#!/usr/bin/env ruby

require 'optparse'

require_relative "./../lib/prometheus_exporter"
require_relative "./../lib/prometheus_exporter/server"

def run
  options = {}
  custom_collector_filename = nil
  custom_type_collectors_filenames = []

  OptionParser.new do |opt|
    opt.banner = "Usage: prometheus_exporter [options]"
    opt.on('-p',
           '--port INTEGER',
           Integer,
           "Port exporter should listen on (default: #{PrometheusExporter::DEFAULT_PORT})") do |o|
      options[:port] = o.to_i
    end
    opt.on('--prefix METRIC_PREFIX', String, "Prefix to apply to all metrics (default: #{PrometheusExporter::DEFAULT_PREFIX})") do |o|
      options[:prefix] = o.to_s
    end
    opt.on('-c', '--collector FILE', String, "(optional) Custom collector to run") do |o|
      custom_collector_filename = o.to_s
    end
    opt.on('-a', '--type-collector FILE', String, "(optional) Custom type collectors to run in main collector") do |o|
      custom_type_collectors_filenames << o
    end
    opt.on('-v', '--verbose') do |o|
      options[:verbose] = true
    end

  end.parse!

  if custom_collector_filename
    eval File.read(custom_collector_filename), nil, File.expand_path(custom_collector_filename)
    found = false

    base_klass = PrometheusExporter::Server::CollectorBase

    ObjectSpace.each_object(Class) do |klass|
      if klass < base_klass && klass != base_klass
        options[:collector_class] = klass
      end
    end

    if !found
      STDERR.puts "[Error] Can not find a class inheriting off PrometheusExporter::Server::CollectorBase"
      exit 1
    end
  end

  if custom_type_collectors_filenames.length > 0
    custom_type_collectors_filenames.each do |t|
      eval File.read(t), nil, File.expand_path(t)
    end

    ObjectSpace.each_object(Class) do |klass|
      if klass < PrometheusExporter::Server::TypeCollector
        options[:type_collectors] ||= []
        options[:type_collectors] << klass
      end
    end
  end

  runner = PrometheusExporter::Server::Runner.new(options)

  puts "#{Time.now} Starting prometheus exporter on port #{runner.port}"
  runner.start
  sleep
end

run