# frozen_string_literal: true

module Gitlab
  module Analytics
    module CycleAnalytics
      module StageEvents
        # Convention:
        # Issue: < 100
        # MergeRequest: >= 100 && < 1000
        # Custom events for default stages: >= 1000 (legacy)
        ENUM_MAPPING = {
          StageEvents::IssueCreated => 1,
          StageEvents::IssueFirstMentionedInCommit => 2,
          StageEvents::MergeRequestCreated => 100,
          StageEvents::MergeRequestFirstDeployedToProduction => 101,
          StageEvents::MergeRequestLastBuildFinished => 102,
          StageEvents::MergeRequestLastBuildStarted => 103,
          StageEvents::MergeRequestMerged => 104,
          StageEvents::CodeStageStart => 1_000,
          StageEvents::IssueStageEnd => 1_001,
          StageEvents::PlanStageStart => 1_002,
          StageEvents::ProductionStageEnd => 1_003
        }.freeze

        EVENTS = ENUM_MAPPING.keys.freeze

        INTERNAL_EVENTS = [
          StageEvents::CodeStageStart,
          StageEvents::IssueStageEnd,
          StageEvents::PlanStageStart,
          StageEvents::ProductionStageEnd
        ].freeze

        # Defines which start_event and end_event pairs are allowed
        PAIRING_RULES = {
          StageEvents::PlanStageStart => [
            StageEvents::IssueFirstMentionedInCommit
          ],
          StageEvents::CodeStageStart => [
            StageEvents::MergeRequestCreated
          ],
          StageEvents::IssueCreated => [
            StageEvents::IssueStageEnd,
            StageEvents::ProductionStageEnd
          ],
          StageEvents::MergeRequestCreated => [
            StageEvents::MergeRequestMerged
          ],
          StageEvents::MergeRequestLastBuildStarted => [
            StageEvents::MergeRequestLastBuildFinished
          ],
          StageEvents::MergeRequestMerged => [
            StageEvents::MergeRequestFirstDeployedToProduction
          ]
        }.freeze

        def self.[](identifier)
          events.find { |e| e.identifier.to_s.eql?(identifier.to_s) } || raise(KeyError)
        end

        # hash for defining ActiveRecord enum: identifier => number
        def self.to_enum
          enum_mapping.each_with_object({}) { |(k, v), hash| hash[k.identifier] = v }
        end

        def self.pairing_rules
          PAIRING_RULES
        end

        def self.events
          EVENTS
        end

        def self.enum_mapping
          ENUM_MAPPING
        end

        # Events that are specific to the 7 default stages
        def self.internal_events
          INTERNAL_EVENTS
        end
      end
    end
  end
end

Gitlab::Analytics::CycleAnalytics::StageEvents.prepend_if_ee('::EE::Gitlab::Analytics::CycleAnalytics::StageEvents')