pay/src/PriceDataProvider.h

/*
 * This file is part of the Flowee project
 * Copyright (C) 2021-2023 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef PRICEDATAPROVIDER_H
#define PRICEDATAPROVIDER_H

#include <QObject>

#include "PriceHistoryDataProvider.h"
#include <QNetworkAccessManager>
#include <QTimer>

class PriceDataProvider : public QObject
{
    Q_OBJECT
    Q_PROPERTY(int price READ price NOTIFY priceChanged)
    Q_PROPERTY(QString currencyName READ currencyName NOTIFY currencySymbolChanged)
    Q_PROPERTY(bool displayCents READ displayCents NOTIFY currencySymbolChanged)
    Q_PROPERTY(QString currencySymbolPrefix READ currencySymbolPrefix NOTIFY currencySymbolChanged)
    Q_PROPERTY(QString currencySymbolPost READ currencySymbolPost NOTIFY currencySymbolChanged)
public:
    explicit PriceDataProvider(const QString &countryCode = QString(), QObject *parent = nullptr);

    void start();

    QString currencyName() const {
        return m_currency;
    }

    // current price in cents
    int price() const {
        return m_currentPrice.price;
    }
    void setCurrency(const QLocale &countryLocale);
    void setCountry(const QString &countrycode);

    /**
     * Return a formatted string with the locale-defined price of the amount of \a sats.
     * This takes the BCH amount (in sats) and renders it into a price as the current locale defines,
     * based on \a price.
     */
    Q_INVOKABLE QString formattedPrice(double amountSats, int64_t price) const;
    /// Return the price as int (in cents) for the number of sats and the given price.
    Q_INVOKABLE int64_t priceFor(double amountSats, int64_t price) const;

    /**
     * Return a formatted string with the locale-defined price of a fiat price from \a cents.
     */
    Q_INVOKABLE QString formattedPrice(int64_t cents) const;

    /**
     * Return the price at a certain time in the past.
     */
    Q_INVOKABLE int historicalPrice(const QDateTime &timestamp) const;

    /**
     * Return the price at a certain time in the past, or 0 if none are on record.
     */
    Q_INVOKABLE int historicalPriceAccurate(const QDateTime &timestamp) const;

    /**
     * Return the price a certain amount of days in the past, or 0 if none are on record.
     */
    Q_INVOKABLE int historicalPriceAccurate(int days) const;

    /// return a string with the given price and needed decimal separator.
    /// Note: the currency indicators are not included, unlike in formattedPrice()
    /// \see currencySymbolPrefix()
    /// \see currencySymbolPost()
    Q_INVOKABLE QString priceToStringSimple(int64_t price) const;

    /**
     * Returns if the locale defined currency wants to display cents.
     *
     * Note: The typical 2 digits behind the separator are lazily called 'cents' here, even
     * though the actual naming is differnt in different currencies.
     */
    bool displayCents() const;

    /**
     * The string to show in front of a fiat price.
     * Fiat prices need some unit, or currency-symbol, which we split into the prefix and post
     * strings to help display in QML.
     */
    QString currencySymbolPrefix() const;

    /**
     * The string to show after a fiat price.
     * Fiat prices need some unit, or currency-symbol, which we split into the prefix and post
     * strings to help display in QML.
     */
    QString currencySymbolPost() const;

    void loadPriceHistory(const QString &basedir);

signals:
    void priceChanged(int32_t price);
    void currencySymbolChanged();

private slots:
    void fetch();
    void finishedDownload();
    void finishedYadioDownload();

private:
    struct Price {
        int32_t price = 0;
        uint32_t timestamp = 0;
    };

    Price m_currentPrice;
    QNetworkAccessManager m_network;
    QNetworkReply *m_reply = nullptr;
    QString m_currency;
    QString m_currencySymbolPrefix, m_currencySymbolPost;
    bool m_displayCents = true; // if true, display 2 digits behind the unit-separator
    int m_failedCount = 0;
    QTimer m_timer;

    // Prices converted via USD
    bool m_yadioViaUSD = false;
    QMap<QString, double> m_currencyConversions;

    QString m_basedir; // where the priceHistory is stored.
    std::unique_ptr<PriceHistoryDataProvider> m_priceHistory;
};

#endif