#!/usr/bin/env ruby

# set ts=2 sw=2 et

require 'pry'
require 'zlib'
require 'net/imap'
require 'pp'
require 'mechanize'
require 'yaml'
require 'hash_validator'
require 'uri'
require 'thor'
require 'json'
require 'mail'
require 'colorize'

#Net::IMAP.debug = true

class Hash
  #take keys of hash and transform those to a symbols
  def self.transform_keys_to_symbols(value)
    return value if not value.is_a?(Hash)
    hash = value.inject({}) do |memo,(k,v)| 
      memo[k.to_sym] = Hash.transform_keys_to_symbols(v); memo
    end
    return hash
  end
end

module Ewoga
  EWOGA_CONFIG_FILE = File.join(ENV['HOME'],'.ewoga','config.yml')
  EWOGA_IGNORE_FILE = File.join(ENV['HOME'],'.ewoga','ignore.yml')

  class InvalidConfiguration < Exception ; end

  class CrawlerApp
    attr_reader :imap
    attr_reader :contacts

    TMPMAIL_FILE = '.tmpmail'

    def initialize config
      @saved_key = 'RFC822'
      @filter_headers = 'BODY[HEADER.FIELDS (FROM TO Subject)]'.upcase
      @config = config
      @imap = nil
    end


    def connect!
      @imap = Net::IMAP.new(
        @config[:imap][:server], 
        ssl: {verify_mode: OpenSSL::SSL::VERIFY_NONE},
        port: 993
      )
      @imap.login(@config[:imap][:login], @config[:imap][:password])
    end

    def disconnect!
      imap.logout
      imap.disconnect
    end

    MAIL_REGEXP = /\b[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}\b/

    def examine_message message
      m = Mail.read_from_string message.attr[@saved_key]
      return if m.from.nil?
      return if m.to.nil?
      return unless m.subject =~ /RUBY\s+NEXTFORMATION/

      begin
        puts "\n### #{m.subject}"
        puts "### #{m.date}"
        print "#{m.from.first} --> #{m.to.join(',')} "

        attach = m.attachments.first 
        fn = "extract/%s/projet.tar" % [m.from.first, attach.filename]
        puts "- #{fn}"
        begin
          FileUtils.mkdir_p File.dirname(fn)
          File.open( fn, "w+b", 0644 ) { |f| f.write attach.decoded}
        rescue Exception => e
          puts "Error : Unable to save data for #{fn} because #{e.message}"
        end
      rescue Encoding::ConverterNotFoundError
        STDERR.puts "ERROR: encoding problem in email. Unable to convert."
      end

      return
    end

    def examine_all
        @imap.select "INBOX" 
        # ids = @imap.search('SUBJECT NEXTFORMATION')
        ids = @imap.sort(['DATE'], ['SUBJECT', 'NEXTFORMATION'], 'US-ASCII')
        if ids.empty?
          puts "\tFound no messages"
        else
          examine_message_list "INBOX", ids
        end
    end

    def examine_message_list mailbox_name, ids
      ids.each do |id|
        @imap.select mailbox_name #GYR: TEST
        message = imap.fetch(id, [@saved_key])[0]
        examine_message message
      end 
    rescue IOError
      # re-connect and try again
      connect!
      retry
    end
  end

  class Crawler < Thor
    CONFIG_FILE = 'config/secrey.yml'

    include Thor::Actions
    default_task :crawl


    desc 'crawl', 'Crawls email to save mails'
    def crawl
      #saved_info = []
      parse_configuration

      ## Run application
      app = CrawlerApp.new @config

      app.connect!
      app.examine_all
      app.disconnect!
    end

    def initialize *args
      @config = {}
      super
    end

    private


    def parse_configuration
      ## Load configuration
      #
      unless File.exist? EWOGA_CONFIG_FILE then
        puts "Creating sample configuration file #{EWOGA_CONFIG_FILE}"
        FileUtils.mkdir_p File.dirname(EWOGA_CONFIG_FILE)
        File.open(EWOGA_CONFIG_FILE, "w") do |fh|
          fh.puts "imap:"
          fh.puts "  server: EXAMPLE.COM"
          fh.puts "  login: FOO"
          fh.puts "  password: BAR"
        end
        exit 1
      end

      @config.merge! Hash.transform_keys_to_symbols(
        YAML::load( File.open( EWOGA_CONFIG_FILE ) )
      )

      ## Validate configuration structure 
      validations = {
        imap: {
          server: 'string',
          login: 'string',
          password: 'string'
        }
      }
      validator = HashValidator.validate(@config, validations)

      raise InvalidConfiguration.new(
        "Configuration is not valid: #{validator.errors.inspect}" 
      ) unless validator.valid?

      raise InvalidConfiguration.new(
        "Configuration is not valid: please modify #{EWOGA_CONFIG_FILE}"
      ) if @config[:imap][:server] == "EXAMPLE.COM"

    end
  end
end

begin
  Ewoga::Crawler.start ARGV
  exit 0
rescue SystemExit => e
  raise e
rescue Exception => e
  puts "ERROR: #{e.class} #{e}"
  exit 1
end