#!/usr/bin/env ruby

require 'json'
require 'pry'

def cf_curl(resource, parameter='')
  response = JSON.parse `cf curl /v2/#{resource}?#{parameter}`
  raise "pagination" if response["total_pages"] && response["total_pages"] > 1
  return response
end

def get_resources(resource, parameter='')
#  puts "/v2/#{resource}?#{parameter}"
  response = cf_curl(resource, parameter)
  return response["resources"]
end


def get_space_name(space_guid)
  unless @space_names[space_guid]
    response = cf_curl("/spaces/#{space_guid}")
    space_name =response['entity']['name']
    org_guid = response['entity']['organization_guid']
    org_name = get_org_name(org_guid)
    @space_names[space_guid] = "#{org_name}/#{space_name}"
  end
  return @space_names[space_guid]
end

def get_org_name(org_guid)
  unless @org_names[org_guid]
    @org_names[org_guid] = cf_curl("/organizations/#{org_guid}")['entity']['name']
  end
  return @org_names[org_guid]
end

@space_names = {}
@org_names = {}

if ARGV.length != 1
  puts "Usage: apps-using-service <SERVICE_NAME>"
  exit 1
end

service_name = ARGV[0]
services = get_resources('services').select {|v| v['entity']['label'] == service_name}
if services.empty?
  puts "can not find service #{service_name}"
  exit 2
end
service_guid = services.first['metadata']['guid']
puts "found service #{service_name} with guid #{service_guid}"
service_plans = get_resources('service_plans', %Q|q=service_guid:#{service_guid}|)
service_plans.each do |plan|
  service_instances = []
  service_bindings = []
  sp_guid = plan['metadata']['guid']
  puts "-- found plan #{plan['entity']['name']} with guid #{sp_guid} --"
  service_instances.concat get_resources("service_plans/#{sp_guid}/service_instances")
  service_instance_guids = service_instances.map { |i| i['metadata']['guid'] }
  service_instance_guids.each do |si_guid|
    service_bindings.concat get_resources("service_bindings", "q=service_instance_guid:#{si_guid}")
  end
  app_guids = service_bindings.map { |i| i['entity']['app_guid'] }
  cfapps = []
  app_guids.each do |app_guid|
    cfapps.push cf_curl("apps/#{app_guid}/summary")
  end
  cfapps.each do |cfapp|
    appname = cfapp['name']
    appspace = get_space_name(cfapp['space_guid'])
    puts "Name: #{appname} Space: #{appspace}"
  end
end