# coding: utf-8

require "json"
require "optparse"
require "net/http"

module Magellan
  class LogFunnel

    class Error < StandardError
    end

    def self.start(argv)
      self.new(argv).run
    end

    def initialize(argv)
      @argv = argv
    end

    def parse_options(argv)
      @conf = {}
      OptionParser.new do |o|
        o.on("--fluentd URI") do |uri|
          @conf[:fluentd] = URI(uri)
        end
        o.on("--project PROJECT") do |proj|
          @conf[:project] = proj
        end
        o.on("--stage STAGE") do |stage|
          @conf[:stage] = stage
        end
        o.on("--worker-version VERSION") do |ver|
          @conf[:version] = ver
        end
        o.on("--container NAME") do |cname|
          @conf[:container] = cname
        end
        o.on("-d", "--[no-]daemon") do |daemon|
          @conf[:daemon] = daemon
        end
        o.order!(argv)
      end
    end

    def now
      Time.now
    end

    def post_msg(msg)
      Net::HTTP.post_form(@conf[:fluentd], json: JSON.generate({
        time: self.now.to_i,
        project: @conf[:project],
        stage: @conf[:stage],
        version: @conf[:version],
        container: @conf[:container],
        message: msg
      }))
    end

    def run
      parse_options(@argv)
      @conf[:fluentd] ||= URI("http://localhost:8888")
      @conf[:fluentd].path = "/worker_logs.#{@conf[:project]}.#{@conf[:stage]}"

      if @conf[:daemon]
        Process.daemon
      end

      begin
        IO.pipe do |out|
          IO.pipe do |err|
            @pid = Process.spawn(*@argv, out: out[1], err: err[1])
            out[1].close
            err[1].close

            th_out = Thread.start do
              begin
                while l = out[0].gets
                  post_msg(l.chomp)
                end
              rescue IOError
              end
            end
            th_err = Thread.start do
              begin
                while l = err[0].gets
                  post_msg(l.chomp)
                end
              rescue IOError
              end
            end
            th_out.join
            th_err.join
            Process.waitpid(@pid)
            @child_status = $?
            return (@child_status.exitstatus || 127)
          end
        end
      end
    ensure
      unless @child_status
        # interrupted by signal or so.
        # stop child process
        if @pid
          Process.kill(:TERM, @pid)
        end
      end
    end
  end
end