discourse/app/services/staff_action_logger.rb

# Responsible for logging the actions of admins and moderators.
class StaffActionLogger
  def initialize(admin)
    @admin = admin
    raise Discourse::InvalidParameters.new('admin is nil') unless @admin && @admin.is_a?(User)
  end

  def log_user_deletion(deleted_user, opts={})
    raise Discourse::InvalidParameters.new('user is nil') unless deleted_user && deleted_user.is_a?(User)
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:delete_user],
      email: deleted_user.email,
      ip_address: deleted_user.ip_address.to_s,
      details: [:id, :username, :name, :created_at, :trust_level, :last_seen_at, :last_emailed_at].map { |x| "#{x}: #{deleted_user.send(x)}" }.join("\n")
    }))
  end

  def log_post_deletion(deleted_post, opts={})
    raise Discourse::InvalidParameters.new("post is nil") unless deleted_post && deleted_post.is_a?(Post)

    topic = deleted_post.topic || Topic.with_deleted.find(deleted_post.topic_id)

    details = [
      "id: #{deleted_post.id}",
      "created_at: #{deleted_post.created_at}",
      "user: #{deleted_post.user.username} (#{deleted_post.user.name})",
      "topic: #{topic.title}",
      "post_number: #{deleted_post.post_number}",
      "raw: #{deleted_post.raw}"
    ]

    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:delete_post],
      post_id: deleted_post.id,
      details: details.join("\n")
    }))
  end

  def log_topic_deletion(deleted_topic, opts={})
    raise Discourse::InvalidParameters.new("topic is nil") unless deleted_topic && deleted_topic.is_a?(Topic)

    details = [
      "id: #{deleted_topic.id}",
      "created_at: #{deleted_topic.created_at}",
      "user: #{deleted_topic.user.username} (#{deleted_topic.user.name})",
      "title: #{deleted_topic.title}"
    ]

    if first_post = deleted_topic.ordered_posts.first
      details << "raw: #{first_post.raw}"
    end

    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:delete_topic],
      topic_id: deleted_topic.id,
      details: details.join("\n")
    }))
  end

  def log_trust_level_change(user, old_trust_level, new_trust_level, opts={})
    raise Discourse::InvalidParameters.new('user is nil') unless user && user.is_a?(User)
    raise Discourse::InvalidParameters.new('old trust level is invalid') unless TrustLevel.valid? old_trust_level
    raise Discourse::InvalidParameters.new('new trust level is invalid') unless TrustLevel.valid? new_trust_level
    UserHistory.create!( params(opts).merge({
      action: UserHistory.actions[:change_trust_level],
      target_user_id: user.id,
      details: "old trust level: #{old_trust_level}\nnew trust level: #{new_trust_level}"
    }))
  end

  def log_site_setting_change(setting_name, previous_value, new_value, opts={})
    raise Discourse::InvalidParameters.new('setting_name is invalid') unless setting_name.present? && SiteSetting.respond_to?(setting_name)
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:change_site_setting],
      subject: setting_name,
      previous_value: previous_value,
      new_value: new_value
    }))
  end

  SITE_CUSTOMIZATION_LOGGED_ATTRS = ['stylesheet', 'header', 'position', 'enabled', 'key', 'override_default_style']

  def log_site_customization_change(old_record, site_customization_params, opts={})
    raise Discourse::InvalidParameters.new('site_customization_params is nil') unless site_customization_params
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:change_site_customization],
      subject: site_customization_params[:name],
      previous_value: old_record ? old_record.attributes.slice(*SITE_CUSTOMIZATION_LOGGED_ATTRS).to_json : nil,
      new_value: site_customization_params.slice(*(SITE_CUSTOMIZATION_LOGGED_ATTRS.map(&:to_sym))).to_json
    }))
  end

  def log_site_customization_destroy(site_customization, opts={})
    raise Discourse::InvalidParameters.new('site_customization is nil') unless site_customization
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:delete_site_customization],
      subject: site_customization.name,
      previous_value: site_customization.attributes.slice(*SITE_CUSTOMIZATION_LOGGED_ATTRS).to_json
    }))
  end

  def log_user_suspend(user, reason, opts={})
    raise Discourse::InvalidParameters.new('user is nil') unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:suspend_user],
      target_user_id: user.id,
      details: reason
    }))
  end

  def log_user_unsuspend(user, opts={})
    raise Discourse::InvalidParameters.new('user is nil') unless user
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:unsuspend_user],
      target_user_id: user.id
    }))
  end

  def log_badge_grant(user_badge, opts={})
    raise Discourse::InvalidParameters.new('user_badge is nil') unless user_badge
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:grant_badge],
      target_user_id: user_badge.user_id,
      details: user_badge.badge.name
    }))
  end

  def log_badge_revoke(user_badge, opts={})
    raise Discourse::InvalidParameters.new('user_badge is nil') unless user_badge
    UserHistory.create( params(opts).merge({
      action: UserHistory.actions[:revoke_badge],
      target_user_id: user_badge.user_id,
      details: user_badge.badge.name
    }))
  end

  def log_check_email(user, opts={})
    raise Discourse::InvalidParameters.new('user is nil') unless user
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:check_email],
      target_user_id: user.id
    }))
  end

  def log_show_emails(users)
    values = []

    users.each do |user|
      values << "(#{@admin.id}, #{UserHistory.actions[:check_email]}, #{user.id}, current_timestamp, current_timestamp)"
    end

    # bulk insert
    UserHistory.exec_sql <<-SQL
      INSERT INTO user_histories (acting_user_id, action, target_user_id, created_at, updated_at)
      VALUES #{values.join(",")}
    SQL
  end

  def log_impersonate(user, opts={})
    raise Discourse::InvalidParameters.new("user is nil") unless user
    UserHistory.create(params(opts).merge({
      action: UserHistory.actions[:impersonate],
      target_user_id: user.id
    }))
  end

  private

  def params(opts)
    { acting_user_id: @admin.id, context: opts[:context] }
  end

end