module Ops
  class IncidentRecorder
    COOLDOWN = -> { ENV.fetch("OPS_NOTIFY_COOLDOWN_MINUTES", "30").to_i.minutes }

    class << self
      def record(finding)
        new.record(finding)
      end

      def resolve(fingerprint:)
        new.resolve(fingerprint: fingerprint)
      end
    end

    def record(finding)
      fingerprint = finding[:fingerprint] || fingerprint_for(finding)
      incident = Ops::Incident.open.find_by(fingerprint: fingerprint)

      if incident
        incident.occurrence_count += 1
        incident.last_seen_at = Time.current
        incident.title = finding[:title] if finding[:title].present?
        incident.message = finding[:message] if finding[:message].present?
        incident.metadata = (incident.metadata || {}).merge(finding[:metadata] || {})
        incident.severity = finding[:severity] if finding[:severity].present?
        incident.status = "open" if incident.status == "acknowledged"
      else
        now = Time.current
        incident = Ops::Incident.new(
          kind: finding[:kind],
          severity: finding[:severity],
          status: "open",
          title: finding[:title],
          message: finding[:message],
          metadata: finding[:metadata] || {},
          fingerprint: fingerprint,
          occurrence_count: 1,
          first_seen_at: now,
          last_seen_at: now
        )
      end

      incident.save!
      maybe_notify!(incident)
      incident
    end

    def resolve(fingerprint:)
      Ops::Incident.open.where(fingerprint: fingerprint).find_each(&:resolve!)
    end

    private

    def fingerprint_for(finding)
      Digest::SHA256.hexdigest([finding[:kind], finding[:title]].join("|"))
    end

    def maybe_notify!(incident)
      return if incident.muted?
      return unless Ops::Notifier.notify_severity?(incident.severity)
      return if incident.notified_at.present? && incident.notified_at > COOLDOWN.call.ago

      Ops::Notifier.new.notify(incident)
      incident.update_column(:notified_at, Time.current)
    end
  end
end