#include "internal/catch_stringref.h"

#include "catch.hpp"

#include <cstring>

namespace Catch {

    // Implementation of test accessors
    struct StringRefTestAccess {
        static auto isOwned( StringRef const& stringRef ) -> bool {
            return stringRef.isOwned();
        }
        static auto isSubstring( StringRef const& stringRef ) -> bool {
            return stringRef.isSubstring();
        }
    };


    namespace {
    auto isOwned( StringRef const& stringRef ) -> bool {
        return StringRefTestAccess::isOwned( stringRef );
    }
    auto isSubstring( StringRef const& stringRef ) -> bool {
        return StringRefTestAccess::isSubstring( stringRef );
    }
    } // end anonymous namespace

} // namespace Catch

TEST_CASE( "StringRef", "[Strings][StringRef]" ) {

    using Catch::StringRef;
    using Catch::isOwned; using Catch::isSubstring;

    SECTION( "Empty string" ) {
        StringRef empty;
        REQUIRE( empty.empty() );
        REQUIRE( empty.size() == 0 );
        REQUIRE( std::strcmp( empty.c_str(), "" ) == 0 );
    }

    SECTION( "From string literal" ) {
        StringRef s = "hello";
        REQUIRE( s.empty() == false );
        REQUIRE( s.size() == 5 );
        REQUIRE( isSubstring( s ) == false );

        auto rawChars = s.currentData();
        REQUIRE( std::strcmp( rawChars, "hello" ) == 0 );

        SECTION( "c_str() does not cause copy" ) {
            REQUIRE( isOwned( s ) == false );

            REQUIRE( s.c_str() == rawChars );

            REQUIRE( isOwned( s ) == false );
        }
    }
    SECTION( "From sub-string" ) {
        StringRef original = StringRef( "original string" ).substr(0, 8);
        REQUIRE( original == "original" );
        REQUIRE( isSubstring( original ) );
        REQUIRE( isOwned( original ) == false );

        original.c_str(); // Forces it to take ownership

        REQUIRE( isOwned( original ) );
    }


    SECTION( "Substrings" ) {
        StringRef s = "hello world!";
        StringRef ss = s.substr(0, 5);

        SECTION( "zero-based substring" ) {
            REQUIRE( ss.empty() == false );
            REQUIRE( ss.size() == 5 );
            REQUIRE( std::strcmp( ss.c_str(), "hello" ) == 0 );
            REQUIRE( ss == "hello" );
        }
        SECTION( "c_str() causes copy" ) {
            REQUIRE( isSubstring( ss ) );
            REQUIRE( isOwned( ss ) == false );

            auto rawChars = ss.currentData();
            REQUIRE( rawChars == s.currentData() ); // same pointer value
            REQUIRE( ss.c_str() != rawChars );

            REQUIRE( isOwned( ss ) );

            SECTION( "Self-assignment after substring" ) {
                ss = *&ss; // the *& are there to suppress warnings (see: "Improvements to Clang's diagnostics" in https://rev.ng/gitlab/revng-bar-2019/clang/raw/master/docs/ReleaseNotes.rst)
                REQUIRE( isOwned(ss) == false );
                REQUIRE( ss == "hello" );
                REQUIRE( rawChars == ss.currentData() ); // same pointer value
            }
        }

        SECTION( "non-zero-based substring") {
            ss = s.substr( 6, 6 );
            REQUIRE( ss.size() == 6 );
            REQUIRE( std::strcmp( ss.c_str(), "world!" ) == 0 );
        }

        SECTION( "Pointer values of full refs should match" ) {
            StringRef s2 = s;
            REQUIRE( s.c_str() == s2.c_str() );
        }

        SECTION( "Pointer values of substring refs should not match" ) {
            REQUIRE( s.c_str() != ss.c_str() );
        }

        SECTION("Past the end substring") {
            REQUIRE(s.substr(s.size() + 1, 123).empty());
        }
    }

    SECTION( "Comparisons" ) {
        REQUIRE( StringRef("hello") == StringRef("hello") );
        REQUIRE( StringRef("hello") != StringRef("cello") );
    }

    SECTION( "from std::string" ) {
        std::string stdStr = "a standard string";

        SECTION( "implicitly constructed" ) {
            StringRef sr = stdStr;
            REQUIRE( sr == "a standard string" );
            REQUIRE( sr.size() == stdStr.size() );
        }
        SECTION( "explicitly constructed" ) {
            StringRef sr( stdStr );
            REQUIRE( sr == "a standard string" );
            REQUIRE( sr.size() == stdStr.size() );
        }
        SECTION( "assigned" ) {
            StringRef sr;
            sr = stdStr;
            REQUIRE( sr == "a standard string" );
            REQUIRE( sr.size() == stdStr.size() );
        }
    }

    SECTION( "to std::string" ) {
        StringRef sr = "a stringref";

        SECTION( "explicitly constructed" ) {
            std::string stdStr( sr );
            REQUIRE( stdStr == "a stringref" );
            REQUIRE( stdStr.size() == sr.size() );
        }
        SECTION( "assigned" ) {
            std::string stdStr;
            stdStr = static_cast<std::string>(sr);
            REQUIRE( stdStr == "a stringref" );
            REQUIRE( stdStr.size() == sr.size() );
        }
    }
}
