/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define __STDC_LIMIT_MACROS

#include <string>
#include <map>
#include <algorithm>
#include <ctype.h>
#include <boost/shared_ptr.hpp>
#include <boost/make_shared.hpp>
#include <boost/weak_ptr.hpp>
#include <boost/any.hpp>

#include "ValidatingCodec.hh"
#include "Symbol.hh"
#include "ValidSchema.hh"
#include "Decoder.hh"
#include "Encoder.hh"
#include "NodeImpl.hh"

#include "../json/JsonIO.hh"

namespace rmf_avro {

namespace parsing {

using boost::shared_ptr;
using boost::static_pointer_cast;

using std::map;
using std::vector;
using std::string;
using std::reverse;
using std::ostringstream;
using std::istringstream;

using rmf_avro::json::JsonParser;
using rmf_avro::json::JsonGenerator;

class JsonGrammarGenerator : public ValidatingGrammarGenerator {
    Production doGenerate(const NodePtr& n,
        std::map<NodePtr, boost::shared_ptr<Production> > &m);
};

static std::string nameOf(const NodePtr& n)
{
    if (n->hasName()) {
        return n->name();
    }
    std::ostringstream oss;
    oss << n->type();
    return oss.str();
}

Production JsonGrammarGenerator::doGenerate(const NodePtr& n,
    std::map<NodePtr, boost::shared_ptr<Production> > &m) {
    switch (n->type()) {
    case AVRO_NULL:
    case AVRO_BOOL:
    case AVRO_INT:
    case AVRO_LONG:
    case AVRO_FLOAT:
    case AVRO_DOUBLE:
    case AVRO_STRING:
    case AVRO_BYTES:
    case AVRO_FIXED:
    case AVRO_ARRAY:
    case AVRO_MAP:
    case AVRO_SYMBOLIC:
        return ValidatingGrammarGenerator::doGenerate(n, m);
    case AVRO_RECORD:
        {
            Production result;

            m.erase(n);

            size_t c = n->leaves();
            result.reserve(2 + 2 * c);
            result.push_back(Symbol::recordStartSymbol());
            for (size_t i = 0; i < c; ++i) {
                const NodePtr& leaf = n->leafAt(i);
                Production v = doGenerate(leaf, m);
                result.push_back(Symbol::fieldSymbol(n->nameAt(i)));
                copy(v.rbegin(), v.rend(), back_inserter(result));
            }
            result.push_back(Symbol::recordEndSymbol());
            reverse(result.begin(), result.end());

            bool found = m.find(n) != m.end();

            shared_ptr<Production> p = boost::make_shared<Production>(result);
            m[n] = p;

            return found ? Production(1, Symbol::indirect(p)) : result;
        }
    case AVRO_ENUM:
        {
            vector<string> nn;
            size_t c = n->names();
            nn.reserve(c);
            for (size_t i = 0; i < c; ++i) {
                nn.push_back(n->nameAt(i));
            }
            Symbol r[] = {
                Symbol::nameListSymbol(nn),
                Symbol::enumSymbol() };
            Production result(r, r + 2);
            m[n] = boost::make_shared<Production>(result);
            return result;
        }
    case AVRO_UNION:
        {
            size_t c = n->leaves();

            vector<Production> vv;
            vv.reserve(c);

            vector<string> names;
            names.reserve(c);

            for (size_t i = 0; i < c; ++i) {
                const NodePtr& nn = n->leafAt(i);
                Production v = doGenerate(nn, m);
                if (nn->type() != AVRO_NULL) {
                    Production v2;
                    v2.push_back(Symbol::recordEndSymbol());
                    copy(v.begin(), v.end(), back_inserter(v2));
                    v.swap(v2);
                }
                vv.push_back(v);
                names.push_back(nameOf(nn));
            }
            Symbol r[] = {
                Symbol::alternative(vv),
                Symbol::nameListSymbol(names),
                Symbol::unionSymbol()
            };
            return Production(r, r + 3);
        }
    default:
        throw Exception("Unknown node type");
    }
}

static void expectToken(JsonParser& in, JsonParser::Token tk)
{
  JsonParser::Token tka = in.advance();
  // handle doubles as long
  if (tka != tk && (tk != JsonParser::tkDouble || tka != JsonParser::tkLong)) {
        ostringstream oss;
        oss << "Incorrect token in the stream. Expected: "
            << JsonParser::toString(tk) << ", found "
            << JsonParser::toString(in.cur());
        throw Exception(oss.str());
    }
}

class JsonDecoderHandler {
    JsonParser& in_;
public:
    JsonDecoderHandler(JsonParser& p) : in_(p) { }
    size_t handle(const Symbol& s) {
        switch (s.kind()) {
        case Symbol::sRecordStart:
            expectToken(in_, JsonParser::tkObjectStart);
            break;
        case Symbol::sRecordEnd:
            expectToken(in_, JsonParser::tkObjectEnd);
            break;
        case Symbol::sField:
            expectToken(in_, JsonParser::tkString);
            if (s.extra<string>() != in_.stringValue()) {
                throw Exception("Incorrect field");
            }
            break;
        default:
            break;
        }
        return 0;
    }
};

template <typename P>
class JsonDecoder : public Decoder {
    JsonParser in_;
    JsonDecoderHandler handler_;
    P parser_;

    void init(InputStream& is);
    void decodeNull();
    bool decodeBool();
    int32_t decodeInt();
    int64_t decodeLong();
    float decodeFloat();
    double decodeDouble();
    void decodeString(string& value);
    void skipString();
    void decodeBytes(vector<uint8_t>& value);
    void skipBytes();
    void decodeFixed(size_t n, vector<uint8_t>& value);
    void skipFixed(size_t n);
    size_t decodeEnum();
    size_t arrayStart();
    size_t arrayNext();
    size_t skipArray();
    size_t mapStart();
    size_t mapNext();
    size_t skipMap();
    size_t decodeUnionIndex();

    void expect(JsonParser::Token tk);
    void skipComposite();
public:

    JsonDecoder(const ValidSchema& s) :
        handler_(in_),
        parser_(JsonGrammarGenerator().generate(s), NULL, handler_) { }

};

template <typename P>
void JsonDecoder<P>::init(InputStream& is)
{
    in_.init(is);
}

template <typename P>
void JsonDecoder<P>::expect(JsonParser::Token tk)
{
    expectToken(in_, tk);
}

template <typename P>
void JsonDecoder<P>::decodeNull()
{
    parser_.advance(Symbol::sNull);
    expect(JsonParser::tkNull);
}

template <typename P>
bool JsonDecoder<P>::decodeBool()
{
    parser_.advance(Symbol::sBool);
    expect(JsonParser::tkBool);
    bool result = in_.boolValue();
    return result;
}

template <typename P>
int32_t JsonDecoder<P>::decodeInt()
{
    parser_.advance(Symbol::sInt);
    expect(JsonParser::tkLong);
    int64_t result = in_.longValue();
    if (result < INT32_MIN || result > INT32_MAX) {
        throw Exception(boost::format("Value out of range for Avro int: %1%")
            % result);
    }
    return static_cast<int32_t>(result);
}

template <typename P>
int64_t JsonDecoder<P>::decodeLong()
{
    parser_.advance(Symbol::sLong);
    expect(JsonParser::tkLong);
    int64_t result = in_.longValue();
    return result;
}

template <typename P>
float JsonDecoder<P>::decodeFloat()
{
    parser_.advance(Symbol::sFloat);
    expect(JsonParser::tkDouble);
    double result = in_.doubleValue();
    return static_cast<float>(result);
}

template <typename P>
double JsonDecoder<P>::decodeDouble()
{
    parser_.advance(Symbol::sDouble);
    expect(JsonParser::tkDouble);
    double result = in_.doubleValue();
    return result;
}

template <typename P>
void JsonDecoder<P>::decodeString(string& value)
{
    parser_.advance(Symbol::sString);
    expect(JsonParser::tkString);
    value = in_.stringValue();
}

template <typename P>
void JsonDecoder<P>::skipString()
{
    parser_.advance(Symbol::sString);
    expect(JsonParser::tkString);
}

static vector<uint8_t> toBytes(const string& s)
{
    return vector<uint8_t>(s.begin(), s.end());
}

template <typename P>
void JsonDecoder<P>::decodeBytes(vector<uint8_t>& value )
{
    parser_.advance(Symbol::sBytes);
    expect(JsonParser::tkString);
    value = toBytes(in_.stringValue());
}

template <typename P>
void JsonDecoder<P>::skipBytes()
{
    parser_.advance(Symbol::sBytes);
    expect(JsonParser::tkString);
}

template <typename P>
void JsonDecoder<P>::decodeFixed(size_t n, vector<uint8_t>& value)
{
    parser_.advance(Symbol::sFixed);
    parser_.assertSize(n);
    expect(JsonParser::tkString);
    value = toBytes(in_.stringValue());
    if (value.size() != n) {
        throw Exception("Incorrect value for fixed");
    }
}

template <typename P>
void JsonDecoder<P>::skipFixed(size_t n)
{
    parser_.advance(Symbol::sFixed);
    parser_.assertSize(n);
    expect(JsonParser::tkString);
    vector<uint8_t> result = toBytes(in_.stringValue());
    if (result.size() != n) {
        throw Exception("Incorrect value for fixed");
    }
}

template <typename P>
size_t JsonDecoder<P>::decodeEnum()
{
    parser_.advance(Symbol::sEnum);
    expect(JsonParser::tkString);
    size_t result = parser_.indexForName(in_.stringValue());
    return result;
}

template <typename P>
size_t JsonDecoder<P>::arrayStart()
{
    parser_.advance(Symbol::sArrayStart);
    expect(JsonParser::tkArrayStart);
    return arrayNext();
}

template <typename P>
size_t JsonDecoder<P>::arrayNext()
{
    parser_.processImplicitActions();
    if (in_.peek() == JsonParser::tkArrayEnd) {
        in_.advance();
        parser_.popRepeater();
        parser_.advance(Symbol::sArrayEnd);
        return 0;
    }
    parser_.setRepeatCount(1);
    return 1;
}

template<typename P>
void JsonDecoder<P>::skipComposite()
{
    size_t level = 0;
    for (; ;) {
        switch (in_.advance()) {
        case JsonParser::tkArrayStart:
        case JsonParser::tkObjectStart:
            ++level;
            continue;
        case JsonParser::tkArrayEnd:
        case JsonParser::tkObjectEnd:
            if (level == 0) {
                return;
            }
            --level;
            continue;
        default:
            continue;
        }
    }
}

template <typename P>
size_t JsonDecoder<P>::skipArray()
{
    parser_.advance(Symbol::sArrayStart);
    parser_.pop();
    parser_.advance(Symbol::sArrayEnd);
    expect(JsonParser::tkArrayStart);
    skipComposite();
    return 0;
}

template <typename P>
size_t JsonDecoder<P>::mapStart()
{
    parser_.advance(Symbol::sMapStart);
    expect(JsonParser::tkObjectStart);
    return mapNext();
}

template <typename P>
size_t JsonDecoder<P>::mapNext()
{
    parser_.processImplicitActions();
    if (in_.peek() == JsonParser::tkObjectEnd) {
        in_.advance();
        parser_.popRepeater();
        parser_.advance(Symbol::sMapEnd);
        return 0;
    }
    parser_.setRepeatCount(1);
    return 1;
}

template <typename P>
size_t JsonDecoder<P>::skipMap()
{
    parser_.advance(Symbol::sMapStart);
    parser_.pop();
    parser_.advance(Symbol::sMapEnd);
    expect(JsonParser::tkObjectStart);
    skipComposite();
    return 0;
}

template <typename P>
size_t JsonDecoder<P>::decodeUnionIndex()
{
    parser_.advance(Symbol::sUnion);

    size_t result;
    if (in_.peek() == JsonParser::tkNull) {
        result = parser_.indexForName("null");
    } else {
        expect(JsonParser::tkObjectStart);
        expect(JsonParser::tkString);
        result = parser_.indexForName(in_.stringValue());
    }
    parser_.selectBranch(result);
    return result;
}


class JsonHandler {
    JsonGenerator& generator_;
public:
    JsonHandler(JsonGenerator& g) : generator_(g) { }
    size_t handle(const Symbol& s) {
        switch (s.kind()) {
        case Symbol::sRecordStart:
            generator_.objectStart();
            break;
        case Symbol::sRecordEnd:
            generator_.objectEnd();
            break;
        case Symbol::sField:
            generator_.encodeString(s.extra<string>());
            break;
        default:
            break;
        }
        return 0;
    }
};

template <typename P>
class JsonEncoder : public Encoder {
    JsonGenerator out_;
    JsonHandler handler_;
    P parser_;

    void init(OutputStream& os);
    void flush();
    void encodeNull();
    void encodeBool(bool b);
    void encodeInt(int32_t i);
    void encodeLong(int64_t l);
    void encodeFloat(float f);
    void encodeDouble(double d);
    void encodeString(const std::string& s);
    void encodeBytes(const uint8_t *bytes, size_t len);
    void encodeFixed(const uint8_t *bytes, size_t len);
    void encodeEnum(size_t e);
    void arrayStart();
    void arrayEnd();
    void mapStart();
    void mapEnd();
    void setItemCount(size_t count);
    void startItem();
    void encodeUnionIndex(size_t e);
public:
    JsonEncoder(const ValidSchema& schema) :
        handler_(out_),
        parser_(JsonGrammarGenerator().generate(schema), NULL, handler_) { }
};

template<typename P>
void JsonEncoder<P>::init(OutputStream& os)
{
    out_.init(os);
}

template<typename P>
void JsonEncoder<P>::flush()
{
    parser_.processImplicitActions();
    out_.flush();
}

template<typename P>
void JsonEncoder<P>::encodeNull()
{
    parser_.advance(Symbol::sNull);
    out_.encodeNull();
}

template<typename P>
void JsonEncoder<P>::encodeBool(bool b)
{
    parser_.advance(Symbol::sBool);
    out_.encodeBool(b);
}

template<typename P>
void JsonEncoder<P>::encodeInt(int32_t i)
{
    parser_.advance(Symbol::sInt);
    out_.encodeNumber(i);
}

template<typename P>
void JsonEncoder<P>::encodeLong(int64_t l)
{
    parser_.advance(Symbol::sLong);
    out_.encodeNumber(l);
}

template<typename P>
void JsonEncoder<P>::encodeFloat(float f)
{
    parser_.advance(Symbol::sFloat);
    out_.encodeNumber(f);
}

template<typename P>
void JsonEncoder<P>::encodeDouble(double d)
{
    parser_.advance(Symbol::sDouble);
    out_.encodeNumber(d);
}

template<typename P>
void JsonEncoder<P>::encodeString(const std::string& s)
{
    parser_.advance(Symbol::sString);
    out_.encodeString(s);
}

template<typename P>
void JsonEncoder<P>::encodeBytes(const uint8_t *bytes, size_t len)
{
    parser_.advance(Symbol::sBytes);
    out_.encodeBinary(bytes, len);
}

template<typename P>
void JsonEncoder<P>::encodeFixed(const uint8_t *bytes, size_t len)
{
    parser_.advance(Symbol::sFixed);
    parser_.assertSize(len);
    out_.encodeBinary(bytes, len);
}

template<typename P>
void JsonEncoder<P>::encodeEnum(size_t e)
{
    parser_.advance(Symbol::sEnum);
    const string& s = parser_.nameForIndex(e);
    out_.encodeString(s);
}

template<typename P>
void JsonEncoder<P>::arrayStart()
{
    parser_.advance(Symbol::sArrayStart);
    out_.arrayStart();
}

template<typename P>
void JsonEncoder<P>::arrayEnd()
{
    parser_.popRepeater();
    parser_.advance(Symbol::sArrayEnd);
    out_.arrayEnd();
}

template<typename P>
void JsonEncoder<P>::mapStart()
{
    parser_.advance(Symbol::sMapStart);
    out_.objectStart();
}

template<typename P>
void JsonEncoder<P>::mapEnd()
{
    parser_.popRepeater();
    parser_.advance(Symbol::sMapEnd);
    out_.objectEnd();
}

template<typename P>
void JsonEncoder<P>::setItemCount(size_t count)
{
    parser_.setRepeatCount(count);
}

template<typename P>
void JsonEncoder<P>::startItem()
{
    parser_.processImplicitActions();
    if (parser_.top() != Symbol::sRepeater) {
        throw Exception("startItem at not an item boundary");
    }
}

template<typename P>
void JsonEncoder<P>::encodeUnionIndex(size_t e)
{
    parser_.advance(Symbol::sUnion);

    const std::string name = parser_.nameForIndex(e);

    if (name != "null") {
        out_.objectStart();
        out_.encodeString(name);
    }
    parser_.selectBranch(e);
}

}   // namespace parsing

DecoderPtr jsonDecoder(const ValidSchema& s)
{
    return boost::make_shared<parsing::JsonDecoder<
        parsing::SimpleParser<parsing::JsonDecoderHandler> > >(s);
}

EncoderPtr jsonEncoder(const ValidSchema& schema)
{
    return boost::make_shared<parsing::JsonEncoder<
        parsing::SimpleParser<parsing::JsonHandler> > >(schema);
}

}   // namespace rmf_avro