decode Diablo II's CubeMain.bin, write to JSON

parser-json.rb

# modified from https://gist.github.com/jankowskib/f886f087d9cb1f578284

# works for at least...
# % ruby --version
# ruby 2.7.7p221 (2022-11-24 revision 168ec2b1e5) [arm64-darwin24]

# usage:
# ruby parser-json.rb ./cubemain.bin somewhere/else/cubemain.json
# ^ assumes you named this file "parser-json.rb", otherwise change the command to match

=begin 
getting the JSON back to a .txt file is involved, as it appears you need to parse various other .bin files to translate from various ids to the strings.
example cell from a .txt file => .bin => .json 
the "output" column's value in cubemain.txt is "Cow Portal", but the output object parsed from the .bin is below. I have no idea how to interpret this yet.
 {
      "item_flags": "0",
      "item_type": "0",
      "item": "0",
      "item_id": "0",
      "param": "0",
      "output_type": "1",
      "lvl": "0",
      "p_lvl": "0",
      "i_lvl": "0",
      "prefix_id": [
        "0",
        "0",
        "0"
      ],
      "suffix_id": [
        "0",
        "0",
        "0"
      ],
      "mods": [
        {
          "mod": "4294967295",
          "mod_param": "0",
          "mod_min": "0",
          "mod_max": "0",
          "mod_chance": "0"
        },
        ...repeats
      ]
    }
=end

require 'bindata'
require 'json'
require 'fileutils'

class CubeMainInput < BinData::Record  # size 0x08
  uint8    :input_flags 			#0x00
  uint8    :item_type		    #0x01
  uint16le :item			      	#0x02
  uint16le :item_id			    #0x04
  uint8    :quality		    	#0x06
  uint8    :quantity		    	#0x07
end

class CubeMainOutputMod < BinData::Record # size 0xC
  uint32le :mod			  	#0x00
  uint16le :mod_param		#0x04
  uint16le :mod_min			#0x06
  uint16le :mod_max			#0x08
  uint16le :mod_chance	#0x0a
end

class CubeMainOutput < BinData::Record # size 0x54
  uint8    :item_flags			#0x00
  uint8    :item_type			  #0x01
  uint16le :item			    	#0x02
  uint16le :item_id			  	#0x04
	uint16le :param           #0x06
  uint8    :output_type			    	#0x08 edited from "type" as that is reserved in this version of Ruby
  uint8    :lvl			    	  #0x09
  uint8    :p_lvl			    	#0x0a
  uint8    :i_lvl			    	#0x0b
  array    :prefix_id, :type => :uint16le, :initial_length  => 3	#0x0c
  array    :suffix_id, :type => :uint16le, :initial_length  => 3  #0x12
  array    :mods, :type => :cube_main_output_mod, :initial_length => 5 #0x18
end

class CubeMainBinRecord < BinData::Record # size 0x148
  uint8    :enabled			#0x00
  uint8    :ladder		  #0x01
  uint8    :mindiff			#0x02
  uint8    :class_id		#0x03
  uint32le :op				  #0x04
  uint32le :param			  #0x08
  uint32le :value_id		#0x0c
  uint16le :numinputs		#0x10
  uint16le :version			#0x12
  array    :inputs, :type => :cube_main_input, :initial_length  => 7
  array    :outputs, :type => :cube_main_output, :initial_length  => 3
end

class CubeMainBin < BinData::Record # size 4+
  uint32le :record_count
  array    :records, :type => :cube_main_bin_record, :initial_length  => :record_count
end

begin
  f = ARGV[0] unless ARGV[0].nil?
  output_path = ARGV[1] unless ARGV[1].nil?
  bin = File.read(f)

  records = CubeMainBin.read(bin).records

  # Helper to recursively convert BinData objects to hashes
  def bin_to_hash(obj)
    if obj.is_a?(BinData::Array) || obj.is_a?(Array)
      obj.map { |el| bin_to_hash(el) }
    elsif obj.is_a?(BinData::Record)
      obj.field_names.each_with_object({}) do |field, h|
        h[field.to_s] = bin_to_hash(obj.send(field))
      end
    else
      obj
    end
  end

  json_records = records.map { |rec| bin_to_hash(rec) }

  input_basename = File.basename(f, File.extname(f))
  json_file = output_path ? output_path : File.join('assets', 'outputs', "#{input_basename}.json")
  FileUtils.mkdir_p(File.dirname(json_file))
  File.write(json_file, JSON.pretty_generate(json_records))
  puts "Wrote #{json_file} with #{json_records.size} records."
end