module Shellator

# File lib/shellator.rb, line 6
def self.noninteractive(cmd, in_directory: nil, stdin_content: [], stdin_newlines: true, stdout:, stderr:)
  raise "cmd must be a String or array of Strings." \
    unless cmd.is_a?(String) || (cmd.is_a?(Array) && cmd.all? { |c| c.is_a?(Stirng) })
  raise "stdout must be a Proc." unless stdout.is_a?(Proc)
  raise "stderr must be a Proc." unless stderr.is_a?(Proc)

  stdin_content = [stdin_content].flatten
  raise "stdin_content must be an Array of Strings." \
    unless stdin_content.is_a?(Array) && stdin_content.all? { |c| c.is_a?(String) }

  computed_cmd = [cmd].flatten.join(" ")

  Dir.chdir(in_directory || Dir.pwd) do
    Open3.popen3(computed_cmd) do |stdin_stream, stdout_stream, stderr_stream, thread|
      stdin_content.each do |input_line|
        stdin_stream.write(input_line)

        stdin_stream.write("\n") unless input_line[-1] == "\n" || !stdin_newlines
      end

      stdin_stream.close

      { stdout_stream => stdout, stderr_stream => stderr }.each_pair do |stream, callback|
        Thread.new do
          until (line = stream.gets).nil?
            callback.call(line)
          end
        end
      end

      thread.join
      thread.value
    end
  end
end