#include "api.h"
#include <QDebug>
#include <QJsonDocument>
#include <QJsonObject>

constexpr const char* json = "application/json";

struct NetworkReplyDeleter {
    void operator () (QNetworkReply* reply) {
        reply->deleteLater();
    }
};

API::API(const QUrl& address, QObject* parent):
    QObject(parent),
    address(address),
    network()
{

}

void API::test(const QString& path, const QJSValue& finished) {
    qDebug() << "Testing" << path;
    QNetworkRequest request(path + "/info");
    request.setHeader(QNetworkRequest::ContentTypeHeader, json);

    QNetworkReply* reply = network.get(request);
    connect(reply, &QNetworkReply::finished,
        std::bind(&API::onTestSuccess, this, reply, finished)
    );
}

void API::onTestSuccess(QNetworkReply* reply, const QJSValue& finished) const {
    std::unique_ptr<QNetworkReply, NetworkReplyDeleter> rpl(reply);
    QNetworkReply::NetworkError error = reply->error();
    if (error != QNetworkReply::NoError) {
        QString err = reply->errorString();
        qDebug() << "Test for" << reply->url() << "failed:" << err;
        callCallback(finished, err);
        return;
    }

    QVariant contentType = reply->header(QNetworkRequest::ContentTypeHeader);
    if (!
        contentType.isValid() ||
        !contentType.canConvert<QString>() ||
        contentType.toString() != json
    ) {
        QString err("wrong response content type");
        qDebug() << "Test for" << reply->url() << "failed:" << err;
        callCallback(finished, err);
        return;
    }

    QByteArray data = reply->readAll();
    QJsonDocument document = QJsonDocument::fromJson(data);
    QJsonObject rootObj = document.object();

    QJsonValue type = rootObj.value("type");
    QJsonValue version = rootObj.value("version");
    if (!type.isString() || !version.isString()) {
        QString err("malformed json");
        qDebug() << "Test for" << reply->url() << "failed:" << err;
        callCallback(finished, err);
        return;
    }

    if (type.toString() != "Pica") {
        QString err("server of this type (" + type.toString() + ") is not supported");
        qDebug() << "Test for" << reply->url() << "failed:" << err;
        callCallback(finished, err);
        return;
    }

    if (version.toString() != "0.0.1") {
        QString err("server of this version (" + version.toString() + ") is not supported");
        qDebug() << "Test for" << reply->url() << "failed:" << err;
        callCallback(finished, err);
        return;
    }

    callCallback(finished, QString(), {QJSValue(true)});
}

void API::callCallback(const QJSValue& callback, const QString& error, const QJSValueList& arguments) const {
    if (callback.isCallable()) {
        if (error.isEmpty())
            callback.call(QJSValueList({QJSValue(QJSValue::NullValue)}) + arguments);
        else
            callback.call({QJSValue(error)});
    }
}