Charging energy -> CO2 output

leif-poc.rb

#!/usr/bin/env ruby

# TODO: Need to work out how to do impact this charging session and impact overall

# <xbar.title>Lush Energy</xbar.title>
# <xbar.version>v1.0</xbar.version>
# <xbar.author>Tim Stone</xbar.author>
# <xbar.author.github>fetimo</xbar.author.github>
# <xbar.desc>This plugin displays the current carbon (gC02equivalent) emmissions per kWh of produced electric energy in the requested country/region </xbar.desc>
# <xbar.dependencies>ruby, CO2 Signal</xbar.dependencies>
# <xbar.abouturl>https://docs.co2signal.com/</xbar.abouturl>
# <xbar.image>https://raw.githubusercontent.com/pygoner/Plugin-Bitbar/main/Bitbar%20C02%20Signal%20Plugin%20Image.png</xbar.image>

require 'csv'
require 'date'
require 'json'
require 'net/http'
require 'uri'
require 'fileutils'

CACHE_FOLDER_NAME = 'co2_cache'.freeze
API_CACHE_NAME = "#{__dir__}/#{CACHE_FOLDER_NAME}/co2.cache.json".freeze
WATTS_CACHE_NAME = "#{__dir__}/#{CACHE_FOLDER_NAME}/watts.cache.json".freeze

# Show current impact
# Reset action to clear caches

FileUtils.mkdir(CACHE_FOLDER_NAME) unless File.directory?(CACHE_FOLDER_NAME)

def read_from_json_file(filename)
  return unless File.exist?(filename)

  file_data = File.read(filename)
  JSON.parse(file_data)
end

def write_to_file(filename, data)
  json = JSON.generate(data)
  File.write(filename, json, mode: 'w')
  JSON.parse(json)
end

def read_co2_cache
  file_json = read_from_json_file(API_CACHE_NAME)
  return unless file_json

  fetched_at = DateTime.parse(file_json['fetched_at'])
  time_difference_in_sec = (DateTime.now.to_time.to_i - fetched_at.to_time.to_i).abs
  # 30 minute cache
  File.delete(API_CACHE_NAME) if time_difference_in_sec > 1800
  file_json
end

def fetch_co2_data
  uri = URI('https://api.carbonintensity.org.uk/intensity')

  req = Net::HTTP::Get.new(uri)
  req['content-type'] = 'application/json'

  res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
    http.request(req)
  end

  JSON.parse(res.body)
end

def obtain_co2_data
  data = read_co2_cache
  unless data
    data = fetch_co2_data
    data['fetched_at'] = DateTime.now.to_time
    write_to_file(API_CACHE_NAME, data) unless data['error']
  end

  data
end

def print_exception(exception, explicit)
  puts "[#{explicit ? 'EXPLICIT' : 'INEXPLICIT'}] #{exception.class}: #{exception.message}"
  puts exception.backtrace.join("\n")
end

def calculate_average_watts
  # Calculate the impact of the last charge.
  timelapse = read_from_json_file(WATTS_CACHE_NAME)
  watt_values = timelapse['measurements'].map { |item| item['value'] }.to_a
  watt_values.sum / watt_values.size
end

def time_charging_in_hours
  # Find the duration of the charge
  data = read_from_json_file(WATTS_CACHE_NAME)
  timelapse = data['measurements'].to_a
  start = DateTime.parse(timelapse.first['timestamp']).to_time
  finish = DateTime.parse(timelapse.last['timestamp']).to_time
  (finish - start) / 60 / 60
end

def calculate_impact
  average = calculate_average_watts
  co2_data = obtain_co2_data

  # Take the carbon intensity for the hour and find what that equates to as a
  # decimal of the time on charge. Then multiply by the average of watts consumed.
  (time_charging_in_hours / co2_data['data'][0]['intensity']['actual']) * average
rescue StandardError => e
  print_exception(e, false)
  0.0
end

def calculate_watts
  watts = `ioreg -rw0 -c AppleSmartBattery | grep BatteryData | grep -o '"AdapterPower"=[0-9]*' | cut -c 16-`
  # This is arcane AF but the ioreg values are stored as unsigned ints
  # which we need to convert to single precision floats.
  [watts.to_i].pack('I').unpack1('f')
end

battery = `pmset -g batt`
is_charging = battery.include? 'AC Power'

if is_charging
  puts '🍂'
  payload = read_from_json_file(WATTS_CACHE_NAME)
  payload ||= write_to_file(WATTS_CACHE_NAME, {
                              total_session: 0,
                              total_overall: 0,
                              measurements: []
                            })

  payload['total_session'] = calculate_impact
  payload['total_overall'] = payload['total_overall'] + payload['total_session']
  payload['measurements'].append({
                                   value: calculate_watts,
                                   timestamp: DateTime.now.to_time
                                 })
  write_to_file(WATTS_CACHE_NAME, payload)
  payload
else
  puts '🍃'
end

if ARGV.include? 'reset'
  File.delete(WATTS_CACHE_NAME)
  File.delete(API_CACHE_NAME)
end

puts '---'
puts "Impact: #{format('%<num>.2f', num: calculate_impact)} gCO2eq"
puts "Reset stats | shell='#{__dir__}/#{__FILE__}' param1=reset terminal=false refresh=true"