function num(v, fallback = NaN) {
  const n = Number.parseFloat(v);
  return Number.isFinite(n) ? n : fallback;
}

function low(v) {
  return (v ?? '').toString().trim().toLowerCase();
}

function parseMaybeJson(v) {
  if (typeof v !== 'string') return v;
  try {
    return JSON.parse(v);
  } catch {
    return v;
  }
}

function extractSnapshot(input) {
  if (typeof input === 'string') return parseMaybeJson(input);
  if (input?.data && typeof input.data === 'string') return parseMaybeJson(input.data);
  if (input?.body && typeof input.body === 'string') return parseMaybeJson(input.body);
  if (input?.data && typeof input.data === 'object') return input.data;
  if (input?.body && typeof input.body === 'object') return input.body;
  return input;
}

function round1(v) {
  return Math.round(v * 10) / 10;
}

function clamp(v, min, max) {
  return Math.min(Math.max(v, min), max);
}

function getParisNowParts() {
  const fmt = new Intl.DateTimeFormat('fr-FR', {
    timeZone: 'Europe/Paris',
    year: 'numeric',
    month: '2-digit',
    day: '2-digit',
    hour: '2-digit',
    minute: '2-digit',
    second: '2-digit',
    hour12: false,
  });

  const parts = Object.fromEntries(
    fmt.formatToParts(new Date())
      .filter(p => p.type !== 'literal')
      .map(p => [p.type, p.value])
  );

  const date = `${parts.year}-${parts.month}-${parts.day}`;
  const stamp = `${date} ${parts.hour}:${parts.minute}:${parts.second}`;

  return {
    year: Number(parts.year),
    month: Number(parts.month),
    day: Number(parts.day),
    hour: Number(parts.hour),
    minute: Number(parts.minute),
    second: Number(parts.second),
    date,
    stamp,
  };
}

function parseLocalStampToMs(s) {
  const text = (s ?? '').toString().trim();
  const m = text.match(/^(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})$/);
  if (!m) return null;

  const y = Number(m[1]);
  const mo = Number(m[2]);
  const d = Number(m[3]);
  const h = Number(m[4]);
  const mi = Number(m[5]);
  const se = Number(m[6]);

  if (![y, mo, d, h, mi, se].every(Number.isFinite)) return null;

  return new Date(y, mo - 1, d, h, mi, se).getTime();
}

const cfg = {
  mobileNotifyDomain: 'notify',
  mobileNotifyService: 'mobile_app_iphone_16_de_tt'
};

const raw = $input.first().json;
const input = extractSnapshot(raw);
const now = getParisNowParts();
const nowMs = parseLocalStampToMs(now.stamp);

const soc = clamp(num(input.soc_percent, 0), 0, 100);
const gridIsOn = low(input.grid_state || 'off') === 'on';
const pvPowerW = Math.max(0, num(input.pv_power_w, 0));

const houseAcPowerW = Math.max(0, num(input.house_ac_power_w, 0));
const gridPowerW = num(input.grid_power_w, 0);

const evcsAcPowerW = Math.max(0, num(input.evcs_ac_power_w, 0));
const evcsCharging = low(input.evcs_charging || 'off') === 'on';
const evcsStatusRaw = num(input.evcs_status_raw, NaN);

const hysteresisEnabled = low(input.hysteresis_enabled || 'off') === 'on';
const notificationsEnabled = low(input.notifications_enabled || 'off') === 'on';
const latchIsOn = low(input.grid_latch || 'off') === 'on';

const gridSocOn = clamp(num(input.grid_soc_on, 22), 0, 100);
const gridSocOff = clamp(num(input.grid_soc_off, 35), 0, 100);
const gridMinOnMinutes = Math.max(0, num(input.grid_min_on_minutes, 45));
const gridCooldownMinutes = Math.max(0, num(input.grid_cooldown_minutes, 15));
const acLoadsMaxSafeW = Math.max(0, num(input.ac_loads_max_safe_w, 7800));

const lastOnAt = (input.last_on_at ?? '').toString().trim();
const lastOffAt = (input.last_off_at ?? '').toString().trim();
const lastSignature = (input.last_signature ?? '').toString().trim();

const lastOnMs = parseLocalStampToMs(lastOnAt);
const lastOffMs = parseLocalStampToMs(lastOffAt);

const minutesSinceLastOn =
  lastOnMs !== null && nowMs !== null ? Math.max(0, (nowMs - lastOnMs) / 60000) : null;

const minutesSinceLastOff =
  lastOffMs !== null && nowMs !== null ? Math.max(0, (nowMs - lastOffMs) / 60000) : null;

const minOnElapsed =
  minutesSinceLastOn === null ? true : minutesSinceLastOn >= gridMinOnMinutes;

const cooldownElapsed =
  minutesSinceLastOff === null ? true : minutesSinceLastOff >= gridCooldownMinutes;

const socBand =
  soc <= gridSocOn ? 'low' :
  soc < gridSocOff ? 'mid' :
  'high';

const evcsSeemsActive = evcsCharging || evcsAcPowerW > 300;
const acOverSafeLimit = houseAcPowerW >= acLoadsMaxSafeW;

let state = 'observe_only';
let reason = [];
let desiredGrid = gridIsOn ? 'on' : 'off';
let desiredLatch = latchIsOn ? 'on' : 'off';

// ======================================================
// Core hysteresis logic V1.1
// ======================================================
if (!hysteresisEnabled) {
  state = 'hysteresis_disabled';
  desiredGrid = gridIsOn ? 'on' : 'off';
  desiredLatch = latchIsOn ? 'on' : 'off';
  reason.push('Automatisme hystérésis réseau désactivé');

} else if (soc <= gridSocOn) {
  // Seuil bas atteint => prise de main immédiate
  desiredGrid = 'on';
  desiredLatch = 'on';

  if (!cooldownElapsed && !gridIsOn) {
    state = 'turn_on_low_soc_cooldown_bypassed';
    reason.push(`SOC ${round1(soc)}% <= seuil ON ${gridSocOn}% : activation EDF malgré cooldown`);
  } else if (!gridIsOn) {
    state = 'turn_on_low_soc';
    reason.push(`SOC ${round1(soc)}% <= seuil ON ${gridSocOn}% : activation EDF`);
  } else if (!latchIsOn) {
    state = 'adopt_existing_grid_on_low_soc';
    reason.push(`SOC ${round1(soc)}% <= seuil ON ${gridSocOn}% : EDF déjà ON, prise de contrôle par latch`);
  } else {
    state = 'hold_on_low_soc';
    reason.push(`SOC encore bas ${round1(soc)}% : maintien EDF ON`);
  }

} else if (gridIsOn && !latchIsOn) {
  // NOUVEAU CAS V1.1 :
  // Le réseau est déjà ON mais ce workflow n'a pas la main.
  if (soc < gridSocOff) {
    desiredGrid = 'on';
    desiredLatch = 'on';
    state = 'adopt_existing_grid_on';
    reason.push(`EDF déjà ON avec latch OFF et SOC ${round1(soc)}% < seuil OFF ${gridSocOff}% : adoption de l'état ON`);
  } else {
    desiredGrid = 'off';
    desiredLatch = 'off';
    state = 'turn_off_stray_grid_on';
    reason.push(`EDF ON avec latch OFF et SOC ${round1(soc)}% >= seuil OFF ${gridSocOff}% : coupure de reprise de contrôle`);
  }

} else if (latchIsOn) {
  // Tant que le latch est actif, on garde la main
  if (!minOnElapsed) {
    desiredGrid = 'on';
    desiredLatch = 'on';
    state = 'hold_on_min_runtime';
    reason.push(`EDF maintenu ON : durée mini ${gridMinOnMinutes} min non atteinte (${round1(minutesSinceLastOn || 0)} min)`);
  } else if (soc < gridSocOff) {
    desiredGrid = 'on';
    desiredLatch = 'on';
    state = 'hold_on_until_soc_off';
    reason.push(`EDF maintenu ON : SOC ${round1(soc)}% < seuil OFF ${gridSocOff}%`);
  } else {
    desiredGrid = 'off';
    desiredLatch = 'off';
    state = 'turn_off_recovered';
    reason.push(`SOC ${round1(soc)}% >= seuil OFF ${gridSocOff}% : coupure EDF`);
  }

} else {
  desiredGrid = 'off';
  desiredLatch = 'off';
  state = 'observe_only';
  reason.push('Aucune action : hors zone d’hystérésis');
}

// ======================================================
// Compare desired vs current
// ======================================================
const gridAction =
  desiredGrid === (gridIsOn ? 'on' : 'off')
    ? 'none'
    : desiredGrid === 'on'
      ? 'turn_on'
      : 'turn_off';

const latchAction =
  desiredLatch === (latchIsOn ? 'on' : 'off')
    ? 'none'
    : desiredLatch === 'on'
      ? 'turn_on'
      : 'turn_off';