#include "chatgpt.h"

#include <string>
#include <vector>
#include <iostream>

#include <QCoreApplication>
#include <QThread>
#include <QEventLoop>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>

//#define DEBUG

ChatGPT::ChatGPT()
    : QObject(nullptr)
    , m_modelName("gpt-3.5-turbo")
    , m_responseCallback(nullptr)
{
}

size_t ChatGPT::requiredMem(const std::string &modelPath)
{
    Q_UNUSED(modelPath);
    return 0;
}

bool ChatGPT::loadModel(const std::string &modelPath)
{
    Q_UNUSED(modelPath);
    return true;
}

void ChatGPT::setThreadCount(int32_t n_threads)
{
    Q_UNUSED(n_threads);
    qt_noop();
}

int32_t ChatGPT::threadCount() const
{
    return 1;
}

ChatGPT::~ChatGPT()
{
}

bool ChatGPT::isModelLoaded() const
{
    return true;
}

// All three of the state virtual functions are handled custom inside of chatllm save/restore
size_t ChatGPT::stateSize() const
{
    return 0;
}

size_t ChatGPT::saveState(uint8_t *dest) const
{
    Q_UNUSED(dest);
    return 0;
}

size_t ChatGPT::restoreState(const uint8_t *src)
{
    Q_UNUSED(src);
    return 0;
}

void ChatGPT::prompt(const std::string &prompt,
        std::function<bool(int32_t)> promptCallback,
        std::function<bool(int32_t, const std::string&)> responseCallback,
        std::function<bool(bool)> recalculateCallback,
        PromptContext &promptCtx) {

    Q_UNUSED(promptCallback);
    Q_UNUSED(recalculateCallback);

    if (!isModelLoaded()) {
        std::cerr << "ChatGPT ERROR: prompt won't work with an unloaded model!\n";
        return;
    }

    // FIXME: We don't set the max_tokens on purpose because in order to do so safely without encountering
    // an error we need to be able to count the tokens in our prompt. The only way to do this is to use
    // the OpenAI tiktokken library or to implement our own tokenization function that matches precisely
    // the tokenization used by the OpenAI model we're calling. OpenAI has not introduced any means of
    // using the REST API to count tokens in a prompt.
    QJsonObject root;
    root.insert("model", m_modelName);
    root.insert("stream", true);
    root.insert("temperature", promptCtx.temp);
    root.insert("top_p", promptCtx.top_p);

    QJsonArray messages;
    for (int i = 0; i < m_context.count() && i < promptCtx.n_past; ++i) {
        QJsonObject message;
        message.insert("role", i % 2 == 0 ? "assistant" : "user");
        message.insert("content", m_context.at(i));
        messages.append(message);
    }

    QJsonObject promptObject;
    promptObject.insert("role", "user");
    promptObject.insert("content", QString::fromStdString(prompt));
    messages.append(promptObject);
    root.insert("messages", messages);

    QJsonDocument doc(root);

#if defined(DEBUG)
    qDebug() << "ChatGPT::prompt begin network request" << qPrintable(doc.toJson());
#endif

    m_responseCallback = responseCallback;

    // The following code sets up a worker thread and object to perform the actual api request to
    // chatgpt and then blocks until it is finished
    QThread workerThread;
    ChatGPTWorker worker(this);
    worker.moveToThread(&workerThread);
    connect(&worker, &ChatGPTWorker::finished, &workerThread, &QThread::quit, Qt::DirectConnection);
    connect(this, &ChatGPT::request, &worker, &ChatGPTWorker::request, Qt::QueuedConnection);
    workerThread.start();
    emit request(m_apiKey, &promptCtx, doc.toJson(QJsonDocument::Compact));
    workerThread.wait();

    promptCtx.n_past += 1;
    m_context.append(QString::fromStdString(prompt));
    m_context.append(worker.currentResponse());
    m_responseCallback = nullptr;

#if defined(DEBUG)
    qDebug() << "ChatGPT::prompt end network request";
#endif
}

bool ChatGPT::callResponse(int32_t token, const std::string& string)
{
    Q_ASSERT(m_responseCallback);
    if (!m_responseCallback) {
        std::cerr << "ChatGPT ERROR: no response callback!\n";
        return false;
    }
    return m_responseCallback(token, string);
}

void ChatGPTWorker::request(const QString &apiKey,
        LLModel::PromptContext *promptCtx,
        const QByteArray &array)
{
    m_ctx = promptCtx;

    QUrl openaiUrl("https://api.openai.com/v1/chat/completions");
    const QString authorization = QString("Bearer %1").arg(apiKey);
    QNetworkRequest request(openaiUrl);
    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");
    request.setRawHeader("Authorization", authorization.toUtf8());
    m_networkManager = new QNetworkAccessManager(this);
    QNetworkReply *reply = m_networkManager->post(request, array);
    connect(qApp, &QCoreApplication::aboutToQuit, reply, &QNetworkReply::abort);
    connect(reply, &QNetworkReply::finished, this, &ChatGPTWorker::handleFinished);
    connect(reply, &QNetworkReply::readyRead, this, &ChatGPTWorker::handleReadyRead);
    connect(reply, &QNetworkReply::errorOccurred, this, &ChatGPTWorker::handleErrorOccurred);
}

void ChatGPTWorker::handleFinished()
{
    QNetworkReply *reply = qobject_cast<QNetworkReply *>(sender());
    if (!reply) {
        emit finished();
        return;
    }

    QVariant response = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
    Q_ASSERT(response.isValid());
    bool ok;
    int code = response.toInt(&ok);
    if (!ok || code != 200) {
        qWarning() << QString("ERROR: ChatGPT responded with error code \"%1-%2\"")
            .arg(code).arg(reply->errorString()).toStdString();
    }
    reply->deleteLater();
    emit finished();
}

void ChatGPTWorker::handleReadyRead()
{
    QNetworkReply *reply = qobject_cast<QNetworkReply *>(sender());
    if (!reply) {
        emit finished();
        return;
    }

    QVariant response = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
    Q_ASSERT(response.isValid());
    bool ok;
    int code = response.toInt(&ok);
    if (!ok || code != 200) {
        m_chat->callResponse(-1, QString("\nERROR: 2 ChatGPT responded with error code \"%1-%2\" %3\n")
            .arg(code).arg(reply->errorString()).arg(qPrintable(reply->readAll())).toStdString());
        emit finished();
        return;
    }

    while (reply->canReadLine()) {
        QString jsonData = reply->readLine().trimmed();
        if (jsonData.startsWith("data:"))
            jsonData.remove(0, 5);
        jsonData = jsonData.trimmed();
        if (jsonData.isEmpty())
            continue;
        if (jsonData == "[DONE]")
            continue;
#if defined(DEBUG)
        qDebug() << "line" << qPrintable(jsonData);
#endif
        QJsonParseError err;
        const QJsonDocument document = QJsonDocument::fromJson(jsonData.toUtf8(), &err);
        if (err.error != QJsonParseError::NoError) {
            m_chat->callResponse(-1, QString("\nERROR: ChatGPT responded with invalid json \"%1\"\n")
                .arg(err.errorString()).toStdString());
            continue;
        }

        const QJsonObject root = document.object();
        const QJsonArray choices = root.value("choices").toArray();
        const QJsonObject choice = choices.first().toObject();
        const QJsonObject delta = choice.value("delta").toObject();
        const QString content = delta.value("content").toString();
        Q_ASSERT(m_ctx);
        m_currentResponse += content;
        if (!m_chat->callResponse(0, content.toStdString())) {
            reply->abort();
            emit finished();
            return;
        }
    }
}

void ChatGPTWorker::handleErrorOccurred(QNetworkReply::NetworkError code)
{
    QNetworkReply *reply = qobject_cast<QNetworkReply *>(sender());
    if (!reply || reply->error() == QNetworkReply::OperationCanceledError /*when we call abort on purpose*/) {
        emit finished();
        return;
    }

    qWarning() << QString("ERROR: ChatGPT responded with error code \"%1-%2\"")
                      .arg(code).arg(reply->errorString()).toStdString();
    emit finished();
}