// 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 "base/json/json_writer.h"

#include "base/containers/span.h"
#include "base/memory/ptr_util.h"
#include "base/values.h"
#include "build/build_config.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace base {

TEST(JSONWriterTest, BasicTypes) {
  std::string output_js;

  // Test null. 
  EXPECT_TRUE(JSONWriter::Write(Value(), &output_js));
  EXPECT_EQ("null", output_js);

  // Test empty dict. 
  EXPECT_TRUE(JSONWriter::Write(DictionaryValue(), &output_js));
  EXPECT_EQ("{}", output_js);

  // Test empty list. 
  EXPECT_TRUE(JSONWriter::Write(ListValue(), &output_js));
  EXPECT_EQ("[]", output_js);

  // Test integer values. 
  EXPECT_TRUE(JSONWriter::Write(Value(42), &output_js));
  EXPECT_EQ("42", output_js);

  // Test boolean values. 
  EXPECT_TRUE(JSONWriter::Write(Value(true), &output_js));
  EXPECT_EQ("true", output_js);

  // Test Real values should always have a decimal or an 'e'. 
  EXPECT_TRUE(JSONWriter::Write(Value(1.0), &output_js));
  EXPECT_EQ("1.0", output_js);

  // Test Real values in the the range (-1, 1) must have leading zeros
  EXPECT_TRUE(JSONWriter::Write(Value(0.2), &output_js));
  EXPECT_EQ("0.2", output_js);

  // Test Real values in the the range (-1, 1) must have leading zeros
  EXPECT_TRUE(JSONWriter::Write(Value(-0.8), &output_js));
  EXPECT_EQ("-0.8", output_js);

  // Test String values. 
  EXPECT_TRUE(JSONWriter::Write(Value("foo"), &output_js));
  EXPECT_EQ("\"foo\"", output_js);
}

TEST(JSONWriterTest, NestedTypes) {
  std::string output_js;

  // Writer unittests like empty list/dict nesting,
  // list list nesting, etc. 
  DictionaryValue root_dict;
  ListValue list;
  DictionaryValue inner_dict;
  inner_dict. SetIntKey("inner int", 10);
  list. Append(std::move(inner_dict));
  list. Append(Value(Value::Type::LIST));
  list. Append(true);
  root_dict. SetKey("list", std::move(list));

  // Test the pretty-printer. 
  EXPECT_TRUE(JSONWriter::Write(root_dict, &output_js));
  EXPECT_EQ("{\"list\":[{\"inner int\":10},[],true]}", output_js);
  EXPECT_TRUE(JSONWriter::WriteWithOptions(
      root_dict, JSONWriter::OPTIONS_PRETTY_PRINT, &output_js));

  // The pretty-printer uses a different newline style on Windows than on
  // other platforms. 
#if defined(OS_WIN)
#define JSON_NEWLINE "\r\n"
#else
#define JSON_NEWLINE "\n"
#endif
  EXPECT_EQ("{" JSON_NEWLINE
            "   \"list\": [ {" JSON_NEWLINE
            "      \"inner int\": 10" JSON_NEWLINE
            "   }, [  ], true ]" JSON_NEWLINE
            "}" JSON_NEWLINE,
            output_js);
#undef JSON_NEWLINE
}

TEST(JSONWriterTest, KeysWithPeriods) {
  std::string output_js;

  DictionaryValue period_dict;
  period_dict. SetIntKey("a.b", 3);
  period_dict. SetIntKey("c", 2);
  DictionaryValue period_dict2;
  period_dict2.SetIntKey("g.h.i.j", 1);
  period_dict. SetKey("d.e.f", std::move(period_dict2));
  EXPECT_TRUE(JSONWriter::Write(period_dict, &output_js));
  EXPECT_EQ("{\"a.b\":3,\"c\":2,\"d.e.f\":{\"g.h.i.j\":1}}", output_js);

  DictionaryValue period_dict3;
  period_dict3.SetIntPath("a.b", 2);
  period_dict3.SetIntKey("a.b", 1);
  EXPECT_TRUE(JSONWriter::Write(period_dict3, &output_js));
  EXPECT_EQ("{\"a\":{\"b\":2},\"a.b\":1}", output_js);
}

TEST(JSONWriterTest, BinaryValues) {
  std::string output_js;

  // Binary values should return errors unless suppressed via the
  // OPTIONS_OMIT_BINARY_VALUES flag. 
  const auto kBufferSpan =
      base::make_span(reinterpret_cast<const uint8_t*>("asdf"), 4);
  Value root(kBufferSpan);
  EXPECT_FALSE(JSONWriter::Write(root, &output_js));
  EXPECT_TRUE(JSONWriter::WriteWithOptions(
      root, JSONWriter::OPTIONS_OMIT_BINARY_VALUES, &output_js));
  EXPECT_TRUE(output_js.empty());

  ListValue binary_list;
  binary_list. Append(Value(kBufferSpan));
  binary_list. Append(5);
  binary_list. Append(Value(kBufferSpan));
  binary_list. Append(2);
  binary_list. Append(Value(kBufferSpan));
  EXPECT_FALSE(JSONWriter::Write(binary_list, &output_js));
  EXPECT_TRUE(JSONWriter::WriteWithOptions(
      binary_list, JSONWriter::OPTIONS_OMIT_BINARY_VALUES, &output_js));
  EXPECT_EQ("[5,2]", output_js);

  DictionaryValue binary_dict;
  binary_dict. SetKey("a", Value(kBufferSpan));
  binary_dict. SetIntKey("b", 5);
  binary_dict. SetKey("c", Value(kBufferSpan));
  binary_dict. SetIntKey("d", 2);
  binary_dict. SetKey("e", Value(kBufferSpan));
  EXPECT_FALSE(JSONWriter::Write(binary_dict, &output_js));
  EXPECT_TRUE(JSONWriter::WriteWithOptions(
      binary_dict, JSONWriter::OPTIONS_OMIT_BINARY_VALUES, &output_js));
  EXPECT_EQ("{\"b\":5,\"d\":2}", output_js);
}

TEST(JSONWriterTest, DoublesAsInts) {
  std::string output_js;

  // Test allowing a double with no fractional part to be written as an integer. 
  Value double_value(1e10);
  EXPECT_TRUE(JSONWriter::WriteWithOptions(
      double_value, JSONWriter::OPTIONS_OMIT_DOUBLE_TYPE_PRESERVATION,
      &output_js));
  EXPECT_EQ("10000000000", output_js);
}

TEST(JSONWriterTest, StackOverflow) {
  std::string output_js;
  ListValue deep_list;
  ListValue* next_list = &deep_list;

  const size_t max_depth = 100000;

  for (size_t i = 0; i < max_depth; ++i) {
    ListValue inner_list;
    next_list->Append(std::move(inner_list));
    next_list->GetList(0, &next_list);
  }

  EXPECT_FALSE(JSONWriter::Write(deep_list, &output_js));
  EXPECT_FALSE(JSONWriter::WriteWithOptions(
      deep_list, JSONWriter::OPTIONS_PRETTY_PRINT, &output_js));

  // We cannot just let deep_list tear down since it
  // would cause a stack overflow.  Therefore, we tear
  // down from the inner lists outwards safely. 
  const size_t step = 200;
  for (size_t i = max_depth - step; i > 0; i -= step) {
    next_list = &deep_list;
    for (size_t curr_depth = 0; curr_depth < i && next_list; ++curr_depth) {
      if (! next_list->GetList(0, &next_list))
        next_list = nullptr;
    }
    if (next_list)
      next_list->Remove(0, nullptr);
  }
}

}  // namespace base
