# frozen_string_literal: true

# AuthProvider is a configuration record, storing parameters of an external Single-Sign On server
class AuthProvider < ApplicationRecord
  # this is a simple stub used for database creation & configuration
  class SimpleAuthProvider < Object
    def providable_type
      DatabaseProvider.name
    end

    def name
      'DatabaseProvider::SimpleAuthProvider'
    end

    def strategy_name
      'database-simpleauthprovider'
    end
  end

  PROVIDABLE_TYPES = %w[DatabaseProvider OAuth2Provider OpenIdConnectProvider].freeze

  belongs_to :providable, polymorphic: true, dependent: :destroy
  accepts_nested_attributes_for :providable

  has_many :auth_provider_mappings, dependent: :destroy
  accepts_nested_attributes_for :auth_provider_mappings, allow_destroy: true

  validates :providable_type, inclusion: { in: PROVIDABLE_TYPES }
  validates :name, presence: true, uniqueness: true
  validates_with UserUidMappedValidator, if: -> { %w[OAuth2Provider OpenIdConnectProvider].include?(providable_type) }

  before_create :set_initial_state
  after_update :write_config

  def build_providable(params)
    raise "Unknown providable_type: #{providable_type}" unless PROVIDABLE_TYPES.include?(providable_type)

    self.providable = providable_type.constantize.new(params)
  end

  ## Return the currently active provider
  def self.active
    local = SimpleAuthProvider.new

    begin
      provider = find_by(status: 'active')
      return local if provider.nil?

      provider.reload
    rescue ActiveRecord::StatementInvalid
      # we fall here on database creation because the table "active_providers" still does not exists at the moment
      local
    end
  end

  ## Return the previously active provider
  def self.previous
    find_by(status: 'previous')
  end

  ## Get the provider matching the omniAuth strategy name
  def self.from_strategy_name(strategy_name)
    return SimpleAuthProvider.new if strategy_name.blank? || all.empty?

    parsed = /^([^-]+)-(.+)$/.match(strategy_name)
    ret = nil
    all.find_each do |strategy|
      if strategy.provider_type == parsed[1] && strategy.name.downcase.parameterize == parsed[2]
        ret = strategy
        break
      end
    end
    ret
  end

  ## Return the name that should be registered in OmniAuth for the corresponding strategy
  def strategy_name
    "#{provider_type}-#{name.downcase.parameterize}"
  end

  ## Return the provider type name without the "Provider" part.
  ## eg. DatabaseProvider will return 'database'
  def provider_type
    providable_type[0..-9]&.downcase
  end

  ## Return the user's profile fields that are currently managed from the SSO
  ## @return [Array]
  def sso_fields
    fields = []
    auth_provider_mappings.each do |mapping|
      fields.push("#{mapping.local_model}.#{mapping.local_field}")
    end
    fields
  end

  ## Return the link the user have to follow to edit his profile on the SSO
  ## @return [String]
  def link_to_sso_profile
    providable.profile_url
  end

  def safe_destroy
    if status == 'active'
      false
    else
      destroy
    end
  end

  private

  def set_initial_state
    # the initial state of a new AuthProvider will be 'pending', except if there is currently
    # no providers in the database, he we will be 'active' (see seeds.rb)
    self.status = 'pending' unless AuthProvider.count.zero?
  end

  def write_config
    return unless status == 'active'

    ProviderConfig.write_active_provider
  end
end