class MailchimpBot
  attr_reader :user, :saved_changes, :gibbon

  def initialize(user)
    @user = user
    @saved_changes = user.saved_changes
    @gibbon = Gibbon::Request.new
  end

  def upsert
    return true unless Rails.env.production? || Rails.env.test?

    manage_community_moderator_list
    manage_tag_moderator_list
    upsert_to_newsletter
  end

  def upsert_to_newsletter
    # attempt to update email if user changed email addresses
    success = false
    begin
      gibbon.lists(SiteConfig.mailchimp_newsletter_id).members(target_md5_email).upsert(
        body: {
          email_address: user.email,
          status: user.email_newsletter ? "subscribed" : "unsubscribed",
          merge_fields: {
            NAME: user.name.to_s,
            USERNAME: user.username.to_s,
            TWITTER: user.twitter_username.to_s,
            GITHUB: user.github_username.to_s,
            IMAGE_URL: user.profile_image_url.to_s,
            ARTICLES: user.articles.size,
            COMMENTS: user.comments.size,
            ONBOARD_PK: user.onboarding_package_requested.to_s,
            EXPERIENCE: user.experience_level || 666
          }
        },
      )

      success = true
    rescue Gibbon::MailChimpError => e
      # If user was previously subscribed, set their status to "pending"
      return resubscribe_to_newsletter if previously_subcribed?(e)

      report_error(e)
    end
    success
  end

  def resubscribe_to_newsletter
    success = false

    begin
      gibbon.lists(SiteConfig.mailchimp_newsletter_id).members(target_md5_email).upsert(
        body: { status: "pending" },
      )
      success = true
    rescue Gibbon::MailChimpError => e
      report_error(e)
    end
    success
  end

  def manage_community_moderator_list
    return false unless user.has_role?(:trusted)

    success = false
    status = user.email_community_mod_newsletter ? "subscribed" : "unsubscribed"
    begin
      gibbon.lists(SiteConfig.mailchimp_community_moderators_id).members(target_md5_email).upsert(
        body: {
          email_address: user.email,
          status: status,
          merge_fields: {
            NAME: user.name.to_s,
            USERNAME: user.username.to_s,
            TWITTER: user.twitter_username.to_s,
            GITHUB: user.github_username.to_s,
            IMAGE_URL: user.profile_image_url.to_s
          }
        },
      )
      success = true
    rescue Gibbon::MailChimpError => e
      report_error(e)
    end
    success
  end

  def manage_tag_moderator_list
    return false unless user.tag_moderator?

    success = false

    tag_ids = user.roles.where(name: "tag_moderator").pluck(:resource_id)
    tag_names = Tag.where(id: tag_ids).pluck(:name)

    status = user.email_tag_mod_newsletter ? "subscribed" : "unsubscribed"

    begin
      gibbon.lists(SiteConfig.mailchimp_tag_moderators_id).members(target_md5_email).upsert(
        body: {
          email_address: user.email,
          status: status,
          merge_fields: {
            NAME: user.name.to_s,
            USERNAME: user.username.to_s,
            TWITTER: user.twitter_username.to_s,
            GITHUB: user.github_username.to_s,
            IMAGE_URL: user.profile_image_url.to_s,
            TAGS: tag_names.join(", ")
          }
        },
      )
      success = true
    rescue Gibbon::MailChimpError => e
      report_error(e)
    end
    success
  end

  def unsub_sustaining_member
    return unless user.tag_moderator?

    gibbon.lists(SiteConfig.mailchimp_tag_moderators_id).members(target_md5_email).update(
      body: {
        status: "unsubscribed"
      },
    )
  end

  def unsub_community_mod
    return unless user.has_role?(:trusted)

    gibbon.lists(SiteConfig.mailchimp_community_moderators_id).members(target_md5_email).update(
      body: {
        status: "unsubscribed"
      },
    )
  end

  def unsub_tag_mod
    return unless a_sustaining_member?

    gibbon.lists(SiteConfig.mailchimp_sustaining_members_id).members(target_md5_email).update(
      body: {
        status: "unsubscribed"
      },
    )
  end

  def unsubscribe_all_newsletters
    success = false
    begin
      gibbon.lists(SiteConfig.mailchimp_newsletter_id).members(target_md5_email).update(
        body: {
          status: "unsubscribed"
        },
      )
      unsub_tag_mod
      unsub_sustaining_member
      unsub_community_mod
      success = true
    rescue Gibbon::MailChimpError => e
      report_error(e)
    end
    success
  end

  private

  def a_sustaining_member?
    # Reasoning for including => saved_changes["monthly_dues"]
    # Is that mailchimp should be updated if a user decides to
    # unsubscribes
    user.monthly_dues.positive? || saved_changes["monthly_dues"]
  end

  def md5_email(email)
    Digest::MD5.hexdigest(email.downcase)
  end

  def report_error(exception)
    Rails.logger.error(exception)
    DatadogStatsClient.increment("mailchimp.errors", tags: ["action:failed", "user_id:#{user.id}", "source:gibbon-gem"])
  end

  def target_md5_email
    email = saved_changes["unconfirmed_email"] ? saved_changes["email"][0] : user.email
    md5_email(email)
  end

  def previously_subcribed?(error)
    error.title.match?(/Member In Compliance State/)
  end
end