#include "apiUtils.h"

#include "core/repositories/secureAppSettingsRepository.h"
#include "core/utils/serverConfigUtils.h"
#include "core/utils/constants/configKeys.h"
#include <QDateTime>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonValue>

#if defined(Q_OS_ANDROID)
    #include "platforms/android/android_controller.h"
#endif

using namespace amnezia;

namespace
{
    const QByteArray AMNEZIA_CONFIG_SIGNATURE = QByteArray::fromHex("000000ff");

    constexpr QLatin1String unprocessableSubscriptionMessage("Failed to retrieve subscription information. Is it activated?");
    constexpr QLatin1String trialAlreadyUsedMessage("trial subscription already used");
    constexpr QLatin1String refreshCaptchaMessage("refresh_captcha");
    constexpr QLatin1String invalidCaptchaMessage("invalid_captcha");
    constexpr QLatin1String rateLimitExceededMessage("rate_limit_exceeded");

    QDateTime subscriptionEndUtcFromString(const QString &subscriptionEndDate)
    {
        if (subscriptionEndDate.isEmpty()) {
            return {};
        }
        QDateTime endDate = QDateTime::fromString(subscriptionEndDate, Qt::ISODateWithMs).toUTC();
        if (!endDate.isValid()) {
            endDate = QDateTime::fromString(subscriptionEndDate, Qt::ISODate).toUTC();
        }
        return endDate;
    }

    QString apiErrorMessageFromJson(const QJsonObject &jsonObj)
    {
        const QJsonValue value = jsonObj.value(QStringLiteral("message"));
        return value.isString() ? value.toString().trimmed() : QString();
    }

    QString escapeUnicode(const QString &input)
    {
        QString output;
        for (QChar c : input) {
            if (c.unicode() < 0x20 || c.unicode() > 0x7E) {
                output += QString("\\u%1").arg(QString::number(c.unicode(), 16).rightJustified(4, '0'));
            } else {
                output += c;
            }
        }
        return output;
    }
}

QString apiUtils::getAppLanguageCode(const SecureAppSettingsRepository *appSettingsRepository)
{
    if (appSettingsRepository == nullptr) {
        return {};
    }
    return appSettingsRepository->getAppLanguage().name().split("_").first();
}

QString apiUtils::getDistributionChannel()
{
#if defined(Q_OS_ANDROID)
    return AndroidController::instance()->isPlay() ? QStringLiteral("googleplay") : QString();
#elif defined(Q_OS_IOS) || defined(MACOS_NE)
    return QStringLiteral("appstore");
#else
    return QStringLiteral("github");
#endif
}

QString apiUtils::getCountryFlagCode(const QString &serverCountryCodeL10n, const QString &serverCountryCode)
{
    if (!serverCountryCodeL10n.isEmpty()) {
        return serverCountryCodeL10n.toUpper();
    }
    if (serverCountryCode.isEmpty()) {
        return {};
    }
    return serverCountryCode.section('-', 0, 0).toUpper();
}

bool apiUtils::isSubscriptionExpired(const QString &subscriptionEndDate)
{
    if (subscriptionEndDate.isEmpty()) {
        return false;
    }
    const QDateTime endDate = subscriptionEndUtcFromString(subscriptionEndDate);
    if (!endDate.isValid()) {
        return false;
    }
    return endDate <= QDateTime::currentDateTimeUtc();
}

bool apiUtils::isSubscriptionExpiringSoon(const QString &subscriptionEndDate, int withinDays)
{
    if (subscriptionEndDate.isEmpty()) {
        return false;
    }
    const QDateTime endDate = subscriptionEndUtcFromString(subscriptionEndDate);
    if (!endDate.isValid()) {
        return false;
    }
    const QDateTime nowUtc = QDateTime::currentDateTimeUtc();
    if (endDate <= nowUtc) {
        return false;
    }
    return endDate <= nowUtc.addDays(withinDays);
}

amnezia::ErrorCode apiUtils::checkApiResponseErrors(const QByteArray &responseBody)
{
    const int httpStatusCodeConflict = 409;
    const int httpStatusCodeNotFound = 404;
    const int httpStatusCodeNotImplemented = 501;
    const int httpStatusCodePaymentRequired = 402;
    const int httpStatusCodeTooManyRequests = 429;
    const int httpStatusCodeRequestTimeout = 408;
    const int httpStatusCodeUnprocessableEntity = 422;

    QJsonDocument jsonDoc = QJsonDocument::fromJson(responseBody);
    if (!jsonDoc.isObject()) {
        return amnezia::ErrorCode::NoError;
    }

    QJsonObject jsonObj = jsonDoc.object();
    const int httpStatusFromBody = jsonObj.value(apiDefs::key::httpStatus).toInt(-1);
    if (httpStatusFromBody < 0) {
        return amnezia::ErrorCode::NoError;
    }

    if (httpStatusFromBody == httpStatusCodeTooManyRequests) {
        return amnezia::ErrorCode::ApiRateLimitError;
    }
    if (httpStatusFromBody == httpStatusCodeConflict) {
        if (apiErrorMessageFromJson(jsonObj).contains(trialAlreadyUsedMessage, Qt::CaseInsensitive)) {
            return amnezia::ErrorCode::ApiTrialAlreadyUsedError;
        }
        return amnezia::ErrorCode::ApiConfigLimitError;
    }
    if (httpStatusFromBody == httpStatusCodeNotFound) {
        return amnezia::ErrorCode::ApiNotFoundError;
    }
    if (httpStatusFromBody == httpStatusCodeRequestTimeout) {
        return amnezia::ErrorCode::ApiConfigTimeoutError;
    }
    if (httpStatusFromBody == httpStatusCodeNotImplemented) {
        return amnezia::ErrorCode::ApiUpdateRequestError;
    }
    if (httpStatusFromBody == httpStatusCodeUnprocessableEntity) {
        if (apiErrorMessageFromJson(jsonObj) == unprocessableSubscriptionMessage) {
            return amnezia::ErrorCode::ApiSubscriptionExpiredError;
        }
        return amnezia::ErrorCode::ApiConfigDownloadError;
    }
    if (httpStatusFromBody == httpStatusCodePaymentRequired) {
        const QString message = apiErrorMessageFromJson(jsonObj);
        if (message.contains(refreshCaptchaMessage, Qt::CaseInsensitive)) {
            return amnezia::ErrorCode::ApiCaptchaRefreshError;
        }
        if (message.contains(invalidCaptchaMessage, Qt::CaseInsensitive)) {
            return amnezia::ErrorCode::ApiCaptchaInvalidError;
        }
        if (jsonObj.contains(apiDefs::key::captchaId) || jsonObj.contains(apiDefs::key::captchaImage)
            || message.contains(rateLimitExceededMessage, Qt::CaseInsensitive)) {
            return amnezia::ErrorCode::ApiCaptchaRequiredError;
        }
        return amnezia::ErrorCode::ApiSubscriptionNotActiveError;
    }

    if (httpStatusFromBody >= 300) {
        return amnezia::ErrorCode::ApiConfigDownloadError;
    }
    return amnezia::ErrorCode::NoError;
}

bool apiUtils::isPremiumServer(const QJsonObject &serverConfigObject)
{
    static const QSet<serverConfigUtils::ConfigType> premiumTypes = { serverConfigUtils::ConfigType::AmneziaPremiumV1, serverConfigUtils::ConfigType::AmneziaPremiumV2,
                                                            serverConfigUtils::ConfigType::ExternalPremium };
    return premiumTypes.contains(serverConfigUtils::configTypeFromJson(serverConfigObject));
}

QString apiUtils::getPremiumV2VpnKey(const QJsonObject &serverConfigObject)
{
    auto configType = serverConfigUtils::configTypeFromJson(serverConfigObject);
    if (configType != serverConfigUtils::ConfigType::AmneziaPremiumV2 && configType != serverConfigUtils::ConfigType::ExternalPremium) {
        return {};
    }

    QString vpnKeyText = "";

    auto apiConfig = serverConfigObject.value(apiDefs::key::apiConfig).toObject();
    auto authData = serverConfigObject.value(QLatin1String("auth_data")).toObject();

    const QString name = serverConfigObject.value(configKey::name).toString();
    const QString description = serverConfigObject.value(configKey::description).toString();
    const double configVersion = serverConfigObject.value(configKey::configVersion).toDouble();

    const QString serviceType = apiConfig.value(apiDefs::key::serviceType).toString();
    const QString serviceProtocol = apiConfig.value(QLatin1String("service_protocol")).toString();
    const QString userCountryCode = apiConfig.value(QLatin1String("user_country_code")).toString();

    const QString apiKey = authData.value(apiDefs::key::apiKey).toString();

    QString vpnKeyStr = "{";
    vpnKeyStr += "\"" + QString(configKey::name) + "\": \"" + name + "\", ";
    vpnKeyStr += "\"" + QString(configKey::description) + "\": \"" + description + "\", ";
    vpnKeyStr += "\"" + QString(configKey::configVersion) + "\": " + QString::number(static_cast<int>(configVersion)) + ", ";

    vpnKeyStr += "\"" + QString(apiDefs::key::apiConfig) + "\": {";
    vpnKeyStr += "\"" + QString(apiDefs::key::serviceType) + "\": \"" + serviceType + "\", ";
    vpnKeyStr += "\"service_protocol\": \"" + serviceProtocol + "\", ";
    vpnKeyStr += "\"user_country_code\": \"" + userCountryCode + "\"";
    vpnKeyStr += "}, ";

    vpnKeyStr += "\"auth_data\": {";
    vpnKeyStr += "\"" + QString(apiDefs::key::apiKey) + "\": \"" + apiKey + "\"";
    vpnKeyStr += "}";

    vpnKeyStr += "}";

    QByteArray vpnKeyCompressed = escapeUnicode(vpnKeyStr).toUtf8();
    vpnKeyCompressed = qCompress(vpnKeyCompressed, 6);
    vpnKeyCompressed = vpnKeyCompressed.mid(4);

    QByteArray signedData = AMNEZIA_CONFIG_SIGNATURE + vpnKeyCompressed;
    vpnKeyText = QString("vpn://%1").arg(QString(signedData.toBase64(QByteArray::Base64UrlEncoding)));

    return vpnKeyText;
}