// Output-coverage tests for examples/02-Dashboard.json :: fn_status_split.
// Exercises every output port in three states (deploy / post-setup / post-demand)
// AND verifies the per-port format contract that every downstream ui-* widget
// or chart expects. Per .claude/rules/output-coverage.md.

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

const flow = JSON.parse(fs.readFileSync(
  path.resolve(__dirname, '../../examples/02-Dashboard.json'), 'utf8'));
const fn = flow.find(n => n.id === 'fn_status_split');

function runFn(msgs) {
  let ctxStore = {};
  const context = {
    get: (k) => ctxStore[k],
    set: (k, v) => { ctxStore[k] = v; },
  };
  const fn_body = new Function('msg', 'context', fn.func);
  return msgs.map(msg => fn_body(msg, context));
}

// Indices into the 17-output return array. Kept here as the manifest contract
// for this function — every test below references these names, never raw ints.
const PORT = {
  text_mode: 0, text_flow: 1, text_power: 2, text_capacity: 3,
  text_machines: 4, text_bep_rel: 5, text_eta: 6, text_eta_peak: 7,
  text_bep_abs: 8, text_ncog: 9,
  chart_flow: 10, chart_capacity: 11, chart_power: 12, chart_bep_rel: 13,
  chart_eta: 14,
  raw_rows: 15, raw_passthrough: 16,
};

const initialMsg = {
  payload: {
    mode: 'optimalControl', scaling: 'normalized',
    absDistFromPeak: 0, relDistFromPeak: 0,
    flowCapacityMax: 0, flowCapacityMin: 0,
    machineCount: 3, machineCountActive: 0,
  },
};
const postSetupMsg = {
  payload: {
    atEquipment_predicted_flow: 0, downstream_predicted_flow: 0,
    atEquipment_predicted_power: 0,
    flowCapacityMax: 450, flowCapacityMin: 0,
    machineCountActive: 0,
    headerDiffPa: 110000, headerDiffMbar: 1100,
  },
};
const postDemandMsg = {
  payload: {
    atEquipment_predicted_flow: 200,
    downstream_predicted_flow: 200,
    atEquipment_predicted_power: 11.4,
    atEquipment_predicted_efficiency: 0.62,
    // Ncog as MGC actually emits it: SUM of per-pump NCog values.
    // 2 pumps each at NCog=0.6 → sum=1.2; per-pump average should display as 60.0 %.
    atEquipment_predicted_Ncog: 1.2,
    absDistFromPeak: 0.05, relDistFromPeak: 0.08,
    flowCapacityMax: 450, machineCountActive: 2,
  },
};

test('manifest: function has exactly 17 outputs and wires array matches', () => {
  assert.equal(fn.outputs, 17);
  assert.equal(fn.wires.length, 17);
});

test('State A (deploy-time): no AT_EQUIPMENT keys → flow/power text show em-dash', () => {
  const [out] = runFn([initialMsg]);
  assert.equal(out[PORT.text_mode].payload, 'optimalControl');
  assert.equal(out[PORT.text_flow].payload, '—');
  assert.equal(out[PORT.text_power].payload, '—');
  assert.equal(out[PORT.text_ncog].payload, '—');
  assert.equal(out[PORT.text_eta].payload, '—');
});

test('State A: charts with no source data emit null msg, never { payload: null }', () => {
  const [out] = runFn([initialMsg]);
  // Charts 10, 12, 14 have no source data in State A → must be null (drop msg).
  assert.equal(out[PORT.chart_flow], null, 'chart_flow must be null when flow missing');
  assert.equal(out[PORT.chart_power], null, 'chart_power must be null when power missing');
  assert.equal(out[PORT.chart_eta], null, 'chart_eta must be null when eta missing');
  // For every msg-emitting chart output: payload is never literally null.
  for (const idx of Object.values(PORT)) {
    if (out[idx] && Object.prototype.hasOwnProperty.call(out[idx], 'payload')) {
      assert.notEqual(out[idx].payload, null,
        `port ${idx} emitted { payload: null } — would crash ui-chart`);
    }
  }
});

test('State B (post-setup, no demand): flow/power = 0, eta missing', () => {
  const [, out] = runFn([initialMsg, postSetupMsg]);
  assert.equal(out[PORT.text_flow].payload, '0.0 m³/h');
  assert.equal(out[PORT.text_power].payload, '0.00 kW');
  assert.equal(out[PORT.text_capacity].payload, '0.0 – 450.0 m³/h');
  // η still missing → '—'
  assert.equal(out[PORT.text_eta].payload, '—');
});

test('State C (post-demand): every text/chart output has real value', () => {
  const [, , out] = runFn([initialMsg, postSetupMsg, postDemandMsg]);
  assert.equal(out[PORT.text_flow].payload, '200.0 m³/h');
  assert.equal(out[PORT.text_power].payload, '11.40 kW');
  assert.equal(out[PORT.text_eta].payload, '62.0 %');
  // BEP abs gap: η-points dimensionless, 3 dp.
  assert.equal(out[PORT.text_bep_abs].payload, '0.050');
  // Charts have numeric payload.
  assert.equal(out[PORT.chart_flow].payload, 200);
  assert.equal(out[PORT.chart_power].payload, 11.4);
  assert.equal(out[PORT.chart_eta].payload, 62);
});

test('NCog formatter: SUM is normalized by machineCountActive before display', () => {
  // The fix under test. MGC emits Ncog as the SUM of per-pump NCog values
  // (range 0..N), so a raw pct() would display 120% for 2 pumps at 0.6 each.
  // The formatter must divide by machineCountActive first.
  const [, , out] = runFn([initialMsg, postSetupMsg, postDemandMsg]);
  // 2 pumps × 0.6 each = sum 1.2, mean 0.6, displayed "60.0 %".
  assert.equal(out[PORT.text_ncog].payload, '60.0 %');
});

test('NCog formatter: ncogSum=0 with active pumps → 0.0 %, not em-dash', () => {
  const msg = { payload: { ...postSetupMsg.payload,
    atEquipment_predicted_Ncog: 0, machineCountActive: 3 } };
  const [out] = runFn([msg]);
  // Today this is exactly what the live MGC emits (per-pump groupNCog=0
  // for the hidrostal-H05K-S03R curve at 110 kPa). The dashboard must show
  // a clean "0.0 %" — not "—" — because we DO have data, it's just zero.
  assert.equal(out[PORT.text_ncog].payload, '0.0 %');
});

test('NCog formatter: ncogSum present but machineCountActive = 0 → em-dash (no /0)', () => {
  const msg = { payload: { atEquipment_predicted_Ncog: 1.5, machineCountActive: 0 } };
  const [out] = runFn([msg]);
  assert.equal(out[PORT.text_ncog].payload, '—');
});

test('NCog formatter: ncogSum present but machineCountActive missing → em-dash', () => {
  const msg = { payload: { atEquipment_predicted_Ncog: 1.5 /* no nAct */ } };
  const [out] = runFn([msg]);
  assert.equal(out[PORT.text_ncog].payload, '—');
});

test('NCog formatter: 3 pumps each at NCog=0.5 (sum 1.5) → 50.0 %, not 150 %', () => {
  // Regression test for the bug class — the formatter was displaying sum × 100,
  // so 1.5 became "150.0 %". Verify the normalization sticks.
  const msg = { payload: {
    atEquipment_predicted_Ncog: 1.5,
    machineCountActive: 3,
  } };
  const [out] = runFn([msg]);
  assert.equal(out[PORT.text_ncog].payload, '50.0 %');
});

test('BEP rel%: undefined bepRel → "—" (degenerate homogeneous-pump case)', () => {
  // After today's groupEfficiency fix, MGC emits relDistFromPeak=undefined when
  // pumps are identical. The dashboard text formatter must display "—" — NOT
  // "0.0 %" via the +null === 0 trap.
  const msg = { payload: { mode: 'optimalControl', relDistFromPeak: undefined } };
  const [out] = runFn([msg]);
  assert.equal(out[PORT.text_bep_rel].payload, '—');
});

test('BEP rel%: null bepRel → "—" (defensive against null emission)', () => {
  // Same trap as the NCog fix: +null === 0 → pct() would return "0.0 %".
  const msg = { payload: { relDistFromPeak: null } };
  const [out] = runFn([msg]);
  assert.equal(out[PORT.text_bep_rel].payload, '—');
});

test('BEP rel% chart: drops msg when bepRel is null/undefined (no payload:null)', () => {
  const msg = { payload: { relDistFromPeak: undefined } };
  const [out] = runFn([msg]);
  assert.equal(out[PORT.chart_bep_rel], null, 'chart must drop msg when bepRel missing');
});

// ── fn_qh_fanout: Q-H curve → chart points ────────────────────────────
const fnQH = flow.find(n => n.id === 'fn_qh_fanout');

function runFanout(payload) {
  const fn_body = new Function('msg', fnQH.func);
  return fn_body({ payload });
}

test('Q-H fanout: trims trailing flat-Q tail so chart axis doesn\'t blow up', () => {
  // Synthetic input mimics buildQHCurve at low ctrl%: useful range followed by
  // a horizontal tail (Q clamped to env minimum across high H).
  const points = [
    { Q: 100, H: 7 }, { Q: 80,  H: 10 }, { Q: 50, H: 15 },
    { Q: 20,  H: 20 }, { Q: 9.5, H: 24 }, { Q: 9.5, H: 28 },
    { Q: 9.5, H: 32 }, { Q: 9.5, H: 36 }, { Q: 9.5, H: 40 },
  ];
  const [out] = runFanout({ points });
  const curvePoints = out.filter(m => m.topic === 'Curve' && m.payload);
  // The 5 tail points at Q=9.5 should collapse to (at most) one — the first
  // one to mark the curve's tail entry, not all five.
  const tailPoints = curvePoints.filter(p => p.payload.Q === 9.5 || p.payload.x === 9.5);
  assert.ok(tailPoints.length <= 1,
    `expected ≤1 flat-tail point, got ${tailPoints.length}: ${JSON.stringify(curvePoints)}`);
});

test('Q-H fanout: still emits the rising portion of the curve unchanged', () => {
  const points = [
    { Q: 100, H: 7 }, { Q: 80,  H: 10 }, { Q: 50, H: 15 }, { Q: 20, H: 20 },
    { Q: 9.5, H: 24 }, { Q: 9.5, H: 28 }, // flat tail
  ];
  const [out] = runFanout({ points });
  const curvePoints = out.filter(m => m.topic === 'Curve' && m.payload);
  const rising = curvePoints.filter(p => p.payload.x > 10);
  assert.equal(rising.length, 4, `expected 4 rising points, got ${rising.length}`);
  // First rising point preserves Q=100, H=7.
  assert.equal(rising[0].payload.x, 100);
  assert.equal(rising[0].payload.y, 7);
});

test('Q-H fanout: empty/error input → null msg', () => {
  assert.equal(runFanout({ error: 'no curve', points: [] }), null);
  assert.equal(runFanout({ points: [] }), null);
});

test('contract: no output ever emits { payload: null } for any of the three states', () => {
  // The original η-null bug. Re-asserted across all three states because a
  // regression here crashes the FlowFuse ui-chart with TypeError on .y.
  const states = runFn([initialMsg, postSetupMsg, postDemandMsg]);
  for (let s = 0; s < states.length; s++) {
    const out = states[s];
    for (let i = 0; i < out.length; i++) {
      const msg = out[i];
      if (msg && Object.prototype.hasOwnProperty.call(msg, 'payload')) {
        assert.notEqual(msg.payload, null,
          `state ${s} port ${i} → { payload: null } would crash ui-chart`);
      }
    }
  }
});