'use strict';

// Priority-based control strategies for machineGroupControl.
//
// equalFlowControl: distribute demand equally across priority-ordered active
// machines, falling back to start/stop the next priority when the current
// active set can't deliver.
//
// prioPercentageControl: percentage-style ctrl distribution (only valid with
// normalized scaling).
//
// Both extracted verbatim from specificClass during the P4 refactor; the
// orchestrator wires them in via the strategies map below. They depend on
// the same group-curve helpers the optimizer uses, so allocation and power
// evaluation stay on the equalised group operating point.

const { POSITIONS } = require('generalFunctions');
const { groupFlow, groupCalcPower } = require('../groupOps/groupCurves');

function sortMachinesByPriority(machines, priorityList) {
    if (priorityList && Array.isArray(priorityList)) {
        return priorityList
            .filter(id => machines[id])
            .map(id => ({ id, machine: machines[id] }));
    }
    return Object.entries(machines)
        .map(([id, machine]) => ({ id, machine }))
        .sort((a, b) => a.id - b.id);
}

function filterOutUnavailableMachines(list) {
    return list.filter(({ machine }) => {
        const state = machine.state.getCurrentState();
        const validActionForMode = machine.isValidActionForMode('execsequence', 'auto');
        return !(state === 'off' || state === 'coolingdown' || state === 'stopping'
            || state === 'emergencystop' || !validActionForMode);
    });
}

function capFlowDemand(Qd, dynamicTotals, logger) {
    if (Qd < dynamicTotals.flow.min && Qd > 0) {
        logger?.warn?.(`Flow demand ${Qd} below min ${dynamicTotals.flow.min}; capping.`);
        return dynamicTotals.flow.min;
    }
    if (Qd > dynamicTotals.flow.max) {
        logger?.warn?.(`Flow demand ${Qd} above max ${dynamicTotals.flow.max}; capping.`);
        return dynamicTotals.flow.max;
    }
    return Qd;
}

async function equalFlowControl(ctx, Qd, _powerCap = Infinity, priorityList = null) {
    const { mgc } = ctx;
    try {
        mgc.equalizePressure();
        const dynamicTotals = mgc.calcDynamicTotals();
        Qd = capFlowDemand(Qd, dynamicTotals, mgc.logger);

        let machinesInPriorityOrder = sortMachinesByPriority(mgc.machines, priorityList);
        machinesInPriorityOrder = filterOutUnavailableMachines(machinesInPriorityOrder);

        const flowDistribution = [];
        let totalFlow = 0;
        let totalPower = 0;
        const totalCog = 0;

        const activeTotals = mgc.totals.activeTotals();

        switch (true) {
            case (Qd < activeTotals.flow.min && activeTotals.flow.min !== 0): {
                let availableFlow = activeTotals.flow.min;
                for (let i = machinesInPriorityOrder.length - 1; i >= 0 && availableFlow > Qd; i--) {
                    const m = machinesInPriorityOrder[i];
                    if (mgc.isMachineActive(m.id)) {
                        flowDistribution.push({ machineId: m.id, flow: 0 });
                        availableFlow -= groupFlow(m.machine).currentFxyYMin;
                    }
                }
                const remaining = machinesInPriorityOrder.filter(({ id }) =>
                    mgc.isMachineActive(id) && !flowDistribution.some(it => it.machineId === id));
                const distributedFlow = Qd / remaining.length;
                for (const m of remaining) {
                    flowDistribution.push({ machineId: m.id, flow: distributedFlow });
                    totalFlow += distributedFlow;
                    totalPower += groupCalcPower(m.machine, distributedFlow);
                }
                break;
            }
            case (Qd > activeTotals.flow.max): {
                let i = 1;
                while (totalFlow < Qd && i <= machinesInPriorityOrder.length) {
                    Qd = Qd / i;
                    if (groupFlow(machinesInPriorityOrder[i - 1].machine).currentFxyYMax >= Qd) {
                        for (let i2 = 0; i2 < i; i2++) {
                            if (!mgc.isMachineActive(machinesInPriorityOrder[i2].id)) {
                                flowDistribution.push({ machineId: machinesInPriorityOrder[i2].id, flow: Qd });
                                totalFlow += Qd;
                                totalPower += groupCalcPower(machinesInPriorityOrder[i2].machine, Qd);
                            }
                        }
                    }
                    i++;
                }
                break;
            }
            default: {
                const countActive = machinesInPriorityOrder.filter(({ id }) => mgc.isMachineActive(id)).length;
                Qd /= countActive;
                for (let i = 0; i < countActive; i++) {
                    flowDistribution.push({ machineId: machinesInPriorityOrder[i].id, flow: Qd });
                    totalFlow += Qd;
                    totalPower += groupCalcPower(machinesInPriorityOrder[i].machine, Qd);
                }
                break;
            }
        }

        const fUnit = mgc.unitPolicy.canonical.power;
        const flUnit = mgc.unitPolicy.canonical.flow;
        mgc.operatingPoint.writeOwn('power', 'predicted', POSITIONS.AT_EQUIPMENT, totalPower, fUnit);
        mgc.operatingPoint.writeOwn('flow',  'predicted', POSITIONS.AT_EQUIPMENT, totalFlow,  flUnit);
        mgc.measurements.type('efficiency').variant('predicted').position(POSITIONS.AT_EQUIPMENT).value(totalFlow / totalPower);
        mgc.measurements.type('Ncog').variant('predicted').position(POSITIONS.AT_EQUIPMENT).value(totalCog);

        await Promise.all(flowDistribution.map(async ({ machineId, flow }) => {
            const machine = mgc.machines[machineId];
            const currentState = machine.state.getCurrentState();
            if (flow > 0) {
                await machine.handleInput('parent', 'flowmovement', mgc._canonicalToOutputFlow(flow));
                if (currentState === 'idle') {
                    await machine.handleInput('parent', 'execsequence', 'startup');
                }
            } else if (currentState === 'operational' || currentState === 'accelerating' || currentState === 'decelerating') {
                await machine.handleInput('parent', 'execsequence', 'shutdown');
            }
        }));
    } catch (err) {
        mgc.logger?.error?.(err);
    }
}

async function prioPercentageControl(ctx, input, priorityList = null) {
    const { mgc } = ctx;
    try {
        if (input < 0) { await mgc.turnOffAllMachines(); return; }
        if (input > 100) input = 100;

        const numOfMachines = Object.keys(mgc.machines).length;
        const procentTotal = numOfMachines * input;
        const machinesNeeded = Math.ceil(procentTotal / 100);
        const activeTotals = mgc.totals.activeTotals();
        const machinesActive = activeTotals.countActiveMachines;
        const machinesInPriorityOrder = sortMachinesByPriority(mgc.machines, priorityList);
        const ctrlDistribution = [];

        if (machinesNeeded > machinesActive) {
            machinesInPriorityOrder.forEach(({ id }, index) => {
                if (index < machinesNeeded) ctrlDistribution.push({ machineId: id, ctrl: 0 });
            });
        }
        if (machinesNeeded < machinesActive) {
            machinesInPriorityOrder.forEach(({ id }, index) => {
                if (mgc.isMachineActive(id)) {
                    ctrlDistribution.push({ machineId: id, ctrl: index < machinesNeeded ? 100 : -1 });
                }
            });
        }
        if (machinesNeeded === machinesActive) {
            const ctrlPerMachine = procentTotal / machinesActive;
            machinesInPriorityOrder.forEach(({ id }) => {
                if (mgc.isMachineActive(id)) {
                    ctrlDistribution.push({ machineId: id, ctrl: Math.max(0, Math.min(ctrlPerMachine, 100)) });
                }
            });
        }

        await Promise.all(ctrlDistribution.map(async ({ machineId, ctrl }) => {
            const machine = mgc.machines[machineId];
            const currentState = machine.state.getCurrentState();
            if (ctrl < 0 && (currentState === 'operational' || currentState === 'accelerating' || currentState === 'decelerating')) {
                await machine.handleInput('parent', 'execsequence', 'shutdown');
            } else if (currentState === 'idle' && ctrl >= 0) {
                await machine.handleInput('parent', 'execsequence', 'startup');
            } else if (currentState === 'operational' && ctrl > 0) {
                await machine.handleInput('parent', 'execmovement', ctrl);
            }
        }));

        const totalPower = [];
        const totalFlow = [];
        Object.values(mgc.machines).forEach(machine => {
            const p = mgc.operatingPoint.readChild(machine, 'power', 'predicted', POSITIONS.AT_EQUIPMENT, mgc.unitPolicy.canonical.power);
            const f = mgc.operatingPoint.readChild(machine, 'flow', 'predicted', POSITIONS.DOWNSTREAM, mgc.unitPolicy.canonical.flow);
            if (p !== null) totalPower.push(p);
            if (f !== null) totalFlow.push(f);
        });

        const sumP = totalPower.reduce((a, b) => a + b, 0);
        const sumF = totalFlow.reduce((a, b) => a + b, 0);
        mgc.operatingPoint.writeOwn('power', 'predicted', POSITIONS.AT_EQUIPMENT, sumP, mgc.unitPolicy.canonical.power);
        mgc.operatingPoint.writeOwn('flow',  'predicted', POSITIONS.AT_EQUIPMENT, sumF, mgc.unitPolicy.canonical.flow);
        if (sumP > 0) {
            mgc.measurements.type('efficiency').variant('predicted').position(POSITIONS.AT_EQUIPMENT).value(sumF / sumP);
        }
    } catch (err) {
        mgc.logger?.error?.(err);
    }
}

module.exports = { equalFlowControl, prioPercentageControl, capFlowDemand, sortMachinesByPriority, filterOutUnavailableMachines };