#include "TestFixtures.h"
#include "core/FlowSolver.h"
#include "core/NetworkModel.h"

#include <QSignalSpy>
#include <QTest>

using namespace diag;

class TestSolver : public QObject {
    Q_OBJECT
private slots:
    void init()
    {
        fixtures::fillRegistry(m_reg);
        delete m_model;
        m_model = new NetworkModel(&m_reg, this);
    }

    void chain_carriesSupplyThrough()
    {
        // source(10) -> pump -> consumer(10)
        const QUuid src = m_model->addNode(QStringLiteral("source"), {0, 0});
        const QUuid pump = m_model->addNode(QStringLiteral("pump"), {200, 0});
        const QUuid c = m_model->addNode(QStringLiteral("consumer"), {400, 0});
        const QUuid e1 = m_model->addEdge(src, "out", pump, "in");
        const QUuid e2 = m_model->addEdge(pump, "out", c, "in");

        const FlowResult r = FlowSolver::solve(*m_model, QStringLiteral("water"));
        QVERIFY(r.ok);
        QVERIFY(qAbs(r.edgeFlow.value(e1) - 10.0) < 1e-6);
        QVERIFY(qAbs(r.edgeFlow.value(e2) - 10.0) < 1e-6);
    }

    void junction_conservesFlow()
    {
        // source(10) -> junction -> two consumers (arbitrary demands).
        const QUuid src = m_model->addNode(QStringLiteral("source"), {0, 0});
        const QUuid j = m_model->addNode(QStringLiteral("junction"), {200, 0});
        const QUuid c1 = m_model->addNode(QStringLiteral("consumer"), {400, -100});
        const QUuid c2 = m_model->addNode(QStringLiteral("consumer"), {400, 100});
        m_model->setNodeProperty(c1, "demand", 4.0);
        m_model->setNodeProperty(c2, "demand", 6.0);

        const QUuid eIn = m_model->addEdge(src, "out", j, "w");
        const QUuid eOut1 = m_model->addEdge(j, "n", c1, "in");
        const QUuid eOut2 = m_model->addEdge(j, "s", c2, "in");

        const FlowResult r = FlowSolver::solve(*m_model, QStringLiteral("water"));
        QVERIFY(r.ok);
        const double in = r.edgeFlow.value(eIn);
        const double out = r.edgeFlow.value(eOut1) + r.edgeFlow.value(eOut2);
        QVERIFY(qAbs(in - out) < 1e-6);          // Kirchhoff at the junction
        QVERIFY(qAbs(in - 10.0) < 1e-6);         // all supply enters
        QVERIFY(qAbs(r.edgeFlow.value(eOut1) - 4.0) < 1e-6);
        QVERIFY(qAbs(r.edgeFlow.value(eOut2) - 6.0) < 1e-6);
    }

    void parallelPipes_widerCarriesMore()
    {
        // Two parallel pipes between two junctions; DN150 vs DN75.
        const QUuid src = m_model->addNode(QStringLiteral("source"), {0, 0});
        const QUuid j1 = m_model->addNode(QStringLiteral("junction"), {200, 0});
        const QUuid j2 = m_model->addNode(QStringLiteral("junction"), {400, 0});
        const QUuid c = m_model->addNode(QStringLiteral("consumer"), {600, 0});
        m_model->addEdge(src, "out", j1, "w");
        const QUuid wide = m_model->addEdge(j1, "n", j2, "n");
        const QUuid narrow = m_model->addEdge(j1, "s", j2, "s");
        m_model->addEdge(j2, "e", c, "in");
        m_model->setEdgeProperty(wide, "diameter", 150.0);
        m_model->setEdgeProperty(narrow, "diameter", 75.0);

        const FlowResult r = FlowSolver::solve(*m_model, QStringLiteral("water"));
        QVERIFY(r.ok);
        const double fWide = r.edgeFlow.value(wide);
        const double fNarrow = r.edgeFlow.value(narrow);
        QVERIFY(fWide > 0 && fNarrow > 0);
        QVERIFY(qAbs(fWide + fNarrow - 10.0) < 1e-6);
        // Conductance ~ d^4: ratio (150/75)^4 = 16.
        QVERIFY(qAbs(fWide / fNarrow - 16.0) < 1e-6);
    }

    void unbalancedInjections_areNormalized()
    {
        // Supply 10 vs demand 4: imbalance is spread, but flow stays conserved.
        const QUuid src = m_model->addNode(QStringLiteral("source"), {0, 0});
        const QUuid c = m_model->addNode(QStringLiteral("consumer"), {200, 0});
        m_model->setNodeProperty(c, "demand", 4.0);
        const QUuid e = m_model->addEdge(src, "out", c, "in");

        const FlowResult r = FlowSolver::solve(*m_model, QStringLiteral("water"));
        QVERIFY(r.ok);
        QVERIFY(qAbs(r.edgeFlow.value(e) - 7.0) < 1e-6);  // (10 + 4) / 2
    }

    void otherRelation_untouched()
    {
        const QUuid src = m_model->addNode(QStringLiteral("source"), {0, 0});
        const QUuid c = m_model->addNode(QStringLiteral("consumer"), {200, 0});
        m_model->addEdge(src, "out", c, "in");
        const FlowResult r = FlowSolver::solve(*m_model, QStringLiteral("power"));
        QVERIFY(r.ok);
        QVERIFY(r.edgeFlow.isEmpty());
    }

    void apply_writesFlowsAndSignals()
    {
        const QUuid src = m_model->addNode(QStringLiteral("source"), {0, 0});
        const QUuid c = m_model->addNode(QStringLiteral("consumer"), {200, 0});
        const QUuid e = m_model->addEdge(src, "out", c, "in");
        QSignalSpy spy(m_model, &NetworkModel::flowChanged);
        FlowSolver::apply(*m_model, FlowSolver::solve(*m_model, QStringLiteral("water")));
        QCOMPARE(spy.count(), 1);
        QVERIFY(m_model->edge(e)->flowRate > 0);
    }

private:
    TypeRegistry m_reg;
    NetworkModel* m_model = nullptr;
};

QTEST_GUILESS_MAIN(TestSolver)
#include "tst_solver.moc"