module Nullalign

# File lib/nullalign.rb, line 20
def self.generate_migration
  models = Nullalign::Models.new($LOAD_PATH)
  models.preload_all

  reporter = Nullalign::Reporter.new

  introspector = Nullalign::Introspectors::ValidatesPresenceOf.new
  problems = problems(models.all, introspector)
  if problems.empty?
    puts "Hooray! All presence validators are backed by a non-null constraint."
  else
    str = "class AddMissingNonnullConstraints < ActiveRecord::Migration[5.1]\n"
    str << "  def change\n"
    null_constraints_by_table_name = problems.map do |model, columns|
      [model.name, model, columns]
    end.sort_by(&:first)
    counter = 0
    null_constraints_by_table_name.each do |table_name, model, columns|
      columns.each do |constraint|
        counter += 1
        str << "    change_column_null :#{model.table_name}, :#{constraint.column}, false\n"
      end
    end
    str << "  end\n"
    str << "end\n"
    filename = "db/migrate/#{Time.now.utc.strftime("%Y%m%d%H%M%S")}_add_missing_nonnull_constraints.rb"
    puts "Adding migration #{File.basename(filename)} containing #{counter} change_column_null entries"
    File.open(filename, "w") {|f| f.syswrite(str)}
  end
end

# File lib/nullalign.rb, line 8
def self.run
  models = Nullalign::Models.new($LOAD_PATH)
  models.preload_all

  reporter = Nullalign::Reporter.new

  introspector = Nullalign::Introspectors::ValidatesPresenceOf.new
  problems = problems(models.all, introspector)
  reporter.report_validates_presence_problems(problems)
  problems.empty?
end

# File lib/nullalign.rb, line 53
def self.problems(models, introspector)
  models.map do |m|
    [m, introspector.missing_nonnull_constraints(m)]
  end.reject do |m, columns|
    columns.empty?
  end
end