#!/usr/bin/env ruby

require 'optparse'

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

def run
  port = PrometheusExporter::DEFAULT_PORT
  prefix = "ruby_"
  collector_filename = nil
  verbose = false
  type_collectors = []
  collector_class = PrometheusExporter::Server::Collector

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

  end.parse!

  PrometheusExporter::Metric::Base.default_prefix = prefix

  if collector_filename
    eval File.read(collector_filename), nil, File.expand_path(collector_filename)

    found = false

    ObjectSpace.each_object(Class) do |klass|
      if klass < PrometheusExporter::Server::CollectorBase
        collector_class = klass
        found = true
      end
    end

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

  collector = collector_class.new

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

    ObjectSpace.each_object(Class) do |klass|
      if klass < PrometheusExporter::Server::TypeCollector
        collector.register_collector klass.new
        STDERR.puts "Registered TypeCollector: #{klass}" if verbose
      end
    end
  end

  puts "#{Time.now} Starting prometheus exporter on port #{port}"
  server = PrometheusExporter::Server::WebServer.new port: port, collector: collector, verbose: verbose
  server.start
  sleep

end

run