# Copyright 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from metrics import Metric
from telemetry.value import scalar

class LoadingMetric(Metric):
  """A metric for page loading time based entirely on window.performance"""

  def Start(self, page, tab):
    raise NotImplementedError()

  def Stop(self, page, tab):
    raise NotImplementedError()

  def AddResults(self, tab, results):
    load_timings = tab.EvaluateJavaScript('window.performance.timing')

    # NavigationStart relative markers in milliseconds.
    load_start = (
      float(load_timings['loadEventStart']) - load_timings['navigationStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'load_start', 'ms', load_start))

    dom_content_loaded_start = (
      float(load_timings['domContentLoadedEventStart']) -
      load_timings['navigationStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'dom_content_loaded_start', 'ms',
        dom_content_loaded_start))

    fetch_start = (
        float(load_timings['fetchStart']) - load_timings['navigationStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'fetch_start', 'ms', fetch_start,
        important=False))

    request_start = (
        float(load_timings['requestStart']) - load_timings['navigationStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'request_start', 'ms', request_start,
        important=False))

    # Phase measurements in milliseconds.
    domain_lookup_duration = (
        float(load_timings['domainLookupEnd']) -
        load_timings['domainLookupStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'domain_lookup_duration', 'ms',
        domain_lookup_duration, important=False))

    connect_duration = (
        float(load_timings['connectEnd']) - load_timings['connectStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'connect_duration', 'ms', connect_duration,
        important=False))

    request_duration = (
        float(load_timings['responseStart']) - load_timings['requestStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'request_duration', 'ms', request_duration,
        important=False))

    response_duration = (
        float(load_timings['responseEnd']) - load_timings['responseStart'])
    results.AddValue(scalar.ScalarValue(
        results.current_page, 'response_duration', 'ms', response_duration,
        important=False))