// Educational browser model source snapshot. Not the native oNeura engine or a validated clinical model.
// Generated from the inline script in icu.html. No patient decisions.

// ============================================================
// ICU SEPSIS SIMULATOR, REAL HEMODYNAMIC MODEL
// ============================================================
// Simulates sepsis cascade over 72 hours using physiological equations.
// Deterministic: same intervention timing always produces same output.
// Deterministic educational approximation; not a calibrated clinical model.

(function() {

// --- PATIENT CONSTANTS ---
const BASELINE = {
  map: 90,       // mmHg
  hr: 75,        // bpm
  temp: 37.0,    // °C
  spo2: 98,      // %
  cvp: 8,        // mmHg
  co: 5.0,       // L/min (cardiac output)
  svr: 1440,     // dyne·s/cm^5
  lactate: 0.8,  // mmol/L
  creatinine: 1.0, // mg/dL
  bilirubin: 0.8,  // mg/dL
  platelets: 250,  // ×10^3/µL
  ph: 7.40,
  pao2: 95,      // mmHg
  wbc: 7.5,      // ×10^3/µL
  // Derived
  strokeVolume: 67,  // mL (CO / HR * 1000)
  edv: 120,          // mL (preload estimate)
  // Body
  weight: 75,        // kg
  bsa: 1.85,         // m²
  // Pathogen model
  pathogenLoad: 1.0, // normalized 0-1
  tnfAlpha: 0.0,     // normalized cytokine
  il6: 0.0,
  endothelialDys: 0.0, // endothelial dysfunction
  capillaryLeak: 0.0,
  // Volume state
  intravascVol: 5.0, // liters (effective)
  thirdSpaceLoss: 0,  // liters lost to third space
  fluidBalance: 0,    // cumulative net fluid L
  // Intervention tracking
  abxGiven: false,
  abxTime: null,
  neoActive: false,
  neoStartTime: null,
  neoDose: 0,       // mcg/kg/min
  fluidsGiven: 0,   // number of fluid boluses
  crrtActive: false,
  crrtStartTime: null,
  // Outcome
  accumulatedInsult: 0,
  deathThreshold: 100,
};

// --- STATE ---
let state = JSON.parse(JSON.stringify(BASELINE));
let currentTime = 24; // hours, start at 24h untreated sepsis for dramatic first impression
let playing = false;
let playSpeed = 1; // multiplier
let playInterval = null;
let interventions = []; // {type, time, ...}
let historyData = []; // array of snapshots per hour
let dead = false;

// Precompute entire simulation cache for chart drawing
let simCache = []; // {t, map, lactate, sofa, ...}

// ============================================================
// PHYSIOLOGY ENGINE
// ============================================================

function sigmoid(x, k, x0) {
  return 1.0 / (1.0 + Math.exp(-k * (x - x0)));
}

function computePathogenLoad(t, abxGiven, abxTime) {
  // Pathogen load grows logistically then is reduced by antibiotics
  let growthRate = 0.08; // per hour
  let carryingCap = 1.0;
  let load = 1.0 - 1.0 / (1.0 + 0.001 * Math.exp(growthRate * t));
  // More precise: logistic growth
  load = 1.0 / (1.0 + 9.0 * Math.exp(-0.15 * t)); // reaches ~0.5 at t=15, ~0.95 at t=40

  // Antibiotics reduce pathogen load starting 6h after given
  if (abxGiven && abxTime !== null) {
    let abxEffectT = t - abxTime;
    if (abxEffectT > 0) {
      // Kill rate increases over first 12h of abx
      let killRate = 0.05 * Math.min(1.0, abxEffectT / 12.0);
      let reduction = 1.0 - Math.exp(-killRate * abxEffectT);
      load = load * (1.0 - reduction);
    }
  }
  return Math.max(0, Math.min(1, load));
}

function computeCytokines(pathogenLoad, t) {
  // TNF-alpha peaks early (2-4h after pathogen detection), then declines
  // IL-6 rises later and sustains
  let tnf = pathogenLoad * sigmoid(t, 0.5, 4) * (1.0 + 0.3 * Math.exp(-0.05 * t));
  let il6 = pathogenLoad * sigmoid(t, 0.3, 8);
  return { tnf: Math.min(2, tnf), il6: Math.min(2, il6) };
}

function computeEndothelialDysfunction(cytokines, t) {
  // Endothelial dysfunction from cytokine damage
  let cytokineSignal = 0.5 * cytokines.tnf + 0.5 * cytokines.il6;
  return Math.min(1.0, cytokineSignal * sigmoid(t, 0.2, 6));
}

function computeCapillaryLeak(endothelialDys, t) {
  // Capillary leak follows endothelial dysfunction with some delay
  return Math.min(1.0, endothelialDys * sigmoid(t, 0.25, 8));
}

function computeVolumeState(capillaryLeak, fluidBoluses, t, fluidTimes) {
  // Baseline intravascular volume ~5L
  let baseline = 5.0;
  // Third space loss from capillary leak
  let thirdSpaceLoss = capillaryLeak * 2.5; // up to 2.5L lost
  // Fluid boluses add 2.25L each (30 mL/kg * 75 kg = 2250 mL)
  let fluidAdded = 0;
  for (let i = 0; i < fluidBoluses; i++) {
    let ft = fluidTimes[i] !== undefined ? fluidTimes[i] : 0;
    // Fluids redistribute over 4h, then third spacing can reclaim
    let timeSince = t - ft;
    if (timeSince > 0) {
      // Initial volume expansion then redistribution
      let expansion = 2.25 * Math.exp(-0.1 * timeSince); // redistributes over ~10h
      // After significant capillary leak, added fluid also leaks
      let leakFraction = capillaryLeak * 0.6;
      fluidAdded += expansion * (1.0 - leakFraction * Math.min(1, timeSince / 12));
    }
  }
  let intravasc = baseline - thirdSpaceLoss + fluidAdded;
  // Illustrative edema signal: fluid and capillary-leak heuristic (not probability)
  let pulmEdemaRisk = 0;
  if (fluidBoluses > 0 && capillaryLeak > 0.5 && t > 24) {
    pulmEdemaRisk = Math.min(1.0, (fluidBoluses * 0.3) * (capillaryLeak - 0.3));
  }
  return { intravasc: Math.max(2, intravasc), thirdSpaceLoss, fluidAdded, pulmEdemaRisk };
}

function computeFrankStarling(edv) {
  // Frank-Starling: stroke volume increases with EDV up to a point
  // SV = 100 * (1 - exp(-0.015 * EDV)), simplified
  // Optimal EDV ~ 120-140 mL
  let sv = 100 * (1.0 - Math.exp(-0.015 * edv));
  return Math.max(20, sv);
}

function computeBaroreflexHR(mapTarget, mapActual, baselineHR) {
  // Baroreflex: HR increases when MAP drops below target
  let mapDeficit = mapTarget - mapActual;
  let hrIncrease = baselineHR * 0.02 * Math.max(0, mapDeficit); // 2% per mmHg deficit
  // Also increased by inflammatory cytokines
  return hrIncrease;
}

function computeSVR(pathogenLoad, endothelialDys, neoActive, neoStartTime, t) {
  // Baseline SVR ~1440. Sepsis causes profound vasodilation.
  let baseline = 1440;
  // Vasodilation from NO release, mediated by cytokines
  let vasodilation = (pathogenLoad * 0.4 + endothelialDys * 0.5) * 700;
  let svr = baseline - vasodilation;

  // Norepinephrine increases SVR
  if (neoActive && neoStartTime !== null) {
    let neoT = t - neoStartTime;
    if (neoT > 0) {
      // Neo effect ramps up over 30 min
      let neoEffect = Math.min(1.0, neoT / 0.5);
      svr += neoEffect * 600; // +600 dyne·s/cm^5
    }
  }

  return Math.max(400, svr);
}

function computeQ10Temp(baselineTemp, metabolicRate) {
  // Q10 effect: every 10°C increase doubles metabolic rate
  // In sepsis, inflammatory pyrogens raise hypothalamic set point
  // Temp increase roughly proportional to cytokine signal
  return baselineTemp + (metabolicRate - 1.0) * 2.0; // simplified
}

function computeLactate(co, oxygenDemand, t) {
  // Lactate rises when oxygen delivery (DO2) < oxygen demand
  // DO2 = CO × CaO2; simplified: lactate inversely proportional to CO when CO low
  let baseline = 0.8;
  // Lactate production increases when CO < 4 L/min
  let lactateProd = 0;
  if (co < 4.0) {
    lactateProd = (4.0 - co) * 1.5; // anaerobic metabolism
  }
  // Also from cytokine-driven hypermetabolism
  lactateProd += oxygenDemand * 0.5;
  // Clearance by liver (impaired in sepsis)
  let clearance = 0.05 * (1.0 - state._endothelialDys * 0.5);
  // Accumulate
  return baseline + lactateProd;
}

function computeSOFA(pao2, platelets, bilirubin, map, neoActive, gcs, creatinine) {
  // SOFA score components (0-4 each)

  // 1. Respiration: PaO2/FiO2 ratio (assume room air FiO2=0.21, then supplemental if needed)
  let fio2 = 0.21;
  if (pao2 < 60) fio2 = 0.4; // supplemental O2
  if (pao2 < 50) fio2 = 0.6;
  let pf = pao2 / fio2;
  let resp = 0;
  if (pf < 100) resp = 4;
  else if (pf < 200) resp = 3;
  else if (pf < 300) resp = 2;
  else if (pf < 400) resp = 1;

  // 2. Coagulation: Platelets
  let coag = 0;
  if (platelets < 20) coag = 4;
  else if (platelets < 50) coag = 3;
  else if (platelets < 100) coag = 2;
  else if (platelets < 150) coag = 1;

  // 3. Liver: Bilirubin
  let liver = 0;
  if (bilirubin >= 12.0) liver = 4;
  else if (bilirubin >= 6.0) liver = 3;
  else if (bilirubin >= 2.0) liver = 2;
  else if (bilirubin >= 1.2) liver = 1;

  // 4. Cardiovascular: MAP and vasopressors
  let cardio = 0;
  if (neoActive && map < 70) cardio = 4;
  else if (neoActive) cardio = 3;
  else if (map < 70) cardio = 3;
  else if (map < 70) cardio = 2; // dopamine ≤5 or dobutamine
  else if (map < 75) cardio = 1;

  // Simplified: use MAP thresholds
  if (map < 50) cardio = 4;
  else if (map < 60) cardio = 3;
  else if (map < 70) cardio = 2;
  else if (map < 80) cardio = 1;
  else cardio = 0;

  // 5. CNS: GCS (simplified, encephalopathy from sepsis)
  // GCS drops with lactate and hypotension
  let gcsActual = gcs;
  let cns = 0;
  if (gcsActual < 6) cns = 4;
  else if (gcsActual < 10) cns = 3;
  else if (gcsActual < 13) cns = 2;
  else if (gcsActual < 15) cns = 1;

  // 6. Renal: Creatinine
  let renal = 0;
  if (creatinine >= 5.0) renal = 4;
  else if (creatinine >= 3.5) renal = 3;
  else if (creatinine >= 2.0) renal = 2;
  else if (creatinine >= 1.2) renal = 1;

  return {
    total: resp + coag + liver + cardio + cns + renal,
    resp, coag, liver, cardio, cns, renal
  };
}

function computeGCS(lactate, map, t) {
  // Sepsis-associated encephalopathy
  // GCS decreases with severity
  let gcs = 15;
  // Lactate effect
  if (lactate > 4) gcs -= 3;
  else if (lactate > 2.5) gcs -= 1;
  // MAP effect (hypotension → decreased cerebral perfusion)
  if (map < 50) gcs -= 4;
  else if (map < 60) gcs -= 2;
  else if (map < 70) gcs -= 1;
  // Time-dependent delirium
  gcs -= Math.floor(t / 24);
  return Math.max(3, Math.min(15, gcs));
}

function computeSpO2(pao2, pulmEdemaRisk) {
  // SpO2 from PaO2 using oxyhemoglobin dissociation curve (simplified)
  let spo2 = 100 * (1.0 / (1.0 + Math.exp(-0.1 * (pao2 - 30))));
  // Pulmonary edema reduces SpO2
  spo2 -= pulmEdemaRisk * 15;
  return Math.max(60, Math.min(100, Math.round(spo2)));
}

// ============================================================
// FULL SIMULATION STEP (for any given time t)
// ============================================================

function simulateAtTime(t) {
  // Count interventions active by time t
  let fluidBoluses = 0;
  let fluidTimes = [];
  let abxGiven = false;
  let abxTime = null;
  let neoActive = false;
  let neoStartTime = null;
  let crrtActive = false;
  let crrtStartTime = null;

  for (let iv of interventions) {
    if (iv.time <= t) {
      if (iv.type === 'fluids') { fluidBoluses++; fluidTimes.push(iv.time); }
      if (iv.type === 'abx') { abxGiven = true; abxTime = iv.time; }
      if (iv.type === 'neo') { neoActive = true; neoStartTime = iv.time; }
      if (iv.type === 'crrt') { crrtActive = true; crrtStartTime = iv.time; }
    }
  }

  // 1. Pathogen load
  let pathogenLoad = computePathogenLoad(t, abxGiven, abxTime);

  // 2. Cytokines
  let cytokines = computeCytokines(pathogenLoad, t);

  // 3. Endothelial dysfunction
  let endothelialDys = computeEndothelialDysfunction(cytokines, t);

  // 4. Capillary leak
  let capillaryLeak = computeCapillaryLeak(endothelialDys, t);

  // 5. Volume state
  let vol = computeVolumeState(capillaryLeak, fluidBoluses, t, fluidTimes);

  // 6. Preload (EDV), reduced by third spacing, increased by fluids
  let edv = 120 * (vol.intravasc / 5.0); // proportional to intravascular volume

  // 7. Frank-Starling mechanism → Stroke Volume
  let sv = computeFrankStarling(edv);

  // 8. SVR (systemic vascular resistance)
  let svr = computeSVR(pathogenLoad, endothelialDys, neoActive, neoStartTime, t);

  // 9. Heart rate, baroreflex + inflammatory tachycardia
  let tempElevation = cytokines.il6 * 1.5;
  let temp = BASELINE.temp + tempElevation;
  // Q10 metabolic scaling: each 1°C increase → ~10% metabolic increase
  let metabolicRate = 1.0 + (temp - 37.0) * 0.1;

  // Inflammatory tachycardia (IL-6, TNF mediated)
  let inflammatoryHR = cytokines.il6 * 30 + cytokines.tnf * 15;

  // Baroreflex: target MAP 90, increase HR when MAP low
  let preliminaryCO = sv * BASELINE.hr / 1000;
  let preliminaryMAP = preliminaryCO * svr / 80; // mmHg conversion factor (CO in L/min, SVR in dyne·s/cm^5: MAP = CO * SVR / 80)
  let baroHR = computeBaroreflexHR(90, preliminaryMAP, BASELINE.hr);

  let hr = BASELINE.hr + inflammatoryHR + baroHR;
  hr = Math.min(160, Math.max(50, hr));

  // 10. Cardiac Output = HR × SV / 1000
  let co = hr * sv / 1000;

  // 11. MAP = CO × SVR (conversion: CO in L/min, SVR in dyne·s/cm^5 → MAP in mmHg)
  // MAP = (CO × SVR) / 80
  let map = (co * svr) / 80;

  // Neo effect already in SVR. But also check MAP target with neo
  // Actually, let's re-derive with neo in SVR already
  // MAP = CO * SVR / 80

  // 12. CVP, low with hypovolemia, high with fluid overload
  let cvp = 8 * (vol.intravasc / 5.0);
  if (neoActive) cvp += 3; // neo increases venous return
  cvp = Math.max(0, cvp);

  // 13. Lactate, from tissue hypoperfusion
  let lactateBase = 0.8;
  let lactateFromHypoperf = 0;
  if (map < 70) lactateFromHypoperf += (70 - map) * 0.1;
  if (co < 3.5) lactateFromHypoperf += (3.5 - co) * 2.0;
  let lactateFromHypermetab = (metabolicRate - 1.0) * 0.5;
  let lactate = lactateBase + lactateFromHypoperf + lactateFromHypermetab;

  // CRRT clears lactate
  if (crrtActive) {
    let crrtT = t - crrtStartTime;
    if (crrtT > 0) {
      let clearanceRate = 0.15; // fraction cleared per hour
      lactate = lactate * Math.exp(-clearanceRate * crrtT);
      lactate = Math.max(0.8, lactate);
    }
  }

  // 14. Organ dysfunction
  // Renal: Creatinine rises with hypoperfusion (MAP < 65) and cytokine damage
  let creatBaseline = 1.0;
  let creatInjury = 0;
  if (map < 65) creatInjury += (65 - map) * 0.04; // acute kidney injury
  creatInjury += cytokines.il6 * 0.3 * sigmoid(t, 0.2, 12);
  let creatinine = creatBaseline + creatInjury;

  // CRRT clears creatinine
  if (crrtActive && crrtStartTime !== null) {
    let crrtT = t - crrtStartTime;
    if (crrtT > 0) {
      creatinine = creatinine * Math.exp(-0.1 * crrtT);
      creatinine = Math.max(1.0, creatinine);
    }
  }

  // Hepatic: Bilirubin
  let biliBaseline = 0.8;
  let biliInjury = cytokines.tnf * 0.4 * sigmoid(t, 0.15, 18);
  let bilirubin = biliBaseline + biliInjury;

  // Coagulation: Platelets drop with DIC (disseminated intravascular coagulation)
  let pltBaseline = 250;
  let pltDrop = (cytokines.tnf + cytokines.il6) * 40 * sigmoid(t, 0.15, 15);
  let platelets = pltBaseline - pltDrop;

  // PaO2, affected by pulmonary capillary leak / ARDS
  let pao2Base = 95;
  let pao2Drop = capillaryLeak * 30 + vol.pulmEdemaRisk * 20;
  let pao2 = pao2Base - pao2Drop;

  // SpO2
  let spo2 = computeSpO2(pao2, vol.pulmEdemaRisk);

  // WBC
  let wbc = 7.5 + pathogenLoad * 15 - (t > 36 && pathogenLoad > 0.5 ? 10 : 0);
  wbc = Math.max(1, wbc);

  // pH, acidosis from lactate and renal failure
  let ph = 7.40 - (lactate - 0.8) * 0.03 - (creatinine - 1.0) * 0.02;
  ph = Math.max(6.9, Math.min(7.45, ph));

  // 15. GCS
  let gcs = computeGCS(lactate, map, t);

  // 16. SOFA score
  let sofa = computeSOFA(pao2, platelets, bilirubin, map, neoActive, gcs, creatinine);

  // 17. Accumulated insult (determines survival)
  // Insult accumulates from tissue hypoperfusion, high lactate, organ failure
  let insultRate = 0;
  insultRate += Math.max(0, (2.0 - lactate) * (-1)) * 0.5; // lactate > 2
  insultRate += Math.max(0, (65 - map)) * 0.3;               // MAP < 65
  insultRate += sofa.total * 0.2;                              // organ failure
  insultRate += (ph < 7.35 ? (7.35 - ph) * 10 : 0);          // acidosis

  // Early antibiotics reduce insult dramatically
  let insultReduction = 0;
  if (abxGiven && abxTime !== null) {
    let abxEffectT = t - abxTime;
    if (abxTime <= 3 && abxEffectT > 0) insultReduction = 0.7;
    else if (abxTime <= 6 && abxEffectT > 0) insultReduction = 0.5;
    else if (abxTime <= 12 && abxEffectT > 0) insultReduction = 0.25;
    else if (abxEffectT > 0) insultReduction = 0.1;
  }

  insultRate *= (1.0 - insultReduction);

  return {
    t, map, hr, temp, spo2, cvp, co, svr, sv, edv,
    lactate, creatinine, bilirubin, platelets, pao2, wbc, ph, gcs,
    pathogenLoad, endothelialDys, capillaryLeak,
    vol, sofa, metabolicRate, insultRate,
    cytokines, neoActive, abxGiven, crrtActive,
    fluidBoluses, pulmEdemaRisk: vol.pulmEdemaRisk
  };
}

// ============================================================
// COMPUTE FULL SIMULATION CACHE
// ============================================================

function recomputeCache() {
  simCache = [];
  let accumulatedInsult = 0;

  for (let t = 0; t <= 72; t += 0.5) {
    let s = simulateAtTime(t);
    accumulatedInsult += s.insultRate * 0.5; // dt = 0.5h
    s.accumulatedInsult = accumulatedInsult;
    simCache.push(s);
  }

  // Compute survival
  let finalInsult = simCache[simCache.length - 1].accumulatedInsult;
  let sofaMax = 0;
  for (let s of simCache) {
    if (s.sofa.total > sofaMax) sofaMax = s.sofa.total;
  }

  // Survival probability based on accumulated insult and max SOFA
  // SOFA > 12: mortality > 50%, > 20: > 90%
  // Early abx bonus
  let abxBonus = 0;
  for (let iv of interventions) {
    if (iv.type === 'abx' && iv.time <= 3) abxBonus = 40;
    else if (iv.type === 'abx' && iv.time <= 6) abxBonus = 25;
    else if (iv.type === 'abx' && iv.time <= 12) abxBonus = 10;
  }

  let survFromInsult = Math.max(0, 100 - accumulatedInsult + abxBonus);
  let survFromSOFA = Math.max(0, 100 - sofaMax * 5);
  let survivalProb = Math.min(survFromInsult, survFromSOFA);
  survivalProb = Math.max(0, Math.min(100, survivalProb));

  state._survivalProb = survivalProb;
  state._accumulatedInsult = accumulatedInsult;
  state._maxSOFA = sofaMax;
}

// ============================================================
// GET STATE AT CURRENT TIME (interpolated from cache)
// ============================================================

function getStateNow() {
  let idx = currentTime / 0.5;
  let i = Math.floor(idx);
  if (i >= simCache.length) return simCache[simCache.length - 1];
  if (i < 0) return simCache[0];
  let frac = idx - i;
  let a = simCache[i];
  let b = simCache[Math.min(i + 1, simCache.length - 1)];
  // Interpolate numeric fields
  let result = {};
  for (let key of Object.keys(a)) {
    if (typeof a[key] === 'number') {
      result[key] = a[key] + (b[key] - a[key]) * frac;
    } else if (typeof a[key] === 'object' && a[key] !== null) {
      result[key] = a[key]; // keep discrete values from nearest
    } else {
      result[key] = a[key];
    }
  }
  return result;
}

// ============================================================
// RENDERING
// ============================================================

// Presentation only: missing or invalid scores must not become normal values.
function formatIllustrativeScore(value) {
  return Number.isFinite(value) ? Math.round(value) + '/100' : 'N/A';
}

function render() {
  let s = getStateNow();
  if (!s) return;

  // Vitals
  document.getElementById('v-map').textContent = Math.round(s.map);
  document.getElementById('v-hr').textContent = Math.round(s.hr);
  document.getElementById('v-spo2').textContent = Math.round(s.spo2);
  document.getElementById('v-temp').textContent = s.temp.toFixed(1);
  document.getElementById('v-cvp').textContent = Math.round(s.cvp);

  // Color vital cards based on severity
  let mapCard = document.querySelector('.vital-card.map');
  mapCard.querySelector('.vital-value').style.color = s.map < 65 ? '#e0795f' : s.map < 75 ? '#d9a85f' : '#f4efe6';
  let hrCard = document.querySelector('.vital-card.hr');
  hrCard.querySelector('.vital-value').style.color = s.hr > 120 ? '#e0795f' : s.hr > 100 ? '#d9a85f' : '#f4efe6';
  let spo2Card = document.querySelector('.vital-card.spo2');
  spo2Card.querySelector('.vital-value').style.color = s.spo2 < 90 ? '#e0795f' : s.spo2 < 94 ? '#d9a85f' : '#f4efe6';

  // Chart values
  document.getElementById('cv-map').textContent = Math.round(s.map);
  document.getElementById('cv-lactate').textContent = s.lactate.toFixed(1);
  document.getElementById('cv-sofa').textContent = s.sofa.total;

  // Labs
  setLabVal('lab-lactate', s.lactate.toFixed(1), s.lactate > 2.0, s.lactate > 4.0);
  setLabVal('lab-ph', s.ph.toFixed(2), s.ph < 7.35 || s.ph > 7.45, s.ph < 7.2);
  setLabVal('lab-pao2', Math.round(s.pao2), s.pao2 < 80, s.pao2 < 60);
  setLabVal('lab-creat', s.creatinine.toFixed(1), s.creatinine > 1.3, s.creatinine > 2.0);
  setLabVal('lab-bili', s.bilirubin.toFixed(1), s.bilirubin > 1.2, s.bilirubin > 2.0);
  setLabVal('lab-plt', Math.round(s.platelets), s.platelets < 150, s.platelets < 100);
  setLabVal('lab-wbc', s.wbc.toFixed(1), s.wbc > 12 || s.wbc < 4, false);

  // Hemodynamics
  document.getElementById('lab-co').textContent = s.co.toFixed(1) + ' L/min';
  document.getElementById('lab-svr').textContent = Math.round(s.svr) + ' dyn·s/cm⁵';
  document.getElementById('lab-sv').textContent = Math.round(s.sv) + ' mL';
  document.getElementById('lab-edv').textContent = Math.round(s.edv) + ' mL';

  // SOFA
  document.getElementById('sofa-total').textContent = s.sofa.total;
  setSofaScore('sofa-resp', s.sofa.resp);
  setSofaScore('sofa-coag', s.sofa.coag);
  setSofaScore('sofa-liver', s.sofa.liver);
  setSofaScore('sofa-cardio', s.sofa.cardio);
  setSofaScore('sofa-cns', s.sofa.cns);
  setSofaScore('sofa-renal', s.sofa.renal);

  // Color SOFA total
  let sofaEl = document.getElementById('sofa-total');
  sofaEl.style.color = s.sofa.total >= 15 ? '#e0795f' : s.sofa.total >= 10 ? '#d5744f' : s.sofa.total >= 5 ? '#d9a85f' : '#f4efe6';

  // Simulation info
  let insult = state._accumulatedInsult || 0;
  let surv = Number.isFinite(state._survivalProb) ? state._survivalProb : null;
  document.getElementById('lab-insult').textContent = insult.toFixed(1) + '%';
  document.getElementById('lab-survival').textContent = formatIllustrativeScore(surv);
  document.getElementById('lab-survival').className = 'lab-val' + (surv !== null && surv < 30 ? ' abnormal' : surv !== null && surv < 60 ? ' warning' : '');

  // Time display
  document.getElementById('time-display').textContent = currentTime.toFixed(1) + ' h';

  // Draw charts
  drawChart('chart-map', s.t, 'map', 40, 110, '#8fb079', 65);
  drawChart('chart-lactate', s.t, 'lactate', 0, 10, '#e0795f', 2.0);
  drawChart('chart-sofa', s.t, 'sofaTotal', 0, 24, '#6fbcab', null);

  // Cascade display
  renderCascade(s);

  // Outcome
  renderOutcome(s);

  // Intervention markers
  renderMarkers();

  // Disable buttons for used interventions
  updateButtons();
}

function setLabVal(id, val, warn, danger) {
  let el = document.getElementById(id);
  el.textContent = val;
  el.className = 'lab-val' + (danger ? ' abnormal' : warn ? ' warning' : '');
}

function setSofaScore(id, score) {
  let el = document.getElementById(id);
  score = Math.round(score);
  el.textContent = score;
  el.className = 'score s' + Math.min(4, score);
}

function renderCascade(s) {
  let steps = [
    { label: 'Infection established (S. pneumoniae)', active: s.pathogenLoad > 0.1 },
    { label: 'TNF-α / IL-6 cytokine release', active: s.cytokines.tnf > 0.2 || s.cytokines.il6 > 0.2 },
    { label: 'Endothelial dysfunction', active: s.endothelialDys > 0.2 },
    { label: 'Capillary leak → hypovolemia', active: s.capillaryLeak > 0.2 },
    { label: '↓ SVR → ↓ MAP (vasodilation)', active: s.svr < 1200 },
    { label: '↑ HR (baroreflex + inflammatory)', active: s.hr > 90 },
    { label: 'Tissue hypoperfusion → ↑ lactate', active: s.lactate > 2.0 },
    { label: 'Renal dysfunction (↑ creatinine)', active: s.creatinine > 1.3 },
    { label: 'Hepatic dysfunction (↑ bilirubin)', active: s.bilirubin > 1.2 },
    { label: 'Coagulopathy (↓ platelets / DIC)', active: s.platelets < 150 },
  ];

  let html = '';
  for (let step of steps) {
    html += '<div class="cascade-step"><span class="dot ' + (step.active ? 'active' : 'inactive') + '"></span><span>' + step.label + '</span></div>';
  }
  document.getElementById('cascade-display').innerHTML = html;

  // Physio note
  let note = 't=' + s.t.toFixed(1) + 'h | Pathogen load: ' + (s.pathogenLoad * 100).toFixed(0) + '% | TNF-α: ' + s.cytokines.tnf.toFixed(2) + ' | IL-6: ' + s.cytokines.il6.toFixed(2) + ' | Endoth. dysfx: ' + (s.endothelialDys * 100).toFixed(0) + '%';
  if (s.pulmEdemaRisk > 0) note += ' | Illustrative edema signal: ' + (s.pulmEdemaRisk * 100).toFixed(0) + '/100';
  document.getElementById('physio-note').textContent = note;
}

function renderOutcome(s) {
  let el = document.getElementById('outcome');
  if (currentTime >= 72) {
    el.style.display = '';
    let surv = state._survivalProb;
    if (!Number.isFinite(surv)) {
      el.className = 'outcome-banner';
      el.style.display = 'block';
      el.textContent = 'Scenario complete. Illustrative score: N/A. No valid score is available; no patient outcome is predicted.';
    } else if (surv >= 50) {
      el.className = 'outcome-banner alive';
      el.textContent = 'Scenario complete. Illustrative score: ' + Math.round(surv) + '/100. This is not a survival probability.';
    } else {
      el.className = 'outcome-banner dead';
      el.textContent = 'Scenario complete. Illustrative score: ' + Math.round(surv) + '/100. A model threshold was crossed; no patient outcome is predicted.';
    }
  } else if (s.sofa.total >= 15 && s.map < 55) {
    el.style.display = '';
    el.className = 'outcome-banner critical';
    el.textContent = 'Illustrative high-stress model state. MAP ' + Math.round(s.map) + ' mmHg; model SOFA ' + s.sofa.total + '. Not a clinical assessment.';
  } else {
    el.className = 'outcome-banner';
    el.style.display = 'none';
  }
}

function renderMarkers() {
  let container = document.getElementById('intervention-markers');
  let html = '';
  let width = container.offsetWidth || 600;
  for (let iv of interventions) {
    let left = (iv.time / 72) * width;
    let color = iv.type === 'fluids' ? '#6fbcab' : iv.type === 'neo' ? '#e0795f' : iv.type === 'abx' ? '#8fb079' : '#c2a07f';
    html += '<div style="position:absolute;left:' + left + 'px;top:0;width:2px;height:14px;background:' + color + ';border-radius:1px;"></div>';
  }
  container.innerHTML = html;
}

function updateButtons() {
  // Allow multiple fluids, but each only once
  // Neo can be given once
  // ABX once
  // CRRT once
  let used = {};
  for (let iv of interventions) {
    used[iv.type] = (used[iv.type] || 0) + 1;
  }
  document.getElementById('btn-abx').disabled = !!used['abx'];
  document.getElementById('btn-neo').disabled = !!used['neo'];
  document.getElementById('btn-crrt').disabled = !!used['crrt'];
  document.getElementById('btn-fluids').disabled = (used['fluids'] || 0) >= 3;
}

// ============================================================
// CHART DRAWING (pure canvas)
// ============================================================

function drawChart(canvasId, currentTimeVal, field, yMin, yMax, color, threshold) {
  let canvas = document.getElementById(canvasId);
  if (!canvas) return;
  let dpr = window.devicePixelRatio || 1;
  let rect = canvas.getBoundingClientRect();
  canvas.width = rect.width * dpr;
  canvas.height = 140 * dpr;
  let ctx = canvas.getContext('2d');
  ctx.scale(dpr, dpr);
  let w = rect.width;
  let h = 140;

  // Background (transparent so chart-card warm dark shows through)
  ctx.clearRect(0, 0, w, h);

  let padL = 36, padR = 10, padT = 10, padB = 24;
  let plotW = w - padL - padR;
  let plotH = h - padT - padB;

  // Grid (warm low-contrast)
  ctx.strokeStyle = 'rgba(244, 239, 230, 0.08)';
  ctx.lineWidth = 0.5;
  let ySteps = 4;
  for (let i = 0; i <= ySteps; i++) {
    let y = padT + plotH * (1 - i / ySteps);
    ctx.beginPath();
    ctx.moveTo(padL, y);
    ctx.lineTo(padL + plotW, y);
    ctx.stroke();
    // Label
    ctx.fillStyle = 'rgba(244, 239, 230, 0.5)';
    ctx.font = '9px IBM Plex Mono, monospace';
    ctx.textAlign = 'right';
    let val = yMin + (yMax - yMin) * (i / ySteps);
    ctx.fillText(val.toFixed(field === 'sofaTotal' ? 0 : 0), padL - 4, y + 3);
  }

  // X axis labels
  ctx.fillStyle = 'rgba(244, 239, 230, 0.5)';
  ctx.font = '9px IBM Plex Mono, monospace';
  ctx.textAlign = 'center';
  for (let hr = 0; hr <= 72; hr += 24) {
    let x = padL + (hr / 72) * plotW;
    ctx.fillText(hr + 'h', x, h - 4);
  }

  // Threshold line (warm terracotta dashed)
  if (threshold !== null) {
    let ty = padT + plotH * (1 - (threshold - yMin) / (yMax - yMin));
    ctx.strokeStyle = 'rgba(213, 116, 79, 0.55)';
    ctx.lineWidth = 1;
    ctx.setLineDash([4, 3]);
    ctx.beginPath();
    ctx.moveTo(padL, ty);
    ctx.lineTo(padL + plotW, ty);
    ctx.stroke();
    ctx.setLineDash([]);
  }

  // Data line
  if (simCache.length > 0) {
    ctx.strokeStyle = color;
    ctx.lineWidth = 2;
    ctx.beginPath();
    let started = false;
    for (let pt of simCache) {
      if (pt.t > currentTimeVal) break;
      let val = field === 'sofaTotal' ? pt.sofa.total : pt[field];
      let x = padL + (pt.t / 72) * plotW;
      let y = padT + plotH * (1 - (val - yMin) / (yMax - yMin));
      y = Math.max(padT, Math.min(padT + plotH, y));
      if (!started) { ctx.moveTo(x, y); started = true; }
      else ctx.lineTo(x, y);
    }
    ctx.stroke();

    // Fill under
    let lastPt = null;
    for (let pt of simCache) {
      if (pt.t > currentTimeVal) break;
      lastPt = pt;
    }
    if (lastPt) {
      let lastX = padL + (lastPt.t / 72) * plotW;
      ctx.lineTo(lastX, padT + plotH);
      ctx.lineTo(padL, padT + plotH);
      ctx.closePath();
      ctx.fillStyle = color + '22';
      ctx.fill();
    }

    // Current point
    if (lastPt) {
      let val = field === 'sofaTotal' ? lastPt.sofa.total : lastPt[field];
      let cx = padL + (lastPt.t / 72) * plotW;
      let cy = padT + plotH * (1 - (val - yMin) / (yMax - yMin));
      cy = Math.max(padT, Math.min(padT + plotH, cy));
      ctx.beginPath();
      ctx.arc(cx, cy, 3.5, 0, Math.PI * 2);
      ctx.fillStyle = color;
      ctx.fill();
      ctx.strokeStyle = '#fff';
      ctx.lineWidth = 1.5;
      ctx.stroke();
    }
  }

  // Intervention markers on chart
  for (let iv of interventions) {
    let x = padL + (iv.time / 72) * plotW;
    ctx.strokeStyle = iv.type === 'fluids' ? '#6fbcab40' : iv.type === 'neo' ? '#e0795f40' : iv.type === 'abx' ? '#8fb07940' : '#c2a07f40';
    ctx.lineWidth = 1;
    ctx.setLineDash([2, 2]);
    ctx.beginPath();
    ctx.moveTo(x, padT);
    ctx.lineTo(x, padT + plotH);
    ctx.stroke();
    ctx.setLineDash([]);
  }

  // Border
  ctx.strokeStyle = '#e2e8f0';
  ctx.lineWidth = 1;
  ctx.strokeRect(padL, padT, plotW, plotH);
}

// ============================================================
// INTERVENTIONS
// ============================================================

window.doIntervention = function(type) {
  // Prevent duplicate (except fluids, max 3)
  let count = interventions.filter(i => i.type === type).length;
  if (type !== 'fluids' && count > 0) return;
  if (type === 'fluids' && count >= 3) return;

  interventions.push({ type, time: currentTime });
  interventions.sort((a, b) => a.time - b.time);

  // Add to history
  let labels = { fluids: 'IV Fluids', neo: 'Norepinephrine', abx: 'Antibiotics', crrt: 'CRRT' };
  let historyList = document.getElementById('history-list');
  if (interventions.length === 1) historyList.innerHTML = '';
  let tag = document.createElement('span');
  tag.className = 'history-tag ' + type;
  tag.textContent = labels[type] + ' @ ' + currentTime.toFixed(1) + 'h';
  historyList.appendChild(tag);

  recomputeCache();
  render();
};

// ============================================================
// TIMELINE CONTROLS
// ============================================================

window.onSlider = function(val) {
  currentTime = parseFloat(val);
  render();
};

window.togglePlay = function() {
  playing = !playing;
  let btn = document.getElementById('btn-play');
  if (playing) {
    btn.innerHTML = '&#9646;&#9646; Pause';
    btn.classList.add('playing');
    startPlayback();
  } else {
    btn.innerHTML = '&#9654; Play';
    btn.classList.remove('playing');
    stopPlayback();
  }
};

function startPlayback() {
  if (playInterval) clearInterval(playInterval);
  playInterval = setInterval(function() {
    currentTime += 0.1 * playSpeed;
    if (currentTime >= 72) {
      currentTime = 72;
      playing = false;
      let btn = document.getElementById('btn-play');
      btn.innerHTML = '&#9654; Play';
      btn.classList.remove('playing');
      clearInterval(playInterval);
      playInterval = null;
    }
    document.getElementById('timeline').value = currentTime;
    render();
  }, 100);
}

function stopPlayback() {
  if (playInterval) { clearInterval(playInterval); playInterval = null; }
}

window.cycleSpeed = function() {
  let speeds = [1, 2, 5, 10];
  let idx = speeds.indexOf(playSpeed);
  playSpeed = speeds[(idx + 1) % speeds.length];
  document.getElementById('btn-speed').innerHTML = playSpeed + '&times;';
  if (playing) { stopPlayback(); startPlayback(); }
};

window.resetSim = function() {
  playing = false;
  stopPlayback();
  currentTime = 0;
  interventions = [];
  state = JSON.parse(JSON.stringify(BASELINE));
  document.getElementById('timeline').value = 0;
  document.getElementById('btn-play').innerHTML = '&#9654; Play';
  document.getElementById('btn-play').classList.remove('playing');
  document.getElementById('history-list').innerHTML = '<span style="font-size:11px;color:var(--text-faint);font-style:italic;">No interventions yet</span>';
  recomputeCache();
  render();
};

// ============================================================
// INIT
// ============================================================

recomputeCache();
render();

// Handle resize
window.addEventListener('resize', function() { render(); });

})();