module IRB::Debug

# File irb/debug.rb, line 8
def insert_debug_break(pre_cmds: nil, do_cmds: nil)
  options = { oneshot: true, hook_call: false }

  if pre_cmds || do_cmds
    options[:command] = ['irb', pre_cmds, do_cmds]
  end
  if DEBUGGER__::LineBreakpoint.instance_method(:initialize).parameters.include?([:key, :skip_src])
    options[:skip_src] = true
  end

  # To make debugger commands like `next` or `continue` work without asking
  # the user to quit IRB after that, we need to exit IRB first and then hit
  # a TracePoint on #debug_break.
  file, lineno = IRB::Irb.instance_method(:debug_break).source_location
  DEBUGGER__::SESSION.add_line_breakpoint(file, lineno + 1, **options)
end

# File irb/debug.rb, line 25
def setup(irb)
  # When debug session is not started at all
  unless defined?(DEBUGGER__::SESSION)
    begin
      require "debug/session"
    rescue LoadError # debug.gem is not written in Gemfile
      return false unless load_bundled_debug_gem
    end
    DEBUGGER__::CONFIG.set_config
    configure_irb_for_debugger(irb)

    DEBUGGER__.initialize_session{ IRB::Debug::UI.new(irb) }
  end

  # When debug session was previously started but not by IRB
  if defined?(DEBUGGER__::SESSION) && !irb.context.with_debugger
    configure_irb_for_debugger(irb)
    DEBUGGER__::SESSION.reset_ui(IRB::Debug::UI.new(irb))
  end

  # Apply patches to debug gem so it skips IRB frames
  unless DEBUGGER__.respond_to?(:capture_frames_without_irb)
    DEBUGGER__.singleton_class.send(:alias_method, :capture_frames_without_irb, :capture_frames)

    def DEBUGGER__.capture_frames(*args)
      frames = capture_frames_without_irb(*args)
      frames.reject! do |frame|
        frame.realpath&.start_with?(IRB_DIR) || frame.path == "<internal:prelude>"
      end
      frames
    end

    DEBUGGER__::ThreadClient.prepend(SkipPathHelperForIRB)
  end

  if !DEBUGGER__::CONFIG[:no_hint] && irb.context.io.is_a?(RelineInputMethod)
    Reline.output_modifier_proc = proc do |input, complete:|
      unless input.strip.empty?
        cmd = input.split(/\s/, 2).first

        if !complete && DEBUGGER__.commands.key?(cmd)
          input = input.sub(/\n$/, " # debug command\n")
        end
      end

      irb.context.colorize_input(input, complete: complete)
    end
  end

  true
end

# File irb/debug.rb, line 79
def configure_irb_for_debugger(irb)
  require 'irb/debug/ui'
  IRB.instance_variable_set(:@debugger_irb, irb)
  irb.context.with_debugger = true
  irb.context.irb_name += ":rdbg"
end

# File irb/debug.rb, line 96
def load_bundled_debug_gem
  # Discover latest debug.gem under GEM_PATH
  debug_gem = Gem.paths.path.flat_map { |path| Dir.glob("#{path}/gems/debug-*") }.select do |path|
    File.basename(path).match?(/\Adebug-\d+\.\d+\.\d+(\w+)?\z/)
  end.sort_by do |path|
    Gem::Version.new(File.basename(path).delete_prefix('debug-'))
  end.last
  return false unless debug_gem

  # Discover debug/debug.so under extensions for Ruby 3.2+
  ext_name = "/debug/debug.#{RbConfig::CONFIG['DLEXT']}"
  ext_path = Gem.paths.path.flat_map do |path|
    Dir.glob("#{path}/extensions/**/#{File.basename(debug_gem)}#{ext_name}")
  end.first

  # Attempt to forcibly load the bundled gem
  if ext_path
    $LOAD_PATH << ext_path.delete_suffix(ext_name)
  end
  $LOAD_PATH << "#{debug_gem}/lib"
  begin
    require "debug/session"
    puts "Loaded #{File.basename(debug_gem)}"
    true
  rescue LoadError
    false
  end
end