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

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

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

class JSONParser
{
public:
    static Result parseAny (String::CharPointerType& t, var& result)
    {
        t = t.findEndOfWhitespace();
        String::CharPointerType t2 (t);

        switch (t2.getAndAdvance())
        {
            case '{':    t = t2; return parseObject (t, result);
            case '[':    t = t2; return parseArray (t, result);
            case '"':    t = t2; return parseString (t, result);

            case '-':
                t2 = t2.findEndOfWhitespace();
                if (! CharacterFunctions::isDigit (*t2))
                    break;

                t = t2;
                return parseNumber (t, result, true);

            case '0': case '1': case '2': case '3': case '4':
            case '5': case '6': case '7': case '8': case '9':
                return parseNumber (t, result, false);

            case 't':   // "true"
                if (t2.getAndAdvance() == 'r' && t2.getAndAdvance() == 'u' && t2.getAndAdvance() == 'e')
                {
                    t = t2;
                    result = var (true);
                    return Result::ok();
                }
                break;

            case 'f':   // "false"
                if (t2.getAndAdvance() == 'a' && t2.getAndAdvance() == 'l'
                      && t2.getAndAdvance() == 's' && t2.getAndAdvance() == 'e')
                {
                    t = t2;
                    result = var (false);
                    return Result::ok();
                }
                break;

            case 'n':   // "null"
                if (t2.getAndAdvance() == 'u' && t2.getAndAdvance() == 'l' && t2.getAndAdvance() == 'l')
                {
                    t = t2;
                    result = var::null;
                    return Result::ok();
                }
                break;

            default:
                break;
        }

        return createFail ("Syntax error", &t);
    }

private:
    static Result createFail (const char* const message, const String::CharPointerType* location = nullptr)
    {
        String m (message);
        if (location != nullptr)
            m << ": \"" << String (*location, 20) << '"';

        return Result::fail (m);
    }

    static Result parseNumber (String::CharPointerType& t, var& result, const bool isNegative)
    {
        String::CharPointerType oldT (t);

        int64 intValue = t.getAndAdvance() - '0';
        jassert (intValue >= 0 && intValue < 10);

        for (;;)
        {
            String::CharPointerType previousChar (t);
            const juce_wchar c = t.getAndAdvance();
            const int digit = ((int) c) - '0';

            if (isPositiveAndBelow (digit, 10))
            {
                intValue = intValue * 10 + digit;
                continue;
            }

            if (c == 'e' || c == 'E' || c == '.')
            {
                t = oldT;
                const double asDouble = CharacterFunctions::readDoubleValue (t);
                result = isNegative ? -asDouble : asDouble;
                return Result::ok();
            }

            if (CharacterFunctions::isWhitespace (c)
                 || c == ',' || c == '}' || c == ']' || c == 0)
            {
                t = previousChar;
                break;
            }

            return createFail ("Syntax error in number", &oldT);
        }

        const int64 correctedValue = isNegative ? -intValue : intValue;

        if ((intValue >> 31) != 0)
            result = correctedValue;
        else
            result = (int) correctedValue;

        return Result::ok();
    }

    static Result parseObject (String::CharPointerType& t, var& result)
    {
        DynamicObject* const resultObject = new DynamicObject();
        result = resultObject;
        NamedValueSet& resultProperties = resultObject->getProperties();

        for (;;)
        {
            t = t.findEndOfWhitespace();

            String::CharPointerType oldT (t);
            const juce_wchar c = t.getAndAdvance();

            if (c == '}')
                break;

            if (c == 0)
                return createFail ("Unexpected end-of-input in object declaration");

            if (c == '"')
            {
                var propertyNameVar;
                Result r (parseString (t, propertyNameVar));

                if (r.failed())
                    return r;

                const String propertyName (propertyNameVar.toString());

                if (propertyName.isNotEmpty())
                {
                    t = t.findEndOfWhitespace();
                    oldT = t;

                    const juce_wchar c2 = t.getAndAdvance();
                    if (c2 != ':')
                        return createFail ("Expected ':', but found", &oldT);

                    resultProperties.set (propertyName, var::null);
                    var* propertyValue = resultProperties.getVarPointer (propertyName);

                    Result r2 (parseAny (t, *propertyValue));

                    if (r2.failed())
                        return r2;

                    t = t.findEndOfWhitespace();
                    oldT = t;

                    const juce_wchar nextChar = t.getAndAdvance();

                    if (nextChar == ',')
                        continue;
                    else if (nextChar == '}')
                        break;
                }
            }

            return createFail ("Expected object member declaration, but found", &oldT);
        }

        return Result::ok();
    }

    static Result parseArray (String::CharPointerType& t, var& result)
    {
        result = var (Array<var>());
        Array<var>* const destArray = result.getArray();

        for (;;)
        {
            t = t.findEndOfWhitespace();

            String::CharPointerType oldT (t);
            const juce_wchar c = t.getAndAdvance();

            if (c == ']')
                break;

            if (c == 0)
                return createFail ("Unexpected end-of-input in array declaration");

            t = oldT;
            destArray->add (var::null);
            Result r (parseAny (t, destArray->getReference (destArray->size() - 1)));

            if (r.failed())
                return r;

            t = t.findEndOfWhitespace();
            oldT = t;

            const juce_wchar nextChar = t.getAndAdvance();

            if (nextChar == ',')
                continue;
            else if (nextChar == ']')
                break;

            return createFail ("Expected object array item, but found", &oldT);
        }

        return Result::ok();
    }

    static Result parseString (String::CharPointerType& t, var& result)
    {
        Array<juce_wchar> buffer;
        buffer.ensureStorageAllocated (256);

        for (;;)
        {
            juce_wchar c = t.getAndAdvance();

            if (c == '"')
                break;

            if (c == '\\')
            {
                c = t.getAndAdvance();

                switch (c)
                {
                    case '"':
                    case '\\':
                    case '/':  break;

                    case 'b':  c = '\b'; break;
                    case 'f':  c = '\f'; break;
                    case 'n':  c = '\n'; break;
                    case 'r':  c = '\r'; break;
                    case 't':  c = '\t'; break;

                    case 'u':
                    {
                        c = 0;

                        for (int i = 4; --i >= 0;)
                        {
                            const int digitValue = CharacterFunctions::getHexDigitValue (t.getAndAdvance());
                            if (digitValue < 0)
                                return createFail ("Syntax error in unicode escape sequence");

                            c = (juce_wchar) ((c << 4) + digitValue);
                        }

                        break;
                    }
                }
            }

            if (c == 0)
                return createFail ("Unexpected end-of-input in string constant");

            buffer.add (c);
        }

        buffer.add (0);
        result = String (CharPointer_UTF32 (buffer.getRawDataPointer()));
        return Result::ok();
    }
};

//==============================================================================
class JSONFormatter
{
public:
    static void write (OutputStream& out, const var& v,
                       const int indentLevel, const bool allOnOneLine)
    {
        if (v.isString())
        {
            writeString (out, v.toString().getCharPointer());
        }
        else if (v.isVoid())
        {
            out << "null";
        }
        else if (v.isBool())
        {
            out << (static_cast<bool> (v) ? "true" : "false");
        }
        else if (v.isArray())
        {
            writeArray (out, *v.getArray(), indentLevel, allOnOneLine);
        }
        else if (v.isObject())
        {
            DynamicObject* const object = v.getDynamicObject();

            jassert (object != nullptr); // Only DynamicObjects can be converted to JSON!

            writeObject (out, *object, indentLevel, allOnOneLine);
        }
        else
        {
            jassert (! v.isMethod()); // Can't convert an object with methods to JSON!

            out << v.toString();
        }
    }

private:
    enum { indentSize = 2 };

    static void writeEscapedChar (OutputStream& out, const unsigned short value)
    {
        out << "\\u" << String::toHexString ((int) value).paddedLeft ('0', 4);
    }

    static void writeString (OutputStream& out, String::CharPointerType t)
    {
        out << '"';

        for (;;)
        {
            const juce_wchar c (t.getAndAdvance());

            switch (c)
            {
                case 0:  out << '"'; return;

                case '\"':  out << "\\\""; break;
                case '\\':  out << "\\\\"; break;
                case '\b':  out << "\\b";  break;
                case '\f':  out << "\\f";  break;
                case '\t':  out << "\\t";  break;
                case '\r':  out << "\\r";  break;
                case '\n':  out << "\\n";  break;

                default:
                    if (c >= 32 && c < 127)
                    {
                        out << (char) c;
                    }
                    else
                    {
                        if (CharPointer_UTF16::getBytesRequiredFor (c) > 2)
                        {
                            CharPointer_UTF16::CharType chars[2];
                            CharPointer_UTF16 utf16 (chars);
                            utf16.write (c);

                            for (int i = 0; i < 2; ++i)
                                writeEscapedChar (out, (unsigned short) chars[i]);
                        }
                        else
                        {
                            writeEscapedChar (out, (unsigned short) c);
                        }
                    }

                    break;
            }
        }
    }

    static void writeSpaces (OutputStream& out, int numSpaces)
    {
        out.writeRepeatedByte (' ', numSpaces);
    }

    static void writeArray (OutputStream& out, const Array<var>& array,
                            const int indentLevel, const bool allOnOneLine)
    {
        out << '[';
        if (! allOnOneLine)
            out << newLine;

        for (int i = 0; i < array.size(); ++i)
        {
            if (! allOnOneLine)
                writeSpaces (out, indentLevel + indentSize);

            write (out, array.getReference(i), indentLevel + indentSize, allOnOneLine);

            if (i < array.size() - 1)
            {
                if (allOnOneLine)
                    out << ", ";
                else
                    out << ',' << newLine;
            }
            else if (! allOnOneLine)
                out << newLine;
        }

        if (! allOnOneLine)
            writeSpaces (out, indentLevel);

        out << ']';
    }

    static void writeObject (OutputStream& out, DynamicObject& object,
                             const int indentLevel, const bool allOnOneLine)
    {
        NamedValueSet& props = object.getProperties();

        out << '{';
        if (! allOnOneLine)
            out << newLine;

        LinkedListPointer<NamedValueSet::NamedValue>* i = &(props.values);

        for (;;)
        {
            NamedValueSet::NamedValue* const v = i->get();

            if (v == nullptr)
                break;

            if (! allOnOneLine)
                writeSpaces (out, indentLevel + indentSize);

            writeString (out, v->name);
            out << ": ";
            write (out, v->value, indentLevel + indentSize, allOnOneLine);

            if (v->nextListItem.get() != nullptr)
            {
                if (allOnOneLine)
                    out << ", ";
                else
                    out << ',' << newLine;
            }
            else if (! allOnOneLine)
                out << newLine;

            i = &(v->nextListItem);
        }

        if (! allOnOneLine)
            writeSpaces (out, indentLevel);

        out << '}';
    }
};

//==============================================================================
var JSON::parse (const String& text)
{
    var result;
    String::CharPointerType t (text.getCharPointer());
    if (! JSONParser::parseAny (t, result))
        result = var::null;

    return result;
}

var JSON::parse (InputStream& input)
{
    return parse (input.readEntireStreamAsString());
}

var JSON::parse (const File& file)
{
    return parse (file.loadFileAsString());
}

Result JSON::parse (const String& text, var& result)
{
    String::CharPointerType t (text.getCharPointer());
    return JSONParser::parseAny (t, result);
}

String JSON::toString (const var& data, const bool allOnOneLine)
{
    MemoryOutputStream mo (1024);
    JSONFormatter::write (mo, data, 0, allOnOneLine);
    return mo.toString();
}

void JSON::writeToStream (OutputStream& output, const var& data, const bool allOnOneLine)
{
    JSONFormatter::write (output, data, 0, allOnOneLine);
}

//==============================================================================
//==============================================================================
#if JUCE_UNIT_TESTS

class JSONTests  : public UnitTest
{
public:
    JSONTests() : UnitTest ("JSON") {}

    static String createRandomWideCharString (Random& r)
    {
        juce_wchar buffer[40] = { 0 };

        for (int i = 0; i < numElementsInArray (buffer) - 1; ++i)
        {
            if (r.nextBool())
            {
                do
                {
                    buffer[i] = (juce_wchar) (1 + r.nextInt (0x10ffff - 1));
                }
                while (! CharPointer_UTF16::canRepresent (buffer[i]));
            }
            else
                buffer[i] = (juce_wchar) (1 + r.nextInt (0xff));
        }

        return CharPointer_UTF32 (buffer);
    }

    static String createRandomIdentifier (Random& r)
    {
        char buffer[30] = { 0 };

        for (int i = 0; i < numElementsInArray (buffer) - 1; ++i)
        {
            static const char chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-:";
            buffer[i] = chars [r.nextInt (sizeof (chars) - 1)];
        }

        return CharPointer_ASCII (buffer);
    }

    static var createRandomVar (Random& r, int depth)
    {
        switch (r.nextInt (depth > 3 ? 6 : 8))
        {
            case 0:     return var::null;
            case 1:     return r.nextInt();
            case 2:     return r.nextInt64();
            case 3:     return r.nextBool();
            case 4:     return r.nextDouble();
            case 5:     return createRandomWideCharString (r);

            case 6:
            {
                var v (createRandomVar (r, depth + 1));

                for (int i = 1 + r.nextInt (30); --i >= 0;)
                    v.append (createRandomVar (r, depth + 1));

                return v;
            }

            case 7:
            {
                DynamicObject* o = new DynamicObject();

                for (int i = r.nextInt (30); --i >= 0;)
                    o->setProperty (createRandomIdentifier (r), createRandomVar (r, depth + 1));

                return o;
            }

            default:
                return var::null;
        }
    }

    void runTest()
    {
        beginTest ("JSON");
        Random r;
        r.setSeedRandomly();

        expect (JSON::parse (String::empty) == var::null);
        expect (JSON::parse ("{}").isObject());
        expect (JSON::parse ("[]").isArray());
        expect (JSON::parse ("1234").isInt());
        expect (JSON::parse ("12345678901234").isInt64());
        expect (JSON::parse ("1.123e3").isDouble());
        expect (JSON::parse ("-1234").isInt());
        expect (JSON::parse ("-12345678901234").isInt64());
        expect (JSON::parse ("-1.123e3").isDouble());

        for (int i = 100; --i >= 0;)
        {
            var v;

            if (i > 0)
                v = createRandomVar (r, 0);

            const bool oneLine = r.nextBool();
            String asString (JSON::toString (v, oneLine));
            var parsed = JSON::parse (asString);
            String parsedString (JSON::toString (parsed, oneLine));
            expect (asString.isNotEmpty() && parsedString == asString);
        }
    }
};

static JSONTests JSONUnitTests;

#endif