/**
 * 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.
 */

#include <ctype.h>
#ifndef _WIN32
#include <sys/time.h>
#endif
#include <iostream>
#include <fstream>
#include <map>
#include <set>

#include <boost/algorithm/string.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/program_options.hpp>

#include <boost/random/mersenne_twister.hpp>
#include <boost/random/uniform_int.hpp>
#include <boost/random/variate_generator.hpp>

#include "Compiler.hh"
#include "ValidSchema.hh"
#include "NodeImpl.hh"

using std::ostream;
using std::ifstream;
using std::ofstream;
using std::map;
using std::set;
using std::string;
using std::vector;
using rmf_avro::NodePtr;
using rmf_avro::resolveSymbol;

using boost::lexical_cast;

using rmf_avro::ValidSchema;
using rmf_avro::compileJsonSchema;

struct PendingSetterGetter {
    string structName;
    string type;
    string name;
    size_t idx;

    PendingSetterGetter(const string& sn, const string& t,
        const string& n, size_t i) :
        structName(sn), type(t), name(n), idx(i) { }
};

struct PendingConstructor {
    string structName;
    string memberName;
    bool initMember;
    PendingConstructor(const string& sn, const string& n, bool im) :
        structName(sn), memberName(n), initMember(im) { }
};

class CodeGen {
    size_t unionNumber_;
    std::ostream& os_;
    bool inNamespace_;
    const std::string ns_;
    const std::string schemaFile_;
    const std::string headerFile_;
    const std::string includePrefix_;
    const bool noUnion_;
    const std::string guardString_;
    boost::mt19937 random_;

    vector<PendingSetterGetter> pendingGettersAndSetters;
    vector<PendingConstructor> pendingConstructors;

    map<NodePtr, string> done;
    set<NodePtr> doing;

    std::string guard();
    std::string fullname(const string& name) const;
    std::string generateEnumType(const NodePtr& n);
    std::string cppTypeOf(const NodePtr& n);
    std::string generateRecordType(const NodePtr& n);
    std::string unionName();
    std::string generateUnionType(const NodePtr& n);
    std::string generateType(const NodePtr& n);
    std::string generateDeclaration(const NodePtr& n);
    std::string doGenerateType(const NodePtr& n);
    void generateEnumTraits(const NodePtr& n);
    void generateTraits(const NodePtr& n);
    void generateRecordTraits(const NodePtr& n);
    void generateUnionTraits(const NodePtr& n);
    void emitCopyright();
public:
    CodeGen(std::ostream& os, const std::string& ns,
        const std::string& schemaFile, const std::string& headerFile,
        const std::string& guardString,
        const std::string& includePrefix, bool noUnion) :
        unionNumber_(0), os_(os), inNamespace_(false), ns_(ns),
        schemaFile_(schemaFile), headerFile_(headerFile),
        includePrefix_(includePrefix), noUnion_(noUnion),
        guardString_(guardString),
        random_(static_cast<uint32_t>(::time(0))) { }
    void generate(const ValidSchema& schema);
};

static string decorate(const rmf_avro::Name& name)
{
    return name.simpleName();
}

string CodeGen::fullname(const string& name) const
{
    return ns_.empty() ? name : (ns_ + "::" + name);
}

string CodeGen::generateEnumType(const NodePtr& n)
{
    string s = decorate(n->name());
    os_ << "enum " << s << " {\n";
    size_t c = n->names();
    for (size_t i = 0; i < c; ++i) {
        os_ << "    " << n->nameAt(i) << ",\n";
    }
    os_ << "};\n\n";
    return s;
}

string CodeGen::cppTypeOf(const NodePtr& n)
{
    switch (n->type()) {
    case rmf_avro::AVRO_STRING:
        return "std::string";
    case rmf_avro::AVRO_BYTES:
        return "std::vector<uint8_t>";
    case rmf_avro::AVRO_INT:
        return "int32_t";
    case rmf_avro::AVRO_LONG:
        return "int64_t";
    case rmf_avro::AVRO_FLOAT:
        return "float";
    case rmf_avro::AVRO_DOUBLE:
        return "double";
    case rmf_avro::AVRO_BOOL:
        return "bool";
    case rmf_avro::AVRO_RECORD:
    case rmf_avro::AVRO_ENUM:
        {
            string nm = decorate(n->name());
            return inNamespace_ ? nm : fullname(nm);
        }
    case rmf_avro::AVRO_ARRAY:
        return "std::vector<" + cppTypeOf(n->leafAt(0)) + " >";
    case rmf_avro::AVRO_MAP:
        return "std::map<std::string, " + cppTypeOf(n->leafAt(1)) + " >";
    case rmf_avro::AVRO_FIXED:
        return "boost::array<uint8_t, " +
            lexical_cast<string>(n->fixedSize()) + ">";
    case rmf_avro::AVRO_SYMBOLIC:
        return cppTypeOf(resolveSymbol(n));
    case rmf_avro::AVRO_UNION:
        return fullname(done[n]);
    default:
        return "$Undefined$";
    }
}

static string cppNameOf(const NodePtr& n)
{
    switch (n->type()) {
    case rmf_avro::AVRO_NULL:
        return "null";
    case rmf_avro::AVRO_STRING:
        return "string";
    case rmf_avro::AVRO_BYTES:
        return "bytes";
    case rmf_avro::AVRO_INT:
        return "int";
    case rmf_avro::AVRO_LONG:
        return "long";
    case rmf_avro::AVRO_FLOAT:
        return "float";
    case rmf_avro::AVRO_DOUBLE:
        return "double";
    case rmf_avro::AVRO_BOOL:
        return "bool";
    case rmf_avro::AVRO_RECORD:
    case rmf_avro::AVRO_ENUM:
    case rmf_avro::AVRO_FIXED:
        return decorate(n->name());
    case rmf_avro::AVRO_ARRAY:
        return "array";
    case rmf_avro::AVRO_MAP:
        return "map";
    case rmf_avro::AVRO_SYMBOLIC:
        return cppNameOf(resolveSymbol(n));
    default:
        return "$Undefined$";
    }
}

string CodeGen::generateRecordType(const NodePtr& n)
{
    size_t c = n->leaves();
    vector<string> types;
    for (size_t i = 0; i < c; ++i) {
        types.push_back(generateType(n->leafAt(i)));
    }

    map<NodePtr, string>::const_iterator it = done.find(n);
    if (it != done.end()) {
        return it->second;
    }

    os_ << "struct " << decorate(n->name()) << " {\n";
    if (! noUnion_) {
        for (size_t i = 0; i < c; ++i) {
            if (n->leafAt(i)->type() == rmf_avro::AVRO_UNION) {
                os_ << "    typedef " << types[i]
                    << ' ' << n->nameAt(i) << "_t;\n";
            }
        }
    }
    for (size_t i = 0; i < c; ++i) {
        if (! noUnion_ && n->leafAt(i)->type() == rmf_avro::AVRO_UNION) {
            os_ << "    " << n->nameAt(i) << "_t";
        } else {
            os_ << "    " << types[i];
        }
        os_ << ' ' << n->nameAt(i) << ";\n";
    }
    os_ << "};\n\n";
    return decorate(n->name());
}

void makeCanonical(string& s, bool foldCase)
{
    for (string::iterator it = s.begin(); it != s.end(); ++it) {
        if (isalpha(*it)) {
            if (foldCase) {
                *it = toupper(*it);
            }
        } else if (! isdigit(*it)) {
            *it = '_';
        }
    }
}

string CodeGen::unionName()
{
    string s = schemaFile_;
    string::size_type n = s.find_last_of("/\\");
    if (n != string::npos) {
        s = s.substr(n);
    }
    makeCanonical(s, false);

    return s + "_Union__" + boost::lexical_cast<string>(unionNumber_++) + "__";
}

static void generateGetterAndSetter(ostream& os,
    const string& structName, const string& type, const string& name,
    size_t idx)
{
    string sn = " " + structName + "::";

    os << "inline\n";

    os << type << sn << "get_" << name << "() const {\n"
        << "    if (idx_ != " << idx << ") {\n"
        << "        throw rmf_avro::Exception(\"Invalid type for "
            << "union\");\n"
        << "    }\n"
        << "    return boost::any_cast<" << type << " >(value_);\n"
        << "}\n\n";

    os << "inline\n"
        << "void" << sn << "set_" << name
        << "(const " << type << "& v) {\n"
        << "    idx_ = " << idx << ";\n"
        << "    value_ = v;\n"
        << "}\n\n";
}

static void generateConstructor(ostream& os,
    const string& structName, bool initMember,
    const string& type) {
    os << "inline " << structName  << "::" << structName << "() : idx_(0)";
    if (initMember) {
        os << ", value_(" << type << "())";
    }
    os << " { }\n";
}

/**
 * Generates a type for union and emits the code.
 * Since unions can encounter names that are not fully defined yet,
 * such names must be declared and the inline functions deferred until all
 * types are fully defined.
 */
string CodeGen::generateUnionType(const NodePtr& n)
{
    size_t c = n->leaves();
    vector<string> types;
    vector<string> names;

    set<NodePtr>::const_iterator it = doing.find(n);
    if (it != doing.end()) {
        for (size_t i = 0; i < c; ++i) {
            const NodePtr& nn = n->leafAt(i);
            types.push_back(generateDeclaration(nn));
            names.push_back(cppNameOf(nn));
        }
    } else {
        doing.insert(n);
        for (size_t i = 0; i < c; ++i) {
            const NodePtr& nn = n->leafAt(i);
            types.push_back(generateType(nn));
            names.push_back(cppNameOf(nn));
        }
        doing.erase(n);
    }
    if (done.find(n) != done.end()) {
        return done[n];
    }

    const string result = unionName();

    os_ << "struct " << result << " {\n"
        << "private:\n"
        << "    size_t idx_;\n"
        << "    boost::any value_;\n"
        << "public:\n"
        << "    size_t idx() const { return idx_; }\n";

    for (size_t i = 0; i < c; ++i) {
        const NodePtr& nn = n->leafAt(i);
        if (nn->type() == rmf_avro::AVRO_NULL) {
            os_ << "    bool is_null() const {\n"
                << "        return (idx_ == " << i << ");\n"
                << "    }\n"
                << "    void set_null() {\n"
                << "        idx_ = " << i << ";\n"
                << "        value_ = boost::any();\n"
                << "    }\n";
        } else {
            const string& type = types[i];
            const string& name = names[i];
            os_ << "    " << type << " get_" << name << "() const;\n"
                   "    void set_" << name << "(const " << type << "& v);\n";
            pendingGettersAndSetters.push_back(
                PendingSetterGetter(result, type, name, i));
        }
    }

    os_ << "    " << result << "();\n";
    pendingConstructors.push_back(PendingConstructor(result, types[0],
        n->leafAt(0)->type() != rmf_avro::AVRO_NULL));
    os_ << "};\n\n";
    
    return result;
}

/**
 * Returns the type for the given schema node and emits code to os.
 */
string CodeGen::generateType(const NodePtr& n)
{
    NodePtr nn = (n->type() == rmf_avro::AVRO_SYMBOLIC) ?  resolveSymbol(n) : n;

    map<NodePtr, string>::const_iterator it = done.find(nn);
    if (it != done.end()) {
        return it->second;
    }
    string result = doGenerateType(nn);
    done[nn] = result;
    return result;
}

string CodeGen::doGenerateType(const NodePtr& n)
{
    switch (n->type()) {
    case rmf_avro::AVRO_STRING:
    case rmf_avro::AVRO_BYTES:
    case rmf_avro::AVRO_INT:
    case rmf_avro::AVRO_LONG:
    case rmf_avro::AVRO_FLOAT:
    case rmf_avro::AVRO_DOUBLE:
    case rmf_avro::AVRO_BOOL:
    case rmf_avro::AVRO_NULL:
    case rmf_avro::AVRO_FIXED:
        return cppTypeOf(n);
    case rmf_avro::AVRO_ARRAY:
        return "std::vector<" + generateType(n->leafAt(0)) + " >";
    case rmf_avro::AVRO_MAP:
        return "std::map<std::string, " + generateType(n->leafAt(1)) + " >";
    case rmf_avro::AVRO_RECORD:
        return generateRecordType(n);
    case rmf_avro::AVRO_ENUM:
        return generateEnumType(n);
    case rmf_avro::AVRO_UNION:
        return generateUnionType(n);
    default:
        break;
    }
    return "$Undefuned$";
}

string CodeGen::generateDeclaration(const NodePtr& n)
{
    NodePtr nn = (n->type() == rmf_avro::AVRO_SYMBOLIC) ?  resolveSymbol(n) : n;
    switch (nn->type()) {
    case rmf_avro::AVRO_STRING:
    case rmf_avro::AVRO_BYTES:
    case rmf_avro::AVRO_INT:
    case rmf_avro::AVRO_LONG:
    case rmf_avro::AVRO_FLOAT:
    case rmf_avro::AVRO_DOUBLE:
    case rmf_avro::AVRO_BOOL:
    case rmf_avro::AVRO_NULL:
    case rmf_avro::AVRO_FIXED:
        return cppTypeOf(nn);
    case rmf_avro::AVRO_ARRAY:
        return "std::vector<" + generateDeclaration(nn->leafAt(0)) + " >";
    case rmf_avro::AVRO_MAP:
        return "std::map<std::string, " +
            generateDeclaration(nn->leafAt(1)) + " >";
    case rmf_avro::AVRO_RECORD:
        os_ << "struct " << cppTypeOf(nn) << ";\n";
        return cppTypeOf(nn);
    case rmf_avro::AVRO_ENUM:
        return generateEnumType(nn);
    case rmf_avro::AVRO_UNION:
        // FIXME: When can this happen?
        return generateUnionType(nn);
    default:
        break;
    }
    return "$Undefuned$";
}

void CodeGen::generateEnumTraits(const NodePtr& n)
{
    string fn = fullname(decorate(n->name()));
    os_ << "template<> struct codec_traits<" << fn << "> {\n"
        << "    static void encode(Encoder& e, " << fn << " v) {\n"
        << "        e.encodeEnum(v);\n"
        << "    }\n"
        << "    static void decode(Decoder& d, " << fn << "& v) {\n"
        << "        v = static_cast<" << fn << ">(d.decodeEnum());\n"
        << "    }\n"
        << "};\n\n";
}

void CodeGen::generateRecordTraits(const NodePtr& n)
{
    size_t c = n->leaves();
    for (size_t i = 0; i < c; ++i) {
        generateTraits(n->leafAt(i));
    }

    string fn = fullname(decorate(n->name()));
    os_ << "template<> struct codec_traits<" << fn << "> {\n"
        << "    static void encode(Encoder& e, const " << fn << "& v) {\n";

    for (size_t i = 0; i < c; ++i) {
        os_ << "        rmf_avro::encode(e, v." << n->nameAt(i) << ");\n";
    }

    os_ << "    }\n"
        << "    static void decode(Decoder& d, " << fn << "& v) {\n";

    for (size_t i = 0; i < c; ++i) {
        os_ << "        rmf_avro::decode(d, v." << n->nameAt(i) << ");\n";
    }

    os_ << "    }\n"
        << "};\n\n";
}

void CodeGen::generateUnionTraits(const NodePtr& n)
{
    size_t c = n->leaves();

    for (size_t i = 0; i < c; ++i) {
        const NodePtr& nn = n->leafAt(i);
        generateTraits(nn);
    }

    string name = done[n];
    string fn = fullname(name);

    os_ << "template<> struct codec_traits<" << fn << "> {\n"
        << "    static void encode(Encoder& e, " << fn << " v) {\n"
        << "        e.encodeUnionIndex(v.idx());\n"
        << "        switch (v.idx()) {\n";

    for (size_t i = 0; i < c; ++i) {
        const NodePtr& nn = n->leafAt(i);
        os_ << "        case " << i << ":\n";
        if (nn->type() == rmf_avro::AVRO_NULL) {
            os_ << "            e.encodeNull();\n";
        } else {
            os_ << "            rmf_avro::encode(e, v.get_" << cppNameOf(nn)
                << "());\n";
        }
        os_ << "            break;\n";
    }

    os_ << "        }\n"
        << "    }\n"
        << "    static void decode(Decoder& d, " << fn << "& v) {\n"
        << "        size_t n = d.decodeUnionIndex();\n"
        << "        if (n >= " << c << ") { throw rmf_avro::Exception(\""
            "Union index too big\"); }\n"
        << "        switch (n) {\n";

    for (size_t i = 0; i < c; ++i) {
        const NodePtr& nn = n->leafAt(i);
        os_ << "        case " << i << ":\n";
        if (nn->type() == rmf_avro::AVRO_NULL) {
            os_ << "            d.decodeNull();\n"
                << "            v.set_null();\n";
        } else {
            os_ << "            {\n"
                << "                " << cppTypeOf(nn) << " vv;\n"
                << "                rmf_avro::decode(d, vv);\n"
                << "                v.set_" << cppNameOf(nn) << "(vv);\n"
                << "            }\n";
        }
        os_ << "            break;\n";
    }
    os_ << "        }\n"
        << "    }\n"
        << "};\n\n";
}

void CodeGen::generateTraits(const NodePtr& n)
{
    switch (n->type()) {
    case rmf_avro::AVRO_STRING:
    case rmf_avro::AVRO_BYTES:
    case rmf_avro::AVRO_INT:
    case rmf_avro::AVRO_LONG:
    case rmf_avro::AVRO_FLOAT:
    case rmf_avro::AVRO_DOUBLE:
    case rmf_avro::AVRO_BOOL:
    case rmf_avro::AVRO_NULL:
        break;
    case rmf_avro::AVRO_RECORD:
        generateRecordTraits(n);
        break;
    case rmf_avro::AVRO_ENUM:
        generateEnumTraits(n);
        break;
    case rmf_avro::AVRO_ARRAY:
    case rmf_avro::AVRO_MAP:
        generateTraits(n->leafAt(n->type() == rmf_avro::AVRO_ARRAY ? 0 : 1));
        break;
    case rmf_avro::AVRO_UNION:
        generateUnionTraits(n);
        break;
    case rmf_avro::AVRO_FIXED:
        break;
    default:
        break;
    }
}

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

string CodeGen::guard()
{
    string h = headerFile_;
    makeCanonical(h, true);
    return h + "_" + lexical_cast<string>(random_()) + "__H_";
}

void CodeGen::generate(const ValidSchema& schema)
{
    emitCopyright();

    string h = guardString_.empty() ? guard() : guardString_;

    os_ << "#ifndef " << h << "\n";
    os_ << "#define " << h << "\n\n\n";

    os_ << "#include \"boost/any.hpp\"\n"
        << "#include \"" << includePrefix_ << "Specific.hh\"\n"
        << "#include \"" << includePrefix_ << "Encoder.hh\"\n"
        << "#include \"" << includePrefix_ << "Decoder.hh\"\n"
        << "\n";

    if (! ns_.empty()) {
        os_ << "namespace " << ns_ << " {\n";
        inNamespace_ = true;
    }

    const NodePtr& root = schema.root();
    generateType(root);

    for (vector<PendingSetterGetter>::const_iterator it =
        pendingGettersAndSetters.begin();
        it != pendingGettersAndSetters.end(); ++it) {
        generateGetterAndSetter(os_, it->structName, it->type, it->name,
            it->idx);
    }

    for (vector<PendingConstructor>::const_iterator it =
        pendingConstructors.begin();
        it != pendingConstructors.end(); ++it) {
        generateConstructor(os_, it->structName,
            it->initMember, it->memberName);
    }

    if (! ns_.empty()) {
        inNamespace_ = false;
        os_ << "}\n";
    }

    os_ << "namespace rmf_avro {\n";

    unionNumber_ = 0;

    generateTraits(root);

    os_ << "}\n";

    os_ << "#endif\n";
    os_.flush();

}

namespace po = boost::program_options;

static const string NS("namespace");
static const string OUT("output");
static const string IN("input");
static const string INCLUDE_PREFIX("include-prefix");
static const string NO_UNION_TYPEDEF("no-union-typedef");

static string readGuard(const string& filename)
{
    std::ifstream ifs(filename.c_str());
    string buf;
    string candidate;
    while (std::getline(ifs, buf)) {
        boost::algorithm::trim(buf);
        if (candidate.empty()) {
            if (boost::algorithm::starts_with(buf, "#ifndef ")) {
                candidate = buf.substr(8);
            }
        } else if (boost::algorithm::starts_with(buf, "#define ")) {
            if (candidate == buf.substr(8)) {
                break;
            }
        } else {
            candidate.erase();
        }
    }
    return candidate;
}

int main(int argc, char** argv)
{
    po::options_description desc("Allowed options");
    desc.add_options()
        ("help,h", "produce help message")
        ("include-prefix,p", po::value<string>()->default_value("avro"),
            "prefix for include headers, - for none, default: avro")
        ("no-union-typedef,U", "do not generate typedefs for unions in records")
        ("namespace,n", po::value<string>(), "set namespace for generated code")
        ("input,i", po::value<string>(), "input file")
        ("output,o", po::value<string>(), "output file to generate");

    po::variables_map vm;
    po::store(po::parse_command_line(argc, argv, desc), vm);
    po::notify(vm);


    if (vm.count("help") || vm.count(IN) == 0 || vm.count(OUT) == 0) {
        std::cout << desc << std::endl;
        return 1;
    }

    string ns = vm.count(NS) > 0 ? vm[NS].as<string>() : string();
    string outf = vm.count(OUT) > 0 ? vm[OUT].as<string>() : string();
    string inf = vm.count(IN) > 0 ? vm[IN].as<string>() : string();
    string incPrefix = vm[INCLUDE_PREFIX].as<string>();
    bool noUnion = vm.count(NO_UNION_TYPEDEF) != 0;
    if (incPrefix == "-") {
        incPrefix.clear();
    } else if (*incPrefix.rbegin() != '/') {
        incPrefix += "/";
    }

    try {
        ValidSchema schema;

        if (! inf.empty()) {
            ifstream in(inf.c_str());
            compileJsonSchema(in, schema);
        } else {
            compileJsonSchema(std::cin, schema);
        }

        if (! outf.empty()) {
            string g = readGuard(outf);
            ofstream out(outf.c_str());
            CodeGen(out, ns, inf, outf, g, incPrefix, noUnion).generate(schema);
        } else {
            CodeGen(std::cout, ns, inf, outf, "", incPrefix, noUnion).
                generate(schema);
        }
        return 0;
    } catch (std::exception &e) {
        std::cerr << "Failed to parse or compile schema: "
            << e.what() << std::endl;
        return 1;
    }

}