Parse output of git clone and show nicer progress output

git_clone_parser.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'open3'
require 'fileutils'
require 'uri'

repo = ARGV[0]
raise 'missing repo argument' unless repo

name = ARGV[1] || File.basename(URI(repo).path).delete_suffix('.git')

FileUtils.rm_rf name

# Requires '--progress', when not in terminal '--quiet' is enforced
args = ['git', 'clone', '--progress', repo, name]

def stream_cmd(*args, &block)
  Open3.popen3(*args) do |_stdin, stdout, stderr, thread|
    readers = [stdout, stderr]

    until readers.empty?
      begin
        # Block until at least one pipe is readable (timeout optional)
        ready, = IO.select(readers, nil, nil, 5)

        next unless ready # timeout hit, loop again

        ready.each do |io|
          line = io.gets # read one line from whichever pipe is ready

          if line
            block.call(io == stdout ? :stdout : :stderr, line)
          else
            readers.delete(io) # EOF on this pipe, stop watching it
          end
        end
      rescue StandardError
        begin
          Process.kill('TERM', thread.pid)
        rescue StandardError => e
          warn "failed to kill process #{thread.pid}:\n#{e}"
        end
        raise
      end
    end

    thread.value.exitstatus
  end
end

EIGHTHS = [' ', '▏', '▎', '▍', '▌', '▋', '▊', '▉', '█'].freeze

def smooth_bar(current, total, width: 20)
  pct        = current.to_f / total
  full_cells = pct * width
  filled     = full_cells.floor
  return '█' * filled if filled == width

  remainder  = full_cells - filled # fractional part 0..1
  tip        = EIGHTHS[(remainder * 8).floor]

  "\e[1;93m\e[1;44m#{'█' * filled}#{tip}#{' ' * (width - filled - 1)}\e[0m"
end

newline = false
begin
  progress = nil
  percent = 0
  exit_code = stream_cmd(*args) do |stream, line|
    case stream
    when :stdout then puts "OUT | #{line.chomp}"
    when :stderr
      case line
      in %r{^(?<prefix>(?<remote>remote: )?[\w\s]+):\s+(?<progress>\d+)%\s\((?<current>\d+)/(?<total>\d+)\)(?<suffix>.*)?}
        current = Regexp.last_match(:current).to_i
        total = Regexp.last_match(:total).to_i
        bar = smooth_bar(current, total)
        percent = Regexp.last_match(:progress).to_i
        prefix = Regexp.last_match(:prefix)
        suffix = Regexp.last_match(:suffix).chomp
        progress = "▕#{bar}▏#{percent.to_s.rjust 5}% | #{prefix} (#{current}/#{total}) #{suffix}\e[K"
      in /^remote:\s(.*)/
        event = 'REMOTE'
      else
        event = 'INFO'
      end
    end

    $stdout.write " #{event.ljust 8}▕ #{line.chomp}\e[K\n" if event

    if progress
      event = 'PROGRESS'
      $stdout.write " #{event.ljust 8}▕#{progress}\e[K\r"
      progress = nil if percent >= 100
      newline = true
    end
  ensure
    $stdout.flush
  end
ensure
  $stdout.write "\n" if newline
  $stdout.write "--\n"
  $stdout.flush
end

puts "Exited with: #{exit_code}"