Sequel.migration do
  up do
    create_table(:memberships) do
      primary_key :id, type: :Bignum

      foreign_key :member_id, :members,
        type: :Bignum,
        null: false

      String :status, null: false, default: "pending"

      DateTime :requested_at,
        null: false,
        default: Sequel::CURRENT_TIMESTAMP

      DateTime :decided_at

      foreign_key :recorded_by, :members,
        type: :Bignum

      index :status

      # Un seul dossier en attente ou une seule adhésion acceptée.
      index :member_id,
        unique: true,
        where: { status: ["pending", "accepted"] }

      constraint :memberships_status_valid,
        Sequel.lit("status IN ('pending', 'accepted', 'rejected')")

      constraint :memberships_decision_consistent,
        Sequel.lit(
          "(status = 'pending' AND decided_at IS NULL " \
          "AND recorded_by IS NULL) " \
          "OR (status IN ('accepted', 'rejected') " \
          "AND decided_at IS NOT NULL)"
        )
    end
  end

  down do
    drop_table(:memberships)
  end
end