class TerraformLandscape::Printer

def apply_prompt(output)
  return unless output =~ /Enter a value:\s+$/
  output[/Do you want to perform these actions.*$/m, 0]
end

def initialize(output)
  @output = output
end

def process_stream(io, options = {}) # rubocop:disable Metrics/MethodLength
  apply = nil
  buffer = StringIO.new
  original_tf_output = StringIO.new
  begin
    block_size = 1024
    done = false
    until done
      readable_fds, = IO.select([io])
      next unless readable_fds
      readable_fds.each do |f|
        begin
          new_output = f.read_nonblock(block_size)
          original_tf_output << new_output
          buffer << strip_ansi(new_output)
        rescue IO::WaitReadable # rubocop:disable Lint/HandleExceptions
          # Ignore; we'll call IO.select again
        rescue EOFError
          done = true
        end
      end
      apply = apply_prompt(buffer.string.encode('UTF-8',
                                                invalid: :replace,
                                                replace: ''))
      done = true if apply
    end
    begin
      process_string(buffer.string)
      @output.print apply if apply
    rescue ParseError, TerraformPlan::ParseError => e
      raise e if options[:trace]
      @output.warning FALLBACK_MESSAGE
      @output.print original_tf_output.string
    end
    @output.write_from(io)
  ensure
    io.close
  end
end

def process_string(plan_output) # rubocop:disable Metrics/MethodLength
  scrubbed_output = strip_ansi(plan_output)
  # Our grammar assumes output with Unix line endings
  scrubbed_output.gsub!("\r\n", "\n")
  # Remove initialization messages like
  # "- Downloading plugin for provider "aws" (1.1.0)..."
  # "- module.base_network"
  # as these break the parser which thinks "-" is a resource deletion
  scrubbed_output.gsub!(/^- .*\.\.\.$/, '')
  scrubbed_output.gsub!(/^- module\..*$/, '')
  # Remove separation lines that appear after refreshing state
  scrubbed_output.gsub!(/^-+$/, '')
  if (matches = scrubbed_output.scan(/^Warning:.*$/))
    matches.each do |warning|
      @output.puts warning.colorize(:yellow)
    end
  end
  # Remove preface
  if (match = scrubbed_output.match(/^Path:[^\n]+/))
    scrubbed_output = scrubbed_output[match.end(0)..-1]
  elsif (match = scrubbed_output.match(/^Terraform.+following\sactions:/))
    scrubbed_output = scrubbed_output[match.end(0)..-1]
  elsif (match = scrubbed_output.match(/^\s*(~|\+|\-)/))
    scrubbed_output = scrubbed_output[match.begin(0)..-1]
  elsif scrubbed_output =~ /^(No changes\.|This plan does nothing)/
    @output.puts 'No changes.'
    return
  else
    raise ParseError, 'Output does not contain proper preface'
  end
  # Remove postface
  if (match = scrubbed_output.match(/^Plan:[^\n]+/))
    plan_summary = scrubbed_output[match.begin(0)..match.end(0)]
    scrubbed_output = scrubbed_output[0...match.begin(0)]
  end
  plan = TerraformPlan.from_output(scrubbed_output)
  plan.display(@output)
  @output.puts plan_summary
end

def strip_ansi(string)
  string.gsub(/\e\[\d+m/, '')
end