const test = require('node:test');
const assert = require('node:assert/strict');

const { calcBestCombination } = require('../../src/optimizer/bestCombination');

function makeMachine({ id, fMin = 0, fMax = 100, NCog = 0.5, costFn } = {}) {
    return {
        config: { general: { id } },
        NCog,
        predictFlow: { currentFxyYMin: fMin, currentFxyYMax: fMax },
        predictPower: { currentFxyYMin: 0, currentFxyYMax: fMax * 2 },
        // Power model: caller picks the cost function so we can shape who wins.
        inputFlowCalcPower: costFn ?? ((flow) => flow * 1.0),
    };
}

function mkCtx(machines) {
    return {
        machines,
        groupCurves: {
            groupFlow: (m) => m.predictFlow,
            groupPower: (m) => m.predictPower,
            groupNCog: (m) => m.NCog ?? 0,
            groupCalcPower: (m, f) => m.inputFlowCalcPower(f),
        },
        logger: { debug: () => {} },
    };
}

test('calcBestCombination: 1 machine in combination receives Qd clamped to its range', () => {
    const machines = { a: makeMachine({ id: 'a', fMin: 5, fMax: 60 }) };
    const ctx = mkCtx(machines);

    const res = calcBestCombination([['a']], 40, ctx);
    assert.ok(res.bestCombination);
    assert.equal(res.bestCombination.length, 1);
    assert.equal(res.bestCombination[0].flow, 40);

    // Above max — clamps to max.
    const high = calcBestCombination([['a']], 200, ctx);
    assert.equal(high.bestCombination[0].flow, 60);
});

test('calcBestCombination: 2 machines with equal NCog split flow evenly', () => {
    const machines = {
        a: makeMachine({ id: 'a', NCog: 0.5, fMin: 0, fMax: 100 }),
        b: makeMachine({ id: 'b', NCog: 0.5, fMin: 0, fMax: 100 }),
    };
    const ctx = mkCtx(machines);
    const res = calcBestCombination([['a', 'b']], 40, ctx);
    const aFlow = res.bestCombination.find(e => e.machineId === 'a').flow;
    const bFlow = res.bestCombination.find(e => e.machineId === 'b').flow;
    assert.ok(Math.abs(aFlow - bFlow) < 1e-6, `expected even split, got a=${aFlow} b=${bFlow}`);
    assert.ok(Math.abs(aFlow + bFlow - 40) < 1e-6);
});

test('calcBestCombination: returns combination with the lowest total power', () => {
    // Two combinations: [a] (expensive) vs [b] (cheap). Both can deliver Qd=20.
    const machines = {
        a: makeMachine({ id: 'a', fMin: 0, fMax: 100, costFn: (f) => f * 10 }),
        b: makeMachine({ id: 'b', fMin: 0, fMax: 100, costFn: (f) => f * 1 }),
    };
    const ctx = mkCtx(machines);
    const res = calcBestCombination([['a'], ['b']], 20, ctx);
    assert.equal(res.bestCombination[0].machineId, 'b');
    assert.equal(res.bestPower, 20);
});