module Middleman::PreviewServer

def mount_instance
  @app = new_app
  @webrick ||= setup_webrick(@options[:debug] || false)
  start_file_watcher
  @webrick.mount "/", ::Rack::Handler::WEBrick, app.class.to_rack_app
end

def needs_to_reload?(paths)
  match_against = [
    %r{^config\.rb},
    %r{^lib/^[^\.](.*)\.rb$},
    %r{^helpers/^[^\.](.*)_helper\.rb$}
  ]
  if @options[:reload_paths]
    @options[:reload_paths].split(',').each do |part|
      match_against << %r{^#{part}}
    end
  end
  paths.any? do |path|
    match_against.any? do |matcher|
      path =~ matcher
    end
  end
end

def new_app
  opts = @options
  @app =::Middleman::Application.server.inst do
    if opts[:environment]
      set :environment, opts[:environment].to_sym
    end
    logger(opts[:debug] ? 0 : 1, opts[:instrumenting] || false)
  end
end

def register_signal_handlers
  %w(INT HUP TERM QUIT).each do |sig|
    if Signal.list[sig]
      Signal.trap(sig) do
        # Do as little work as possible in the signal context
        $mm_shutdown = true
        @webrick.stop
      end
    end
  end
end

def reload
  logger.info "== The Middleman is reloading"
  unmount_instance
  mount_instance
  logger.info "== The Middleman is standing watch at http://#{host}:#{port}"
end

def setup_webrick(is_logging)
  http_opts = {
    :BindAddress => host,
    :Port        => port,
    :AccessLog   => []
  }
  if is_logging
    http_opts[:Logger] = FilteredWebrickLog.new
  else
    http_opts[:Logger] = ::WEBrick::Log.new(nil, 0)
  end
  begin
    ::WEBrick::HTTPServer.new(http_opts)
  rescue Errno::EADDRINUSE => e
    logger.error "== Port #{port} is unavailable. Either close the instance of Middleman already running on #{port} or start this Middleman on a new port with: --port=#{port.to_i+1}"
    exit(1)
  end
end

def shutdown
  stop
  @webrick.shutdown
end

def start(opts={})
  @options = opts
  @host = @options[:host] || Socket.gethostname
  @port = @options[:port] || DEFAULT_PORT
  mount_instance
  logger.info "== The Middleman is standing watch at http://#{host}:#{port}"
  @initialized ||= false
  unless @initialized
    @initialized = true
    register_signal_handlers
    # Save the last-used @options so it may be re-used when
    # reloading later on.
    ::Middleman::Profiling.report("server_start")
    @webrick.start
    # $mm_shutdown is set by the signal handler
    if $mm_shutdown
      shutdown
      exit
    end
  end
end

def start_file_watcher
  return if @options[:disable_watcher]
  first_run = !@listener
  if first_run
    # Watcher Library
    require "listen"
    @listener = Listen.to(Dir.pwd, :relative_paths => true, :force_polling => @options[:force_polling])
  end
  @listener.change do |modified, added, removed|
    added_and_modified = (modified + added)
    # See if the changed file is config.rb or lib/*.rb
    if needs_to_reload?(added_and_modified) || needs_to_reload?(removed)
      reload
    else
      added_and_modified.each do |path|
        app.files.did_change(path)
      end
      removed.each do |path|
        app.files.did_delete(path)
      end
    end
  end
  # Don't block this thread
  @listener.start(false) if first_run
end

def stop
  begin
    logger.info "== The Middleman is shutting down"
  rescue
    # if the user closed their terminal STDOUT/STDERR won't exist
  end
  if @listener
    @listener.stop
    @listener = nil
  end
  unmount_instance
end

def unmount_instance
  @webrick.unmount "/"
  @app = nil
end