class TextInjector

# File lib/text_injector.rb, line 7
def initialize(options={})
  @options = options
  @file = @options[:file]
  raise "required :file option missing" unless @file
  @identifier = @options[:identifier] || default_identifier
  @content = @options[:content]
end

# File lib/text_injector.rb, line 15
def run
  if File.exists?(@file)
    write_file(updated_file)
  else
    write_file(marked_content)
  end
end

# File lib/text_injector.rb, line 23
def say(msg)
  puts msg unless @options[:mute]
end

# File lib/text_injector.rb, line 27
def tmp_path
  "#{@file}.tmp"
end

# File lib/text_injector.rb, line 78
def comment_base
  "TextInjector marker for #{@identifier}"
end

# File lib/text_injector.rb, line 86
def comment_close
  "# End #{comment_base}\n"
end

# File lib/text_injector.rb, line 82
def comment_open
  "# Begin #{comment_base}"
end

# File lib/text_injector.rb, line 33
def default_identifier
  File.expand_path(@file)
end

# File lib/text_injector.rb, line 37
def marked_content
  @marked_content = [comment_open, @content, comment_close].join("\n")
end

# File lib/text_injector.rb, line 41
def read_file
  return @current_file if @current_file
  results = ''
  File.open(@file, 'r') {|f| results = f.readlines.join("") }
  @current_file = results
end

# File lib/text_injector.rb, line 60
def updated_file
  # Check for unopened or unclosed identifier blocks
  if read_file.index(comment_open) && !read_file.index(comment_close)
    warn "[fail] Unclosed indentifier; Your file contains '#{comment_open}', but no '#{comment_close}'"
    exit(1)
  elsif !read_file.index(comment_open) && read_file.index(comment_close)
    warn "[fail] Unopened indentifier; Your file contains '#{comment_close}', but no '#{comment_open}'"
    exit(1)
  end

  # If an existing identifier block is found, replace it with the content text
  if read_file.index(comment_open) && read_file.index(comment_close)
    read_file.gsub(Regexp.new("#{comment_open}.+#{comment_close}", Regexp::MULTILINE), marked_content)
  else # Otherwise, append the new content after
    [read_file, marked_content].join("\n\n")
  end
end

# File lib/text_injector.rb, line 48
def write_file(contents)
  File.open(tmp_path, 'w') do |file|
    file.write(contents)
  end
  if @options[:tmp_file]
    say "Tmp file written to #{tmp_path}"
  else
    say "Updated #{@file}"
    FileUtils.mv(tmp_path, @file)
  end
end