// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright (C) 2025 - 2026, Patrick Schurig / ETM PowerSync

#include "relayrouter.h"
#include "plugininfo.h"

#include <QDateTime>
#include <QMap>
#include <QSet>
#include <integrations/thingmanager.h>
#include <integrations/thing.h>
#include <types/action.h>
#include <types/param.h>

namespace {
//! Au-delà, 2^N combinaisons explose. 16 relais = 65536 combos — bien au-delà de tout ECS réel.
constexpr int MaxRelays = 16;
}

RelayRouter::RelayRouter(ThingManager *thingManager,
                         const QString &id,
                         const QString &label,
                         const QList<LoadConfigRelay> &relays,
                         int minOnS,
                         int minOffS,
                         int priority,
                         const LoadNeeds &needs,
                         QObject *parent)
    : QObject(parent)
    , m_thingManager(thingManager)
    , m_id(id)
    , m_label(label)
    , m_minOnS(minOnS)
    , m_minOffS(minOffS)
    , m_priority(priority)
    , m_needs(needs)
{
    int n = relays.size();
    if (n > MaxRelays) {
        qCWarning(dcNymeaEnergy()) << "[RelayRouter]" << m_label << "—" << n
                                   << "relais > max" << MaxRelays << ": tronqué.";
        n = MaxRelays;
    }

    // Paliers DÉRIVÉS : toutes les sommes de sous-ensembles, dédupliquées par puissance, triées
    // (QMap = clés croissantes), 0 inclus (sous-ensemble vide = masque 0). Pour des puissances
    // identiques (ex. deux relais 1000 W), on garde la première combinaison rencontrée.
    QMap<int, QList<QString>> byPower;
    for (int mask = 0; mask < (1 << n); ++mask) {
        int sum = 0;
        QList<QString> set;
        for (int i = 0; i < n; ++i) {
            if (mask & (1 << i)) {
                sum += relays.at(i).powerW;
                set.append(relays.at(i).thingId);
            }
        }
        if (!byPower.contains(sum))
            byPower.insert(sum, set);
    }
    for (auto it = byPower.constBegin(); it != byPower.constEnd(); ++it) {
        m_levels.append(it.key());
        m_relayMapping.append(it.value());
    }
    // byPower contient toujours la clé 0 (masque vide) → m_levels[0] == 0.
    Q_ASSERT(!m_levels.isEmpty() && m_levels.first() == 0);
}

LoadDescriptor RelayRouter::descriptor() const
{
    LoadDescriptor d;
    d.id       = m_id;
    d.label    = m_label;
    d.adapter  = QStringLiteral("relay-router");
    d.priority = m_priority;

    // Paliers DÉRIVÉS exposés à l'optimiseur (watts) — JAMAIS les relais.
    d.declared.powerLevels = m_levels;
    d.declared.maxPowerW   = m_levels.isEmpty() ? 0 : m_levels.last();
    d.limits.minOnS        = m_minOnS;
    d.limits.minOffS       = m_minOffS;
    d.needs                = m_needs;

    d.supportedKinds = { LoadAction::Setpoint };
    return d;
}

LoadTelemetry RelayRouter::telemetry() const
{
    LoadTelemetry t;
    t.available    = true;
    t.lastActionAt = m_lastActionAt;

    // currentPowerW :
    //   - MESURÉ dès qu'au moins un relais du palier expose un state "currentPower" (somme).
    //     Un thermostat coupé (relais ON mais 0 W) → 0, jamais de puissance fantôme.
    //   - NOMINAL commandé (repli) si aucun relais actif ne mesure (GPIO bool nu). Dans ce cas
    //     currentPowerW reflète le COMMANDÉ, pas le mesuré (contrat rév. 3 §3.a).
    double power   = 0;
    bool   metered = false;
    const QList<QString> activeRelays = m_currentStage < m_relayMapping.size()
                                          ? m_relayMapping.at(m_currentStage)
                                          : QList<QString>();
    for (const QString &thingId : activeRelays) {
        Thing *relay = m_thingManager->findConfiguredThing(ThingId(thingId));
        if (!relay)
            continue;
        if (!relay->thingClass().stateTypes().findByName("currentPower").id().isNull()) {
            metered = true;
            power  += relay->stateValue("currentPower").toDouble();
        }
    }
    if (!metered && m_currentStage > 0 && m_currentStage < m_levels.size())
        power = m_levels.at(m_currentStage);  // nominal commandé

    t.currentPowerW = power;
    return t;
}

LoadContext RelayRouter::toLoadContext(const QDateTime &now) const
{
    Q_UNUSED(now)   // pas de fenêtre de verrou exposée : le verrou est INTERNE (frontière rév. 3).

    LoadContext ctx;
    ctx.id       = m_id;
    ctx.adapter  = QStringLiteral("relay-router");
    ctx.label    = m_label;
    ctx.priority = m_priority;
    ctx.declared = descriptor().declared;   // powerLevels/maxPowerW dérivés (watts)
    ctx.needs    = m_needs;

    ctx.telemetry.currentPowerW = telemetry().currentPowerW;
    // Aucun stage/minStage/maxStage : ces champs n'existent plus (rév. 2) et le relais ne
    // franchit pas la frontière. L'optimiseur ne voit que des watts.
    return ctx;
}

LoadAction RelayRouter::applyAction(const LoadAction &action, const QDateTime &now)
{
    if (action.kind != LoadAction::Setpoint)
        return action;

    if (action.reason.isEmpty()) {
        qCWarning(dcNymeaEnergy()) << "[RelayRouter]" << m_label
                                   << "— LoadAction sans reason rejetée.";
        return action;
    }

    int newStage = stageForPower(action.powerW);

    // Verrou anti-rebond INTERNE (clamp), au temps de cycle. Bypass si force==true (repli L2).
    if (!action.force) {
        int minStage, maxStage;
        lockWindow(now, minStage, maxStage);
        newStage = qBound(minStage, newStage, maxStage);
    }

    LoadAction applied = action;
    applied.powerW          = m_levels.at(newStage);
    applied.estimatedPowerW = m_levels.at(newStage);

    if (newStage == m_currentStage)
        return applied;  // idempotent — pas de re-commutation

    qCInfo(dcNymeaEnergy()) << "[RelayRouter]" << m_label
                            << "→ consigne" << qRound(action.powerW) << "W → palier"
                            << m_levels.at(newStage) << "W"
                            << (action.force ? "(force)" : "")
                            << "|" << action.reason;

    applyRelayStage(newStage);

    m_currentStage = newStage;
    m_lastSwitch   = now;
    m_lastActionAt = now;
    return applied;
}

// ---- privé ---------------------------------------------------------------

int RelayRouter::stageForPower(double powerW) const
{
    int stage = 0;  // m_levels[0] == 0 garanti
    for (int i = 0; i < m_levels.size(); ++i) {
        if (m_levels.at(i) <= powerW)
            stage = i;
        else
            break;  // m_levels triés croissants
    }
    return stage;
}

void RelayRouter::lockWindow(const QDateTime &now, int &minStage, int &maxStage) const
{
    const int topStage   = m_levels.size() - 1;
    const bool valid     = m_lastSwitch.isValid();
    const qint64 elapsed = valid ? m_lastSwitch.secsTo(now) : 0;

    // Plancher : si ON et minOn non écoulé → interdit de descendre (puissance engagée non-coupable).
    minStage = (m_currentStage > 0 && valid && elapsed < m_minOnS) ? m_currentStage : 0;
    // Plafond : si à l'arrêt et minOff non écoulé → interdit de redémarrer.
    maxStage = (m_currentStage == 0 && valid && elapsed < m_minOffS) ? 0 : topStage;
}

void RelayRouter::applyRelayStage(int stage)
{
    // Set CIBLE du palier (delta complet : chaque relais connu amené à son état on/off cible).
    // Gère les mappings NON-CASCADÉS (monter d'un palier peut éteindre des relais).
    const QSet<QString> wantOn = [&]() {
        QSet<QString> s;
        if (stage < m_relayMapping.size())
            for (const QString &id : m_relayMapping.at(stage))
                s.insert(id);
        return s;
    }();

    QSet<QString> allRelays;
    for (const auto &list : m_relayMapping)
        for (const QString &id : list)
            allRelays.insert(id);

    auto writeRelay = [&](const QString &thingId, bool on) {
        Thing *relay = m_thingManager->findConfiguredThing(ThingId(thingId));
        if (!relay) {
            qCWarning(dcNymeaEnergy()) << "[RelayRouter]" << m_label << "— relais non trouvé:" << thingId;
            return;
        }
        StateType powerStateType = relay->thingClass().stateTypes().findByName("power");
        if (!powerStateType.id().isNull()) {
            Action powerAction(powerStateType.id(), relay->id(), Action::TriggeredByRule);
            powerAction.setParams(ParamList() << Param(powerStateType.id(), on));
            m_thingManager->executeAction(powerAction);
        } else {
            relay->setStateValue("power", on);  // repli mock
        }
    };

    // off-before-on : couper d'abord les relais hors-cible, puis enclencher la cible → pas de
    // sur-puissance transitoire (somme des deux paliers) sur une transition non-cascadée.
    for (const QString &id : allRelays)
        if (!wantOn.contains(id))
            writeRelay(id, false);
    for (const QString &id : wantOn)
        writeRelay(id, true);
}