firb0

#!/usr/bin/env -S ruby --disable=gems
# ====================
# Depends: ruby (>= 3.1)
#
# rubocop:disable Style/GlobalVars
# frozen_string_literal: true

# ====================
# NOTE: call `Cinnabar::Utils.gems!` or `require 'rubygems'` to re-enable `::Gem` module.
# For faster loading, consider using `gems.then(&require_gems)` instead of `require 'rubygems'`;
# e.g., `%w[irb rdoc reline].then(&require_gems)`
#
# The first run automatically generates a cache JSON, so it may take a little longer.
# On the second run and beyond, it reuses the cache whenever possible to maximize startup speed.
#
# Usage:
#   - `firb0` => Start IRB
#   - `firb0 -h` => Display help info
#   - `firb0 -e "puts 2"` => Equivalent to `ruby -e "puts 2"`, but with `ENV['RUBYOPT'] = '--disable=gems'`
#
# Note:
#
# On Alpine v3.23, if you encounter any rdoc‑related errors, you can try running the following command.
#
# ```ash
#   unlink ~/.cache/ruby/gem_path.json
#   su -c 'unlink /usr/lib/ruby/3.4.0/rdoc.rb'
#   gem install rdoc
# ```
#
# If you encounter any issues related to `env -S`, you can wrap it into a new script.
#
# ```sh
# #!/bin/sh
# # You need to replace /path/to/firb0 with the actual path
# ruby --disable=gems /path/to/firb0 "$@"
# ```
# ==============
Kernel.warn "  ruby:\t#{RUBY_VERSION}" if ARGV.empty?

$ruby_cache_dir = -> {
  require 'pathname'

  env_dir = ENV['xdg_cache_home'.upcase]
  case env_dir
    when nil, ''
      Pathname(Dir.home).join('.cache/ruby')
    else
      Pathname(env_dir).join('ruby')
  end
}.call

-> {
  libs = %w[gem_path utils]
  lib_dir = File.expand_path('../../../lib/cinnabar', __dir__).then { Pathname _1 }
  if lib_dir.exist?
    libs.each { require lib_dir.join(_1) }
    return
  end

  dir = $ruby_cache_dir.join('lib/cinnabar')
  libs.each { require dir.join(_1) }
}.call

def new_cinnabar_gem_path_class(gems)
  {
    cache_dir: $ruby_cache_dir,
    gems:,
  }
    .then(&Cinnabar.new_gem_path_proc)
end

def require_gems = ->(gems) {
  new_cinnabar_gem_path_class(gems)
    .append_load_path!

  gems.each { require _1 }
}

def start_irb
  major_ver = RUBY_VERSION.split('.').first.to_i

  %w[
    irb rdoc
  ]
    .tap { _1 << 'fiddle' if Cinnabar::Utils::OS.windows? }
    .tap { _1 << 'reline' if major_ver >= 4 }
    .then(&require_gems)

  two_spaces = '  '

  Kernel.warn <<~GEM_VER
    #{two_spaces}irb:\t#{IRB::VERSION}
    #{two_spaces}rdoc:\t#{RDoc::VERSION}
    #{Dir.pwd}
  GEM_VER

  IRB.start
end

begin
  require_relative '../lib/version'
rescue StandardError
  nil
end

unless ARGV.empty?
  require 'rbconfig'
  ENV['RUBYOPT'] = '--disable=gems'
  exec RbConfig.ruby, *ARGV
end

start_irb