RailsEventStore/rails_event_store

# frozen_string_literal: true

require "erb"

class Migrator
  module Binding
    module_function

    def clean_binding
      binding
    end

    def from_hash(**variables)
      clean_binding.tap { |b| variables.each { |k, v| b.local_variable_set(k, v) } }
    end
  end

  def initialize(template_root)
    @template_root = template_root
  end

  def run_migration(name, template_name = nil)
    eval(migration_code(template_name || name))
    migration_class(name).new.change
  end

  def migration_code(name)
    migration_template(name).result_with_hash(migration_version: migration_version, data_type: data_type)
  end

  private

  def migration_class(name)
    Migrator.const_get(name.camelize)
  end

  def data_type
    ENV.fetch("DATA_TYPE") { "binary" }
  end

  def migration_version
    ::ActiveRecord::Migration.current_version
  end

  def migration_template(name)
    ERB.new(File.read(File.join(@template_root, "#{name}_template.erb")))
  end
end