/**
 * test_main_window.cpp — Tests for the GUI skeleton (Step 1, C++).
 *
 * QTest FRAMEWORK:
 * ================
 * Qt provides its own test framework, QTest. It's simpler than GoogleTest
 * but integrates perfectly with Qt's event loop and widget system.
 *
 * Key differences from pytest:
 *   pytest:  assert window.windowTitle() == "..."
 *   QTest:   QCOMPARE(window.windowTitle(), QString("..."))
 *
 * Test discovery:
 *   - Each test class inherits QObject and has Q_OBJECT
 *   - Test methods are private slots named test_*() or *_test()
 *   - QTEST_MAIN() generates main() that runs all test slots
 *
 * QCOMPARE vs QVERIFY:
 *   QVERIFY(condition)         — like assert condition
 *   QCOMPARE(actual, expected) — like assert actual == expected, but prints both values on failure
 */

#include <QtTest/QtTest>
#include <QDockWidget>
#include <QTableWidget>
#include <QSpinBox>
#include <QLineEdit>
#include <QPushButton>
#include <QCheckBox>
#include <QComboBox>
#include <QLabel>
#include "main_window.h"

class TestMainWindow : public QObject
{
    Q_OBJECT

private:
    MainWindow* m_window;

private slots:
    // ── Setup/Teardown ──
    // init() runs BEFORE each test, cleanup() runs AFTER each test.
    // This gives each test a fresh MainWindow (like pytest fixtures).
    void init()
    {
        m_window = new MainWindow();
    }

    void cleanup()
    {
        delete m_window;
        m_window = nullptr;
    }

    // ─── Window Basics ────────────────────────────────────────────

    void test_windowTitle()
    {
        QCOMPARE(m_window->windowTitle(), QString("LIN Simulator"));
    }

    void test_minimumSize()
    {
        QVERIFY(m_window->minimumWidth() >= 1024);
        QVERIFY(m_window->minimumHeight() >= 768);
    }

    void test_centralWidgetExists()
    {
        QVERIFY(m_window->centralWidget() != nullptr);
    }

    // ─── Menu Bar ─────────────────────────────────────────────────

    void test_menuBarExists()
    {
        QVERIFY(m_window->menuBar() != nullptr);
    }

    void test_loadLdfActionExists()
    {
        QVERIFY(m_window->loadLdfAction() != nullptr);
        QCOMPARE(m_window->loadLdfAction()->text(), QString("&Load LDF..."));
    }

    void test_loadLdfShortcut()
    {
        QCOMPARE(m_window->loadLdfAction()->shortcut().toString(), QString("Ctrl+O"));
    }

    // ─── LDF Toolbar ──────────────────────────────────────────────

    void test_ldfPathFieldExists()
    {
        QVERIFY(m_window->ldfPathEdit() != nullptr);
        QVERIFY(m_window->ldfPathEdit()->isReadOnly());
    }

    void test_ldfPathPlaceholder()
    {
        QCOMPARE(m_window->ldfPathEdit()->placeholderText(),
                 QString("No LDF file loaded"));
    }

    void test_browseButtonExists()
    {
        QVERIFY(m_window->browseButton() != nullptr);
    }

    void test_autoReloadDefaultChecked()
    {
        QVERIFY(m_window->autoReloadCheck()->isChecked());
    }

    // ─── Tx Table ─────────────────────────────────────────────────

    void test_txTableExists()
    {
        auto* table = m_window->txTable();
        QVERIFY(table != nullptr);
        // qobject_cast is Qt's type-safe dynamic cast.
        // Returns nullptr if the object isn't the expected type.
        QVERIFY(qobject_cast<QTableWidget*>(table) != nullptr);
    }

    void test_txTableColumns()
    {
        auto* table = m_window->txTable();
        QCOMPARE(table->columnCount(), 7);

        QStringList expected = {
            "Frame Name", "Frame ID", "Length", "Interval (ms)",
            "Data", "Signals", "Action"
        };
        for (int i = 0; i < table->columnCount(); ++i) {
            QCOMPARE(table->horizontalHeaderItem(i)->text(), expected[i]);
        }
    }

    void test_txTableAlternatingColors()
    {
        QVERIFY(m_window->txTable()->alternatingRowColors());
    }

    // ─── Rx Table ─────────────────────────────────────────────────

    void test_rxTableExists()
    {
        auto* table = m_window->rxTable();
        QVERIFY(table != nullptr);
        QVERIFY(qobject_cast<QTableWidget*>(table) != nullptr);
    }

    void test_rxTableColumns()
    {
        auto* table = m_window->rxTable();
        QCOMPARE(table->columnCount(), 5);

        QStringList expected = {
            "Timestamp", "Frame Name", "Frame ID", "Data", "Signals"
        };
        for (int i = 0; i < table->columnCount(); ++i) {
            QCOMPARE(table->horizontalHeaderItem(i)->text(), expected[i]);
        }
    }

    void test_rxTableNotEditable()
    {
        QCOMPARE(m_window->rxTable()->editTriggers(),
                 QAbstractItemView::NoEditTriggers);
    }

    // ─── Connection Dock ──────────────────────────────────────────

    void test_dockExists()
    {
        // findChildren<T>() searches the widget tree for all children of type T
        auto docks = m_window->findChildren<QDockWidget*>();
        QCOMPARE(docks.size(), 1);
        QCOMPARE(docks[0]->windowTitle(), QString("Connection"));
    }

    void test_deviceComboExists()
    {
        QVERIFY(m_window->deviceCombo() != nullptr);
    }

    void test_connectButtonExists()
    {
        QVERIFY(m_window->connectButton() != nullptr);
        QVERIFY(m_window->connectButton()->isEnabled());
    }

    void test_disconnectButtonDisabledInitially()
    {
        QVERIFY(!m_window->disconnectButton()->isEnabled());
    }

    void test_statusLabelShowsDisconnected()
    {
        QVERIFY(m_window->connStatusLabel()->text().contains("Disconnected"));
    }

    void test_baudRateLabelExists()
    {
        QVERIFY(m_window->baudRateLabel() != nullptr);
    }

    void test_baudRateShowsPlaceholderBeforeLdf()
    {
        QVERIFY(m_window->baudRateLabel()->text().contains("load LDF"));
    }

    // ─── Control Bar ──────────────────────────────────────────────

    void test_scheduleComboExists()
    {
        QVERIFY(m_window->scheduleCombo() != nullptr);
    }

    void test_schedulerButtonsDisabledInitially()
    {
        QVERIFY(!m_window->startButton()->isEnabled());
        QVERIFY(!m_window->stopButton()->isEnabled());
        QVERIFY(!m_window->pauseButton()->isEnabled());
    }

    void test_manualSendDisabledInitially()
    {
        QVERIFY(!m_window->manualSendButton()->isEnabled());
    }

    void test_globalRateSpinboxExists()
    {
        QVERIFY(m_window->globalRateSpin() != nullptr);
    }

    void test_globalRateDefault50ms()
    {
        QCOMPARE(m_window->globalRateSpin()->value(), 50);
    }

    void test_globalRateRange()
    {
        QCOMPARE(m_window->globalRateSpin()->minimum(), 1);
        QCOMPARE(m_window->globalRateSpin()->maximum(), 10000);
    }

    void test_globalRateSuffix()
    {
        QCOMPARE(m_window->globalRateSpin()->suffix(), QString(" ms"));
    }

    // ─── Status Bar ───────────────────────────────────────────────

    void test_statusBarExists()
    {
        QVERIFY(m_window->statusBar() != nullptr);
    }

    void test_connectionStatusLabel()
    {
        QVERIFY(m_window->statusConnectionLabel()->text().contains("Disconnected"));
    }
};

// QTEST_MAIN generates a main() function that:
//   1. Creates a QApplication
//   2. Instantiates TestMainWindow
//   3. Runs all private slots as test cases
//   4. Reports results
QTEST_MAIN(TestMainWindow)

// This #include is required when the test class is defined in a .cpp file
// (not a .h file). It includes the MOC-generated code for our Q_OBJECT class.
// Without it, the linker would fail with "undefined reference to vtable".
#include "test_main_window.moc"