#
# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
# or more contributor license agreements. Licensed under the Elastic License;
# you may not use this file except in compliance with the Elastic License.
#

# frozen_string_literal: true
#
require 'active_support/core_ext/hash'
require 'connectors/connector_status'
require 'connectors/job_trigger_method'
require 'connectors/sync_status'
require 'utility'
require 'elastic-transport'

module Core
  class JobAlreadyRunningError < StandardError
    def initialize(connector_id)
      super("Sync job for connector '#{connector_id}' is already running.")
    end
  end

  class JobNotCreatedError < StandardError
    def initialize(connector_id, response)
      super("Sync job for connector '#{connector_id}' could not be created. Response: #{response}")
    end
  end

  class ConnectorVersionChangedError < StandardError
    def initialize(connector_id, seq_no, primary_term)
      super("Version conflict: seq_no [#{seq_no}] and primary_term [#{primary_term}] do not match for connector '#{connector_id}'.")
    end
  end

  class ElasticConnectorActions
    class << self

      def force_sync(connector_id)
        update_connector_fields(connector_id, :scheduling => { :enabled => true }, :sync_now => true)
      end

      def create_connector(index_name, service_type)
        body = {
          :scheduling => { :enabled => true },
          :index_name => index_name,
          :service_type => service_type
        }
        response = client.index(:index => Utility::Constants::CONNECTORS_INDEX, :body => body)
        response['_id']
      end

      def get_connector(connector_id)
        # TODO: remove the usage of with_indifferent_access. Ideally this should return a hash or nil if not found
        client.get(:index => Utility::Constants::CONNECTORS_INDEX, :id => connector_id, :ignore => 404).with_indifferent_access
      end

      def get_job(job_id)
        # TODO: remove the usage of with_indifferent_access. Ideally this should return a hash or nil if not found
        client.get(:index => Utility::Constants::JOB_INDEX, :id => job_id, :ignore => 404).with_indifferent_access
      end

      def connectors_meta
        # TODO: remove the usage of with_indifferent_access. Ideally this should return a hash or nil if not found
        alias_mappings = client.indices.get_mapping(:index => Utility::Constants::CONNECTORS_INDEX, :ignore => 404).with_indifferent_access
        index = get_latest_index_in_alias(Utility::Constants::CONNECTORS_INDEX, alias_mappings.keys)
        alias_mappings.dig(index, 'mappings', '_meta') || {
          :extract_binary_content => true,
          :name => 'ent-search-generic-ingestion',
          :reduce_whitespace => true,
          :run_ml_inference => false,
        }
      end

      def search_connectors(query, page_size, offset)
        client.search(
          :index => Utility::Constants::CONNECTORS_INDEX,
          :ignore => 404,
          :body => {
            :size => page_size,
            :from => offset,
            :query => query,
            :sort => ['name']
          }
        )
      end

      def search_jobs(query, page_size, offset)
        client.search(
          :index => Utility::Constants::JOB_INDEX,
          :ignore => 404,
          :body => {
              :size => page_size,
              :from => offset,
              :query => query,
              :sort => ['created_at']
          }
        )
      end

      def delete_jobs_by_query(query)
        client.delete_by_query(
          :index => Utility::Constants::JOB_INDEX,
          :body => { :query => query }
        )
      end

      def delete_indices(indices)
        client.indices.delete(:index => indices, :ignore_unavailable => true)
      end

      def update_connector_configuration(connector_id, configuration)
        update_connector_fields(connector_id, :configuration => configuration)
      end

      def enable_connector_scheduling(connector_id, cron_expression)
        payload = { :enabled => true, :interval => cron_expression }
        update_connector_fields(connector_id, :scheduling => payload)
      end

      def disable_connector_scheduling(connector_id)
        payload = { :enabled => false }
        update_connector_fields(connector_id, :scheduling => payload)
      end

      def set_configurable_field(connector_id, field_name, label, value)
        payload = { field_name => { :value => value, :label => label } }
        update_connector_configuration(connector_id, payload)
      end

      def update_filtering_validation(connector_id, filter_validation_results)
        return if filter_validation_results.empty?

        filtering = get_connector(connector_id).dig(:_source, :filtering)

        case filtering
        when Hash
          update_filter_validation(filtering, filter_validation_results)
        when Array
          return unless should_update_validations?(filter_validation_results, filtering)

          filtering.each do |filter|
            update_filter_validation(filter, filter_validation_results)
          end
        else
          Utility::Logger.warn("Elasticsearch returned invalid filtering format: #{filtering}. Skipping validation.")
          return
        end

        update_connector_fields(connector_id, { :filtering => filtering })
      end

      def update_connector_sync_now(connector_id, sync_now)
        doc = connector_with_concurrency_control(connector_id)

        body = { sync_now: sync_now, last_synced: Time.now }

        update_connector_fields(
          connector_id,
          body,
          doc[:seq_no],
          doc[:primary_term]
        )
      end

      def update_connector_sync_start(connector_id)
        doc = connector_with_concurrency_control(connector_id)

        body = {
            last_sync_status: Connectors::SyncStatus::IN_PROGRESS,
            last_sync_error: nil,
            status: Connectors::ConnectorStatus::CONNECTED
        }

        update_connector_fields(
          connector_id,
          body,
          doc[:seq_no],
          doc[:primary_term]
        )
      end

      def update_connector_custom_scheduling_last_synced(connector_id, schedule_key)
        doc = connector_with_concurrency_control(connector_id)

        body = {
          :custom_scheduling => {
            schedule_key => {
              :last_synced => Time.now
            }
          }
        }

        update_connector_fields(
          connector_id,
          body,
          doc[:seq_no],
          doc[:primary_term]
        )
      end

      def connector_with_concurrency_control(connector_id)
        seq_no = nil
        primary_term = nil

        doc = client.get(
          :index => Utility::Constants::CONNECTORS_INDEX,
          :id => connector_id,
          :ignore => 404,
          :refresh => true
        ).tap do |response|
          seq_no = response['_seq_no']
          primary_term = response['_primary_term']
        end

        { doc: doc, seq_no: seq_no, primary_term: primary_term }
      end

      def create_job(connector_settings:)
        body = {
          status: Connectors::SyncStatus::PENDING,
          created_at: Time.now,
          last_seen: Time.now,
          trigger_method: connector_settings.sync_now? ? Connectors::JobTriggerMethod::ON_DEMAND : Connectors::JobTriggerMethod::SCHEDULED,
          connector: {
            id: connector_settings.id,
            filtering: convert_connector_filtering_to_job_filtering(connector_settings.filtering),
            index_name: connector_settings.index_name,
            language: connector_settings[:language],
            pipeline: connector_settings[:pipeline],
            service_type: connector_settings.service_type,
            configuration: connector_settings.configuration
          }
        }

        index_response = client.index(index: Utility::Constants::JOB_INDEX, body: body, refresh: true)

        return index_response if index_response['result'] == 'created'

        raise JobNotCreatedError.new(connector_settings.id, index_response)
      end

      def convert_connector_filtering_to_job_filtering(connector_filtering)
        return [] unless connector_filtering
        connector_filtering = [connector_filtering] unless connector_filtering.is_a?(Array)
        connector_filtering.each_with_object([]) do |filtering_domain, job_filtering|
          snippet = filtering_domain.dig('active', 'advanced_snippet') || {}
          job_filtering << {
            'domain' => filtering_domain['domain'],
            'rules' => filtering_domain.dig('active', 'rules'),
            'advanced_snippet' => snippet['value'] || snippet,
            'warnings' => [] # TODO: in https://github.com/elastic/enterprise-search-team/issues/3174
          }
        end
      end

      def update_connector_status(connector_id, status, error_message = nil)
        if status == Connectors::ConnectorStatus::ERROR && error_message.nil?
          raise ArgumentError, 'error_message is required when status is error'
        end
        body = {
          :status => status,
          :error => status == Connectors::ConnectorStatus::ERROR ? error_message : nil
        }
        update_connector_fields(connector_id, body)
      end

      def fetch_document_ids(index_name)
        page_size = 1000
        result = []
        begin
          pit_id = client.open_point_in_time(:index => index_name, :keep_alive => '1m', :expand_wildcards => 'all')['id']
          body = {
            :query => { :match_all => {} },
            :sort => [{ :id => { :order => :asc } }],
            :pit => {
              :id => pit_id,
              :keep_alive => '1m'
            },
            :size => page_size,
            :_source => false
          }
          loop do
            response = client.search(:body => body)
            hits = response.dig('hits', 'hits') || []

            ids = hits.map { |h| h['_id'] }
            result += ids
            break if hits.size < page_size

            body[:search_after] = hits.last['sort']
            body[:pit][:id] = response['pit_id']
          end
        ensure
          client.close_point_in_time(:index => index_name, :body => { :id => pit_id })
        end

        result
      end

      def ensure_content_index_exists(index_name, use_icu_locale = false, language_code = nil)
        settings = Utility::Elasticsearch::Index::TextAnalysisSettings.new(:language_code => language_code, :analysis_icu => use_icu_locale).to_h
        mappings = Utility::Elasticsearch::Index::Mappings.default_text_fields_mappings(:connectors_index => true)

        body_payload = { settings: settings, mappings: mappings }
        ensure_index_exists(index_name, body_payload)
      end

      def ensure_index_exists(index_name, body = {})
        if client.indices.exists?(:index => index_name)
          return unless body[:mappings]
          Utility::Logger.debug("Index #{index_name} already exists. Checking mappings...")
          Utility::Logger.debug("New mappings: #{body[:mappings]}")
          response = client.indices.get_mapping(:index => index_name)
          existing = response[index_name]['mappings']
          if existing.empty?
            Utility::Logger.debug("Index #{index_name} has no mappings. Adding mappings...")
            client.indices.put_mapping(:index => index_name, :body => body[:mappings], :expand_wildcards => 'all')
            Utility::Logger.debug("Index #{index_name} mappings added.")
          else
            Utility::Logger.debug("Index #{index_name} already has mappings: #{existing}. Skipping...")
          end
        else
          client.indices.create(:index => index_name, :body => body)
          Utility::Logger.debug("Created index #{index_name}")
        end
      end

      def system_index_body(alias_name: nil, mappings: nil)
        body = {
          :settings => {
            :index => {
              :hidden => true,
              :number_of_replicas => 0,
              :auto_expand_replicas => '0-5'
            }
          }
        }
        body[:aliases] = { alias_name => { :is_write_index => true } } unless alias_name.nil? || alias_name.empty?
        body[:mappings] = mappings unless mappings.nil?
        body
      end

      # DO NOT USE this method
      # Creation of connector index should be handled by Kibana, this method is only used by ftest.rb
      def ensure_connectors_index_exists
        mappings = {
          :dynamic => false,
          :properties => {
            :api_key_id => { :type => :keyword },
            :configuration => { :type => :object },
            :custom_schedule => { :type => :object },
            :description => { :type => :text },
            :error => { :type => :keyword },
            :features => {
              :properties => {
                :filtering_advanced_config => { :type => :boolean },
                :filtering_rules => { :type => :boolean }
              }
            },
            :filtering => {
              :properties => {
                :domain => { :type => :keyword },
                :active => {
                  :properties => {
                    :rules => {
                      :properties => {
                        :id => { :type => :keyword },
                        :policy => { :type => :keyword },
                        :field => { :type => :keyword },
                        :rule => { :type => :keyword },
                        :value => { :type => :keyword },
                        :order => { :type => :short },
                        :created_at => { :type => :date },
                        :updated_at => { :type => :date }
                      }
                    },
                    :advanced_snippet => {
                      :properties => {
                        :value => { :type => :object },
                        :created_at => { :type => :date },
                        :updated_at => { :type => :date }
                       }
                    },
                    :validation => {
                      :properties => {
                        :state => { :type => :keyword },
                        :errors => {
                          :properties => {
                            :ids => { :type => :keyword },
                            :messages => { :type => :text }
                          }
                        }
                      }
                    }
                  }
                },
                :draft => {
                  :properties => {
                    :rules => {
                      :properties => {
                        :id => { :type => :keyword },
                        :policy => { :type => :keyword },
                        :field => { :type => :keyword },
                        :rule => { :type => :keyword },
                        :value => { :type => :keyword },
                        :order => { :type => :short },
                        :created_at => { :type => :date },
                        :updated_at => { :type => :date }
                      }
                    },
                    :advanced_snippet => {
                      :properties => {
                        :value => { :type => :object },
                        :created_at => { :type => :date },
                        :updated_at => { :type => :date }
                      }
                    },
                    :validation => {
                      :properties => {
                        :state => { :type => :keyword },
                        :errors => {
                          :properties => {
                            :ids => { :type => :keyword },
                            :messages => { :type => :text }
                          }
                        }
                      }
                    }
                  }
                }
              }
            },
            :index_name => { :type => :keyword },
            :is_native => { :type => :boolean },
            :language => { :type => :keyword },
            :last_seen => { :type => :date },
            :last_sync_error => { :type => :keyword },
            :last_sync_status => { :type => :keyword },
            :last_synced => { :type => :date },
            :last_deleted_document_count => { :type => :long },
            :last_indexed_document_count => { :type => :long },
            :name => { :type => :keyword },
            :pipeline => {
              :properties => {
                :extract_binary_content => { :type => :boolean },
                :name => { :type => :keyword },
                :reduce_whitespace => { :type => :boolean },
                :run_ml_inference => { :type => :boolean }
              }
            },
            :scheduling => {
              :properties => {
                :enabled => { :type => :boolean },
                :interval => { :type => :text }
              }
            },
            :service_type => { :type => :keyword },
            :status => { :type => :keyword },
            :sync_now => { :type => :boolean }
          }
        }
        ensure_index_exists("#{Utility::Constants::CONNECTORS_INDEX}-v1", system_index_body(:alias_name => Utility::Constants::CONNECTORS_INDEX, :mappings => mappings))
      end

      # DO NOT USE this method
      # Creation of job index should be handled by Kibana, this method is only used by ftest.rb
      def ensure_job_index_exists
        mappings = {
          :dynamic => false,
          :properties => {
            :cancelation_requested_at => { :type => :date },
            :canceled_at => { :type => :date },
            :completed_at => { :type => :date },
            :connector => {
              :properties => {
                :configuration => { :type => :object },
                :filtering => {
                  :properties => {
                    :domain => { :type => :keyword },
                    :rules => {
                      :properties => {
                        :id => { :type => :keyword },
                        :policy => { :type => :keyword },
                        :field => { :type => :keyword },
                        :rule => { :type => :keyword },
                        :value => { :type => :keyword },
                        :order => { :type => :short },
                        :created_at => { :type => :date },
                        :updated_at => { :type => :date }
                      }
                    },
                    :advanced_snippet => {
                      :properties => {
                        :value => { :type => :object },
                        :created_at => { :type => :date },
                        :updated_at => { :type => :date }
                      }
                    },
                    :warnings => {
                      :properties => {
                        :ids => { :type => :keyword },
                        :messages => { :type => :text }
                      }
                    }
                  }
                },
                :id => { :type => :keyword },
                :index_name => { :type => :keyword },
                :language => { :type => :keyword },
                :pipeline => {
                  :properties => {
                    :extract_binary_content => { :type => :boolean },
                    :name => { :type => :keyword },
                    :reduce_whitespace => { :type => :boolean },
                    :run_ml_inference => { :type => :boolean }
                  }
                },
                :service_type => { :type => :keyword }
              }
            },
            :created_at => { :type => :date },
            :deleted_document_count => { :type => :integer },
            :error => { :type => :text },
            :indexed_document_count => { :type => :integer },
            :indexed_document_volume => { :type => :integer },
            :last_seen => { :type => :date },
            :metadata => { :type => :object },
            :started_at => { :type => :date },
            :status => { :type => :keyword },
            :total_document_count => { :type => :integer },
            :trigger_method => { :type => :keyword },
            :worker_hostname => { :type => :keyword }
          }
        }
        ensure_index_exists("#{Utility::Constants::JOB_INDEX}-v1", system_index_body(:alias_name => Utility::Constants::JOB_INDEX, :mappings => mappings))
      end

      def update_connector_fields(connector_id, doc = {}, seq_no = nil, primary_term = nil)
        update_doc_fields(Utility::Constants::CONNECTORS_INDEX, connector_id, doc, seq_no, primary_term)
      end

      def update_job_fields(job_id, doc = {}, seq_no = nil, primary_term = nil)
        update_doc_fields(Utility::Constants::JOB_INDEX, job_id, doc, seq_no, primary_term)
      end

      def document_count(index_name)
        client.indices.refresh(:index => index_name, :ignore_unavailable => true)
        client.count(:index => index_name, :ignore_unavailable => true)['count']
      end

      private

      def should_update_validations?(domain_validations, filtering)
        domains_present = filtering.collect { |filter| filter[:domain] }
        domains_to_update = domain_validations.keys

        # non-empty intersection -> domains to update present
        !(domains_present & domains_to_update).empty?
      end

      def client
        @client ||= Utility::EsClient.new(App::Config[:elasticsearch])
      end

      def get_latest_index_in_alias(alias_name, indicies)
        index_versions = indicies.map { |index| index.gsub("#{alias_name}-v", '').to_i }
        index_version = index_versions.max # gets the largest suffix number
        "#{alias_name}-v#{index_version}"
      end

      def update_filter_validation(filter, domain_validations)
        domain = filter[:domain]

        if domain_validations.key?(domain)
          new_validation_state = { :draft => { :validation => domain_validations[domain] } }
          filter.deep_merge!(new_validation_state)
        end
      end

      def update_doc_fields(index, id, doc = {}, seq_no = nil, primary_term = nil)
        return if doc.empty?
        update_args = {
          :index => index,
          :id => id,
          :body => { :doc => doc },
          :refresh => true,
          :retry_on_conflict => 3
        }

        if seq_no && primary_term
          update_args[:if_seq_no] = seq_no
          update_args[:if_primary_term] = primary_term
          update_args.delete(:retry_on_conflict)
        end

        begin
          client.update(update_args)
        rescue Elastic::Transport::Transport::Errors::Conflict
          # VersionConflictException
          # see https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-index_.html#optimistic-concurrency-control-index
          raise ConnectorVersionChangedError.new(id, seq_no, primary_term)
        end
      end
    end
  end
end