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# Copyright (c) 2016-present WeWantToKnow AS
#
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require 'u3d/utils'
require 'u3d_core/core_ext/string'
require 'fileutils'
require 'file-tail'

module U3d
  # Launches Unity with given arguments
  class Runner
    def run(installation, args, raw_logs: false)
      log_file = find_and_prepare_logfile(installation, args)

      if raw_logs
        output_callback = proc do |line|
          UI.command_output(line.rstrip)
        end
      else
        analyzer = LogAnalyzer.new
        output_callback = proc do |line|
          analyzer.parse_line(line)
        end
      end

      if log_file
        tail_thread = start_tail_thread(log_file, output_callback)
        return unless tail_thread.status
        tail_thread.run
      end

      begin
        args.unshift(installation.exe_path)
        args.map!(&:argescape)

        U3dCore::CommandExecutor.execute_command(command: args, output_callback: output_callback)
      ensure
        if tail_thread
          sleep 1
          Thread.kill(tail_thread)
        end
      end
    end

    def find_and_prepare_logfile(installation, args)
      log_file = Runner.find_logFile_in_args(args)

      return nil if log_file == '/dev/stdout'

      if log_file # we wouldn't want to do that for the default log file.
        File.delete(log_file) if File.file?(log_file) # We only delete real files
      else
        log_file = installation.default_log_file
      end

      Utils.ensure_dir File.dirname(log_file)
      FileUtils.touch(log_file) unless File.exist? log_file
      log_file
    end

    class << self
      # rubocop:disable MethodName
      def find_logFile_in_args(args)
        # rubocop:enable MethodName
        find_arg_in_args('-logFile', args)
      end

      def find_projectpath_in_args(args)
        find_arg_in_args('-projectPath', args)
      end

      def find_arg_in_args(arg_to_find, args)
        raise 'Only arguments of type array supported right now' unless args.is_a?(Array)
        args.each_with_index do |arg, index|
          return args[index + 1] if arg == arg_to_find && index < args.count - 1
        end
        nil
      end
    end

    private

    def start_tail_thread(log_file, output_callback)
      tail_thread = Thread.new do
        begin
          pipe(log_file) { |line| output_callback.call(line) }
        rescue StandardError => e
          UI.error "Failure while trying to pipe #{log_file}: #{e.message}"
          e.backtrace.each { |l| UI.error "  #{l}" }
        end
      end

      # Wait for tail_thread setup to be complete
      sleep 0.5 while tail_thread.status == 'run'
      tail_thread
    end

    def pipe(file)
      File.open(file, 'r') do |f|
        f.extend File::Tail
        f.interval = 0.1
        f.max_interval = 0.4
        f.backward 0
        Thread.stop
        f.tail { |l| yield l }
      end
    end
  end
end