#!/usr/bin/env ruby

require 'rest-client'
require 'json'

URL = ENV['SLACK_WEBHOOK_URL']

channel = ARGV.shift
content = ARGV.empty? ? ARGF.read : StringIO.new(ARGV.join("\n")).read
exit 0 if content.empty?

begin
  RestClient.post(
    URL,
    payload: {
      username: ENV['SLACKBOT_USERNAME'] || 'slackbot',
      channel: channel,
      text: content,
      icon_emoji: ":ghost:"
    }.to_json
  )
rescue RestClient::Exceptions => e
  puts "Error posting to slack #{e.message}:\n#{e.backtrace}"
end