#!/usr/bin/env ruby

require "erb"

TEMPLATE = <<EOF
float[2][] vertices = [
    <%= vertices.map {|v| v[0, 2].inspect}.join(",\n    ") %>
];
<% objects.each_pair do |obj_name, obj_array| %>
  <% obj_array.each_with_index do |oa, index| %>

ushort[<%= oa.size * oa.first.size %>] <%= obj_name %>_<%= index %> = [
    <%= oa.map {|indices| indices.join(", ")}.join(",\n    ") %>
    ];
  <% end %>

ushort[][] get_<%= obj_name %>()
{
    return [
  <% obj_array.each_with_index do |oa, index| -%>
        <%= obj_name %>_<%= index %>,
  <% end -%>
    ];
}
<% end %>
EOF

def main(obj_fname, d_fname)
  objects = {}
  vertices = []
  cur_obj = nil
  File.read(obj_fname).each_line do |line|
    if line =~ /^v\s+(\S+)\s+(\S+)/
      vertices << [$1.to_f, $2.to_f]
    elsif line =~ /^o\s+(..)-(\d+)/
      obj_class, obj_class_index = $1, $2.to_i
      objects[obj_class] ||= []
      objects[obj_class][obj_class_index] ||= []
      cur_obj = objects[obj_class][obj_class_index]
    elsif line =~ /^o\s+(.*)/
      raise "Do not know how to handle object #{$1.inspect}"
    elsif line =~ /^f\s+(\d+)\s+(\d+)\s+(\d+)/
      cur_obj << [$1, $2, $3].map {|v| v.to_i - 1}
    elsif line =~ /^l\s+(\d+)\s+(\d+)/
      cur_obj << [$1, $2].map {|v| v.to_i - 1}
    end
  end
  File.open(d_fname, "w") do |fh|
    fh.puts ERB.new(TEMPLATE, nil, "<>-").result(binding)
  end
end

main(*ARGV)