir = $self->model_dir ;

    croak "write_all: unexpected parameters ",join(' ', keys %args) if %args ;

    $self->write_app_files;

    my $map = $self->{map} ;

    $dir->mkdir;

    # get list of all classes loaded by the editor
    my %loaded_classes
      = map { ($_ => 1); }
        $root_obj->fetch_element('class')->fetch_all_indexes ;

    # remove classes that are listed in map
    foreach my $file (keys %$map) {
        foreach my $class_name (@{$map->{$file}}) {
            delete $loaded_classes{$class_name} ;
        }
    }

    # add remaining classes in map
    my %new_map;
    foreach my $class (keys %loaded_classes) {
        my $f = $class =~ s!::!/!gr;
        $new_map{"$f.pl"} = [ $class ] ;
    }

    my %map_to_write = (%$map,%new_map) ;

    foreach my $file (keys %map_to_write) {
        my ($data,$notes) = $self->check_model_to_write($file, \%map_to_write, \%loaded_classes);
        next unless @$data ; # don't write empty model
        write_model_file ($dir->child($file), $self->{header}{$file}, $notes, $data);
        delete $map_to_write{$file};
    }

    # remove existing files that contain only deleted classes
    foreach my $goner (%map_to_write) {
        $logger->debug("Removing model file $goner.");
        $dir->child($goner)->remove;
    }
    $self->meta_instance->clear_changes ;
}

sub check_model_to_write {
    my ($self, $file, $map_to_write, $loaded_classes) = @_;
    $logger->info("checking model file $file");

    my @data ;
    my @notes ;
    my $file_needs_write = 0;

    # check if any a class of a file was modified
    foreach my $class_name (@{$map_to_write->{$file}}) {
        $file_needs_write++ if $self->class_needs_write($class_name);
        $logger->info("file $file class $class_name needs write ",$file_needs_write);
    }

    if ($file_needs_write) {
        foreach my $class_name (@{$map_to_write->{$file}}) {
            $logger->info("writing class $class_name");
            my $model = $self-> get_perl_data_model(class_name => $class_name) ;
            push @data, $model if defined $model and keys %$model;

            my $node = $self->{meta_root}->grab("class:".$class_name) ;
            push @notes, $node->dump_annotations_as_pod ;
            # remove class name from above list
            delete $loaded_classes->{$class_name} ;
        }
    }

    return (\@data, \@notes);
}

sub write_model_plugin {
    my $self = shift ;
    my %args = @_ ;
    my $plugin_dir = delete $args{plugin_dir}
      || croak __PACKAGE__," write_model_plugin: undefined plugin_dir";
    my $plugin_name = delete $args{plugin_name}
        || croak __PACKAGE__," write_model_plugin: undefined plugin_name";
    croak "write_model_plugin: unexpected parameters ",join(' ', keys %args) if %args ;

    my $model = $self->meta_root->dump_as_data(mode => 'custom') ;
    # print (Dumper( $model)) ;

    my @raw_data = @{$model->{class} || []} ;
    while (@raw_data) {
        my ( $class , $data ) = splice @raw_data,0,2 ;
        $data ->{name} = $class ;

        # does not distinguish between notes from underlying model or snipper notes ...
        my @notes = $self->meta_root->grab("class:$class")->dump_annotations_as_pod ;
        my $plugin_file = $class.'.pl';
        $plugin_file =~ s!::!/!g;
        write_model_file ("$plugin_dir/$plugin_name/$plugin_file", [], \@notes, [ $data ]);
    }

    $self->meta_instance->clear_changes ;
}

sub read_model_plugin {
    my $self = shift ;
    my %args = @_ ;
    my $plugin_dir = delete $args{plugin_dir}
      || croak __PACKAGE__," write_model_plugin: undefined plugin_dir";
    my $plugin_name = delete $args{plugin_name}
      || croak __PACKAGE__," read_model_plugin: undefined plugin_name";

    croak "read_model_plugin: unexpected parameters ",join(' ', keys %args) if %args ;

    my @files ;
    my $wanted = sub {
        my $n = $File::Find::name ;
        push @files, $n if (-f $_ and not /~$/
                            and $n !~ /CVS/
                            and $n !~ m!.(svn|orig|pod)$!
                            and $n =~ m!\.d/$plugin_name!
                           ) ;
    } ;
    find ($wanted, $plugin_dir ) ;

    foreach my $load_file (@files) {
        $self->read_plugin_file($load_file);
    }
}

sub read_plugin_file {
    my ($self, $load_file) = @_;

    $logger->info("trying to read plugin $load_file");
    my $class_element = $self->meta_root->fetch_element('class') ;

    $load_file = "./$load_file" if $load_file !~ m!^/! and -e $load_file;

    my $plugin = do $load_file ;

    unless ($plugin) {
        if ($@) {die "couldn't parse $load_file: $@"; }
        elsif (not defined $plugin) {die  "couldn't do $load_file: $!"}
        else { die  "couldn't run $load_file" ;}
    }

    # there should be only only class in each plugin file
    foreach my $model (@$plugin) {
        my $class_name = delete $model->{name} ;
        # load with a array ref to avoid warnings about missing order
        $class_element->fetch_with_id($class_name)->load_data( $model ) ;
    }

    # load annotations
    $logger->info("loading annotations from plugin file $load_file");
    my $fh = IO::File->new($load_file) || die "Can't open $load_file: $!" ;
    my @lines = $fh->getlines ;
    $fh->close;
    $self->meta_root->load_pod_annotation(join('',@lines)) ;
}

#
# New subroutine "write_model_file" extracted - Mon Mar 12 13:38:29 2012.
#
sub write_model_file {
    my $wr_file  = shift;
    my $comments = shift ;
    my $notes    = shift;
    my $data     = shift;

    my $wr_dir = dirname($wr_file);
    unless ( -d $wr_dir ) {
        mkpath( $wr_dir, 0, oct(755) ) || die "Can't mkpath $wr_dir:$!";
    }

    my $wr = IO::File->new( $wr_file, '>' )
      || croak "Cannot open file $wr_file:$!" ;
    $logger->info("in $wr_file");

    my $dumper = Data::Dumper->new( [ \@$data ] );
    $dumper->Indent(1);    # avoid too deep indentation
    $dumper->Terse(1);     # allow unnamed variables in dump
    $dumper->Sortkeys(1);     # sort keys in hash

    my $dump = $dumper->Dump;

    # munge pod text embedded in values to avoid spurious pod formatting
    $dump =~ s/\n=/\n'.'=/g;

    $wr->print( @$comments ) ;
    $wr->print( "use strict;\nuse warnings;\n\n" );
    $wr->print( "return $dump;\n\n" );

    $wr->print( join( "\n", @$notes ) );

    $wr->close;

}



sub list_class_element {
    my $self = shift ;
    my $pad  =  shift || '' ;

    my $res = '';
    my $meta_class = $self->{meta_root}->fetch_element('class') ;
    foreach my $class_name ($meta_class->fetch_all_indexes ) {
        $res .= $self->list_one_class_element($class_name) ;
    }
    return $res ;
}

sub list_one_class_element {
    my $self = shift ;
    my $class_name = shift || return '' ;
    my $pad  =  shift || '' ;

    my $res = $pad."Class: $class_name\n";
    my $meta_class = $self->{meta_root}->fetch_element('class')
       -> fetch_with_id($class_name) ;

    my @elts = $meta_class->fetch_element('element')->fetch_all_indexes ;

    my @include = $meta_class->fetch_element('include')->fetch_all_values ;
    my $inc_after = $meta_class->grab_value('include_after') ;

    if (@include and not defined $inc_after) {
        foreach my $inc (@include) {
            $res .= $self->list_one_class_element($inc,$pad.'  ') ;
        }
    }

    return $res unless @elts ;

    foreach my $elt_name ( @elts) {
        my $type = $meta_class->grab_value("element:$elt_name type") ;

        $res .= $pad."  - $elt_name ($type)\n";
        if (@include and defined $inc_after and $inc_after eq $elt_name) {
            foreach my $inc (@include) {
                $res .= $self->list_one_class_element($inc,$pad.'  ') ;
            }
        }
    }
    return $res ;
}


sub get_dot_diagram {
    my $self = shift ;
    my $dot = "digraph model {\n" ;

    my $meta_class = $self->{meta_root}->fetch_element('class') ;
    foreach my $class_name ($meta_class->fetch_all_indexes ) {
        my $d_class = $class_name ;
        $d_class =~ s/::/__/g;

        my $elt_list = '';
        my $use = '';

        my $class_obj =  $self->{meta_root}->grab(qq!class:"$class_name"!);
        my @elts =  $class_obj ->grab(qq!element!) ->fetch_all_indexes ;
        foreach my $elt_name ( @elts ) {
            my $of = '';
            my $elt_obj = $class_obj->grab(qq!element:"$elt_name"!) ;
            my $type = $elt_obj->grab_value("type") ;
            if ($type =~ /^list|hash$/) {
                my $cargo = $elt_obj->grab("cargo");
                my $ct = $cargo->grab_value("type") ;
                $of = " of $ct" ;
                $use .= $self->scan_used_class($d_class,$elt_name,$cargo);
            }
            else {
                $use .= $self->scan_used_class($d_class,$elt_name,$elt_obj);
            }
            $elt_list .= "- $elt_name ($type$of)\\n";
        }

        $dot .= $d_class
             .  qq! [shape=box label="$class_name\\n$elt_list"];\n!
             .  $use . "\n";

        $dot .= $self->scan_includes($class_name, $class_obj) ;
    }

    $dot .="}\n";

    return $dot ;
}

sub scan_includes {
    my ($self,$class_name, $class_obj) = @_ ;
    my $d_class = $class_name ;
    $d_class =~ s/::/__/g;

    my @includes = $class_obj->grab('include')->fetch_all_values ;
    my $dot = '';
    foreach my $c (@includes) {
        say "$class_name includes $c";
        my $t = $c;
        $t =~ s/::/__/g;
        $dot.= qq!$d_class -> $t ;\n!;
    }
    return $dot;
}

sub scan_used_class {
    my ($self,$d_class,$elt_name, $elt_obj) = @_ ;

    # define leaf call back
    my $disp_leaf = sub {
        my ($scanner, $data_ref, $node,$element_name,$index, $leaf_object) = @_ ;
        return unless $element_name eq 'config_class_name';
        my $v =  $leaf_object->fetch;
        return unless $v;
        $v =~ s/::/__/g;
        $$data_ref .= qq!$d_class -> $v !
            . qq![ style=dashed, label="$elt_name" ];\n!;
    } ;

    # simple scanner, (print all values)
    my $scan = Config::Model::ObjTreeScanner-> new (
        leaf_cb => $disp_leaf, # only mandatory parameter
    ) ;

    my $result = '' ;
    $scan->scan_node(\$result, $elt_obj) ;
    return $result ;
}

__PACKAGE__->meta->make_immutable;

1;


# ABSTRACT: Model (or schema) editor for Config::Model

__END__


=pod

=head1 SYNOPSIS

 # Itself constructor returns an object to read or write the data
 # structure containing the model to be edited
 my $meta_model = Config::Model::Itself -> new( ) ;

 # now load the model to be edited
 $meta_model -> read_all( ) ;

 # For Curses UI prepare a call-back to write model
 my $wr_back = sub { $meta_model->write_all(); }

 # create Curses user interface
 my $dialog = Config::Model::CursesUI-> new (
      store => $wr_back,
 ) ;

 # start Curses dialog to edit the mode
 $dialog->start( $meta_model->config_root )  ;

 # that's it. When user quits curses interface, Curses will call
 # $wr_back sub ref to write the modified model.

=head1 DESCRIPTION

Config::Itself module and its model files provide a model of Config:Model
(hence the Itself name).

Let's step back a little to explain. Any configuration data is, in
essence, structured data. A
configuration model is a way to describe the structure and relation of
all items of a configuration data set.

This configuration model is also expressed as structured data. This
structure data follows a set of rules which are
described for humans in L<Config::Model>.

The structure and rules documented in L<Config::Model> are also
expressed in a model in the files provided with
C<Config::Model::Itself>.

Hence the possibity to verify, modify configuration data provided by
L<Config::Model> can also be applied on configuration models. Using the
same user interface.

From a Perl point of view, Config::Model::Itself provides a class
dedicated to read and write a set of model files.

=head1 Constructor

=head2 new ( [ cm_lib_dir => ... ] )

Creates a new read/write handler. If no model_object is passed, the required
objects are created. C<cm_lib_dir> specifies where are the model files (defaults to
C<./lib/Config/Model>.

C<cm_lib_dir> is either a C<Path::Tiny> object or a string.

By default, this constructor will create all necessary
C<Config::Model*> objects.  If needed, you can pass already created
object with options C<config_model> (L<Config::Model> object),
C<meta_instance> (L<Config::Model::Instance> object) or C<meta_root>
(L<Config::Model::Node> object).

=head2 Methods

=head1 read_all ( [ root_model => ... ], [ force_load => 1 ] )

Load all the model files contained in C<model_dir> and all its
subdirectories. C<root_model> is used to filter the classes read.

Use C<force_load> if you are trying to load a model containing errors.

C<read_all> returns a hash ref containing ( class_name => file_name , ...)

=head2 write_all

Will write back configuration model in the specified directory. The
structure of the read directory is respected.

=head2 write_model_plugin( plugin_dir => foo, plugin_name => bar )

Write plugin models in the  passed C<plugin_dir> directory. The written file is path is
made of plugin name and class names. E.g. a plugin named C<bar> for class
C<Foo::Bar> is written in C<bar/Foo/Bar.pl> file. This file is to be used
by L<augment_config_class|Config::Model/"augment_config_class (name => '...', class_data )">

=head2 read_model_plugin( plugin_dir => foo, plugin_name => bar.pl )

This method searched recursively C<$plugin_dir/$plugin_name> and load
all C<*.pl> files found there.

=head2 list_class_element

Returns a string listing all the class and elements. Useful for
debugging your configuration model.

=head2 get_dot_diagram

Returns a graphviz dot file that represents the structure of the
configuration model:

=over

=item *

C<include> relations are represented by solid lines

=item *

Class usage (i.e. C<config_class_name> parameter) is represented by
dashed lines. The name of the element is attached to the dashed line.

=back

=head1 BUGS

Test menu entries are created from the content of C<application> model
parameter.  Unfortunately, there's no way to build the menu
dynamically. So user cme must be restarted to change the menu if the
application list is changed.

=head1 CREDITS

Here's the list of people who helped improve this project:

=over

=item Gregor Herrmann

=back

Thanks for the patches !

=head1 SEE ALSO

L<Config::Model>, L<Config::Model::Node>, L<Path::Tiny>

=cut
