#include "ssh_session_backend.h"

#include <QTest>

#include <memory>

#ifndef ORBITHUB_TEST_FIXTURES_DIR
#error "ORBITHUB_TEST_FIXTURES_DIR must be defined by the build"
#endif

namespace {
Profile makeProfile(const QString& fixtureHost)
{
    Profile profile;
    profile.name = QStringLiteral("Test Profile");
    profile.host = fixtureHost;
    profile.port = 22;
    profile.username = QStringLiteral("tester");
    profile.protocol = QStringLiteral("SSH");
    profile.authMode = QStringLiteral("Password");
    return profile;
}

SessionConnectOptions makeOptions()
{
    SessionConnectOptions options;
    options.password = QStringLiteral("dummy-password");
    return options;
}
}

class TestSshSessionBackend : public QObject
{
    Q_OBJECT

private slots:
    // Pure-function coverage -- no process involved.
    void mapSshErrorRecognizesKnownPatterns();
    void mapSshErrorFallsBackForUnknownText();
    void mapSshErrorHandlesEmptyInput();
    void escapeForShellSingleQuotesNeutralizesQuotes();
    void escapeForShellSingleQuotesLeavesPlainTextAlone();

    // State-machine coverage, driven against tests/fixtures/fake_ssh.sh
    // instead of a real ssh binary or network.
    void init();
    void cleanup();
    void successfulConnectReachesConnectedThenDisconnects();
    void authFailureReachesFailedStateWithMappedMessage();
    void connectionRefusedReachesFailedState();
    void sendInputEchoesThroughOutputReceived();
    void reconnectRestartsAndReachesConnectedAgain();

private:
    QString fixturePath() const;
    void createBackend(const QString& fixtureHost);

    std::unique_ptr<SshSessionBackend> m_backend;
    SessionState m_lastState = SessionState::Disconnected;
    QString m_lastErrorDisplay;
    QString m_lastErrorRaw;
    QString m_receivedOutput;
};

QString TestSshSessionBackend::fixturePath() const
{
    return QStringLiteral(ORBITHUB_TEST_FIXTURES_DIR "/fake_ssh.sh");
}

void TestSshSessionBackend::createBackend(const QString& fixtureHost)
{
    m_backend =
        std::make_unique<SshSessionBackend>(makeProfile(fixtureHost), fixturePath(), nullptr);
    connect(m_backend.get(),
            &SessionBackend::stateChanged,
            this,
            [this](SessionState state, const QString&) { m_lastState = state; });
    connect(m_backend.get(),
            &SessionBackend::connectionError,
            this,
            [this](const QString& display, const QString& raw) {
                m_lastErrorDisplay = display;
                m_lastErrorRaw = raw;
            });
    connect(m_backend.get(),
            &SessionBackend::outputReceived,
            this,
            [this](const QString& chunk) { m_receivedOutput += chunk; });
}

void TestSshSessionBackend::mapSshErrorRecognizesKnownPatterns()
{
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("Permission denied (publickey,password).")),
             QStringLiteral("Authentication failed. Check username and credentials."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("Host key verification failed.")),
             QStringLiteral("Host key verification failed."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("ssh: Could not resolve hostname bogus")),
             QStringLiteral("Host could not be resolved."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("ssh: connect to host x port 22: Connection timed out")),
             QStringLiteral("Connection timed out."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("ssh: connect to host x port 22: Connection refused")),
             QStringLiteral("Connection refused by remote host."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("ssh: connect to host x port 22: No route to host")),
             QStringLiteral("No route to host."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("Identity file /nope not accessible: No such file.")),
             QStringLiteral("Private key file is not accessible."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("posix_spawn: /usr/bin/ssh-askpass: No such file or directory")),
             QStringLiteral("SSH password helper is missing or failed to launch."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("open /some/other/path: No such file or directory")),
             QStringLiteral("Required file was not found."));
}

void TestSshSessionBackend::mapSshErrorFallsBackForUnknownText()
{
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("some completely novel ssh error text")),
             QStringLiteral("SSH connection failed."));
}

void TestSshSessionBackend::mapSshErrorHandlesEmptyInput()
{
    QCOMPARE(SshSessionBackend::mapSshError(QString()),
             QStringLiteral("SSH connection failed for an unknown reason."));
    QCOMPARE(SshSessionBackend::mapSshError(QStringLiteral("   ")),
             QStringLiteral("SSH connection failed for an unknown reason."));
}

void TestSshSessionBackend::escapeForShellSingleQuotesNeutralizesQuotes()
{
    // A password containing a single quote must not be able to break out
    // of the single-quoted printf argument in the askpass script -- this
    // is the actual security boundary, not just cosmetic escaping.
    const QString malicious = QStringLiteral("pw' ; rm -rf ~ ; echo '");
    const QString escaped = SshSessionBackend::escapeForShellSingleQuotes(malicious);
    const QString reconstructedScriptArg = QStringLiteral("'") + escaped + QStringLiteral("'");
    // Every single quote in the reconstructed argument must be either the
    // outer boundary quote (open at index 0, close at the very end) or the
    // start of a full '"'"' re-opening sequence -- never a bare, unescaped
    // quote that could close the argument early.
    int index = 0;
    while (index < reconstructedScriptArg.length()) {
        if (reconstructedScriptArg.at(index) != QChar::fromLatin1('\'')) {
            ++index;
            continue;
        }
        if (index == 0 || index == reconstructedScriptArg.length() - 1) {
            ++index;
            continue;
        }
        QCOMPARE(reconstructedScriptArg.mid(index, 5), QStringLiteral("'\"'\"'"));
        index += 5;
    }
}

void TestSshSessionBackend::escapeForShellSingleQuotesLeavesPlainTextAlone()
{
    QCOMPARE(SshSessionBackend::escapeForShellSingleQuotes(QStringLiteral("plain-password-123")),
             QStringLiteral("plain-password-123"));
}

void TestSshSessionBackend::init()
{
#ifdef Q_OS_WIN
    // fixtures/fake_ssh.sh is a POSIX shell script; there's no Windows
    // fixture yet, so skip only the tests that actually launch it. The
    // pure-function tests above (mapSshError*, escapeForShellSingleQuotes*)
    // don't touch the fixture and still run everywhere.
    const QByteArray currentTest = QTest::currentTestFunction();
    if (!currentTest.startsWith("mapSshError") && !currentTest.startsWith("escapeForShellSingleQuotes")) {
        QSKIP("No Windows equivalent of tests/fixtures/fake_ssh.sh yet");
    }
#endif

    m_lastState = SessionState::Disconnected;
    m_lastErrorDisplay.clear();
    m_lastErrorRaw.clear();
    m_receivedOutput.clear();
    // Individual tests call createBackend() with the fixture host they
    // need; most want "succeed", so provide it as the default here.
    createBackend(QStringLiteral("succeed"));
}

void TestSshSessionBackend::cleanup()
{
    if (m_backend) {
        m_backend->disconnectSession();
    }
    m_backend.reset();
}

void TestSshSessionBackend::successfulConnectReachesConnectedThenDisconnects()
{
    m_backend->connectSession(makeOptions());
    QTRY_COMPARE(m_lastState, SessionState::Connected);

    m_backend->disconnectSession();
    QTRY_COMPARE(m_lastState, SessionState::Disconnected);
}

void TestSshSessionBackend::authFailureReachesFailedStateWithMappedMessage()
{
    createBackend(QStringLiteral("fail-auth"));
    m_backend->connectSession(makeOptions());
    QTRY_COMPARE(m_lastState, SessionState::Failed);
    QCOMPARE(m_lastErrorDisplay, QStringLiteral("Authentication failed. Check username and credentials."));
    QVERIFY(m_lastErrorRaw.contains(QStringLiteral("Permission denied")));
}

void TestSshSessionBackend::connectionRefusedReachesFailedState()
{
    createBackend(QStringLiteral("refuse"));
    m_backend->connectSession(makeOptions());
    QTRY_COMPARE(m_lastState, SessionState::Failed);
    QCOMPARE(m_lastErrorDisplay, QStringLiteral("Connection refused by remote host."));
}

void TestSshSessionBackend::sendInputEchoesThroughOutputReceived()
{
    m_backend->connectSession(makeOptions());
    QTRY_COMPARE(m_lastState, SessionState::Connected);

    m_backend->sendInput(QStringLiteral("hello-from-test\n"));
    QTRY_VERIFY(m_receivedOutput.contains(QStringLiteral("hello-from-test")));
}

void TestSshSessionBackend::reconnectRestartsAndReachesConnectedAgain()
{
    m_backend->connectSession(makeOptions());
    QTRY_COMPARE(m_lastState, SessionState::Connected);

    m_lastState = SessionState::Connecting;
    m_backend->reconnectSession(makeOptions());
    QTRY_COMPARE(m_lastState, SessionState::Connected);
}

QTEST_GUILESS_MAIN(TestSshSessionBackend)
#include "test_ssh_session_backend.moc"