# frozen_string_literal: true

require "sequel/timestamp_migrator_undo_extension"

namespace :sequel do
  # Rollback migrations that are absent in revision when deploying on staging
  task rollback_missing_migrations: :environment do
    # Extract migrations
    def extract_migrations(path)
      Dir.glob("#{path}/db/migrate/*.rb").map { |filename| File.basename(filename).to_i }
    end

    old_migrations = extract_migrations(ENV.fetch("OLD_RELEASE"))
    new_migrations = extract_migrations(ENV.fetch("NEW_RELEASE"))
    migrations_to_rollback = old_migrations - new_migrations

    next if migrations_to_rollback.empty?

    puts "Rolling back migrations:"
    puts migrations_to_rollback

    path = ::Rails.root.join("db/migrate")
    migrator = Sequel::TimestampMigrator.new(DB, path, allow_missing_migration_files: true)
    applied_migrations = migrator.applied_migrations.map(&:to_i)
    migrations = applied_migrations.select { |m| m.in?(migrations_to_rollback) }.sort.reverse

    migrations.each { |migration| migrator.undo(migration) }
  end
end