#!/usr/bin/env ruby

require 'motion_vj'

require 'fileutils'
require 'optparse'
require 'yaml'

class App
  attr_accessor :options, :config

  def initialize(argv)
    parse!(argv)
    load_config!
    start
  end

  private

  def parse!(argv)
    self.options = {}
    opt_parser = OptionParser.new do |opts|
      opts.banner = 'Usage: motionvj [options]'

      opts.separator 'Required:'

      opts.on('-c', '--config-file [CONFIG_YAML_FILE]', 'Path to the configuration YAML file') do |config_filepath|
        self.options[:config_filepath] = config_filepath
      end

      opts.separator 'Optional:'

      opts.on('-t', '--get-token', 'Get the Dropbox token') do
        self.options[:get_token] = true
      end

      opts.separator 'Common:'

      opts.on_tail('-h', '--help', 'Show this message') do
        puts opts
        exit
      end

      opts.on_tail('-v', '--version', 'Show version') do
        puts MotionVj::VERSION
        exit
      end
    end

    begin
      opt_parser.parse!(argv)
    rescue OptionParser::InvalidOption => e
      $stderr.puts 'Invalid option.'
      abort opt_parser.to_s
    end

    if self.options[:config_filepath].nil? || self.options[:config_filepath].to_s.strip.empty?
      $stderr.puts 'The configuration YAML file is required.'
      abort opt_parser.to_s
    end
  end

  def load_config!
    self.config = YAML.load_file(self.options[:config_filepath])
    blank_config_msg = %w( db_videos_dir motion_cmd pid_file videos_dir videos_extension ).map { |key|
      key if /\A[[:space:]]*\z/ === self.config[key].to_s
    }.compact
    abort "The following configuration options are missing:\n#{ blank_config_msg.join("\n") }" unless blank_config_msg.empty?
  rescue Errno::ENOENT
    abort "Could not open the configuration file: #{ self.options[:config_filepath] }"
  end

  def start
    trap('INT') do
      remove_pid_file
      exit 2
    end

    create_pid_file

    if options[:get_token]
      MotionVj.get_dropbox_token(self.config['db_app_key'], self.config['db_app_secret'])
    else
      MotionVj.start(db_app_token:     self.config['db_app_token'],
                     videos_dir:       self.config['videos_dir'],
                     videos_extension: self.config['videos_extension'],
                     motion_cmd:       self.config['motion_cmd'],
                     db_videos_dir:    self.config['db_videos_dir'])
      sleep
    end
  ensure
    remove_pid_file
  end

  def read_pid
    pid = nil
    if File.exist?(self.config['pid_file'])
      File.open(self.config['pid_file'], 'r') do |f|
        pid = f.gets.to_i rescue nil
      end
    end
    pid
  end

  def create_pid_file
    pid = read_pid
    if pid && !pid.zero?
      pid_exist = !!Process.kill(0, pid) rescue false
      abort "motionvj is already running. Please check the PID in '#{ self.config['pid_file'] }'." if pid_exist
    end

    File.open(self.config['pid_file'], 'w') do |f|
      f.puts Process.pid
    end
  end

  def remove_pid_file
    pid = read_pid
    FileUtils.rm_f(self.config['pid_file']) if pid && pid === Process.pid
  end
end

App.new(ARGV)