package PathsTree;

use strict;

use dir_node qw(:all);

use Cwd qw(cwd abs_path getcwd);
use File::Basename qw(fileparse);
use File::Spec::Functions qw(file_name_is_absolute splitdir catfile catdir);

sub new {
    my ($class) = @_;
    my $self = {
        _root_node => new DirNode('/',"dir")
    };
    bless $self, $class;
    return $self;
    
}

sub display_tree {
    my ($self) = @_;
    return $self->{"_root_node"}->display_tree("-");
}

sub get_links {
    my ($self) = @_;
    return $self->{"_root_node"}->get_links();
}

sub get_files {
    my ($self) = @_;
    return $self->{"_root_node"}->get_files();
}

sub get_dirs {
    my ($self) = @_;
    return $self->{"_root_node"}->get_dirs();
}

sub get_node_by_path {
    my ($self,$path) = @_;
    my @subpaths = splitdir($path);
    my $prev_node = $self->{_root_node};
    for my $index (0..$#subpaths) {
        next if (@subpaths[$index] eq "");
        my $current_node_name = @subpaths[$index];
        my $current_child = $prev_node->get_child_node_by_name(@subpaths[$index]);
        unless ($current_child) {
            return undef;
        }
        $prev_node = $current_child;
    }

    return $prev_node;
}

sub add_path {
    my ($self,$path) = @_;

    my @subpaths = splitdir($path);
    my $prev_node = $self->{_root_node};


    for my $index (0..$#subpaths) {
        next if (@subpaths[$index] eq ""); # Ignore empty strings
        my $current_path = catdir(@subpaths[0..$index]);
        my $current_node_name = @subpaths[$index];
        
        if (-l $current_path) {
            my @resloved_links = resolve_symlink($current_path);
            foreach my $link (@resloved_links) {
                if ($link eq $current_path) {
                    next;
                }
                $self->add_path($link);
            }
            my $current_link_target = readlink($current_path);
            my $child_node = $self->get_node_by_path($current_path);
            if ($child_node) {
                $prev_node = $child_node;
            } else {
                $child_node = $prev_node->add_child_link_node($current_node_name,$current_link_target,"regular_link");
                $prev_node = $child_node;
            }
            $prev_node = $self->get_node_by_path($current_link_target);
        } elsif (-f $current_path) {
            my $child_node = $self->get_node_by_path($current_path);
            if ($child_node) {
                $prev_node = $child_node;
            } else {
                $child_node = $prev_node->add_child_node($current_node_name,"file");
                $prev_node = $child_node;
            }
        } elsif (-d $current_path) {
            my $child_node = $self->get_node_by_path($current_path);
            if ($child_node) {
                $prev_node = $child_node;
            } else {
                $child_node = $prev_node->add_child_node($current_node_name,"dir");
                $prev_node = $child_node;
            }
        } else {
            log("Ignoring path with unknown type: $current_path");
        }
    }
    
}

# TODO: Move to a separated file
sub resolve_symlink {
    my ($file) = @_;
    unless (file_name_is_absolute($file)) {
        log("Failed to resolve link $file");
        return;
    }
    my @files;
    my $origwd = getcwd;
    my $rv = eval {
        my $f = $file;
        while (1) {
            my $dir;
            ($f,$dir) = fileparse($f);
            last unless (-d $dir);
            chdir $dir or die "chdir $dir: $!";
            push @files, catfile(getcwd,$f);
            last unless (-l $f);
            defined( $f = readlink $f ) or die "readlink $f (cwd=".getcwd."): $!";
        }
    1 }; my $err = $@ || 'unknown error';
    chdir $origwd or (log("Failed to chdir $origwd: $!") && return);
    die $err unless ($rv);
    return @files ? @files : ($file);
}

1;