require 'update_repo/version'
require 'yaml'
require 'colorize'
require 'confoog'
require 'trollop'

# Overall module with classes performing the functionality
# Contains Class UpdateRepo::WalkRepo
module UpdateRepo
  # This constant holds the name to the config file, located in ~/
  CONFIG_FILE = '.updaterepo'.freeze

  # An encapsulated class to walk the repo directories and update all Git
  # repositories found therein.
  class WalkRepo
    # Class constructor. No parameters required.
    # @return [void]
    def initialize
      # @counter - this will be incremented with each repo updated.
      @counter = 0
      # @skip_counter - will count all repos deliberately skipped
      @skip_count = 0
      # @ start_time - will be used to get elapsed time
      @start_time = 0
      # read the options from Trollop and store in temp variable.
      # we do it this way around otherwise if configuration file is missing it
      # gives the error messages even on '--help' and '--version'
      temp_opt = set_options
      # @config - Class. Reads the configuration from a file in YAML format and
      # allows easy access to the configuration data
      @config = Confoog::Settings.new(filename: CONFIG_FILE,
                                      prefix: 'update_repo',
                                      autoload: true,
                                      autosave: false)
      # store the command line variables in a configuration variable
      @config['cmd'] = temp_opt
      config_error unless @config.status[:errors] == Status::INFO_FILE_LOADED
    end

    # This function will perform the required actions to traverse the Repo.
    # @example
    #   walk_repo = UpdateRepo::WalkRepo.new
    #   walk_repo.start
    def start
      show_header(@config['exceptions'])
      @config['location'].each do |loc|
        recurse_dir(loc)
      end
      # print out an informative footer...
      footer
    end

    private

    def config_error
      if @config.status[:errors] == Status::ERR_CANT_LOAD
        print 'Note that the the default configuration file was '.red,
              "changed to ~/#{CONFIG_FILE} from v0.4.0 onwards\n\n".red
      end
      exit 1
    end

    # rubocop:disable Metrics//MethodLength
    def set_options
      Trollop.options do
        version "\nupdate_repo version #{VERSION} (C)2016 G. Ramsay\n"
        banner <<-EOS
Keep multiple local Git-Cloned Repositories up to date with one command.

Usage:
      update_repo [options]

Options are not required. If none are specified then the program will read from
the standard configuration file (~/#{CONFIG_FILE}) and automatically update the
specified Repositories.

Options:
EOS
        # opt :color, 'Use colored output', default: true
        # opt :quiet, 'Only minimal output to the terminal', default: false
        # opt :silent, 'Completely silent, no output to terminal at all.',
        #    default: false
      end
    end
    # rubocop:enable Metrics//MethodLength

    # take each directory contained in the Repo directory, if it is detected as
    # a Git repository then update it (or as directed by command line)
    # @param dirname [string] Contains the directory to search for Git repos.
    def recurse_dir(dirname)
      Dir.chdir(dirname) do
        Dir['**/'].each do |dir|
          notexception?(dir) ? update_repo(dir) : skip_repo(dir) if gitdir?(dir)
        end
      end
    end

    # tests to see if the given directory is an exception and should be skipped
    # @param dir [string] Directory to be checked
    # @return [boolean] True if this is NOT an exception, False otherwise
    def notexception?(dir)
      !@config['exceptions'].include?(File.basename(dir))
    end

    # Display a simple header to the console
    # @example
    #   show_header(exceptions)
    # @return [void]
    def show_header(exceptions)
      # print an informative header before starting
      print "\nGit Repo update utility (v", VERSION, ')',
            " \u00A9 Grant Ramsay <seapagan@gmail.com>\n"
      print "Using Configuration from '#{@config.config_path}'\n"
      list_locations
      if exceptions
        print "\nExclusions:".underline, ' ',
              exceptions.join(', ').yellow, "\n"
      end
      # save the start time for later display in the footer...
      @start_time = Time.now
      print "\n" # blank line before processing starts
    end

    # print out a brief footer. This will be expanded later.
    # @return [void]
    def footer
      duration = Time.now - @start_time
      print "\nUpdates completed : ", @counter.to_s.green,
            ' repositories processed'
      print ' / ', @skip_count.to_s.yellow, ' skipped' unless @skip_count == 0
      print ' in ', show_time(duration), "\n\n"
    end

    def list_locations
      print "\nRepo location(s):\n".underline
      @config['location'].each do |loc|
        print '-> ', loc.cyan, "\n"
      end
    end

    def skip_repo(dirpath)
      Dir.chdir(dirpath.chomp!('/')) do
        repo_url = `git config remote.origin.url`.chomp
        print '* Skipping ', Dir.pwd.yellow, " (#{repo_url})\n"
        @skip_count += 1
      end
    end

    def update_repo(dirname)
      Dir.chdir(dirname.chomp!('/')) do
        repo_url = `git config remote.origin.url`.chomp
        print '* Checking ', Dir.pwd.green, " (#{repo_url})\n", '  -> '
        system 'git pull'
        @counter += 1
      end
    end

    def gitdir?(dirpath)
      gitpath = dirpath + '/.git'
      File.exist?(gitpath) && File.directory?(gitpath)
    end

    def show_time(duration)
      time_taken = Time.at(duration).utc
      time_taken.strftime('%-H hours, %-M Minutes and %-S seconds.').cyan
    end
  end
end