class RorVsWild::Plugin::Middleware

def self.setup
  return if @installed
  Rails.application.config.middleware.unshift(RorVsWild::Plugin::Middleware, nil) if defined?(Rails)
  @installed = true
end

def call(env)
  RorVsWild.agent.start_request
  RorVsWild.agent.current_data[:path] = env["ORIGINAL_FULLPATH"]
  section = RorVsWild::Section.start
  section.file, section.line = rails_engine_location
  section.commands << "Rails::Engine#call"
  code, headers, body = @app.call(env)
  [code, headers, body]
ensure
  RorVsWild::Section.stop
  inject_server_timing(RorVsWild.agent.stop_request, headers)
end

def format_server_timing_ascii(sections, total_width = 80)
  max_time = sections.map(&:self_ms).max
  chart_width = (total_width * 0.25).to_i
  rows = sections.map { |section|
    [
      section.kind == "view" ? section.file : "#{section.file}:#{section.line}",
      "█" * (section.self_ms * (chart_width-1) / max_time),
      "%.1fms" % section.self_ms,
    ]
  }
  time_width = rows.map { |cols| cols[2].size }.max + 1
  label_width = total_width - chart_width - time_width
  rows.each { |cols| cols[0] = truncate_backwards(cols[0], label_width) }
  template = "%-#{label_width}s%#{chart_width}s%#{time_width}s"
  rows.map { |cols| format(template, *cols) }.join("\n")
end

def format_server_timing_header(sections)
  sections.map do |section|
    if section.kind == "view"
      "#{section.kind};dur=#{section.self_ms.round};desc=\"#{section.file}\""
    else
      "#{section.kind};dur=#{section.self_ms.round};desc=\"#{section.file}:#{section.line}\""
    end
  end.join(", ")
end

def initialize(app, config)
  @app, @config = app, config
end

def inject_server_timing(data, headers)
  return if !data || !data[:send_server_timing] || !(sections = data[:sections])
  sections = sections.sort_by(&:self_ms).reverse[0,10]
  headers["Server-Timing"] = format_server_timing_header(sections)
  if data[:name] && RorVsWild.logger.level <= Logger::Severity::DEBUG
    RorVsWild.logger.debug(["┤ #{data[:name]} ├".center(80, "─"),
      format_server_timing_ascii(sections),
      "─" * 80, nil].join("\n")
    )
  end
end

def rails_engine_location
  @rails_engine_location = ::Rails::Engine.instance_method(:call).source_location
end

def truncate_backwards(string, width)
  string.size > width ? "…" + string[-(width - 1)..-1] : string
end