How to change Unity meta script references from a DLL to individual files

fix_unity_guids.rb

require 'tempfile'
require 'fileutils'

puts ARGV.inspect
base_path = "unity-project"

file_suffixes = ["*.unity", "*.prefab", "*.controller", "*.mat"]
$unity_loose_file_id = "11500000" # unity hardcoded value

source_data = """
Asset: AbstractMemberBinding,InstanceID: 11912,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -186702827
Asset: AbstractTemplateSelector,InstanceID: 11914,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1283446872
Asset: AdapterOptions,InstanceID: 11916,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -855988391
Asset: AnimatorParameterBinding,InstanceID: 11918,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -945915645
Asset: BoolToColorAdapterOptions,InstanceID: 11920,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -343842708
Asset: BoolToColorBlockAdapterOptions,InstanceID: 11922,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -150226926
Asset: BoolToStringAdapterOptions,InstanceID: 11924,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: 2072353759
Asset: CollectionBinding,InstanceID: 11926,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: 1223786303,ReplacementGUID: fc8f6e4a5f0376443b6e8516f9aa1cc1
Asset: ColorToColorBlockAdapterOptions,InstanceID: 11928,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -970752098
Asset: DateTimeToStringAdapterOptions,InstanceID: 11930,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1789889822
Asset: DropdownBinding,InstanceID: 11932,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: 822021643, ReplacementGUID: 0c001c91b7bb4ad4cbcd38435b06117e
Asset: EventBinding,InstanceID: 11934,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1360956885,ReplacementGUID: 890ec8e82e868b34a8fce21566d83944
Asset: FloatToStringAdapterOptions,InstanceID: 11936,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: 846165451
Asset: OneWayPropertyBinding,InstanceID: 11938,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1670825535, ReplacementGUID: fc2d9c62932c0394ba2174cf22af8c74
Asset: StringCultureToDateTimeAdapterOptions,InstanceID: 11940,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: 637168853
Asset: SubViewModelBinding,InstanceID: 11942,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1830646146
Asset: Template,InstanceID: 11944,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: 526415227
Asset: TemplateBinding,InstanceID: 11946,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -456091253
Asset: ToggleActiveBinding,InstanceID: 11948,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1613660816, ReplacementGUID: a5affc014ccc9214f91fe6a375b020f9
Asset: TwoWayPropertyBinding,InstanceID: 11950,GUID: 33bb0041ebdea4bb8bad0be557ea70a1,FileID: -1957390036, ReplacementGUID: ff0db41e5d06b3e458e4e720862fa166
"""

class UnityScriptReference
    attr_accessor :name, :instance_id, :guid, :file_id, :replacement_guid
    def initialize(name, instance_id, guid, file_id, replacement_guid)
        @name = name
        @instance_id = instance_id
        @guid = guid
        @file_id = file_id
        @replacement_guid = replacement_guid
    end
    
    def to_s
        return "USR: name=#{name} / instance_id=#{instance_id} / guid=#{guid} / file_id=#{file_id} / replacement_guid=#{replacement_guid}"
    end
end

$script_references_dict = {}

source_data.split(/\n/).each do |data_line|
    
    dict = {}
    
    data_line.split(",").each do |element|
        key, value = element.split(":")
        key.strip!
        value.strip!
        #puts "'#{key}' -> '#{value}'"
        dict[key] = value
    end

    if dict["Asset"]
        usr = UnityScriptReference.new(dict["Asset"], dict["InstanceID"], dict["GUID"], dict["FileID"], dict["ReplacementGUID"])        

        #puts "Created #{usr}"
        if $script_references_dict.has_key?(usr.guid)
            #puts "Extending #{usr.guid}"
            script_references = $script_references_dict[usr.guid]
            script_references << usr
            $script_references_dict[usr.guid] = script_references
        else
            #puts "Seeding #{usr.guid}"
            $script_references_dict[usr.guid] = [usr]
        end

    end
    
end

puts "$script_references_dict"
$script_references_dict.keys.each do |key|
    usrs = $script_references_dict[key]
    usrs.each do |usr|
        puts "#{key} -> #{usr}"
    end
end


def file_edit(source_file_path, line_replacements)
    file_basename = File.basename(source_file_path)
    
    puts "Rewriting #{source_file_path}"
    tmpfile = Tempfile.new(file_basename)
    begin
        input_line_number = 0
        File.readlines(source_file_path).each do |line|
            replacement_usr = line_replacements[input_line_number]
            if replacement_usr
                #puts "RAW_LINE: #{line}"

                matches = line.match(/fileID: (-?[\d]+), guid: ([a-z0-9]+), type: ([\d]+)/)
                file_ref_fileid = matches[1].strip
                file_ref_guid = matches[2].strip
                file_ref_type = matches[3].strip
                
                #puts("Replacing guid #{file_ref_guid} with #{replacement_usr.replacement_guid}")
                line = line.gsub(file_ref_guid, replacement_usr.replacement_guid)
                line = line.gsub(file_ref_fileid, $unity_loose_file_id)
                #puts "EDITED_LINE: #{line}"
            end
            
            tmpfile << line
            
            input_line_number += 1
        end
    ensure
       tmpfile.close
       FileUtils.copy(tmpfile.path, source_file_path)
       tmpfile.unlink   # deletes the temp file
    end
end


file_suffixes.each do |suffix|
    glob_path = File.join(base_path, "**", suffix)
    Dir.glob(glob_path).each do |f|
        #puts "File: #{f}"
        line_number = 0
        line_replacements = {}
        
        if !File.file?(f)
            puts "Skipping non-file #{f}"
            continue
        end

        File.readlines(f).each do |line|
            line.strip!
            if line =~ /m\_Script/
                #puts "found m_Script in #{f}"
                #puts line
                # Match e.g. "  m_Script: {fileID: 11500000, guid: 10801da39a3e6457b83c39f229dd5114, type: 3}"
                
                matches = line.match(/fileID: (-?[\d]+), guid: ([a-z0-9]+), type: ([\d]+)/)
                if matches && matches.length == 4 
                    file_ref_fileid = matches[1].strip
                    file_ref_guid = matches[2].strip
                    file_ref_type = matches[3].strip
                    
                    #puts "#{f} contains guid: #{file_ref_guid}"
                    
                    script_refs = $script_references_dict[file_ref_guid]
                    if script_refs
                        script_refs.each do |usr|
                            if file_ref_fileid == usr.file_id && file_ref_guid == usr.guid
                                puts "#{f}[#{line_number}] MATCHES #{usr.name}"
                                puts line
                                
                                line_replacements[line_number] = usr
                            end
                        end
                    end
                else
                    puts "Problem with regexp!"
                    exit(1)
                end
            end
            
            line_number += 1
        end
        
        if line_replacements.keys.count > 0
            file_edit(f, line_replacements)
        end

    end
end