class RuboCop::Cop::Generator

def generate(template)
  format(template, department: badge.department, cop_name: badge.cop_name)
end

def generated_source
  generate(SOURCE_TEMPLATE)
end

def generated_spec
  generate(SPEC_TEMPLATE)
end

def initialize(name, github_user, output: $stdout)
  @badge = Badge.parse(name)
  @github_user = github_user
  @output = output
  return if badge.qualified?
  raise ArgumentError, 'Specify a cop name with Department/Name style'
end

def inject_config(config_file_path: 'config/enabled.yml')
  config = File.readlines(config_file_path)
  content = <<-YAML.strip_indent
    #{badge}:
      Description: 'TODO: Write a description of the cop.'
      Enabled: true
  YAML
  target_line = config.find.with_index(1) do |line, index|
    next if line =~ /^[\s#]/
    break index - 1 if badge.to_s < line
  end
  config.insert(target_line, content)
  File.write(config_file_path, config.join)
  output.puts <<-MESSAGE.strip_indent
    [modify] A configuration for the cop is added into #{config_file_path}.
             If you want to disable the cop by default, move the added config to config/disabled.yml
  MESSAGE
end

def inject_require(root_file_path: 'lib/rubocop.rb')
  RequireFileInjector.new(
    source_path: source_path,
    root_file_path: root_file_path
  ).inject
end

def snake_case(camel_case_string)
  return 'rspec' if camel_case_string == 'RSpec'
  camel_case_string
    .gsub(/([^A-Z])([A-Z]+)/, '\1_\2')
    .gsub(/([A-Z])([A-Z][^A-Z\d]+)/, '\1_\2')
    .downcase
end

def source_path
  File.join(
    'lib',
    'rubocop',
    'cop',
    snake_case(badge.department.to_s),
    "#{snake_case(badge.cop_name.to_s)}.rb"
  )
end

def spec_path
  File.join(
    'spec',
    'rubocop',
    'cop',
    snake_case(badge.department.to_s),
    "#{snake_case(badge.cop_name.to_s)}_spec.rb"
  )
end

def todo
  <<-TODO.strip_indent
    Do 3 steps:
      1. Add an entry to the "New features" section in CHANGELOG.md,
         e.g. "Add new `#{badge}` cop. ([@#{github_user}][])"
      2. Modify the description of #{badge} in config/enabled.yml
      3. Implement your new cop in the generated file!
  TODO
end

def write_source
  write_unless_file_exists(source_path, generated_source)
end

def write_spec
  write_unless_file_exists(spec_path, generated_spec)
end

def write_unless_file_exists(path, contents)
  if File.exist?(path)
    warn "rake new_cop: #{path} already exists!"
    exit!
  end
  dir = File.dirname(path)
  FileUtils.mkdir_p(dir) unless File.exist?(dir)
  File.write(path, contents)
  output.puts "[create] #{path}"
end