On feast days display feast title

feast.cr

# 2016-11-18
# connects to the Church Calendar API
# If there is a celebration of rank feast or higher, prints it's title

# For me to fill a textbox widget in awesome:
# In rc.lua:
#
# calendarbox = widget({ type = "textbox" })
# calendarbox.text = awful.util.pread("/path/to/feast --calendar=czech-pha")

require "http/client"
require "json"
require "option_parser"

api_uri = "http://calapi.inadiutorium.cz/api/v0"
calendar = "default"
$verbose = false
rank = 3
day = "today"

def verbose_puts(s, io=STDOUT)
  return unless $verbose
  io.puts s
end

OptionParser.parse! do |parser|
  parser.banner = "Usage: feast [options]"
  parser.on("-c", "--calendar=CAL", "API ID of the calendar to query") {|c| calendar = c }
  parser.on("-v", "--verbose", "Enable verbose output") { $verbose = true }
  parser.on("-u", "--uri=URI", "API base URI - default: #{api_uri}") {|u| api_uri = u }
  parser.on("-r", "--rank=RANK", "Maximum (the smaller number, the greater rank) celebration rank to print - default: #{rank}") {|r| rank = r.to_f }
  parser.on("-d", "--day=DAY", "Day") {|d| day = d }
  parser.on("-h", "--help", "Show this help") { puts parser }
end

endpoint_uri = api_uri + "/en/calendars/" + calendar + "/" + day

verbose_puts "GET #{endpoint_uri}"
response = HTTP::Client.get endpoint_uri

if response.status_code != 200
  verbose_puts "Error: API returned unexpected HTTP status #{response.status_code}. Exiting.", STDERR
  exit(1)
end

json = response.body.lines.join("")
verbose_puts "Received:\n#{json}"

verbose_puts "Parsing JSON"
data = JSON.parse(json)

verbose_puts "Searching for a celebration with rank of less than #{rank}"
feast = data["celebrations"].find do |c|
  c["rank_num"].as_f < rank &&
    !c["title"].as_s.empty?
end
if feast
  verbose_puts "Found celebration of rank #{feast["rank_num"]}:"
  puts feast["title"]
else
  verbose_puts "No celebration matching conditions found."
end