#include "useragent.h"

#include <QWebEngineClientHints>
#include <QWebEngineProfile>
#include <QtWebEngineCore/qtwebenginecoreglobal.h>

namespace useragent {

namespace {

// Gecko and WebKit versions can't come from the engine, so they are pinned
// here; bump them now and then so att doesn't look like an outdated browser.
constexpr auto kFirefoxVersion = "155.0";
constexpr auto kSafariVersion = "27.0";

// Chrome-based presets claim the engine's own Chromium major version, as
// qutebrowser does: a newer claim would make sites use features the engine
// lacks. Chrome's reduced UA string zeroes the minor parts.
QString chromeVersion()
{
    return QString::fromLatin1(qWebEngineChromiumVersion()).section(QLatin1Char('.'), 0, 0)
        + QStringLiteral(".0.0.0");
}

// What Sec-CH-UA-* (and navigator.userAgentData) should say, so they don't
// contradict the User-Agent string. Chromium always sends the low-entropy ones
// (brands, platform, mobile), even with client hints disabled, so every preset
// sets a matching platform. Firefox and Safari send no hints at all, so for
// them the high-entropy ones are disabled.
struct Hints {
    bool enabled;
    QString brand; // "Google Chrome" etc., next to Chromium's own brands
    QString platform;
    QString platformVersion;
    QString arch;
    QString bitness;
    bool mobile;
};

// The full version list for a brand: Chrome sends its own brand next to
// Chromium's (and a GREASE "Not A Brand"); an empty brand gives the engine's.
QVariantMap brands(const QString &brand)
{
    const QString full = QString::fromLatin1(qWebEngineChromiumVersion());
    QVariantMap list{{QStringLiteral("Chromium"), full},
        {QStringLiteral("Not=A?Brand"), QStringLiteral("24.0.0.0")}};
    if (!brand.isEmpty())
        list.insert(brand, full);
    return list;
}

struct Entry {
    Preset preset;
    Hints hints;
};

QList<Entry> buildEntries()
{
    const QString chrome = chromeVersion();
    const QString firefox = QString::fromLatin1(kFirefoxVersion);
    const QString safari = QString::fromLatin1(kSafariVersion);
    const auto chromeOn = [&](const QString &platform) {
        return QStringLiteral("Mozilla/5.0 (%1) AppleWebKit/537.36 (KHTML, like Gecko) "
                              "Chrome/%2 Safari/537.36")
            .arg(platform, chrome);
    };
    const auto firefoxOn = [&](const QString &platform) {
        return QStringLiteral("Mozilla/5.0 (%1; rv:%2) Gecko/20100101 Firefox/%2")
            .arg(platform, firefox);
    };

    return {
        {{QStringLiteral("chrome-linux"), chromeOn(QStringLiteral("X11; Linux x86_64"))},
            {true, QStringLiteral("Google Chrome"), QStringLiteral("Linux"), QString(),
                QStringLiteral("x86"), QStringLiteral("64"), false}},
        {{QStringLiteral("chrome-windows"),
             chromeOn(QStringLiteral("Windows NT 10.0; Win64; x64"))},
            {true, QStringLiteral("Google Chrome"), QStringLiteral("Windows"),
                QStringLiteral("19.0.0"), QStringLiteral("x86"), QStringLiteral("64"), false}},
        {{QStringLiteral("chrome-mac"),
             chromeOn(QStringLiteral("Macintosh; Intel Mac OS X 10_15_7"))},
            {true, QStringLiteral("Google Chrome"), QStringLiteral("macOS"),
                QStringLiteral("15.0.0"), QStringLiteral("arm"), QStringLiteral("64"), false}},
        {{QStringLiteral("chrome-android"),
             QStringLiteral("Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 "
                            "(KHTML, like Gecko) "
                            "Chrome/%1 Mobile Safari/537.36")
                 .arg(chrome)},
            {true, QStringLiteral("Google Chrome"), QStringLiteral("Android"),
                QStringLiteral("15.0.0"), QString(), QString(), true}},
        {{QStringLiteral("edge-windows"),
             chromeOn(QStringLiteral("Windows NT 10.0; Win64; x64"))
                 + QStringLiteral(" Edg/%1").arg(chrome)},
            {true, QStringLiteral("Microsoft Edge"), QStringLiteral("Windows"),
                QStringLiteral("19.0.0"), QStringLiteral("x86"), QStringLiteral("64"), false}},
        {{QStringLiteral("firefox-linux"), firefoxOn(QStringLiteral("X11; Linux x86_64"))},
            {false, {}, QStringLiteral("Linux"), {}, {}, {}, false}},
        {{QStringLiteral("firefox-windows"),
             firefoxOn(QStringLiteral("Windows NT 10.0; Win64; x64"))},
            {false, {}, QStringLiteral("Windows"), {}, {}, {}, false}},
        {{QStringLiteral("firefox-mac"),
             firefoxOn(QStringLiteral("Macintosh; Intel Mac OS X 10.15"))},
            {false, {}, QStringLiteral("macOS"), {}, {}, {}, false}},
        {{QStringLiteral("safari-mac"),
             QStringLiteral("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) "
                            "AppleWebKit/605.1.15 "
                            "(KHTML, like Gecko) Version/%1 Safari/605.1.15")
                 .arg(safari)},
            {false, {}, QStringLiteral("macOS"), {}, {}, {}, false}},
        {{QStringLiteral("safari-iphone"),
             QStringLiteral("Mozilla/5.0 (iPhone; CPU iPhone OS 18_6 like Mac OS X) "
                            "AppleWebKit/605.1.15 "
                            "(KHTML, like Gecko) Version/%1 Mobile/15E148 Safari/604.1")
                 .arg(safari)},
            {false, {}, QStringLiteral("iOS"), {}, {}, {}, true}},
        // QtWebEngine's own string, which names it and gets some sites to
        // refuse or degrade service.
        {{QStringLiteral("qtwebengine"),
             QStringLiteral("Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
                            "(KHTML, like Gecko) "
                            "QtWebEngine/%1 Chrome/%2 Safari/537.36")
                 .arg(QString::fromLatin1(qVersion()),
                     QString::fromLatin1(qWebEngineChromiumVersion()))},
            {true, {}, QStringLiteral("Linux"), QString(), QStringLiteral("x86"),
                QStringLiteral("64"), false}},
    };
}

const QList<Entry> &entries()
{
    static const QList<Entry> all = buildEntries();
    return all;
}

QString &currentName()
{
    static QString name;
    return name;
}

} // namespace

const QList<Preset> &presets()
{
    static const QList<Preset> all = [] {
        QList<Preset> list;
        for (const Entry &entry : entries())
            list.append(entry.preset);
        return list;
    }();
    return all;
}

bool apply(QWebEngineProfile *profile, const QString &name)
{
    for (const Entry &entry : entries()) {
        if (entry.preset.name != name)
            continue;
        profile->setHttpUserAgent(entry.preset.userAgent);
        QWebEngineClientHints *hints = profile->clientHints();
        hints->setAllClientHintsEnabled(entry.hints.enabled);
        hints->setPlatform(entry.hints.platform);
        hints->setPlatformVersion(entry.hints.platformVersion);
        hints->setArch(entry.hints.arch);
        hints->setBitness(entry.hints.bitness);
        hints->setIsMobile(entry.hints.mobile);
        hints->setFullVersionList(brands(entry.hints.brand));
        currentName() = name;
        return true;
    }
    return false;
}

QString current()
{
    return currentName();
}

} // namespace useragent