/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

class CharPointer_UTF8Test final : public UnitTest
{
public:
    CharPointer_UTF8Test() : UnitTest { "CharPointer_UTF8", UnitTestCategories::text } {}

    void runTest() final
    {
        using Utf8Vector = std::vector<CharPointer_UTF8::CharType>;

        testCase ("String validation - empty string / null-terminator", [&]
        {
            const Utf8Vector string { '\0' };
            expect (CharPointer_UTF8::isValidString (string.data(), (int) string.size()));
        });

        testCase ("String validation - ascii", [&]
        {
            const Utf8Vector string { 'T', 'e', 's', 'T', '!', '\0' }; // Test!
            expect (CharPointer_UTF8::isValidString (string.data(), (int) string.size()));
        });

        constexpr auto continuationCharacter = static_cast<char> (0x80);

        testCase ("String validation - continuation characters are invalid when not proceeded by the correct bytes", [&]
        {
            const Utf8Vector string { continuationCharacter };
            expect (! CharPointer_UTF8::isValidString (string.data(), (int) string.size()));
        });

        testCase ("String validation - characters after a null terminator are ignored", [&]
        {
            const Utf8Vector string { 'T', 'e', 's', 'T', '\0', continuationCharacter };
            expect (CharPointer_UTF8::isValidString (string.data(), (int) string.size()));
        });

        testCase ("String validation - characters exceeding max bytes are ignored", [&]
        {
            const Utf8Vector string { 'T', 'e', 's', 'T', continuationCharacter };
            expect (CharPointer_UTF8::isValidString (string.data(), 4));
        });

        testCase ("String validation - all unicode characters", [&]
        {
            for (uint32_t c = 0; c < 0x110000; ++c)
            {
                std::array<CharPointer_UTF8::CharType, 4> string = {};
                CharPointer_UTF8 utf8 { string.data() };
                utf8.write ((juce_wchar) c);
                expect (CharPointer_UTF8::isValidString (string.data(), (int) string.size()) == CharPointer_UTF32::canRepresent ((juce_wchar) c));
            }
        });

        testCase ("String validation - the top two bits of continuation characters must be '10'", [&]
        {
            const auto isValid = [&] (auto... x)
            {
                const char items[] { static_cast<char> (x)... };
                return CharPointer_UTF8::isValidString (items, (int) std::size (items));
            };

            expect (  isValid (0xc2, 0x80));
            expect (  isValid (0xdf, 0xbf));
            expect (! isValid (0xc2));
            expect (! isValid (0xdf));
            expect (! isValid (0xc2, 0x00));
            expect (! isValid (0xc2, 0xff));
            expect (! isValid (0xdf, 0x00));
            expect (! isValid (0xdf, 0xff));

            expect (  isValid (0xe1, 0x80, 0x80));
            expect (  isValid (0xef, 0xbf, 0xbf));
            expect (! isValid (0xe1, 0x80));
            expect (! isValid (0xef, 0xbf));
            expect (! isValid (0xe1, 0x00, 0x00));
            expect (! isValid (0xe1, 0x80, 0x00));
            expect (! isValid (0xe1, 0x00, 0x80));
            expect (! isValid (0xe1, 0xff, 0xff));
            expect (! isValid (0xe1, 0x80, 0xff));
            expect (! isValid (0xe1, 0xff, 0x80));

            expect (  isValid (0xf0, 0x90, 0x80, 0x80));
            expect (  isValid (0xf4, 0x8f, 0xbf, 0xbf));
            expect (! isValid (0xf0, 0x90));
            expect (! isValid (0xf0, 0x90, 0x80));
            expect (! isValid (0xf0, 0x90, 0x00, 0x00));
            expect (! isValid (0xf0, 0xff, 0xff, 0xff));
        });

        testCase ("Dereferencing a malformed string produces replacement character", [&]
        {
            const auto doDeref = [&] (auto... x)
            {
                const char items[] { static_cast<char> (x)... };
                return CharPointer_UTF8 { items }.getAndAdvance();
            };

            static constexpr juce_wchar replacement = 0xfffd;

            expectEquals (doDeref (0x80), replacement);
            expectEquals (doDeref (0xbf), replacement);

            expectEquals (doDeref (0xe0, 0xa0, 0x00), replacement);
            expectEquals (doDeref (0xe0, 0x00, 0x80), replacement);

            expectEquals (doDeref (0xf0, 0x90, 0x80, 0x00), replacement);
            expectEquals (doDeref (0xf0, 0x90, 0x00, 0x80), replacement);
            expectEquals (doDeref (0xf0, 0x00, 0x80, 0x80), replacement);

            // overlong sequences
            expectEquals (doDeref (0xc0, 0x80), replacement);
            expectEquals (doDeref (0xe0, 0x80, 0x80), replacement);
            expectEquals (doDeref (0xf0, 0x80, 0x80, 0x80), replacement);

            // beyond upper range
            expectEquals (doDeref (0xf4, 0x90, 0x80, 0x80), replacement);
        });
    }
};


static CharPointer_UTF8Test charPointer_UTF8Test;

} // namespace juce
