// Copyright (c) 2012 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.

#include "chrome/browser/omnibox/omnibox_field_trial.h"

#include <string>

#include "base/metrics/field_trial.h"
#include "base/string_util.h"
#include "base/stringprintf.h"
#include "base/strings/string_number_conversions.h"
#include "chrome/common/metrics/metrics_util.h"
#include "chrome/common/metrics/variations/variation_ids.h"
#include "chrome/common/metrics/variations/variations_util.h"

namespace {

// Field trial names.
const char kDisallowInlineHQPFieldTrialName[] = "OmniboxDisallowInlineHQP";
// Because we regularly change the name of the suggest field trial in
// order to shuffle users among groups, we use the date the current trial
// was created as part of the name.
const char kSuggestFieldTrialStarted2013Q1Name[] =
    "OmniboxSearchSuggestTrialStarted2013Q1";
const char kHQPNewScoringFieldTrialName[] = "OmniboxHQPNewScoringMax1400";
const char kHUPCullRedirectsFieldTrialName[] = "OmniboxHUPCullRedirects";
const char kHUPCreateShorterMatchFieldTrialName[] =
    "OmniboxHUPCreateShorterMatch";
const char kHQPReplaceHUPScoringFieldTrialName[] =
    "OmniboxHQPReplaceHUPProhibitTrumpingInlineableResult";

// The autocomplete dynamic field trial name prefix.  Each field trial is
// configured dynamically and is retrieved automatically by Chrome during
// the startup.
const char kAutocompleteDynamicFieldTrialPrefix[] = "AutocompleteDynamicTrial_";
// The maximum number of the autocomplete dynamic field trials (aka layers).
const int kMaxAutocompleteDynamicFieldTrials = 5;

// Field trial experiment probabilities.

// For inline History Quick Provider field trial, put 0% ( = 0/100 )
// of the users in the disallow-inline experiment group.
const base::FieldTrial::Probability kDisallowInlineHQPFieldTrialDivisor = 100;
const base::FieldTrial::Probability
    kDisallowInlineHQPFieldTrialExperimentFraction = 0;

// For the search suggestion field trial, divide the people in the
// trial into 20 equally-sized buckets.  The suggest provider backend
// will decide what behavior (if any) to change based on the group.
const int kSuggestFieldTrialNumberOfGroups = 20;

// For History Quick Provider new scoring field trial, put 0% ( = 0/100 )
// of the users in the new scoring experiment group.
const base::FieldTrial::Probability kHQPNewScoringFieldTrialDivisor = 100;
const base::FieldTrial::Probability
    kHQPNewScoringFieldTrialExperimentFraction = 0;

// For HistoryURL provider cull redirects field trial, put 0% ( = 0/100 )
// of the users in the don't-cull-redirects experiment group.
// TODO(mpearson): Remove this field trial and the code it uses once I'm
// sure it's no longer needed.
const base::FieldTrial::Probability kHUPCullRedirectsFieldTrialDivisor = 100;
const base::FieldTrial::Probability
    kHUPCullRedirectsFieldTrialExperimentFraction = 0;

// For HistoryURL provider create shorter match field trial, put 0%
// ( = 25/100 ) of the users in the don't-create-a-shorter-match
// experiment group.
// TODO(mpearson): Remove this field trial and the code it uses once I'm
// sure it's no longer needed.
const base::FieldTrial::Probability
    kHUPCreateShorterMatchFieldTrialDivisor = 100;
const base::FieldTrial::Probability
    kHUPCreateShorterMatchFieldTrialExperimentFraction = 0;

// For the field trial that removes searching/scoring URLs from
// HistoryURL provider and adds a HistoryURL-provider-like scoring
// mode to HistoryQuick provider, put 0% ( = 0/100 ) of the users in
// the experiment group.
const base::FieldTrial::Probability
    kHQPReplaceHUPScoringFieldTrialDivisor = 100;
const base::FieldTrial::Probability
    kHQPReplaceHUPScoringFieldTrialExperimentFraction = 0;


// Field trial IDs.
// Though they are not literally "const", they are set only once, in
// ActivateStaticTrials() below.

// Whether the static field trials have been initialized by
// ActivateStaticTrials() method.
bool static_field_trials_initialized = false;

// Field trial ID for the disallow-inline History Quick Provider
// experiment group.
int disallow_inline_hqp_experiment_group = 0;

// Field trial ID for the History Quick Provider new scoring experiment group.
int hqp_new_scoring_experiment_group = 0;

// Field trial ID for the HistoryURL provider cull redirects experiment group.
int hup_dont_cull_redirects_experiment_group = 0;

// Field trial ID for the HistoryURL provider create shorter match
// experiment group.
int hup_dont_create_shorter_match_experiment_group = 0;

// Field trial ID for the HistoryQuick provider replaces HistoryURL provider
// experiment group.
int hqp_replace_hup_scoring_experiment_group = 0;


// Concatenates the autocomplete dynamic field trial prefix with a field trial
// ID to form a complete autocomplete field trial name.
std::string DynamicFieldTrialName(int id) {
  return base::StringPrintf("%s%d", kAutocompleteDynamicFieldTrialPrefix, id);
}

}  // namespace


void OmniboxFieldTrial::ActivateStaticTrials() {
  DCHECK(!static_field_trials_initialized);

  // Create inline History Quick Provider field trial.
  // Make it expire on November 8, 2012.
  scoped_refptr<base::FieldTrial> trial(
      base::FieldTrialList::FactoryGetFieldTrial(
      kDisallowInlineHQPFieldTrialName, kDisallowInlineHQPFieldTrialDivisor,
      "Standard", 2012, 11, 8, NULL));
  // Because users tend to use omnibox without attention to it--habits
  // get ingrained, users tend to learn that a particular suggestion is
  // at a particular spot in the drop-down--we're going to make these
  // field trials sticky.  We want users to stay in them once assigned
  // so they have a better experience and also so we don't get weird
  // effects as omnibox ranking keeps changing and users learn they can't
  // trust the omnibox.
  trial->UseOneTimeRandomization();
  disallow_inline_hqp_experiment_group = trial->AppendGroup("DisallowInline",
      kDisallowInlineHQPFieldTrialExperimentFraction);

  // Create the suggest field trial.
  // Make it expire on September 1, 2013.
  trial = base::FieldTrialList::FactoryGetFieldTrial(
      kSuggestFieldTrialStarted2013Q1Name, kSuggestFieldTrialNumberOfGroups,
      "0", 2013, 9, 1, NULL);
  trial->UseOneTimeRandomization();

  // Mark this group in suggest requests to Google.
  chrome_variations::AssociateGoogleVariationID(
      chrome_variations::GOOGLE_WEB_PROPERTIES,
      kSuggestFieldTrialStarted2013Q1Name, "0",
      chrome_variations::SUGGEST_TRIAL_STARTED_2013_Q1_ID_MIN);
  DCHECK_EQ(kSuggestFieldTrialNumberOfGroups,
      chrome_variations::SUGGEST_TRIAL_STARTED_2013_Q1_ID_MAX -
      chrome_variations::SUGGEST_TRIAL_STARTED_2013_Q1_ID_MIN + 1);

  // We've already created one group; now just need to create
  // kSuggestFieldTrialNumGroups - 1 more. Mark these groups in
  // suggest requests to Google.
  for (int i = 1; i < kSuggestFieldTrialNumberOfGroups; i++) {
    const std::string group_name = base::IntToString(i);
    trial->AppendGroup(group_name, 1);
    chrome_variations::AssociateGoogleVariationID(
        chrome_variations::GOOGLE_WEB_PROPERTIES,
        kSuggestFieldTrialStarted2013Q1Name, group_name,
        static_cast<chrome_variations::VariationID>(
            chrome_variations::SUGGEST_TRIAL_STARTED_2013_Q1_ID_MIN + i));
  }

  // Make sure that we participate in the suggest experiment by calling group()
  // on the newly created field trial.  This is necessary to activate the field
  // trial group as there are no more references to it within the Chrome code.
  trial->group();

  // Create inline History Quick Provider new scoring field trial.
  // Make it expire on April 14, 2013.
  trial = base::FieldTrialList::FactoryGetFieldTrial(
      kHQPNewScoringFieldTrialName, kHQPNewScoringFieldTrialDivisor,
      "Standard", 2013, 4, 14, NULL);
  trial->UseOneTimeRandomization();
  hqp_new_scoring_experiment_group = trial->AppendGroup("NewScoring",
      kHQPNewScoringFieldTrialExperimentFraction);

  // Create the HistoryURL provider cull redirects field trial.
  // Make it expire on March 1, 2013.
  trial = base::FieldTrialList::FactoryGetFieldTrial(
      kHUPCullRedirectsFieldTrialName, kHUPCullRedirectsFieldTrialDivisor,
      "Standard", 2013, 3, 1, NULL);
  trial->UseOneTimeRandomization();
  hup_dont_cull_redirects_experiment_group =
      trial->AppendGroup("DontCullRedirects",
                         kHUPCullRedirectsFieldTrialExperimentFraction);

  // Create the HistoryURL provider create shorter match field trial.
  // Make it expire on March 1, 2013.
  trial = base::FieldTrialList::FactoryGetFieldTrial(
      kHUPCreateShorterMatchFieldTrialName,
      kHUPCreateShorterMatchFieldTrialDivisor, "Standard", 2013, 3, 1, NULL);
  trial->UseOneTimeRandomization();
  hup_dont_create_shorter_match_experiment_group =
      trial->AppendGroup("DontCreateShorterMatch",
                         kHUPCreateShorterMatchFieldTrialExperimentFraction);

  // Create the field trial that makes HistoryQuick provider score
  // some results like HistoryURL provider and simultaneously disable
  // HistoryURL provider from searching the URL database.  Make it
  // expire on June 23, 2013.
  trial = base::FieldTrialList::FactoryGetFieldTrial(
    kHQPReplaceHUPScoringFieldTrialName, kHQPReplaceHUPScoringFieldTrialDivisor,
      "Standard", 2013, 6, 23, NULL);
  trial->UseOneTimeRandomization();
  hqp_replace_hup_scoring_experiment_group = trial->AppendGroup("HQPReplaceHUP",
      kHQPReplaceHUPScoringFieldTrialExperimentFraction);

  static_field_trials_initialized = true;
}

void OmniboxFieldTrial::ActivateDynamicTrials() {
  // Initialize all autocomplete dynamic field trials.  This method may be
  // called multiple times.
  for (int i = 0; i < kMaxAutocompleteDynamicFieldTrials; ++i)
    base::FieldTrialList::FindValue(DynamicFieldTrialName(i));
}

int OmniboxFieldTrial::GetDisabledProviderTypes() {
  // Make sure that Autocomplete dynamic field trials are activated.  It's OK to
  // call this method multiple times.
  ActivateDynamicTrials();

  // Look for group names in form of "DisabledProviders_<mask>" where "mask"
  // is a bitmap of disabled provider types (AutocompleteProvider::Type).
  int provider_types = 0;
  for (int i = 0; i < kMaxAutocompleteDynamicFieldTrials; ++i) {
    std::string group_name = base::FieldTrialList::FindFullName(
        DynamicFieldTrialName(i));
    const char kDisabledProviders[] = "DisabledProviders_";
    if (!StartsWithASCII(group_name, kDisabledProviders, true))
      continue;
    int types = 0;
    if (!base::StringToInt(base::StringPiece(
            group_name.substr(strlen(kDisabledProviders))), &types)) {
      LOG(WARNING) << "Malformed DisabledProviders string: " << group_name;
      continue;
    }
    if (types == 0)
      LOG(WARNING) << "Expecting a non-zero bitmap; group = " << group_name;
    else
      provider_types |= types;
  }
  return provider_types;
}

bool OmniboxFieldTrial::InDisallowInlineHQPFieldTrial() {
  return base::FieldTrialList::TrialExists(kDisallowInlineHQPFieldTrialName);
}

bool OmniboxFieldTrial::InDisallowInlineHQPFieldTrialExperimentGroup() {
  if (!base::FieldTrialList::TrialExists(kDisallowInlineHQPFieldTrialName))
    return false;

  // Return true if we're in the experiment group.
  const int group = base::FieldTrialList::FindValue(
      kDisallowInlineHQPFieldTrialName);
  return group == disallow_inline_hqp_experiment_group;
}

bool OmniboxFieldTrial::GetActiveSuggestFieldTrialHash(
    uint32* field_trial_hash) {
  if (!base::FieldTrialList::TrialExists(kSuggestFieldTrialStarted2013Q1Name))
    return false;

  *field_trial_hash = metrics::HashName(kSuggestFieldTrialStarted2013Q1Name);
  return true;
}

bool OmniboxFieldTrial::InHQPNewScoringFieldTrial() {
  return base::FieldTrialList::TrialExists(kHQPNewScoringFieldTrialName);
}

bool OmniboxFieldTrial::InHQPNewScoringFieldTrialExperimentGroup() {
  if (!InHQPNewScoringFieldTrial())
    return false;

  // Return true if we're in the experiment group.
  const int group = base::FieldTrialList::FindValue(
      kHQPNewScoringFieldTrialName);
  return group == hqp_new_scoring_experiment_group;
}

bool OmniboxFieldTrial::InHUPCullRedirectsFieldTrial() {
  return base::FieldTrialList::TrialExists(kHUPCullRedirectsFieldTrialName);
}

bool OmniboxFieldTrial::InHUPCullRedirectsFieldTrialExperimentGroup() {
  if (!base::FieldTrialList::TrialExists(kHUPCullRedirectsFieldTrialName))
    return false;

  // Return true if we're in the experiment group.
  const int group = base::FieldTrialList::FindValue(
      kHUPCullRedirectsFieldTrialName);
  return group == hup_dont_cull_redirects_experiment_group;
}

bool OmniboxFieldTrial::InHUPCreateShorterMatchFieldTrial() {
  return
      base::FieldTrialList::TrialExists(kHUPCreateShorterMatchFieldTrialName);
}

bool OmniboxFieldTrial::InHUPCreateShorterMatchFieldTrialExperimentGroup() {
  if (!base::FieldTrialList::TrialExists(kHUPCreateShorterMatchFieldTrialName))
    return false;

  // Return true if we're in the experiment group.
  const int group = base::FieldTrialList::FindValue(
      kHUPCreateShorterMatchFieldTrialName);
  return group == hup_dont_create_shorter_match_experiment_group;
}

bool OmniboxFieldTrial::InHQPReplaceHUPScoringFieldTrial() {
  return base::FieldTrialList::TrialExists(kHQPReplaceHUPScoringFieldTrialName);
}

bool OmniboxFieldTrial::InHQPReplaceHUPScoringFieldTrialExperimentGroup() {
  if (!InHQPReplaceHUPScoringFieldTrial())
    return false;

  // Return true if we're in the experiment group.
  const int group = base::FieldTrialList::FindValue(
      kHQPReplaceHUPScoringFieldTrialName);
  return group == hqp_replace_hup_scoring_experiment_group;
}