require 'omniauth-oauth2'

module OmniAuth
  module Strategies
    class LinkedIn < OmniAuth::Strategies::OAuth2
      option :name, 'linkedin'

      option :client_options, {
        :site => 'https://api.linkedin.com',
        :authorize_url => 'https://www.linkedin.com/oauth/v2/authorization?response_type=code',
        :token_url => 'https://www.linkedin.com/oauth/v2/accessToken',
        :token_method => :post_with_query_string
      }

      option :scope, 'openid profile email'
      option :fields, %w(
        id full-name first-name last-name picture-url email-address
      )
      option :redirect_url

      uid do
        raw_info['sub']
      end

      info do
        {
          email: raw_info['email'],
          first_name: raw_info['given_name'],
          last_name: raw_info['family_name'],
          picture_url: raw_info['picture']
        }
      end

      extra do
        { 'raw_info' => raw_info }
      end

      def callback_url
        return options.redirect_url if options.redirect_url

        full_host + script_name + callback_path
      end

      alias :oauth2_access_token :access_token

      def access_token
        ::OAuth2::AccessToken.new(client, oauth2_access_token.token, {
          expires_in: oauth2_access_token.expires_in,
          expires_at: oauth2_access_token.expires_at,
          refresh_token: oauth2_access_token.refresh_token
        })
      end

      def raw_info
        @raw_info ||= access_token.get(profile_endpoint).parsed
      end

      private

      def fields_mapping
        # https://learn.microsoft.com/en-us/linkedin/consumer/integrations/self-serve/sign-in-with-linkedin-v2?context=linkedin%2Fconsumer%2Fcontext#api-request-to-retreive-member-details
        {
          'id' => 'sub',
          'full-name' => 'name',
          'first-name' => 'given_name',
          'last-name' => 'family_name',
          'picture-url' => 'picture'
        }
      end

      def fields
        options.fields.each.with_object([]) do |field, result|
          result << fields_mapping[field] if fields_mapping.has_key? field
        end
      end

      def profile_endpoint
        '/v2/userinfo'
      end

      def token_params
        super.tap do |params|
          params.client_secret = options.client_secret
        end
      end
    end
  end
end

OmniAuth.config.add_camelization 'linkedin', 'LinkedIn'