18F/identity-idp

# frozen_string_literal: true

# Drop in replacement for ServiceProviderRequest. Moves us from Postgres to Redis
# To manage the migration and still respect in flight transactions code will default
# to checking the db if no redis object is available. Following release can remove db dependence.
# To migrate code simply replace ServiceProviderRequest with ServiceProviderRequestProxy
class ServiceProviderRequestProxy
  REDIS_KEY_PREFIX = 'redis-pool:spr:'

  # This is used to support the .last method. That method is only used in the
  # test environment
  cattr_accessor :redis_last_uuid

  def self.from_uuid(uuid)
    return NullServiceProviderRequest.new if uuid.to_s.blank?
    find_by(uuid: uuid.to_s) || NullServiceProviderRequest.new
  rescue ArgumentError # a null byte in the uuid will raise this
    NullServiceProviderRequest.new
  end

  def self.delete(request_id)
    return unless request_id
    REDIS_POOL.with { |client| client.del(key(request_id)) }
    self.redis_last_uuid = nil if Rails.env.test?
  end

  def self.find_by(uuid:)
    return if uuid.blank?
    str = REDIS_POOL.with { |client| client.get(key(uuid)) }
    hash_to_spr(JSON.parse(str, symbolize_names: true), uuid) if str
  end

  def self.find_or_create_by(uuid:)
    obj = find_by(uuid: uuid)
    return obj if obj
    spr = ServiceProviderRequest.new(
      uuid: uuid,
      issuer: nil,
      url: nil,
      requested_attributes: nil,
      acr_values: nil,
      vtr: nil,
    )

    yield(spr)
    create(
      uuid: uuid,
      issuer: spr.issuer,
      url: spr.url,
      requested_attributes: spr.requested_attributes,
      acr_values: spr.acr_values,
      vtr: spr.vtr,
    )
  end

  def self.create(hash)
    uuid = hash[:uuid]
    obj = hash.slice(
      :issuer,
      :url,
      :requested_attributes,
      :vtr,
      :acr_values,
    )
    write(obj, uuid)
    hash_to_spr(obj, uuid)
  end

  def self.write(obj, uuid)
    REDIS_POOL.with do |client|
      client.setex(
        key(uuid),
        IdentityConfig.store.service_provider_request_ttl_hours.hours.in_seconds,
        obj.to_json,
      )
    end
    self.redis_last_uuid = uuid if Rails.env.test?
  end

  def self.create!(hash)
    create(hash)
  end

  # The .last uuid written is stored only in test mode to support existing specs
  def self.last
    find_by(uuid: redis_last_uuid)
  end

  def self.key(uuid)
    REDIS_KEY_PREFIX + uuid
  end

  def self.flush
    REDIS_POOL.with { |client| client.flushdb } if Rails.env.test?
  end

  def self.hash_to_spr(hash, uuid)
    ServiceProviderRequest.new(**hash.merge(uuid: uuid))
  end
end