// 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/common/metrics/variations/variations_util.h"

#include <set>
#include <string>

#include "base/metrics/field_trial.h"
#include "base/strings/string_split.h"
#include "base/strings/utf_string_conversions.h"
#include "base/time/time.h"
#include "components/variations/metrics_util.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace chrome_variations {

namespace {

const VariationID TEST_VALUE_A = 3300200;
const VariationID TEST_VALUE_B = 3300201;
const VariationID TEST_VALUE_C = 3300202;
const VariationID TEST_VALUE_D = 3300203;

// Tests whether a field trial is active (i.e. group() has been called on it).
bool IsFieldTrialActive(const std::string& trial_name) {
  base::FieldTrial::ActiveGroups active_groups;
  base::FieldTrialList::GetActiveFieldTrialGroups(&active_groups);
  for (size_t i = 0; i < active_groups.size(); ++i) {
    if (active_groups[i].trial_name == trial_name)
      return true;
  }
  return false;
}

// Call FieldTrialList::FactoryGetFieldTrial() with a future expiry date.
scoped_refptr<base::FieldTrial> CreateFieldTrial(
    const std::string& trial_name,
    int total_probability,
    const std::string& default_group_name,
    int* default_group_number) {
  return base::FieldTrialList::FactoryGetFieldTrial(
      trial_name, total_probability, default_group_name,
      base::FieldTrialList::kNoExpirationYear, 1, 1,
      base::FieldTrial::SESSION_RANDOMIZED, default_group_number);
}

}  // namespace

class VariationsUtilTest : public ::testing::Test {
 public:
  VariationsUtilTest() : field_trial_list_(NULL) {
  }

  virtual ~VariationsUtilTest() {
    // Ensure that the maps are cleared between tests, since they are stored as
    // process singletons.
    testing::ClearAllVariationIDs();
  }

 private:
  base::FieldTrialList field_trial_list_;

  DISALLOW_COPY_AND_ASSIGN(VariationsUtilTest);
};

TEST_F(VariationsUtilTest, GetFieldTrialActiveGroups) {
  typedef std::set<ActiveGroupId, ActiveGroupIdCompare> ActiveGroupIdSet;
  std::string trial_one("trial one");
  std::string group_one("group one");
  std::string trial_two("trial two");
  std::string group_two("group two");

  base::FieldTrial::ActiveGroups active_groups;
  base::FieldTrial::ActiveGroup active_group;
  active_group.trial_name = trial_one;
  active_group.group_name = group_one;
  active_groups.push_back(active_group);

  active_group.trial_name = trial_two;
  active_group.group_name = group_two;
  active_groups.push_back(active_group);

  // Create our expected groups of IDs.
  ActiveGroupIdSet expected_groups;
  ActiveGroupId name_group_id;
  name_group_id.name = metrics::HashName(trial_one);
  name_group_id.group = metrics::HashName(group_one);
  expected_groups.insert(name_group_id);
  name_group_id.name = metrics::HashName(trial_two);
  name_group_id.group = metrics::HashName(group_two);
  expected_groups.insert(name_group_id);

  std::vector<ActiveGroupId> active_group_ids;
  testing::TestGetFieldTrialActiveGroupIds(active_groups, &active_group_ids);
  EXPECT_EQ(2U, active_group_ids.size());
  for (size_t i = 0; i < active_group_ids.size(); ++i) {
    ActiveGroupIdSet::iterator expected_group =
        expected_groups.find(active_group_ids[i]);
    EXPECT_FALSE(expected_group == expected_groups.end());
    expected_groups.erase(expected_group);
  }
  EXPECT_EQ(0U, expected_groups.size());
}

TEST_F(VariationsUtilTest, BuildGoogleUpdateExperimentLabel) {
  struct {
    const char* active_group_pairs;
    const char* expected_ids;
  } test_cases[] = {
    // Empty group.
    {"", ""},
    // Group of 1.
    {"FieldTrialA#Default", "3300200"},
    // Group of 1, doesn't have an associated ID.
    {"FieldTrialA#DoesNotExist", ""},
    // Group of 3.
    {"FieldTrialA#Default#FieldTrialB#Group1#FieldTrialC#Default",
     "3300200#3300201#3300202"},
    // Group of 3, one doesn't have an associated ID.
    {"FieldTrialA#Default#FieldTrialB#DoesNotExist#FieldTrialC#Default",
     "3300200#3300202"},
    // Group of 3, all three don't have an associated ID.
    {"FieldTrialX#Default#FieldTrialB#DoesNotExist#FieldTrialC#Default",
     "3300202"},
  };

  // Register a few VariationIDs.
  AssociateGoogleVariationID(GOOGLE_UPDATE_SERVICE, "FieldTrialA", "Default",
                             TEST_VALUE_A);
  AssociateGoogleVariationID(GOOGLE_UPDATE_SERVICE, "FieldTrialB", "Group1",
                             TEST_VALUE_B);
  AssociateGoogleVariationID(GOOGLE_UPDATE_SERVICE, "FieldTrialC", "Default",
                             TEST_VALUE_C);
  AssociateGoogleVariationID(GOOGLE_UPDATE_SERVICE, "FieldTrialD", "Default",
                             TEST_VALUE_D);  // Not actually used.

  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_cases); ++i) {
    // Parse the input groups.
    base::FieldTrial::ActiveGroups groups;
    std::vector<std::string> group_data;
    base::SplitString(test_cases[i].active_group_pairs, '#', &group_data);
    ASSERT_EQ(0U, group_data.size() % 2);
    for (size_t j = 0; j < group_data.size(); j += 2) {
      base::FieldTrial::ActiveGroup group;
      group.trial_name = group_data[j];
      group.group_name = group_data[j + 1];
      groups.push_back(group);
    }

    // Parse the expected output.
    std::vector<std::string> expected_ids_list;
    base::SplitString(test_cases[i].expected_ids, '#', &expected_ids_list);

    std::string experiment_labels_string = UTF16ToUTF8(
        BuildGoogleUpdateExperimentLabel(groups));

    // Split the VariationIDs from the labels for verification below.
    std::vector<std::string> split_labels;
    std::set<std::string> parsed_ids;
    base::SplitString(experiment_labels_string, ';', &split_labels);
    for (std::vector<std::string>::const_iterator it = split_labels.begin();
         it != split_labels.end(); ++it) {
      // The ID is precisely between the '=' and '|' characters in each label.
      size_t index_of_equals = it->find('=');
      size_t index_of_pipe = it->find('|');
      ASSERT_NE(std::string::npos, index_of_equals);
      ASSERT_NE(std::string::npos, index_of_pipe);
      ASSERT_GT(index_of_pipe, index_of_equals);
      parsed_ids.insert(it->substr(index_of_equals + 1,
                                   index_of_pipe - index_of_equals - 1));
    }

    // Verify that the resulting string contains each of the expected labels,
    // and nothing more. Note that the date is stripped out and ignored.
    for (std::vector<std::string>::const_iterator it =
             expected_ids_list.begin(); it != expected_ids_list.end(); ++it) {
      std::set<std::string>::iterator it2 = parsed_ids.find(*it);
      EXPECT_TRUE(parsed_ids.end() != it2);
      parsed_ids.erase(it2);
    }
    EXPECT_TRUE(parsed_ids.empty());
  }  // for
}

TEST_F(VariationsUtilTest, CombineExperimentLabels) {
  struct {
    const char* variations_labels;
    const char* other_labels;
    const char* expected_label;
  } test_cases[] = {
    {"A=B|Tue, 21 Jan 2014 15:30:21 GMT",
     "C=D|Tue, 21 Jan 2014 15:30:21 GMT",
     "C=D|Tue, 21 Jan 2014 15:30:21 GMT;A=B|Tue, 21 Jan 2014 15:30:21 GMT"},
    {"A=B|Tue, 21 Jan 2014 15:30:21 GMT",
     "",
     "A=B|Tue, 21 Jan 2014 15:30:21 GMT"},
    {"",
     "A=B|Tue, 21 Jan 2014 15:30:21 GMT",
     "A=B|Tue, 21 Jan 2014 15:30:21 GMT"},
    {"A=B|Tue, 21 Jan 2014 15:30:21 GMT;C=D|Tue, 21 Jan 2014 15:30:21 GMT",
     "P=Q|Tue, 21 Jan 2014 15:30:21 GMT;X=Y|Tue, 21 Jan 2014 15:30:21 GMT",
     "P=Q|Tue, 21 Jan 2014 15:30:21 GMT;X=Y|Tue, 21 Jan 2014 15:30:21 GMT;"
     "A=B|Tue, 21 Jan 2014 15:30:21 GMT;C=D|Tue, 21 Jan 2014 15:30:21 GMT"},
    {"",
     "",
     ""},
  };

  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_cases); ++i) {
    std::string result = UTF16ToUTF8(CombineExperimentLabels(
        ASCIIToUTF16(test_cases[i].variations_labels),
        ASCIIToUTF16(test_cases[i].other_labels)));
    EXPECT_EQ(test_cases[i].expected_label, result);
  }
}

TEST_F(VariationsUtilTest, ExtractNonVariationLabels) {
  struct {
    const char* input_label;
    const char* expected_output;
  } test_cases[] = {
    // Empty
    {"", ""},
    // One
    {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT",
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
    // Three
    {"CrVar1=123|Tue, 21 Jan 2014 15:30:21 GMT;"
     "experiment1=456|Tue, 21 Jan 2014 15:30:21 GMT;"
     "experiment2=789|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar1=123|Tue, 21 Jan 2014 15:30:21 GMT",
     "experiment1=456|Tue, 21 Jan 2014 15:30:21 GMT;"
     "experiment2=789|Tue, 21 Jan 2014 15:30:21 GMT"},
    // One and one Variation
    {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT",
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
    // One and one Variation, flipped
    {"CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;"
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT",
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
    // Sandwiched
    {"CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;"
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar2=3310003|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar3=3310004|Tue, 21 Jan 2014 15:30:21 GMT",
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
    // Only Variations
    {"CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar2=3310003|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar3=3310004|Tue, 21 Jan 2014 15:30:21 GMT",
     ""},
    // Empty values
    {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT",
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
    // Trailing semicolon
    {"gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT;"
     "CrVar1=3310002|Tue, 21 Jan 2014 15:30:21 GMT;",  // Note the semi here.
     "gcapi_brand=123|Tue, 21 Jan 2014 15:30:21 GMT"},
    // Semis
    {";;;;", ""},
  };

  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_cases); ++i) {
    std::string non_variation_labels = UTF16ToUTF8(
        ExtractNonVariationLabels(ASCIIToUTF16(test_cases[i].input_label)));
    EXPECT_EQ(test_cases[i].expected_output, non_variation_labels);
  }
}

}  // namespace chrome_variations