Utility for post-processing MST models to workaround circular dependencies

Post-processing mst-gql models

# Ruby script to post-process mst-gql models.
# This is a stop-gap to remove circular dependencies and other artifacts.
# The plan is to update [this fork](https://github.com/jkolyer/mst-gql) with the
# post-processing code and other fixes.

# Usage:
# add these scripts to the package.json in the examples/5-nextjs folder:
#    "scaffold": "../../generator/mst-gql-scaffold.js",
#    "did:scaffold": "ruby base-model-imports.rb ./src/models ./mst-gql.config.js",
# update the examples/5-nextjs/mst-gql.config.js with your root models
# start your gql server and run these on command line:
#    `npm run scaffold`
#    `npm run did:scaffold`
# then copy the generated models into your project 

# This script post-processes the model and base model files to remove
# TS circular dependencies.  
# It joins all the base models into AllBaseModels.ts, except RootStore.base
# which remains separate.
# Root model type are defined in the rootModelTypes.ts file.
# 

# expected arguments are the model source directory, and
# comma-separated list of root domains (same as in the generator config) 
dir = ARGV[0] + '/*.ts'
configFile = ARGV[1]

File.read(configFile) =~ /roots: \[(.*)\]/
rootModels = $1.gsub('"','').split(',').map(&:strip) 


base_imports = {
  withTypedRefs: "import { withTypedRefs } from 'mst-gql'\n",
  MSTGQLRef: "import { MSTGQLRef } from 'mst-gql'\n",
  ModelBase: "import { ModelBase } from 'mst-gql'\n",
}
all_base_models = ''
root_store_base = ''
base_files = []
root_store_base_file = ''
rootModelTypeRegex = Regexp.union(rootModels.collect { |rm| ", #{rm}ModelType" })
lateTypeModels = {}

# iterate over all generated files
Dir.glob(dir) do |fpath|
  
  # process base model files first
  if fpath =~ /\.base\.ts$/

    # save root store base file name for delayed processing
    if fpath =~ /RootStore\.base/
      root_store_base_file = fpath
      next
    end
    
    base_files.append(fpath)
    File.open(fpath).each do |line|
      if line =~ /^import/
        from = line.split(' ')[-1]
        next if from.end_with?('.base"')
        next if from.end_with?('Model"')
        # next if from.end_with?('Enum"')
        next if from.end_with?('ModelBase"')
        if not base_imports[from]
          # if line =~ /from "mst-gql"/
          #   line.gsub!('from "mst-gql"', 'from "../lib"')
          # end
          base_imports[from] = line
        end
        next
      end
      next if line.start_with?('/* eslint') ||
              line.start_with?('/* tslint') ||
              line =~ /mst-gql generated file/
      if line =~ /types.late\(\(\): any \=\> ([^\)]+)/
        lower = "#{$1[0].downcase}#{$1[1..-1]}"
        lateTypeModels[$1] = lower
        code = "types.late((): any => #{$1})"
        replace = "types.late((): any => #{lower}())"
        line.sub!(code, replace)
      end
      all_base_models += line
    end
    all_base_models += "\n/******END CLASS******/"
    next
  end

  # process regular model files
  # update imports as needed
  fname = fpath.split('/')[-1].split('.')[0]
  file_stuff = ''
  File.open(fpath).each do |line|
    # if line =~ /from "mst-gql"/
    #   file_stuff += line.gsub(/from "mst-gql"/, 'from "../lib"')
    #   next
    # end   
    if fname != 'RootStore'
      file_stuff += line.gsub(/\.\/.*\.base/, './AllBaseModels')
    else
      file_stuff += line
    end
  end

  if fname == 'index'
    file_stuff += "export * from './rootModelTypes'\n"
  end

  # write out new model file with new imports
  puts 'Rewriting '+fpath
  File.open(fpath, 'w') do |ff|
    ff.write(file_stuff)
  end
end

# rewrite RootStore.base with new imports
# and custom header
puts "Building RootStore.base.ts"
importModelTypes = ''
rootModels.each do |rootModel|
  importModelTypes += "#{rootModel}ModelType, "
end
root_store_base += "import { #{importModelTypes}} from './rootModelTypes'\n"

File.open(root_store_base_file).each do |line|
  if line =~ /^import/
    if line =~ /from "mst-gql"/
      # line.gsub!('from "mst-gql"', 'from "../lib"')
    elsif line =~ /Model\.base/
      line.gsub!(/from "\.\/.*Model\.base"/, 'from "./AllBaseModels"')
    end
  else
    next if line =~ /lint.disable/
    next if line =~ /mst-gql generated file/
  end
  if line =~ /^import/
    line.gsub!(/#{rootModelTypeRegex}/, '')
  end
  root_store_base += line
end

base_hdr = "/* *** AUTOGENERATED FILES BY mst-gql *** DO NOT EDIT *** */\n"
base_hdr += "/* *** POST-PROCESSED WITH #{File.basename(__FILE__)} *** */\n"
base_hdr += "/* *** #{Time.now.utc.strftime('%FT%TZ')} *** */\n\n"
base_hdr += "/* eslint-disable */\n"
base_hdr += "/* tslint-disable */\n\n"
no_edit_hdr = base_hdr

rootModelTypeImports = 'import { '
rootModels.each do |rootModel|
  rootModelTypeImports += "#{rootModel}ModelType, "
end
rootModelTypeImports += '} from "./rootModelTypes"'
base_imports['rootModel'] = rootModelTypeImports

base_imports.each do |from, import|
  next if import =~ /RootStoreType/
  base_hdr += import
end

base_hdr += "\nimport { \n"
lateTypeModels.each do |lateModel, lowercase|
  base_hdr += "  #{lowercase},\n"
end
base_hdr += "} from './lateModels'\n"

all_base_models = base_hdr + all_base_models

puts "Writing AllBaseModels.ts"
File.open(ARGV[0]+'/AllBaseModels.ts','w') do |ff|
  ff.write(all_base_models)
end

# rootModelTypes.ts is used to remove circular dependencies
# between RootStore and the leaf model files
puts "Writing rootModelTypes.ts"
File.open(ARGV[0]+'/rootModelTypes.ts','w') do |ff|
  ff.write(no_edit_hdr)
  ff.write("import { Instance } from 'mobx-state-tree'\n")
  exports = []
  rootModels.each do |rootModel|
    ff.write("import { #{rootModel}Model } from './#{rootModel}Model'\n")
    exp = "export type #{rootModel}ModelType = Instance<typeof #{rootModel}Model>\n"
    exports.append(exp)
  end
  ff.write("\n")
  exports.each do |exp|
    ff.write(exp)
  end
end

puts "Writing lateModels.ts"
File.open(ARGV[0]+'/lateModels.ts','w') do |ff|
  ff.write(no_edit_hdr)
  ff.write("/**** These functions embed requires for each model with a type.late reference to avoid circular depdencies from AllBaseModels ****/\n\n")
  lateTypeModels.each do |lateModel, lowercase|
    fcnName = lowercase
    lateRequire = "let _#{fcnName} = undefined\n"
    lateRequire += "export function #{fcnName}() {\n"
    lateRequire += "  if (!_#{fcnName}) {\n"
    lateRequire += "    _#{fcnName} = require('./#{lateModel}')\n"
    lateRequire += "  }\n"
    lateRequire += "  return (_#{fcnName} as any).#{lateModel}\n"
    lateRequire += "}\n"
    ff.write(lateRequire)
  end
end

puts "Writing RootStore.base.ts file"
root_store_base = "#{no_edit_hdr}\n#{root_store_base}"
File.open(root_store_base_file,'w') do |ff|
  ff.write(root_store_base)
end

puts 'Deleting base files...'
base_files.each do |fpath|
  File.delete(fpath)
end