#!/usr/bin/env ruby

require 'motion_vj'

require 'dotenv'
require 'fileutils'
require 'optparse'

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

      opts.separator 'Required:'

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

      opts.separator 'Optional:'

      opts.on('-t', '--get-token', 'Get the Dropbox token') do
        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 options[:config_filepath].nil? || options[:config_filepath].to_s.strip.empty?
      $stderr.puts 'The configuration file is required.'
      abort opt_parser.to_s
    end

    options
  end

  def self.start(options)
    Dotenv.load(options[:config_filepath])
    self.check_config

    trap('INT') do
      self.remove_pid_file
      exit 2
    end

    self.create_pid_file

    if options[:get_token]
      MotionVj.get_dropbox_token(self.get_env('DP_APP_KEY'), self.get_env('DP_APP_SECRET'))
    else
      MotionVj.start(get_env('DP_APP_TOKEN'))
      sleep
    end
  end

  private

  def self.check_config
    %w( MOTION_CMD VIDEOS_DIR VIDEO_EXTENTION PID_FILE DB_VIDEOS_DIR ).each { |key| self.get_env(key) }
  end

  def self.get_env(key)
    value = ENV[key]
    abort "The environment variable '#{key}' is blank or defined." if value.to_s.strip.empty?
    value
  end

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

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

    File.open(ENV['PID_FILE'], 'w') do |f|
      f.puts Process.pid
    end
  end

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

options = App.parse!(ARGV)
App.start(options)