// Licensed under the Apache-2.0 license. See README.md for details.

#include "Json.h"

#include <QFile>

#include "FileSystem.h"
#include <math.h>

namespace Json
{
void write(const QJsonDocument &doc, const QString &filename)
{
    FS::write(filename, doc.toJson());
}
void write(const QJsonObject &object, const QString &filename)
{
    write(QJsonDocument(object), filename);
}
void write(const QJsonArray &array, const QString &filename)
{
    write(QJsonDocument(array), filename);
}

QByteArray toBinary(const QJsonObject &obj)
{
    return QJsonDocument(obj).toBinaryData();
}
QByteArray toBinary(const QJsonArray &array)
{
    return QJsonDocument(array).toBinaryData();
}
QByteArray toText(const QJsonObject &obj)
{
    return QJsonDocument(obj).toJson(QJsonDocument::Compact);
}
QByteArray toText(const QJsonArray &array)
{
    return QJsonDocument(array).toJson(QJsonDocument::Compact);
}

static bool isBinaryJson(const QByteArray &data)
{
    decltype(QJsonDocument::BinaryFormatTag) tag = QJsonDocument::BinaryFormatTag;
    return memcmp(data.constData(), &tag, sizeof(QJsonDocument::BinaryFormatTag)) == 0;
}
QJsonDocument requireDocument(const QByteArray &data, const QString &what)
{
    if (isBinaryJson(data))
    {
        QJsonDocument doc = QJsonDocument::fromBinaryData(data);
        if (doc.isNull())
        {
            throw JsonException(what + ": Invalid JSON (binary JSON detected)");
        }
        return doc;
    }
    else
    {
        QJsonParseError error;
        QJsonDocument doc = QJsonDocument::fromJson(data, &error);
        if (error.error != QJsonParseError::NoError)
        {
            throw JsonException(what + ": Error parsing JSON: " + error.errorString());
        }
        return doc;
    }
}
QJsonDocument requireDocument(const QString &filename, const QString &what)
{
    return requireDocument(FS::read(filename), what);
}
QJsonObject requireObject(const QJsonDocument &doc, const QString &what)
{
    if (!doc.isObject())
    {
        throw JsonException(what + " is not an object");
    }
    return doc.object();
}
QJsonArray requireArray(const QJsonDocument &doc, const QString &what)
{
    if (!doc.isArray())
    {
        throw JsonException(what + " is not an array");
    }
    return doc.array();
}

void writeString(QJsonObject &to, const QString &key, const QString &value)
{
    if (!value.isEmpty())
    {
        to.insert(key, value);
    }
}

void writeStringList(QJsonObject &to, const QString &key, const QStringList &values)
{
    if (!values.isEmpty())
    {
        QJsonArray array;
        for(auto value: values)
        {
            array.append(value);
        }
        to.insert(key, array);
    }
}

template<>
QJsonValue toJson<QUrl>(const QUrl &url)
{
    return QJsonValue(url.toString(QUrl::FullyEncoded));
}
template<>
QJsonValue toJson<QByteArray>(const QByteArray &data)
{
    return QJsonValue(QString::fromLatin1(data.toHex()));
}
template<>
QJsonValue toJson<QDateTime>(const QDateTime &datetime)
{
    return QJsonValue(datetime.toString(Qt::ISODate));
}
template<>
QJsonValue toJson<QDir>(const QDir &dir)
{
    return QDir::current().relativeFilePath(dir.absolutePath());
}
template<>
QJsonValue toJson<QUuid>(const QUuid &uuid)
{
    return uuid.toString();
}
template<>
QJsonValue toJson<QVariant>(const QVariant &variant)
{
    return QJsonValue::fromVariant(variant);
}


template<> QByteArray requireIsType<QByteArray>(const QJsonValue &value, const QString &what)
{
    const QString string = ensureIsType<QString>(value, what);
    // ensure that the string can be safely cast to Latin1
    if (string != QString::fromLatin1(string.toLatin1()))
    {
        throw JsonException(what + " is not encodable as Latin1");
    }
    return QByteArray::fromHex(string.toLatin1());
}

template<> QJsonArray requireIsType<QJsonArray>(const QJsonValue &value, const QString &what)
{
    if (!value.isArray())
    {
        throw JsonException(what + " is not an array");
    }
    return value.toArray();
}


template<> QString requireIsType<QString>(const QJsonValue &value, const QString &what)
{
    if (!value.isString())
    {
        throw JsonException(what + " is not a string");
    }
    return value.toString();
}

template<> bool requireIsType<bool>(const QJsonValue &value, const QString &what)
{
    if (!value.isBool())
    {
        throw JsonException(what + " is not a bool");
    }
    return value.toBool();
}

template<> double requireIsType<double>(const QJsonValue &value, const QString &what)
{
    if (!value.isDouble())
    {
        throw JsonException(what + " is not a double");
    }
    return value.toDouble();
}

template<> int requireIsType<int>(const QJsonValue &value, const QString &what)
{
    const double doubl = requireIsType<double>(value, what);
    if (fmod(doubl, 1) != 0)
    {
        throw JsonException(what + " is not an integer");
    }
    return int(doubl);
}

template<> QDateTime requireIsType<QDateTime>(const QJsonValue &value, const QString &what)
{
    const QString string = requireIsType<QString>(value, what);
    const QDateTime datetime = QDateTime::fromString(string, Qt::ISODate);
    if (!datetime.isValid())
    {
        throw JsonException(what + " is not a ISO formatted date/time value");
    }
    return datetime;
}

template<> QUrl requireIsType<QUrl>(const QJsonValue &value, const QString &what)
{
    const QString string = ensureIsType<QString>(value, what);
    if (string.isEmpty())
    {
        return QUrl();
    }
    const QUrl url = QUrl(string, QUrl::StrictMode);
    if (!url.isValid())
    {
        throw JsonException(what + " is not a correctly formatted URL");
    }
    return url;
}

template<> QDir requireIsType<QDir>(const QJsonValue &value, const QString &what)
{
    const QString string = requireIsType<QString>(value, what);
    // FIXME: does not handle invalid characters!
    return QDir::current().absoluteFilePath(string);
}

template<> QUuid requireIsType<QUuid>(const QJsonValue &value, const QString &what)
{
    const QString string = requireIsType<QString>(value, what);
    const QUuid uuid = QUuid(string);
    if (uuid.toString() != string) // converts back => valid
    {
        throw JsonException(what + " is not a valid UUID");
    }
    return uuid;
}

template<> QJsonObject requireIsType<QJsonObject>(const QJsonValue &value, const QString &what)
{
    if (!value.isObject())
    {
        throw JsonException(what + " is not an object");
    }
    return value.toObject();
}

template<> QVariant requireIsType<QVariant>(const QJsonValue &value, const QString &what)
{
    if (value.isNull() || value.isUndefined())
    {
        throw JsonException(what + " is null or undefined");
    }
    return value.toVariant();
}

template<> QJsonValue requireIsType<QJsonValue>(const QJsonValue &value, const QString &what)
{
    if (value.isNull() || value.isUndefined())
    {
        throw JsonException(what + " is null or undefined");
    }
    return value;
}

}
