def change_plan
  account = Account.find(params[:id])

  old_plan = account.plan
  new_plan = Plan.find(params[:account][:plan_id])

  account.change_plan!(params[:account][:plan_id])

  SlackService.new.plan_change(current_user, account, old_plan, new_plan).deliver
  redirect_to action: "show", id: params[:id]
end

require 'net/http'

class SlackService
  NAME_AND_ICON = {
    username: 'Dashboard',
    icon_emoji: ':bat:'
  }

  SLACK_WEBHOOK_URL =  "https://hooks.slack.com/services/###/###/###"
  SLACK_WEBHOOK_CHANNEL = Rails.env.production? ? "###" : "###"

  def initialize(channel = SLACK_WEBHOOK_CHANNEL)
    @uri = URI(SLACK_WEBHOOK_URL)
    @channel = channel
  end

  def plan_change(user, account, old_plan, new_plan)
    params = {
      attachments: [
          {
            author_name: "#{user.first_name} #{user.last_name}",
            text: "Account: #{account.name} (#{account.id})",
            title: 'Dashboard Plan Change',
            fields: [
              {
                title: 'Old Plan',
                value: "#{old_plan.name} (#{ActionController::Base.helpers.number_to_currency(old_plan.price)})",
                short: true
              },
              {
                title: 'New Plan',
                value: "#{new_plan.name} ($#{ActionController::Base.helpers.number_to_currency(new_plan.price)})",
                short: true
              },
            ]
          }
        ]
    }
    @params = generate_payload(params)
    self
  end

  def deliver
    begin
      Net::HTTP.post_form(@uri, @params)
    rescue => e
      Rails.logger.error("SlackService: Error when sending: #{e.message}")
    end
  end

  private

  def generate_payload(params)
    {
      payload: NAME_AND_ICON
        .merge(channel: @channel)
        .merge(params).to_json
    }
  end
end