#!/usr/bin/ruby
#
# A CGI/HTML application enabling one to identify lines in the agenda and/or
# minutes which contain non-UTF-8 characters, and to select a replacement line.
#
# Requires: Ruby (1.8 or 1.9), the 'cgi-spa' gem, and JQuery.
#
# To install a suexec-compatible wrapper into your Apache DOCRoot, simply run:
#
#   ruby zap-gremlins.rb --install=/path/to/docroot
#
# Place the following file into the same directory as the wrapper:
#
#   http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js
#

require 'rubygems'
require 'cgi-spa'

# list of files to process
$files ||= Dir['board_*.txt']

# replace invalid characters with the Unicode replacement character
def cleanse(line)
  filter = Proc.new {|c| c.unpack('U').first rescue 0xFFFD}
  if line.respond_to?(:force_encoding)
    line.chars.map(&filter).pack('U*').force_encoding('utf-8')
  else
    line.gsub(/[^\x00-\x7f]+/) { |s| s.split(//u).map(&filter).pack('U*') }
  end
end

# replace specified line, after verifying the original
$cgi.json do
  begin
    line = $param.line.to_i - 1
    lines = open($param.file) {|file| file.readlines}
    if cleanse(lines[line]).strip == $param.original
      indent = cleanse(lines[line]).slice(/^\s*/)

      replacement = $param.replacement
      if replacement.respond_to? :force_encoding
        replacement.force_encoding(lines[line].encoding)
      end

      lines[line] = indent + replacement + "\n"
      open($param.file, 'w') {|file| file.write lines.join}
      {:status => :OK}
    else
      {:message => "File verification error."}
    end
  rescue
    {:message => $!.to_s + "\n" + $!.backtrace.join("\n")}
  end
end

# main output
$cgi.html do |x|
  x.header do
    x.title 'Gremlin Zapper'

    x.style! %{
      body {margin:0; background: #f5f5dc}
      footer pre, h2 {margin-left: 10%}
      fieldset {width: 80%; margin-left: 10%; border-color: #828}
      legend:before {content: "line "}
      h2:after {content: ":"}
      .disabled {opacity: 0.5; cursor: wait important!}
      h3.dirty {display: none}
      h3 {margin-left: 20%; color: #828; font-size: 200%}
      button {color: #828; background: #C9C}

      h1 {
        background: #C9C; color: #828; text-align: center;
        font: 40px "Times New Roman",serif;
        font-weight: normal; font-variant: small-caps;
        padding: 10px 0; border-bottom: 2px solid; margin: 0 0 0.5em 0;
      }

      legend {
        color: #dfd; background: #828; font-family: sans-serif;
        margin: 0 10%; padding: 0.2em 1em;
      }

      fieldset, legend, button {
        -moz-border-radius: 1em;
        -khtml-border-radius: 1em;
      }
    }

    x.script '', :src => 'jquery-1.3.2.min.js'
  end

  x.body do
    x.h1 'Gremlin Zapper'

    mac = Iconv.new('utf-8', 'Mac')
    win = Iconv.new('utf-8', 'Windows-1252')

    $files.each do |fname|
      x.section do
        x.h2 fname

        open(fname) do |file|
          dirty = false

          file.each_line do |line|
            begin
              line.unpack('U*')
            rescue
              dirty = true
              clean = cleanse(line)

              x.fieldset do
                x.legend file.lineno
                x.table do
                  x.tr do
                    x.td {x.button 'Src'}
                    x.td {x.pre clean.strip}
                  end
                  x.tr do
                    x.td {x.button 'Win'}
                    x.td {x.pre((win.iconv(line) rescue clean).strip)}
                  end
                  x.tr do
                    x.td {x.button 'Mac'}
                    x.td {x.pre((mac.iconv(line) rescue clean).strip)}
                  end
                end
              end
            end
          end

          x.h3 'Clean!', ({:class => 'dirty'} if dirty)
        end
      end
    end

    x.script! %{
      $('section button').click(function() {
        // disable the fieldset/table
        var tr = $(this).closest('tr');
        var fieldset = tr.closest('fieldset');
        fieldset.addClass('disabled');
        fieldset.find('button').attr('disabled','disabled');

        // gather data: file, line, original (for verification), replacement
        args = {
          file        : fieldset.siblings('h2').text(),
          line        : fieldset.find('legend').text(),
          original    : fieldset.find('tr:eq(0) td:eq(1) pre').text(),
          replacement : tr.find('td:eq(1) pre').text()
        };

        // send the request
        $.getJSON("#{SELF?}", args, function(response) {
          if (response.message) {
            alert(response.message); 
            fieldset.removeClass('disabled');
            fieldset.find('button').removeAttr('disabled');
          } else {
            fieldset.hide('blind');
            if (fieldset.siblings('fieldset:visible').length == 0) {
              fieldset.siblings('h3').removeClass('dirty');
            }
          }
        });

        // don't propagate event
        return false;
      });
    }
  end
end

# statements to include in installation files
__END__
$files = Dir['board_*.txt']