/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
/*
    Piper C++

    An API for audio analysis and feature extraction plugins.

    Centre for Digital Music, Queen Mary, University of London.
    Copyright 2006-2016 Chris Cannam and QMUL.
  
    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use, copy,
    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the names of the Centre for
    Digital Music; Queen Mary, University of London; and Chris Cannam
    shall not be used in advertising or otherwise to promote the sale,
    use or other dealings in this Software without prior written
    authorization.
*/

#include "vamp-json/VampJson.h"
#include "vamp-capnp/VampnProto.h"
#include "vamp-support/RequestOrResponse.h"
#include "vamp-support/PreservingPluginHandleMapper.h"

#include <iostream>
#include <sstream>
#include <stdexcept>

#include <capnp/serialize.h>

// for _setmode stuff
#ifdef _WIN32
#include <io.h>
#include <fcntl.h>
#endif

using namespace std;
using namespace json11;
using namespace piper_vamp;

void usage()
{
    string myname = "piper-convert";
    cerr << "\n" << myname <<
        ": Validate and convert Piper request and response messages\n\n"
        "    Usage: " << myname << " [-i <informat>] [-o <outformat>] request\n"
        "           " << myname << " [-i <informat>] [-o <outformat>] response\n\n"
        "    where\n"
        "       <informat>: the format to read from stdin\n"
        "           (\"json\" or \"capnp\", default is \"json\")\n"
        "       <outformat>: the format to convert to and write to stdout\n"
        "           (\"json\", \"json-b64\" or \"capnp\", default is \"json\")\n"
        "       request|response: whether messages are Vamp request or response type\n\n"
        "If <informat> and <outformat> differ, convert from <informat> to <outformat>.\n"
        "If <informat> and <outformat> are the same, just check validity of incoming\n"
        "messages and pass them to output.\n\n"
        "Specifying \"json-b64\" as output format forces base64 encoding for process and\n"
        "feature blocks, unlike the \"json\" output format which uses text encoding.\n"
        "The \"json\" input format accepts either.\n\n";

    exit(2);
}

Json
convertRequestJson(string input, string &err)
{
    Json j = Json::parse(input, err);
    if (err != "") {
        err = "invalid json: " + err;
        return {};
    }
    if (!j.is_object()) {
        err = "object expected at top level";
    } else if (!j["method"].is_string()) {
        err = "string expected for method field";
    } else if (!j["params"].is_null() && !j["params"].is_object()) {
        err = "object expected for params field";
    }
    return j;
}

Json
convertResponseJson(string input, string &err)
{
    Json j = Json::parse(input, err);
    if (err != "") {
        err = "invalid json: " + err;
        return {};
    }
    if (!j.is_object()) {
        err = "object expected at top level";
    } else {
        if (!j["result"].is_object()) {
            if (!j["error"].is_object()) {
                err = "expected either result or error object";
            }
        }
    }
    return j;
}

//!!! Lots of potential for refactoring the conversion classes based
//!!! on the common matter in the following eight functions...

PreservingPluginHandleMapper mapper;

static RequestOrResponse::RpcId
readJsonId(const Json &j)
{
    RequestOrResponse::RpcId id;

    if (j["id"].is_number()) {
        id.type = RequestOrResponse::RpcId::Number;
        id.number = j["id"].number_value();
    } else if (j["id"].is_string()) {
        id.type = RequestOrResponse::RpcId::Tag;
        id.tag = j["id"].string_value();
    } else {
        id.type = RequestOrResponse::RpcId::Absent;
    }

    return id;
}

static Json
writeJsonId(const RequestOrResponse::RpcId &id)
{
    if (id.type == RequestOrResponse::RpcId::Number) {
        return id.number;
    } else if (id.type == RequestOrResponse::RpcId::Tag) {
        return id.tag;
    } else {
        return Json();
    }
}

template <typename Reader, typename Id>
static RequestOrResponse::RpcId
readCapnpId(const Reader &r)
{
    int number;
    string tag;
    switch (r.getId().which()) {
    case Id::Which::NUMBER:
        number = r.getId().getNumber();
        return { RequestOrResponse::RpcId::Number, number, "" };
    case Id::Which::TAG:
        tag = r.getId().getTag();
        return { RequestOrResponse::RpcId::Tag, 0, tag };
    case Id::Which::NONE:
        return { RequestOrResponse::RpcId::Absent, 0, "" };
    }
    return { RequestOrResponse::RpcId::Absent, 0, "" };
}

template <typename Builder>
static void
buildCapnpId(Builder &b, const RequestOrResponse::RpcId &id)
{
    switch (id.type) {
    case RequestOrResponse::RpcId::Number:
        b.getId().setNumber(id.number);
        break;
    case RequestOrResponse::RpcId::Tag:
        b.getId().setTag(id.tag);
        break;
    case RequestOrResponse::RpcId::Absent:
        b.getId().setNone();
        break;
    }
}

RequestOrResponse
readRequestJson(string &err, bool &eof)
{
    RequestOrResponse rr;
    rr.direction = RequestOrResponse::Request;

    string input;
    if (!getline(cin, input)) {
        // the EOF case, not actually an error
        eof = true;
        return rr;
    }
    
    Json j = convertRequestJson(input, err);
    if (err != "") return {};

    rr.type = VampJson::getRequestResponseType(j, err);
    if (err != "") return {};

    rr.id = readJsonId(j);

    VampJson::BufferSerialisation serialisation =
        VampJson::BufferSerialisation::Array;

    switch (rr.type) {

    case RRType::List:
        rr.listRequest = VampJson::toRpcRequest_List(j, err);
        break;
    case RRType::Load:
        rr.loadRequest = VampJson::toRpcRequest_Load(j, err);
        break;
    case RRType::Configure:
        rr.configurationRequest = VampJson::toRpcRequest_Configure(j, mapper, err);
        break;
    case RRType::Process:
        rr.processRequest = VampJson::toRpcRequest_Process(j, mapper, serialisation, err);
        break;
    case RRType::Finish:
        rr.finishRequest = VampJson::toRpcRequest_Finish(j, mapper, err);
        break;
    case RRType::NotValid:
        break;
    }

    return rr;
}

void
writeRequestJson(RequestOrResponse &rr, bool useBase64)
{
    Json j;

    VampJson::BufferSerialisation serialisation =
        (useBase64 ?
         VampJson::BufferSerialisation::Base64 :
         VampJson::BufferSerialisation::Array);

    Json id = writeJsonId(rr.id);
    
    switch (rr.type) {

    case RRType::List:
        j = VampJson::fromRpcRequest_List(rr.listRequest, id);
        break;
    case RRType::Load:
        j = VampJson::fromRpcRequest_Load(rr.loadRequest, id);
        break;
    case RRType::Configure:
        j = VampJson::fromRpcRequest_Configure(rr.configurationRequest, mapper, id);
        break;
    case RRType::Process:
        j = VampJson::fromRpcRequest_Process
            (rr.processRequest, mapper, serialisation, id);
        break;
    case RRType::Finish:
        j = VampJson::fromRpcRequest_Finish(rr.finishRequest, mapper, id);
        break;
    case RRType::NotValid:
        break;
    }

    cout << j.dump() << endl;
}

RequestOrResponse
readResponseJson(string &err, bool &eof)
{
    RequestOrResponse rr;
    rr.direction = RequestOrResponse::Response;

    string input;
    if (!getline(cin, input)) {
        // the EOF case, not actually an error
        eof = true;
        return rr;
    }

    Json j = convertResponseJson(input, err);
    if (err != "") return {};

    rr.type = VampJson::getRequestResponseType(j, err);
    if (err != "") return {};

    rr.id = readJsonId(j);
    
    VampJson::BufferSerialisation serialisation =
        VampJson::BufferSerialisation::Array;

    const bool isSuccess = j["result"].is_object();
    const bool isError = j["error"].is_object();
    rr.success = isSuccess;
    rr.errorText = isError ? j["error"]["message"].string_value() : "";

    switch (rr.type) {

    case RRType::List:
        rr.listResponse = VampJson::toRpcResponse_List(j, err);
        break;
    case RRType::Load:
        rr.loadResponse = VampJson::toRpcResponse_Load(j, mapper, err);
        break;
    case RRType::Configure:
        rr.configurationResponse = VampJson::toRpcResponse_Configure(j, mapper, err);
        break;
    case RRType::Process: 
        rr.processResponse = VampJson::toRpcResponse_Process(j, mapper, serialisation, err);
        break;
    case RRType::Finish:
        rr.finishResponse = VampJson::toRpcResponse_Finish(j, mapper, serialisation, err);
        break;
    case RRType::NotValid:
        break;
    }

    return rr;
}

void
writeResponseJson(RequestOrResponse &rr, bool useBase64)
{
    Json j;

    VampJson::BufferSerialisation serialisation =
        (useBase64 ?
         VampJson::BufferSerialisation::Base64 :
         VampJson::BufferSerialisation::Array);

    Json id = writeJsonId(rr.id);

    if (!rr.success) {
         // errorText here likely contains a full message produced by simple-server
         // setting writeVerbatimError to true avoids doubling error descriptions 
        j = VampJson::fromError(rr.errorText, rr.type, id, true);

    } else {
        switch (rr.type) {

        case RRType::List:
            j = VampJson::fromRpcResponse_List(rr.listResponse, id);
            break;
        case RRType::Load:
            j = VampJson::fromRpcResponse_Load(rr.loadResponse, mapper, id);
            break;
        case RRType::Configure:
            j = VampJson::fromRpcResponse_Configure(rr.configurationResponse,
                                                    mapper, id);
            break;
        case RRType::Process:
            j = VampJson::fromRpcResponse_Process
                (rr.processResponse, mapper, serialisation, id);
            break;
        case RRType::Finish:
            j = VampJson::fromRpcResponse_Finish
                (rr.finishResponse, mapper, serialisation, id);
            break;
        case RRType::NotValid:
            j = VampJson::fromError(rr.errorText, rr.type, id);
            break;
        }
    }
    
    cout << j.dump() << endl;
}

RequestOrResponse
readRequestCapnp(kj::BufferedInputStreamWrapper &buffered)
{
    RequestOrResponse rr;
    rr.direction = RequestOrResponse::Request;

    capnp::InputStreamMessageReader message(buffered);
    piper::RpcRequest::Reader reader = message.getRoot<piper::RpcRequest>();
    
    rr.type = VampnProto::getRequestResponseType(reader);
    rr.id = readCapnpId<piper::RpcRequest::Reader, piper::RpcRequest::Id>
        (reader);

    switch (rr.type) {

    case RRType::List:
        VampnProto::readRpcRequest_List(rr.listRequest, reader);
        break;
    case RRType::Load:
        VampnProto::readRpcRequest_Load(rr.loadRequest, reader);
        break;
    case RRType::Configure:
        VampnProto::readRpcRequest_Configure(rr.configurationRequest,
                                             reader, mapper);
        break;
    case RRType::Process:
        VampnProto::readRpcRequest_Process(rr.processRequest, reader, mapper);
        break;
    case RRType::Finish:
        VampnProto::readRpcRequest_Finish(rr.finishRequest, reader, mapper);
        break;
    case RRType::NotValid:
        break;
    }

    return rr;
}

void
writeRequestCapnp(RequestOrResponse &rr)
{
    capnp::MallocMessageBuilder message;
    piper::RpcRequest::Builder builder = message.initRoot<piper::RpcRequest>();

    buildCapnpId(builder, rr.id);
    
    switch (rr.type) {

    case RRType::List:
        VampnProto::buildRpcRequest_List(builder, rr.listRequest);
        break;
    case RRType::Load:
        VampnProto::buildRpcRequest_Load(builder, rr.loadRequest);
        break;
    case RRType::Configure:
        VampnProto::buildRpcRequest_Configure(builder,
                                              rr.configurationRequest, mapper);
        break;
    case RRType::Process:
        VampnProto::buildRpcRequest_Process(builder, rr.processRequest, mapper);
        break;
    case RRType::Finish:
        VampnProto::buildRpcRequest_Finish(builder, rr.finishRequest, mapper);
        break;
    case RRType::NotValid:
        break;
    }

    writeMessageToFd(1, message);
}

RequestOrResponse
readResponseCapnp(kj::BufferedInputStreamWrapper &buffered)
{
    RequestOrResponse rr;
    rr.direction = RequestOrResponse::Response;

    capnp::InputStreamMessageReader message(buffered);
    piper::RpcResponse::Reader reader = message.getRoot<piper::RpcResponse>();
    
    rr.type = VampnProto::getRequestResponseType(reader);
    rr.success = true;
    rr.errorText = "";
    rr.id = readCapnpId<piper::RpcResponse::Reader, piper::RpcResponse::Id>
        (reader);
    int errorCode = 0;

    switch (rr.type) {

    case RRType::List:
        VampnProto::readRpcResponse_List(rr.listResponse, reader);
        break;
    case RRType::Load:
        VampnProto::readRpcResponse_Load(rr.loadResponse, reader, mapper);
        break;
    case RRType::Configure:
        VampnProto::readRpcResponse_Configure(rr.configurationResponse,
                                              reader, mapper);
        break;
    case RRType::Process:
        VampnProto::readRpcResponse_Process(rr.processResponse, reader, mapper);
        break;
    case RRType::Finish:
        VampnProto::readRpcResponse_Finish(rr.finishResponse, reader, mapper);
        break;
    case RRType::NotValid:
        VampnProto::readRpcResponse_Error(errorCode, rr.errorText, reader);
        break;
    }

    return rr;
}

void
writeResponseCapnp(RequestOrResponse &rr)
{
    capnp::MallocMessageBuilder message;
    piper::RpcResponse::Builder builder = message.initRoot<piper::RpcResponse>();

    buildCapnpId(builder, rr.id);

    if (!rr.success) {

        VampnProto::buildRpcResponse_Error(builder, rr.errorText, rr.type);

    } else {
        
        switch (rr.type) {

        case RRType::List:
            VampnProto::buildRpcResponse_List(builder, rr.listResponse);
            break;
        case RRType::Load:
            VampnProto::buildRpcResponse_Load(builder, rr.loadResponse, mapper);
            break;
        case RRType::Configure:
            VampnProto::buildRpcResponse_Configure(builder, rr.configurationResponse, mapper);
            break;
        case RRType::Process:
            VampnProto::buildRpcResponse_Process(builder, rr.processResponse, mapper);
            break;
        case RRType::Finish:
            VampnProto::buildRpcResponse_Finish(builder, rr.finishResponse, mapper);
            break;
        case RRType::NotValid:
            VampnProto::buildRpcResponse_Error(builder, rr.errorText, rr.type);
            break;
        }
    }
    
    writeMessageToFd(1, message);
}

RequestOrResponse
readInputJson(RequestOrResponse::Direction direction, string &err, bool &eof)
{
    if (direction == RequestOrResponse::Request) {
        return readRequestJson(err, eof);
    } else {
        return readResponseJson(err, eof);
    }
}

RequestOrResponse
readInputCapnp(RequestOrResponse::Direction direction, bool &eof)
{
    static kj::FdInputStream stream(0); // stdin
    static kj::BufferedInputStreamWrapper buffered(stream);

    if (buffered.tryGetReadBuffer() == nullptr) {
        eof = true;
        return {};
    }
    
    if (direction == RequestOrResponse::Request) {
        return readRequestCapnp(buffered);
    } else {
        return readResponseCapnp(buffered);
    }
}

RequestOrResponse
readInput(string format, RequestOrResponse::Direction direction, bool &eof)
{
    eof = false;
    
    if (format == "json") {
        string err;
        auto result = readInputJson(direction, err, eof);
        if (err != "") throw runtime_error(err);
        else return result;
    } else if (format == "capnp") {
        return readInputCapnp(direction, eof);
    } else {
        throw runtime_error("unknown input format \"" + format + "\"");
    }
}

void
writeOutput(string format, RequestOrResponse &rr)
{
    if (format == "json") {
        if (rr.direction == RequestOrResponse::Request) {
            writeRequestJson(rr, false);
        } else {
            writeResponseJson(rr, false);
        }
    } else if (format == "json-b64") {
        if (rr.direction == RequestOrResponse::Request) {
            writeRequestJson(rr, true);
        } else {
            writeResponseJson(rr, true);
        }
    } else if (format == "capnp") {
        if (rr.direction == RequestOrResponse::Request) {
            writeRequestCapnp(rr);
        } else {
            writeResponseCapnp(rr);
        }
    } else {
        throw runtime_error("unknown output format \"" + format + "\"");
    }
}

int main(int argc, char **argv)
{
    if (argc < 2) {
        usage();
    }

    string informat = "json", outformat = "json";
    RequestOrResponse::Direction direction = RequestOrResponse::Request;
    bool haveDirection = false;
    
    for (int i = 1; i < argc; ++i) {

        string arg = argv[i];
        bool final = (i + 1 == argc);
        
        if (arg == "-i") {
            if (final) usage();
            else informat = argv[++i];

        } else if (arg == "-o") {
            if (final) usage();
            else outformat = argv[++i];

        } else if (arg == "request") {
            direction = RequestOrResponse::Request;
            haveDirection = true;

        } else if (arg == "response") {
            direction = RequestOrResponse::Response;
            haveDirection = true;
            
        } else {
            usage();
        }
    }

    if (informat == "" || outformat == "" || !haveDirection) {
        usage();
    }

#ifdef _WIN32
    if (informat == "capnp") {
        int result = _setmode(_fileno(stdin), _O_BINARY);
        if (result == -1) {
            cerr << "Failed to set binary mode on stdin, necessary for capnp format" << endl;
            exit(1);
        }
    }
    if (outformat == "capnp") {
        int result = _setmode(_fileno(stdout), _O_BINARY);
        if (result == -1) {
            cerr << "Failed to set binary mode on stdout, necessary for capnp format" << endl;
            exit(1);
        }
    }
#endif

    while (true) {

        try {

            bool eof = false;
            RequestOrResponse rr = readInput(informat, direction, eof);
            if (eof) break;

            writeOutput(outformat, rr);

        } catch (std::exception &e) {
            cerr << "Error: " << e.what() << endl;
            exit(1);
        }
    }

    exit(0);
}