package Text::Dokuwiki;

use strict;
use warnings;
use feature qw/ switch /;
use utf8;

use Data::Dumper;

sub new {
  my ($class) = @_;
  my $self = {};

  return bless($self, $class);
}

sub parse {
  my ($self, $text) = @_;
  my ($tree, $mode, $attrs, $buf) = ([], 'text', '', '');

  my @lines = split /\r?\n/o, $text;
  my $linenum = 0;

  foreach my $line (@lines) {
    $linenum++;

    given ($mode) {
      when (m!block/(file|code|nowiki)!o) {
        if ($line =~ m{^\s*</$1>}o) {
          if ($1 eq 'file') {
            my $dt = [dt => {}, 0 => $attrs->{file}];
            my $dd = [dt => {}, 0 => [pre => {class => $attrs->{class}}, 0 => $buf]];
            push @{ $tree }, [dl => {class => 'file'}, [$dt, $dd]];
          } elsif ($1 eq 'nowiki') {
            push @{ $tree }, [pre  => {}, 0 => $buf];
          } else {
            push @{ $tree }, [code => {class => $attrs->{class}}, 0 => $buf];
          }
          ($buf, $attrs, $mode) = ('', {}, undef); next;
        }
        $buf .= $line . "\n";
      }
      when ("code") {
        if ($line =~ m/^\s{2}(.+)/o) {
          $buf .= $line . "\n"; next;
        } else {
          push @{ $tree }, [pre => {}, 0 => $buf];
          ($buf, $attrs, $mode) = ('', {}, undef); continue;
        }
      }
      when ("list") {
        if ($line =~ m/^\s{2}([\*-])\s+(.+)/o) {
          push @{ $buf }, [li => {}, 0 => $2];
          next;
        } else {
          push @{ $tree }, [ul => {}, @$buf]; # TODO: lost list type
          ($buf, $attrs, $mode) = ('', {}, undef); continue;
        }
      }
      when ("table") {
        ...
      }
    }


    given ($line) {
      # header
      when (m/^\s?(={2,6}) (.+) \g{1}\s*/o) {
        my $level = $1 =~ tr/=/=/;
        $level = 7 - $level; # invert
        push @{ $tree }, ["h$level" => {}, 0 => $2];
        next;
      }
      # code/file block
      when (m/^\s?<(code|file)(?:\s+(\S+)\s+(\S+))?>\s*$/o) {
        $mode = "block/$1";
        $attrs = ($2) ? {class => $2, file => $3} : {};
        next;
      }
      # nowiki block
      when (m/\s?<nowiki>/o) {
        $mode = "block/nowiki";
        next;
      }
      # lists
      when (m/^\s{2}([\*-])\s+(.+)/o) {
        $mode = 'list';
        $buf  = [];
        push @{ $buf }, [li => {}, 0 => $2];
        next;
      }
      # quotes
      when (m/^\s?(>)+\s*(.+)/o) {
        my $level = $1 =~ tr/>/>/;
        push @{ $tree }, [blockquote => {level => $level}, 0 => $2];
        next;
      }
      # table
      when (m/^\s?[\|\^]/o) {
        $mode = 'table';
        $buf = $line . "\n"; # render later
        next;
      }
      # code idented with two spaces
      when (m/^\s{2}(\S.+)/o) {
        $mode = 'code';
        $buf = $line . "\n";
        next;
      }
      # nonempty line
      when (m/^\s?(\S.+)/o) {
        push @{ $tree }, [p => {}, 0 => $1];
        next;
      }
      # empty lines;
      when (m/^\s*$/) {
        push @{ $tree }, [br => {}];
        $mode = undef;
        next;
      }
      # catchall
      default {
        printf "Unmatched % 3d: %s\n", $linenum, $line;
        continue;
      }
    }
  }

  return $tree;
}

1;

__END__

[div => {class => 'block'},           # <div class='block'>
  0 => 'text1',                       #   Hello!
  [strong => {}, 0 => 'bold text'],   #   <strong>user</strong>
  0 => ', this is converted text.',   #   , this is converted text.
  [br => {}],                         #   <br/>
  [p => {}, 0 => 'Second paragraph']  #   <p>Second paragraph</p>
]                                     # </div>