
//              Copyright Catch2 Authors
// Distributed under the Boost Software License, Version 1.0.
//   (See accompanying file LICENSE.txt or copy at
//        https://www.boost.org/LICENSE_1_0.txt)

// SPDX-License-Identifier: BSL-1.0

#include <catch2/catch_test_macros.hpp>
#include <catch2/catch_template_test_macros.hpp>
#include <catch2/benchmark/catch_benchmark.hpp>
#include <catch2/generators/catch_generators.hpp>
#include <catch2/internal/catch_jsonwriter.hpp>
#include <catch2/matchers/catch_matchers_string.hpp>

#include <limits>
#include <locale>
#include <sstream>

namespace {
    struct Custom {};
    static std::ostream& operator<<( std::ostream& os, Custom const& ) {
        return os << "custom";
    }

    // Obviously wrong numpunct if it is actually used by the JSON writer.
    class TestNumpunct : public std::numpunct<char> {
        char do_decimal_point() const override { return '?'; }
        char do_thousands_sep() const override { return '!'; }
        std::string do_grouping() const override { return "\1"; }
        std::string do_truename() const override { return "real"; }
        std::string do_falsename() const override { return "fake"; }
    };

    class LocaleGuard {
        std::locale m_previous_locale;

    public:
        explicit LocaleGuard( std::locale const& locale ):
            m_previous_locale{ std::locale() } {
            std::locale::global( locale );
        }

        ~LocaleGuard() { std::locale::global( m_previous_locale ); }
    };

TEST_CASE( "JsonWriter", "[JSON][JsonWriter]" ) {

    std::stringstream stream;
    SECTION( "Newly constructed JsonWriter does nothing" ) {
        Catch::JsonValueWriter writer{ stream };
        REQUIRE( stream.str() == "" );
    }

    SECTION( "Calling writeObject will create an empty pair of braces" ) {
        { auto writer = Catch::JsonValueWriter{ stream }.writeObject(); }
        REQUIRE( stream.str() == "{\n}" );
    }

    SECTION( "Calling writeObject with key will create an object to write the "
             "value" ) {
        using Catch::Matchers::ContainsSubstring;
        {
            auto writer = Catch::JsonValueWriter{ stream }.writeObject();
            writer.write( "int" ).write( 1 );
            writer.write( "double" ).write( 1.5 );
            writer.write( "true" ).write( true );
            writer.write( "false" ).write( false );
            writer.write( "string" ).write( "this is a string" );
            writer.write( "array" ).writeArray().write( 1 ).write( 2 );
        }
        REQUIRE_THAT(
            stream.str(),
            ContainsSubstring( "\"int\": 1," ) &&
                ContainsSubstring( "\"double\": 1.5," ) &&
                ContainsSubstring( "\"true\": true," ) &&
                ContainsSubstring( "\"false\": false," ) &&
                ContainsSubstring( "\"string\": \"this is a string\"," ) &&
                ContainsSubstring( "\"array\": [\n    1,\n    2\n  ]\n}" ) );
    }

    SECTION( "nesting objects" ) {
        using Catch::Matchers::ContainsSubstring;
        {
            auto writer = Catch::JsonValueWriter{ stream }.writeObject();
            writer.write( "empty_object" ).writeObject();
            writer.write( "fully_object" )
                .writeObject()
                .write( "key" )
                .write( 1 );
        }
        REQUIRE_THAT( stream.str(),
                      ContainsSubstring( "\"empty_object\": {\n  }," ) &&
                          ContainsSubstring(
                              "\"fully_object\": {\n    \"key\": 1\n  }" ) );
    }

    SECTION( "Calling writeArray will create an empty pair of braces" ) {
        { auto writer = Catch::JsonValueWriter{ stream }.writeArray(); }
        REQUIRE( stream.str() == "[\n]" );
    }

    SECTION( "Calling writeArray creates array to write the values to" ) {
        {
            auto writer = Catch::JsonValueWriter{ stream }.writeArray();
            writer.write( 1 );
            writer.write( 1.5 );
            writer.write( true );
            writer.write( false );
            writer.write( "this is a string" );
            writer.writeObject().write( "object" ).write( 42 );
            writer.writeArray().write( "array" ).write( 42.5 );
        }
        REQUIRE( stream.str() == "[\n  1,\n  1.5,\n  true,\n  false,\n  \"this is a string\",\n  {\n    \"object\": 42\n  },\n  [\n    \"array\",\n    42.5\n  ]\n]" );
    }

    SECTION(
        "Moved from JsonObjectWriter shall not insert superfluous brace" ) {
        {
            auto writer = Catch::JsonObjectWriter{ stream };
            auto another_writer = std::move( writer );
        }
        REQUIRE( stream.str() == "{\n}" );
    }
    SECTION(
        "Moved from JsonArrayWriter shall not insert superfluous bracket" ) {
        {
            auto writer = Catch::JsonArrayWriter{ stream };
            auto another_writer = std::move( writer );
        }
        REQUIRE( stream.str() == "[\n]" );
    }
    SECTION( "Custom class shall be quoted" ) {
        Catch::JsonValueWriter{ stream }.write( Custom{} );
        REQUIRE( stream.str() == "\"custom\"" );
    }
}

TEST_CASE( "JsonWriter escapes characters in strings properly", "[JsonWriter]" ) {
    std::stringstream sstream;
    SECTION( "Quote in a string is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\"" );
        REQUIRE( sstream.str() == "\"\\\"\"" );
    }
    SECTION("Backslash in a string is escaped") {
        Catch::JsonValueWriter{ sstream }.write( "\\" );
        REQUIRE( sstream.str() == "\"\\\\\"" );
    }
    SECTION( "Forward slash in a string is **not** escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "/" );
        REQUIRE( sstream.str() == "\"/\"" );
    }
    SECTION( "Backspace in a string is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\b" );
        REQUIRE( sstream.str() == "\"\\b\"" );
    }
    SECTION( "Formfeed in a string is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\f" );
        REQUIRE( sstream.str() == "\"\\f\"" );
    }
    SECTION( "linefeed in a string is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\n" );
        REQUIRE( sstream.str() == "\"\\n\"" );
    }
    SECTION( "carriage return in a string is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\r" );
        REQUIRE( sstream.str() == "\"\\r\"" );
    }
    SECTION( "tab in a string is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\t" );
        REQUIRE( sstream.str() == "\"\\t\"" );
    }
    SECTION( "combination of characters is escaped" ) {
        Catch::JsonValueWriter{ sstream }.write( "\\/\t\r\n" );
        REQUIRE( sstream.str() == "\"\\\\/\\t\\r\\n\"" );
    }
}

TEST_CASE( "JsonWriter serializes numbers independently of the global locale",
           "[JsonWriter]" ) {
    using Catch::Matchers::ContainsSubstring;

    LocaleGuard locale_guard{ std::locale{ std::locale(), new TestNumpunct } };

    std::stringstream sstream;
    {
        auto writer = Catch::JsonValueWriter{ sstream }.writeObject();
        writer.write( "double" ).write( 1.5 );
        writer.write( "int" ).write( 1234567 );
        writer.write( "bool-1" ).write( true );
        writer.write( "bool-2" ).write( false );
        writer.write( "array" ).writeArray().write( 2.5 ).write( 1234567 );
    }

    REQUIRE_THAT( sstream.str(),
                  ContainsSubstring( "\"double\": 1.5," ) &&
                      ContainsSubstring( "\"int\": 1234567," ) &&
                      ContainsSubstring( "\"bool-1\": true," ) &&
                      ContainsSubstring( "\"bool-2\": false," ) &&
                      ContainsSubstring(
                          "\"array\": [\n    2.5,\n    1234567\n  ]\n}" ) );
}

TEMPLATE_TEST_CASE( "JsonWriter serializes non-finite FP using Python spelling",
                    "[JsonWriter][floating-point]",
                    float,
                    double ) {
    std::stringstream sstream;

    SECTION( "NaN" ) {
        Catch::JsonValueWriter{ sstream }.write(
            std::numeric_limits<TestType>::quiet_NaN() );
        REQUIRE( sstream.str() == "NaN" );
    }
    SECTION( "Pos nf" ) {
        Catch::JsonValueWriter{ sstream }.write(
            std::numeric_limits<TestType>::infinity() );
        REQUIRE( sstream.str() == "Infinity" );
    }
    SECTION( "Neg inf" ) {
        Catch::JsonValueWriter{ sstream }.write(
            -std::numeric_limits<TestType>::infinity() );
        REQUIRE( sstream.str() == "-Infinity" );
    }
}

TEST_CASE( "JsonWriter benchmarks", "[JsonWriter][!benchmark]" ) {
    const auto input_length = GENERATE( as<size_t>{}, 10, 100, 10'000 );
    std::string test_input( input_length, 'a' );
    BENCHMARK_ADVANCED( "write string, no-escaping, len=" +
                        std::to_string( input_length ) )(
        Catch::Benchmark::Chronometer meter ) {
        std::stringstream sstream;
        meter.measure( [&]( int ) {
            Catch::JsonValueWriter( sstream ).write( test_input );
        } );
    };

    std::string escape_input( input_length, '\b' );
    BENCHMARK_ADVANCED( "write string, all-escaped, len=" +
                        std::to_string( input_length ) )(
        Catch::Benchmark::Chronometer meter ) {
        std::stringstream sstream;
        meter.measure( [&]( int ) {
            Catch::JsonValueWriter( sstream ).write( escape_input );
        } );
    };
}

} // namespace
